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Edward Bindon Marten
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Title: Records of Steam Boiler Explosions
Author: Edward Bindon Marten
Release Date: December 23, 2014 [EBook #47762]
Language: English
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RECORDS
OF
STEAM BOILER EXPLOSIONS,
BY
EDWARD BINDON MARTEN,
MEM. INST. OF MECHANICAL ENGINEERS; ASSOCIATE OF INSTITUTION OF
CIVIL ENGINEERS, AND CHIEF ENGINEER TO THE
MIDLAND STEAM BOILER INSPECTION AND ASSURANCE CO.
LONDON;
E. & F. N. SPON, 48, CHARING CROSS.
STOURBRIDGE:
R. BROOMHALL, 148, HIGH STREET.
1872.
PREFACE.
Accurate information as to Boiler Explosions must always be useful to
those who are interested in the safe working of Steam Boilers.
The following pages contain very brief abstracts of records obtained
for the Midland Steam Boiler Inspection and Assurance Company, by whose
permission they are now republished in a compact and convenient form.
By permission of the Council of the Institution of Mechanical
Engineers, the records are prefaced by a Paper on Steam Boiler
Explosions and their records, and on Inspection as a means of
prevention, read before that Institution at Manchester, August 1st,
1866, and a further Paper on the "Conclusions derived from the
experience of recent Steam Boiler Explosions," read before the same
Institution at Nottingham, August 3rd, 1870.
All names of Works or Firms are omitted from the records as
unnecessary.
ON STEAM BOILER EXPLOSIONS AND THEIR RECORDS, AND ON INSPECTION AS A
MEANS OF PREVENTION, BY EDWARD B. MARTEN, MEM. INST. M.E. A.I.C.E.,
EXCERPT MINUTES OF PROCEEDINGS OF THE MEETING OF THE INSTITUTION
OF MECHANICAL ENGINEERS, AT MANCHESTER, 1ST AUGUST, 1866, JOSEPH
WHITWORTH, ESQ., PRESIDENT, IN THE CHAIR. BY PERMISSION OF THE COUNCIL.
The subject of Steam Boiler Explosions, which was brought before this
Institution in June, 1848, in a paper by the late Mr. William Smith
of Dudley in reference to an explosion near that place, and again in
1859 in a paper by Mr. Longridge on the economy and durability of
stationary boilers, is one of great importance and is now attracting
increased attention. The first public notice of the subject was by a
parliamentary committee in 1817, which was appointed in consequence
of a very fatal boiler explosion in London in 1815; evidence was then
collected as to steamboats, and many boiler explosions were referred
to. That committee recommended among other things that boilers should
be made of wrought iron, instead of cast iron or copper, which had been
the materials mainly used previously; that they should be inspected
and tested; and that there should be two safety valves, each loaded
to one third of the test pressure, under penalties for any excess. A
great part of the information now existing upon the subject, especially
in regard to the earlier explosions, is to be found in the records of
inquests after fatal cases; and some of the careful reports of eminent
engineers on those occasions have materially assisted in the formation
of correct views as to the causes of explosion. Latterly also the
printed reports of the inspectors of mines, and more especially the
reports of the explosions of locomotives, illustrated by diagrams by
the inspectors of railways, have furnished very valuable information.
Since the subject has been taken up by private associations for the
prevention of explosions, many more records have been published,
although their usefulness is much impaired by their not containing the
names of the places whereby the explosions could be identified.
When the writer's attention was first directed to this subject, he
met with great difficulty in obtaining correct records of boiler
explosions, from which to arrive at the results of past experience;
and wishing to base his own opinion on facts, rather than on the
inferences of others however reliable, he followed the example of the
Franklin Institute in their elaborate investigation of the subject, and
collected all the records he could find; and by way of facilitating
reference, arranged an index, a manuscript copy of which is presented
with the present paper to the Library of this Institution. All must
be agreed as to the importance of reliable information on such
accidents as boiler explosions; and the writer would suggest that
this Institution may materially aid in obtaining the desired records
and placing them within easy access, by becoming the depository of
reports on explosions, and by inducing those who have the opportunity
to forward copies of reports, that these may be arranged so as to be
easily found and consulted. It is very desirable that these reports
should as far as possible be illustrated by sketches, as aids to
the description; and also by slight models like those now shown to
the meeting, by which the whole matter may be seen at a glance. So
few persons comparatively have the opportunity of examining boilers
after explosion, that the most erroneous ideas have prevailed, and
theories have been advanced which would soon be dissipated by practical
experience or by reading accurate reports. It would also very much
aid in the understanding of published matter on the subject, if full
descriptions of each case alluded to in illustration could be obtained.
These records are as useful to the engineer as the "precedents" or
"cases" to the lawyer or the surgeon. After any serious explosion,
the newspapers of the neighbourhood in which it has occurred contain
voluminous articles describing the disastrous result and the damage
done, which, although useful as far as they go, do not in the least
assist in arriving at the cause of explosion. The really important
particulars, such as the description and construction of the boiler,
its dimensions, and the pressure at which it worked, are in most cases
omitted altogether.
The record of explosions presented to the Institution contains a list
of the boiler explosions in each year of the present century, as far as
known to the writer, with the names of the places, and the description
and sizes of the boilers, and the supposed cause of explosion, together
with references to the books or papers from which further information
may be obtained. Of course many of the explosions have to be put down
as uncertain in some of the particulars; but every year improves the
record, as fresh information is obtained, and with the assistance of
the members of this Institution it might be made far more perfect and
extensive.
* * * * *
The total number of explosions here recorded is 1046, and they caused
the death of 4076 persons and the injury of 2903. The causes assigned
for the several explosions are very numerous, and are no doubt
incorrect in many cases; but they may be generally stated as follows:
397 are too uncertain to place under any heading; but of the rest
145 were from the boilers being worn out, or from corrosion, or
from deteriorated plates or rivets.
137 from over pressure, from safety valves being wedged or
overweighted, in some cases intentionally, or from other
acts of carelessness.
125 from faulty construction of boiler or fittings, want of stays, or
neglect of timely repair.
119 from collapse of internal tubes, generally from insufficient
strength.
114 from shortness of water, or from scurf preventing the proper
contact of the water with the plates; or from improper
setting so as to expose the sides of the boiler to the flame
above the water line.
9 from extraneous causes, such as effect of lightning striking
down the stacks upon the boilers, or from fire in the building
or explosion of gas in the flues.
----
1046 total number of explosions.
====
The exploded boilers were of the following descriptions:--
232 are not sufficiently described to place under any head; but of
the rest
320 were Marine boilers of various forms.
141 were Cornish, Lancashire, or other boilers internally fired.
120 were Locomotive, or other multitubular boilers.
116 were plain Cylindrical boilers, externally fired.
64 were Balloon or haystack, wagon, Butterley, British-tube,
elephant, or Trevithick boilers.
29 were Portable, agricultural, upright, or crane boilers.
14 were Heating apparatus or kitchen boilers.
10 were Upright boilers attached to puddling or mill furnaces at
ironworks.
----
1046 total number of explosions.
====
[Illustration: _Fig. 1._]
The theories as to the causes of explosion have been numerous. In
the early days of the steam engine, when the steam was used only as
a condensing medium and the pressure in the boiler was frequently
allowed to get below atmospheric pressure, many boilers were destroyed
by the access of the external atmospheric pressure becoming too great,
causing them to be collapsed or crumpled up; and this led to the use
of the atmospheric valve still found on old boilers. Even so lately as
last year, 1865, a boiler in the neighbourhood of Bury, Lancashire,
has suffered in this way by collapse from external pressure; its
appearance after the accident is shown in Fig. 1, which is copied
from a photograph. The early explosions were so palpably due to the
weakness of the boilers, which compared with those of the present day
were most ill constructed, that no one thought of any other cause than
the insufficient strength of the vessel to bear the expansive force
of the steam contained in it. When the advantages of high-pressure
steam became recognized, and the boilers were improved so as to bear
the increased strain, the tremendous havoc caused by an explosion led
many to think that something more must be required than the expansive
force of the steam to produce such an effect; and they appear to have
attributed to steam under certain conditions a detonating force, or
a sudden access of expansive power that overcame all resistance.
To support this somewhat natural supposition, it was asserted that
the steam became partially decomposed into its constituent gases,
forming an explosive mixture within the boiler. That this belief is
still sometimes entertained is seen from the verdict of a jury even
in the present year, 1866, in the case of the explosion of a plain
cylindrical boiler at Leicester, shown in Fig. 2., the real cause of
which appears to have been that the shell of the boiler was weakened
by the manhole. It seems hardly necessary to point out the fallacy of
imagining decomposition and recomposition of the steam to take place
in succession in the same vessel without the introduction of any
new element for causing a change of chemical combination; but it is
necessary to refer to this supposition, as the idea is shown to be not
yet extinct.
[Illustration: _Fig. 2._]
Again it has been asserted that the steam when remaining quite still
in the boiler becomes heated much beyond the temperature due to the
pressure; and that therefore when it is stirred or mixed or brought
more in contact with the water by the opening of a valve or other
cause, the water evaporates so rapidly as to produce an excessive
pressure by accumulation of steam. In support of this view the
frequency of explosions upon the starting of the engine after a short
stand is adduced; but it is very doubtful whether by this means a
sufficient extra pressure could be produced to cause an explosion,
unless the boiler had been previously working up to within a very
small margin of its strength. Explosions are seldom caused by a sudden
increase of pressure, but rather by the pressure gradually mounting to
the bursting point, when of course the effect is sudden enough. Nor
is it necessary in many cases to look for much increase of pressure
as the cause of explosion; for it is far more often the case that the
strength of the boiler has gradually degenerated by wear or corrosion,
until unable to bear even the ordinary working pressure. It is so very
easy, when examining the scene of an explosion, for the first cause of
rupture to be confounded with the causes of the subsequent mischief,
that in many cases erroneous conclusions have been arrived at in this
way.
The most important points to find out in connection with any explosion
are the condition of the boiler and all belonging to it immediately
before the explosion, together with the locality of the first rent, the
direction of the line of rupture, and the nature of the fracture; as
everything occurring after the instant of the first rent is an effect
and not a cause of explosion. As soon as the first rent has taken
place, the balance of strain in the fabric is disturbed, and therefore
the internal pressure has greatly increased power in continuing the
rupture; and also the pressure being then removed from the surface of
the water, which is already heated to the temperature of the steam,
the whole body of the water gives out its heat in the form of steam
at a considerable pressure, and thus supplies the volume of steam for
carrying on the work of destruction. When thus quickly generated, the
steam perhaps carries part of the water with it in the same way that
it does in ordinary priming; and it has been thought by some that the
impact of the water is thus added to that of the steam, to aid in the
shock given to all surrounding obstacles.
It is seldom that one out of a bed of boilers explodes without more
or less injury to the others on either side of it; but sometimes
two boilers in one bed, or three, or even five, have exploded
simultaneously.
* * * * *
The causes of boiler explosions may be considered under the two general
heads of--
Firstly, faults in the fabric of the boiler itself as originally
constructed, such as bad shape, want of stays, bad material, defective
workmanship, or injudicious setting:--and
Secondly, mischief arising during working, either from wear and tear,
or from overheating through shortness of water or accumulation of
scurf; or from corrosion, in its several forms of general thinning,
pitting, furrowing, or channelling of the plates; or from flaws or
fractures in the material, or injury by the effect of repeated strain;
or from undue pressure through want of adequate arrangements for escape
of surplus steam.
[Illustration: _Fig. 3._]
[Illustration: _Fig. 4._]
[Illustration: _Fig. 5._]
There is no doubt that many of the early explosions were from faults
of construction. The stronger materials now used were then found so
difficult to manipulate that others easier to work were chosen, and
often the shape of the boiler was only selected as the one easiest to
make. The early boilers were made of copper or cast iron, with leaden
or even wooden tops, and of the weakest possible shape. Such was the
boiler used by Savery, shown in Fig. 3., and the Tun Boiler and Flange
boiler, Figs. 4 and 5. The very fatal explosion in London in 1815,
referred to by the parliamentary commission previously named, was of a
cast-iron boiler, which failed because one side was too thin to bear
the pressure, as the casting was of irregular thickness. The steam
being at that time used only at or below atmospheric pressure as a
means of obtaining a vacuum by condensation for working by the external
pressure of the atmosphere, so little was pressure of the steam thought
of, that boilers were proposed and it is believed were actually
constructed with hooped wooden shells, like barrels, and internal
fireplaces and flues of copper; and even a stone chamber was named
as being a suitable shell for a boiler, with internal fireplace and
copper flue passing three times the length of the inside and out at the
top, like an ordinary stove and piping. These boilers must have been
something like the sketches given in Figs. 6 and 7, and were intended
to be exposed only to the external pressure of the atmosphere.
[Illustration: _Fig. 6._]
[Illustration: _Fig. 7._]
[Illustration: _Fig. 8._]
[Illustration: _Fig. 9._]
[Illustration: _Fig. 10._]
Cast iron was frequently used for the shell of boilers, with an
internal fireplace and tubes of wrought iron, as shown in Fig. 8, and
boilers of this construction are still to be found in use at some of
the older works at the present day. As the outside shell and front
plate are 1-1/2 inch thick and are not exposed to any wear at all,
these boilers are sufficiently strong. A duplicate front plate with
set of tubes attached is always kept on hand in case of need. Another
form of cast-iron boiler is shown in Fig. 9., made in several parts
put together with flange joints, with an internal fireplace and flue
also made of cast iron. When cast iron was used for the parts exposed
to the fire in boilers intended for high pressure, it was sometimes
employed in the form of tubes of small diameter and proportionately
thinner; as in Woolf's boiler, so much spoken of in the evidence
before the parliamentary committee of 1817. This boiler, shown in Fig.
10., consisted of nine cast-iron pipes, about 1 foot diameter and 9
feet long, set in brickwork so that the flame played all round them.
These small tubes were connected with another of larger size placed
transversely above them, forming a steam receiver, and this again with
a still larger one, which formed a steam chamber. No details of any
explosions of the three last mentioned boilers have been obtained; but
it is known that the cast iron was found a most treacherous material,
especially when exposed to the action of the fire; and that the effect
of explosion was very disastrous, because the boiler burst at once into
many pieces, each of which was driven out with great velocity, and the
danger was not mitigated by the circumstance of large masses holding
together, as is found to be the case with wrought-iron boilers when
exploded.
* * * * *
[Illustration: _Fig. 11._]
[Illustration: _Fig. 12._]
When wrought-iron boilers came into use the shapes were most varied,
and the dimensions much larger than before. One of the earliest was the
Wagon boiler, shown in Fig. 11, with round top and plain flat sides,
which could only be made to bear even the smallest pressure by being
strengthened with numerous stays. In most cases of explosion of this
class of boiler the bottom was torn off, owing to the angle iron round
it being weakened by the alternate bending backwards and forwards under
each variation of pressure, as all the sides and the bottom must be
constantly springing when at work. Such was the explosion at Chester
in 1822, and many others. This shape was soon improved in its steam
generating powers by making the sides concave instead of flat, as shown
in Fig. 12, so that the heating surface was greater and also in a
better position to receive the heat from the flame in the flues. This
shape was further elaborated by rounding the ends as in Fig 13, and
in some cases making the bottom convex to correspond with the top, as
in Fig. 14. All these forms however still required numerous stays to
retain them in shape, the safety of the boiler being dependent upon
the stays; and numerous explosions show the weakness of these boilers.
They generally gave way at the bottom, as in an explosion that occurred
at Manchester in 1842, where the boiler had been weakened by frequent
patching; they also sometimes exploded through the failure of the stays.
[Illustration: _Fig. 13._]
[Illustration: _Fig. 14._]
[Illustration: _Fig. 15._]
[Illustration: _Fig. 16._]
[Illustration: _Fig. 17._]
[Illustration: _Fig. 18._]
A very early improvement in the right direction consisted in making
the shell circular; and some few large boilers still exist that were
made completely spherical, as show in Fig. 15, so that the whole of
the iron was exposed to tension only, and required no assistance from
stays, and the boiler had no tendency to alter its shape under varying
pressure. This shape however had the great disadvantage of possessing
the least amount of heating surface for its size or cubic contents; and
also it was very liable to injury from sediment on the bottom, which
accumulated on the most central spot. The spherical form was therefore
soon modified into the shape shown in Fig. 16, by making the bottom
more shallow, although still convex; and afterwards by putting flat or
concave sides and a flat or concave bottom, with the angle constructed
either of bent plates or angle iron, as in Figs. 17 and 18, which
represent the forms known so well in the Staffordshire district as the
common Balloon or Haystack boiler. Many of these have been made of very
great size, measuring as much as 20 feet diameter, and containing so
much water and steam as to be most formidable magazines for explosion.
Perhaps no form of boiler has exploded more than this, partly because
of the great number that have been used, but chiefly because of the
inherent weakness of the shape. The records however have not been
obtained of the great majority of these explosions, because they seldom
caused sufficient damage or loss of life to attract much attention, as
these boilers generally worked in isolated positions at collieries.
The bottom is only prevented from blowing down into the fireplace by
numerous stays from the top, and the angle iron round the bottom of the
sides is much tried by the constant springing of the plates under every
alternation of pressure; and the weakness thus occasioned is increased
by the angle resting on the brickwork and being exposed to corrosion.
The effect of this continued alternation of strain is well shown by the
elastic model exhibited.
[Illustration: _Fig. 19._]
[Illustration: _Fig. 20._]
[Illustration: _Fig. 21._]
[Illustration: _Fig. 22._]
Notwithstanding the dependence of these boilers upon stays for their
strength, many have been made as large as 12 and 15 feet diameter
without stays; and explosion sooner or later has been the consequence.
Such was an explosion that took place at Smethwick in 1862, which
is shown in Fig. 19. As the force of the explosion was only slight,
the effect of the bottom giving way, and the consequent rolling over
caused by the reaction of the issuing steam and water, is clearly seen.
Another example that occurred at Wednesbury in 1862 is shown in Fig.
20, where the explosion was rather more violent, the bottom of the
boiler being torn off all round and left upon the firegrate, and rent
nearly into two pieces; while the top and sides were thrown some height
in one mass, and were only put out of shape by the fall. The weakness
of this boiler had been further increased by making the bottom angle of
angle iron, as shown enlarged in Fig. 21, with a ring of flat plate
A interposed between the angle-iron ring and the concave bottom of
the boiler; so that all the effect of the springing of the bottom, as
shown by the dotted lines, was thrown upon the angle iron, which was
accordingly found cut off all round. Had the concave bottom been made
to rise direct from the angle iron, as in Fig. 22, the springing could
not have been so great, and the angle iron would only have had to stand
the shearing strain of retaining in its place the rigid bottom; but as
about one foot all round the bottom was flat, and the concavity was
only in the central part, the angle-iron ring had to bear an up and
down strain, as shown by the dotted lines in Fig. 21, and the bending
action was more severe than it would have been if the bottom had even
been made quite flat all over.
[Illustration: _Fig. 23._]
A further form of the Balloon boiler is shown in Fig. 23, where the
heating surface of the bottom is increased by an internal central
dome-shaped fireplace, with an arched and curved flue conducting the
flame through one revolution within the boiler before passing again
round the outside. This construction however must necessarily have
diminished the strength of the boiler greatly. In the drawing the top
of the boiler, as indicated by the dotted lines, is removed to show the
interior.
The desire to add to the strength of boilers by lessening the diameter
of the shell led to the construction of the Plain Cylindrical boilers.
They were made first with flat ends of cast iron, which frequently
cracked and gave way when exposed to the fire, as described in many
of the early American explosions. The flat ends when made of wrought
iron, as shown in Fig. 24, are exposed to the same strain as the bottom
of the balloon and wagon boilers, and are constantly springing with
variation of pressure like drum heads, causing injury to the angle-iron
joint. They also require long stays through them to hold in the ends,
and these are subject to so much vibration that they seldom continue
sound for long together, especially when joined with forked ends and
cotters.
[Illustration: _Fig. 24._]
* * * * *
As the flat ends of such boilers are always being sprung by each
alternation of pressure into a more or less spherical shape, as shown
by the elastic model exhibited, this consideration no doubt led to
the ends being made hemispherical, as shown in Fig. 25; and plain
cylindrical boilers with these hemispherical ends are now so commonly
used that they far outnumber any other form of boiler. Their shape
renders them very strong, as the whole of the iron is in simple
tension, and internal pressure has no tendency to alter the shape, as
is shown by the elastic model exhibited. There is one circumstance very
much in favour of the plain cylindrical boilers, and that is that they
can be so easily cleaned and repaired, as a man can stand properly at
his work at every part and the whole of the interior surface is exposed
equally to view. They are of course exposed to all the evils of boilers
externally fired, the part under greatest strain being weakened by
the action of the fire; and the bottom is also exposed to injury from
accumulation of mud and chips of scurf, which cannot be prevented from
falling there, and lying upon the part exposed to the direct action of
the fire. When made of great length, such as 70 or 80 feet, as is the
practice for applying the waste gas from blast furnaces, these boilers
are also liable to seam-rips or "broken backs," owing to the greater
expansion of the bottom exposed to the fierce flame for its whole
length, than of the top which is kept cooler by exposure to the air;
and it would therefore be better to have a succession of short boilers,
rather than only a single one, where great length is required.
[Illustration: _Fig. 25._]
One boiler has been seen by the writer where extreme length was avoided
by curling the boiler round until the ends met forming a Ring or
Annular boiler. This boiler is shown in Fig. 26, and is 5 feet diameter
with 25 feet external diameter of the ring, or a mean length of about
63 feet; it has been found to work well for some years, although
exposed to the heat of six puddling furnaces.
[Illustration: _Fig. 26._]
[Illustration: _Fig. 27._]
Explosions of plain cylindrical boilers have been very frequent indeed,
although they have not caused a proportionate number of deaths, because
they work usually in isolated positions at colliery and mine engines.
The sketch shown in Fig. 27, represents an explosion that occurred
at Darlaston in 1863, and illustrates the way in which these boilers
usually explode. They generally open first at a longitudinal seam over
the fire, which has become deteriorated by accumulations of scurf
preventing proper contact of the water, so that the plates become
overheated, their quality injured, their edges cracked or burnt, and
the rivets drawn or loosened. The rent generally continues in the
longitudinal direction to the sound seam beyond the bridge at the one
end, and at the other end to the seam joining the front end to the
shell; and then runs up each of the transverse seams, allowing the rent
part of the shell to open out flat on both sides, and liberating both
ends of the boiler, which fly off in opposite directions. Of course
it is seldom that an explosion is quite so simple as this, as the
direction of the flight of the various pieces is so much influenced by
the last part that held in contact with the main body of the boiler.
The want of due observation of this point has often led to erroneous
conclusions.
[Illustration: _Fig. 28._]
In the explosion shown in Fig. 28, and in the model exhibited, which
occurred at Westbromwich in 1864, the lower part of the side of an
upright boiler was blown out; and the liberated part was also divided
into two pieces, each of which fell some distance behind the boiler, in
an opposite direction to the side from which they came. The explanation
of this became obvious on examination, as the cause of the rupture
had been the corrosion of the bottom, and the rent had run up the
seams until it met the angle iron of the side tubes, round which it
ran to the first seam above. This seam acted as a hinge on which the
ruptured pieces turned, and they swung round so violently that they
were wrenched off, but not before they had pulled the boiler over and
received the diverting force which gave them their direction, for they
flew off at a tangent, to the circle in which they had swung round on
the sound upper seam as upon a hinge.
[Illustration: _Fig. 29._]
[Illustration: _Fig. 30._]
In order to avoid having a large diameter for plain cylindrical
boilers, especially where exposed to the fire, boilers have been used
that have supplied the required steam power by a combination of several
cylinders of small diameter. One of these known as the Elephant boiler,
has been so much used in France that it is sometimes called the French
boiler; it is shown in Fig. 29, and consists of two cylinders of small
diameter connected by upright conical tubes to a large cylinder above.
Another form called the Retort Boiler, shown in Fig. 30, has been
described at a previous meeting of this Institution (see Proceedings
Inst. M. E. 1855 page 191). The disadvantages of these two combinations
of plain cylinders are that they are not easy to clean or examine
internally, and also there is not free exit for the steam, which has
to find its way along small channels, and carries the water away with
it, causing priming, and also retarding the generation of steam and
endangering the boiler plates. With a view to strengthen the plain
cylinder made of wrought-iron plates, the seams are sometimes made to
run diagonally, as shown in Fig. 31, on the principle that, as the
longitudinal is the weakest seam and the transverse the strongest, a
diagonal between them gives the greatest amount of strength to the
boiler as a whole.
[Illustration: _Fig. 31._]
* * * * *
[Illustration: _Fig. 32._]
[Illustration: _Fig. 33._]
[Illustration: _Fig. 34._]
[Illustration: _Fig. 35._]
Plain cylindrical and wagon boilers have for many years been made with
internal tubes of various shapes and arrangement, through which the
flame passes to add to the heating surface. These are shown in dotted
lines on the previous drawings of wagon boilers, Figs. 11 and 12. They
are also shown in Fig. 32, where a tube passes from over the fire to
the front of a plain cylindrical boiler; in Fig. 33 two tubes pass
from the sides to the front: in Fig. 34 the tube passes from the back,
but returns over the fire and passes again to the back: and in Fig. 35
a tube from the back passes out through a cross tube in each side. The
boilers in all these cases are fired externally. This addition of tubes
has tended very much to increase the size of these boilers in order to
make room for the tubes. These boilers are now found of 9, 10, and
even 11 feet diameter; and this large shell being fired externally is
exposed to the same dangers as those described in the plain cylindrical
boiler, while it is not so easy to keep clean on account of the
obstruction offered by the internal flues. When the flame has passed
under the whole length of the bottom of these large boilers before
going through any tube, it is doubtful whether the heating surface of
the tube helps much in the generation of steam; but the tube is of
use in reducing the quantity of water in the boiler, as it occupies a
considerable space.
[Illustration: _Fig. 36._]
Explosions of these boilers have sometimes taken place by collapse of
the tubes, but much more generally by the failure of the shell over the
fire, as shown in the sketch Fig. 36, representing an explosion that
occurred at Wolverhampton in 1865, in which the first rent took place
in a seam over the fire where frequent repair had led to a considerable
length of longitudinal seam being in one continuous line. The four
plates over the fire parted and opened out until they had ripped two
seams completely round the boiler; and the plates were thrown in one
flat piece, as shown, upon a bank behind. The main body of the boiler
with the tubes was turned over, and the front end blown away.
[Illustration: _Fig. 37._]
A modification or amalgamation of several of the forms of boilers
already mentioned led to the construction known as the Butterley
boiler, shown in Fig. 37, with a wagon-shaped end over the fire,
continued in a single tube within a plain cylindrical shell beyond.
This boiler has been found to generate steam very rapidly; but the
extreme weakness of the construction over the fire and along the tube,
especially at the part where the front end of the tube widens out in
a bell mouth to meet the wagon-topped fireplace, has led to so many
explosions that few boilers are now made of this form. A very early
explosion that occurred at Edinburgh in 1821 was of a boiler somewhat
of this shape, only that the wagon-topped fireplace was much longer.
Other explosions of this form of boiler occurred at Ashton-under-Lyne
in 1845, at Wolverhampton in 1854, and at Tipton in 1856.
[Illustration: _Fig. 38._]
[Illustration: _Fig. 39._]
[Illustration: _Fig. 40._]
[Illustration: _Fig. 41._]
The desire to economise fuel led to placing the fire inside the boiler,
in a tube running from end to end, as shown in Fig. 38, and the great
number of boilers of this form used in Cornwall gave it the name of the
Cornish boiler. The exceedingly good duty performed by these boilers
led many to believe them the most perfect for economy and durability;
but the great number of explosions, or more properly of collapsed
flues, that have happened, have altered this opinion, and led to the
double-flue boiler shown in Fig. 39, in which not only is the heating
surface increased but the strength also, by having two tubes of smaller
diameter in the same shell. There are a great many varieties of the
two-tube boiler, which have been made for the purpose of obtaining
various particular results. In some cases the two tubes have been made
to unite into a single tube immediately behind the fires, forming what
is known as the Breeches-tube boiler, as shown in Fig. 40, and in other
instances the outside shell of the boiler has been made oval, as shown
in Fig. 41, with the two tubes continued through from end to end. The
heating surface has also been increased, and the strength of the main
tubes, by placing smaller transverse tubes across them at right angles;
but these advantages are gained by increased complication, leading of
course to greater difficulty in examination and repair.
* * * * *
The frequent failure of tubes by collapse when used for high pressures,
and also the results of careful experiments, led to the simple addition
of strengthening rings of different makes around the exterior of these
tubes, by which the shell and the tubes are rendered of equal strength.
It has taken considerable time for the belief in the weakness of large
tubes when exposed to external pressure to become general, and a great
many boilers are still made and used having even large tubes without
the strengthening rings; and in some districts such boilers are used
in great numbers and at far higher pressures than can be considered
judicious. In more than one bed of boilers, one boiler after another
has exploded by the collapse of the tube from the want of strengthening
rings, and yet these have still been believed unnecessary; and the
cases of isolated boilers of this construction where the large tubes
have collapsed are extremely numerous, yet any other reason than the
weakness of the tube has been considered more probable as the cause of
explosion. A sketch of a boiler with collapsed flue is given in Fig.
42, which exploded at Burton-on-Trent in 1865; and it is selected from
many others because it was a new boiler, well made and mounted, and was
a good example of the weakness of a large tube to resist high external
pressure when made of great length without the support of strengthening
rings.
[Illustration: _Fig. 42._]
There are a great many advantages in the tubular boiler internally
fired. The shell which is exposed to the greatest tension is not also
exposed to the first action of the fire. The fire is in the midst of
the water, so that the greatest effect is obtained from it; and the
heating surface immediately over the fire, from which most steam is
generated, has not so great a depth of water above it for the steam to
pass through as in the externally fired boilers heated from the bottom.
The tubes also act as stays to the ends; and the mud in the water falls
off the tubes, where it would do mischief, and settles on the bottom,
where it is comparatively harmless.
These tubular boilers are however subject to disadvantages peculiarly
their own. It is not so easy to move about within them for cleaning
and examination as in the plain cylindrical boiler, as the tubes fill
up the space so much. The difference of expansion between the highly
heated tube and the comparatively cool shell produces a strain, which
causes the ends to bulge out; or if the ends are made rigid, the strain
sets up a contortion in the tube, which causes furrowing of the plates
by making the iron softer or more susceptible of corrosion in certain
lines of strain. Notwithstanding these drawbacks however this form of
boiler is an excellent one.
Many modifications in the forms of boilers have been made to enable the
manufacturers to use the waste heat from various processes, especially
from the making of iron. The plain cylindrical boiler has been used
in this way, with sometimes as many as eight puddling furnaces made to
work upon one boiler. One of the earliest special arrangements for this
purpose was the Upright boiler with central tube, shown in Fig. 43,
which was originally made for two furnaces; and about 7 feet diameter
and 16 feet high. The size has since been increased to 10 feet diameter
and 28 feet high, as shown in Fig. 44. These boilers are made for one,
two, three, or four puddling furnaces; and consist of a cylinder with
spherical ends, standing upright, with a central tube from the bottom
to about half the height, into which the side tubes join. The heat from
each furnace plays over a portion of the shell, and then passes through
the side tubes and down the centre tube into the underground flue to
the chimney.
[Illustration: _Fig. 43._]
[Illustration: _Fig. 44._]
These boilers have many good points: there is great heating surface;
and the shell being heated all round does not strain the plates
and seams by unequal expansion so much as in the horizontal plain
cylindrical boiler heated only at the bottom; and as both ends are
spherical there is no alteration of shape under internal pressure.
Moreover in consequence of the upright position of the boiler a safe
depth of water can easily be maintained, and yet the steam is taken off
so high above its surface that there is little priming; and every part
can most easily be cleaned and examined, as a man can stand upright
both in the boiler and in the flues. But the great drawback to this
class of boilers is that they must stand in the midst of the workmen;
so that, although they are not more liable to explode than any other
form of boiler, yet when they do burst they necessarily endanger more
lives than is usually the case with other boilers that can be placed
more away from the men employed at the works. Should anything arise
with the boiler to make it desirable to withdraw the fire, this cannot
be done without much delay, as the furnaces have to be stopped and the
iron run out. Also an explosion can hardly happen without some of the
melted iron being scattered among the men at work.
[Illustration: _Fig. 45._]
[Illustration: _Fig. 46._]
Some of the most fatal explosions of these boilers have arisen from
careless construction. Such was the case in an explosion at Dudley in
1862, shown in Fig. 45, where the crown plate forming the top of the
centre tube was attached to the sides of the tube by so slight an angle
iron, as shown enlarged in Fig. 46, that the pressure of steam on the
flat crown plate fairly sheared the angle iron through, and allowed the
plate to be blown down the centre tube into the chimney flue, whereupon
the boiler was violently thrown off its seating by the reaction of the
issuing steam and water thus liberated.
* * * * *
The double-tube horizontal boiler is also used in connection with
iron-making furnaces in many places, one furnace working into each
tube. Although by this arrangement the boiler can be placed a little
further from the workmen, some very fatal explosions have happened to
such boilers, as at Masborough in 1862.
* * * * *
[Illustration: _Fig. 47._]
Single-furnace boilers have been much used in the form of a single-tube
boiler standing on end, as shown in Fig. 47, with the flame passing up
the tube, which is continued in the form of a chimney on the top of the
boiler. The tube passes through the steam at the top, so that the plate
is not protected from overheating by contact with water; and this has
caused explosion in some instances, although the tube has been lined on
the inside with firebrick to shield the plate from the flame. Another
great disadvantage of this Chimney boiler is that the space between the
tube and the shell is so narrow that it is almost impossible to examine
or clean it internally.
* * * * *
A further arrangement for a single-furnace boiler is the Elbow boiler,
shown in Fig. 48, where the two difficulties mentioned in the previous
boiler are avoided.
* * * * *
Many internally fired upright boilers of various shapes have been
constructed to suit various purposes. One of a large size that has been
at work many years is shown in Fig. 49, with an internal fireplace and
a suspended cone and cross tube for increasing the heating surface.
This boiler is set in brickwork in such a way that the heat passes
through the side tubes and round the exterior shell before going off to
the chimney.
[Illustration: _Fig. 48._]
[Illustration: _Fig. 49._]
A very fatal explosion at Stoke-upon-Trent, in 1863, resulted from an
attempt to work a boiler of somewhat the same general form, but without
the same careful attention to the details of construction. This boiler
is shown in Fig. 50; the internal fireplace is of conical shape, 4
ft. 6 ins. diameter on the top and 6 ft. 10 ins. at bottom, and was
joined to the external shell by a flat annular bottom. Almost the first
time it was worked at high pressure the conical fireplace collapsed,
breaking off at the seam at the top of the cone, and blowing down upon
the grate, as shown in Fig. 51. The flat bottom was then left without
the support of the cone and side tubes, and gave way all round the
outside angle iron; and the top flew up a great height into the air,
and fell a crumpled heap, as shown in the sketch. In this case the only
wonder is that a boiler of such weak construction worked at all without
explosion.
[Illustration: _Fig. 50._]
[Illustration: _Fig. 51._]
* * * * *
There yet remains to be noticed a very large and varied class of
boilers that have been designed with the express object of avoiding
explosion. Some of these, made of cast-iron pipes of small diameter,
have already been referred to. When steam carriages were first
constructed, boilers were tried made of a cluster of small pipes,
set both upright and horizontally, connected with a general receiver
and with each other by still smaller pipes. These were found to
have such small circulation of water that they very soon burnt out,
and also led to much priming. Afterwards, narrow chambers made of
corrugated plates set like the cells of a battery were tried, but
without much success. The multitubular boilers of the locomotive type
soon superseded all others as quick steam generators, and until lately
they have been considered as almost absolutely safe from explosion.
It is found however that the barrel of these boilers is peculiarly
liable to furrowing, owing to the strain weakening the iron in certain
lines. Perhaps no boiler shows more clearly than the locomotive how
necessary it is that every part should be open to examination; and also
how unwise it would be to use for stationary purposes small cramped
up boilers, only intended to meet the necessities of locomotion. Many
explosions of locomotive boilers have taken place; but it is not
necessary to give details in this paper, as they are fully given in the
published official reports of the government inspectors.
Among the form of boilers designed to obtain very rapid generation of
steam, combined with increased safety from explosion, may be specially
named that consisting of a system of small pipes within a shell with
an artificial circulation of water, and also the boiler consisting
of a cluster of cast-iron spheres, both of which have been described
at previous meetings of the Institution (see Proceedings Inst. M. E.
1861 page 30, and 1864 page 61); but neither has been much used in
this country at present. The boilers also which consist chiefly of
small tubes hanging down into the fire, with smaller tubes or other
arrangements within them for securing a natural circulation, deserve
mention, as they appear successfully to accomplish that end.
The principle of all these small boilers appears to be that only a
small quantity of water should be contained in them, so that there
should not be a reservoir of danger in the shape of a mass of highly
heated water ready to be converted into steam if a rupture takes place:
and it cannot be denied that this is an advantage. But on the other
hand these boilers of small capacity, which evaporate their whole
contents in a few minutes, are subject to new dangers from that very
cause; and although admirably adapted for purposes where steam is
wanted quickly on a sudden emergency, as in the case of fire engines,
or where the generating power required varies each moment, as in
the locomotive, they are for the most part ill adapted for ordinary
stationary purposes, such as the mill or the colliery. They require
constant firing and vigilant attention to the feed, and cannot be left
for a time with safety like the ordinary stationary boilers. It has to
be borne in mind also that the very reservoir of danger so much dreaded
is also a reservoir of power, which assists in the steady maintenance
of the machinery in motion. The large mass of water heated to the
evaporating point, the heated brickwork of the flues, and the large
fireplace, are so many assistances to regularity, and enable the man
in charge to attend to his other duties without the risk of spoiling
the boiler or letting down the steam by a few minutes' absence from the
stoke hole. Steam employers are found at present to prefer the known
dangers of the large boilers to the supposed safety of small boilers,
which they fear are troublesome in practice.
* * * * *
Many of the early boilers were rendered weak by the injudicious
manner of arranging the seams. The longitudinal seams were made in a
continuous line from end to end, as shown in Fig. 24, page 20, with
the transverse seams also continued completely round the boiler, so
that at the corner of each plate there were four thicknesses of iron.
The crossing of the seams, as in Fig. 25, page 21, adds much to the
strength, and also often prevents a rent from continuing forward to a
dangerous extent.
It is scarcely requisite to mention the necessity of good material
and workmanship to secure strength in a boiler, however perfect the
design. If the plates are of weak and brittle iron, or imperfectly
manufactured, they will never make a good boiler. Apart from the strain
upon the boiler when at work, the iron has to undergo the strain of the
necessary manipulation, shaping, and punching, during the construction
of the boiler. If the plates forming the boiler are not well fitted to
their places before the rivet holes are made, the errors have to be
partially rectified by using the drift in the holes to an unwarrantable
extent, and then using imperfect rivets to fill up the holes that do
not correspond with each other; and the mischief is too frequently
increased afterwards by excessive caulking, in the endeavour to stop
the leaking which is sure to show itself. In this way a boiler is often
exposed to most unequal internal strain between its several parts
before it is set to work at all; and when the heat is applied to it,
the mere expansion causes undue contortion, and leads to seam rips,
and ultimately to disaster. Several specimens of faulty rivetting and
caulking were exhibited to the meeting, and a sketch of one of them is
shown in Fig. 52.
[Illustration: _Fig. 52._]
The strength of a boiler is often very much lessened by the injudicious
manner in which the mountings are fixed upon the boiler, and many
explosions are the consequence of this defect. Not only are a great
many holes for fittings cut out of the boiler in one line, but these
holes are made needlessly large. Steam domes are often so placed as
greatly to weaken the shell of the boiler, the hole cut out of the
plate being made the full diameter of the dome; and in some cases the
domes or steam chests have been made square or rectangular, so as to
weaken the shell still more, as shown in Fig. 53.
Manholes are often a source of danger, if not properly arranged and
duly strengthened. Even in very small boilers they are often placed
with the longest diameter in the longitudinal direction of the boiler,
so that the shell is greatly weakened, as in the sketch, Fig. 54, of
an exploded boiler at Walsall in 1865. This boiler was 5 ft. 3 ins.
long and 2 ft. 6 ins. diameter, and yet the manhole was 18 inches by 13
inches, and placed within a few inches of one end. The end was fastened
in by angle iron, which was not welded, and consequently there was so
little strength at the small portion of the shell between the end and
the manhole that it gave way and liberated the end and the manhole lid,
after which the main body of the boiler was thrown by the reaction
across several streets to a great distance.
[Illustration: _Fig. 53._]
[Illustration: _Fig. 54._]
A somewhat similar injudicious arrangement of the manhole is shown
in Fig. 55, where a manhole 17 inches by 14 inches was cut out of
the flat top of a steam dome only 2 ft. 6 ins. diameter, without
any strengthening ring to compensate for it. The repeated strain of
screwing up the manhole lid, combined with the pressure of the steam,
caused the lid to force its way out through the plate and blow away.
This explosion occurred at Birmingham in 1865.
[Illustration: _Fig. 55._]
The preceding examples have shown how explosions often result from
faults in the construction of boilers; and the following instances
illustrate the explosions caused by mischief arising during working.
A boiler perhaps more than any other structure is subject to wear
and tear; and let it be worked ever so carefully, it will seriously
deteriorate. The wonder is, considering the work they have to perform,
that so many boilers are found which have worked twenty, thirty, or
even fifty years without explosion. The terms wear and tear however
are too vague for this subject, and the mischief met with must be
considered under distinct heads.
There is no doubt that the thing most to be dreaded for boilers is
corrosion; because when the plate is once thinned, it cannot be
strengthened again, but must remain permanently weakened. Corrosion
the more deserves attention because it is easily detected by moderate
vigilance, and can generally be prevented by moderate care, or by the
boilers being so arranged that they can be readily examined in every
part. Corrosion has been the direct and unmistakeable cause of a very
large proportion of the explosions that have happened: it occurs both
inside and outside the boiler, according to circumstances, and attacks
the iron in various ways and in different places.
[Illustration: _Fig. 56._]
[Illustration: _Fig. 57._]
[Illustration: _Fig. 58._]
[Illustration: _Fig. 59._]
_Internal corrosion_ sometimes takes place from bad feed water, and
its effects are different in extent in the different parts of the same
boiler. It very seldom thins the plate over a large surface regularly,
but attacks the iron in spots, pitting it in a number of holes. These
are sometimes large, as if gradually increasing from a centre of
action; and sometimes small, but so close together as to leave very
little more space whole than that which is attacked. A very curious
example of the latter was exhibited to the meeting, and shown in Figs.
56 and 57, cut from the lower part of the shell of a large tubular
boiler externally fired. The corrosion was greatest along that part of
the shell most exposed to heat, and was so extensive that two boilers
exploded simultaneously. The boilers had been at work sixteen years,
but the corrosion commenced about eight years before the explosion,
when the feed water was rendered corrosive by being obtained from
some iron mines. This explosion occurred at Aberaman in 1864. The
corrosion had been seen going on for years, and was not considered
sufficient to cause danger; but the depth to which it extended through
the thickness of the metal is seen in the half size section, Fig.
57. Another sample equally curious was exhibited to the meeting, and
shown in Figs. 58 and 59, taken from the sweep plate over the fire
in a plain cylindrical boiler which had worked about ten years. The
feed water was occasionally bad, and attacked the iron over the area
DDD, where unprotected by scale. The protection afforded by scale
against occasional corrosive feed water is worthy of notice. In the two
specimens exhibited it is seen that the protection has been perfect
where the scale has not been chipped off; and the edge of the sound
part projects over the hollow, as seen in the half size sections,
Figs. 57 and 59, the corrosive water having eaten away a larger area
beneath than that through which it first entered the surface of the
iron.
Internal corrosion is frequently observed where boilers are fed
from canals or streams in the neighbourhood of chemical works from
which corrosive matter is discharged at intervals into the water.
The corrosion takes place in isolated spots, but causes deep holes;
which seems to be accounted for on the supposition that the scale
previously upon the plate cracks during the cooling of the boiler for
cleaning, and forms a blister, so that a piece of about 2 inches area
is raised slightly from the iron. When the boiler is again put to
work, this blister becomes filled with the corrosive water, which is
held there without circulation and causes corrosion. When the boiler
is again emptied these blisters may be seen, and if broken show the
blackened water and the injured surface. In future working each of
these blisters forms a constant unprotected point for attack. It is
frequently seen further that such corrosion is arrested if water be
used which deposits scurf; but fresh blisters and renewed corrosion
will result from a return to the use of the bad water.
The internal corrosion called furrowing has proved a frequent cause
of explosion, especially in locomotive boilers. It differs from other
corrosion by being in deep narrow continuous lines with abrupt edges.
It will sometimes go completely through a plate; and is found where a
sudden change of thickness occurs, either along the lines of the seams,
or opposite the edge of angle-iron attachments. This effect is supposed
to be due to the alternate springing of the plates under each variation
of the pressure or temperature, causing the line of least resistance to
receive a strain somewhat similar to that produced by bending a piece
of iron backwards and forwards for the purpose of breaking it. This
line of injury is exposed to constant attack from corrosion, because
the scurf is always thrown off from it.
* * * * *
_External corrosion_ is a far more frequent cause of explosion in
stationary boilers; and it arises from many causes. The most frequent
cause, although the most easily detected, is leakage from the joints
of the fittings on the top of the boiler, which are too frequently
attached by bolts instead of rivets. This evil is much increased when
the boilers are covered with brickwork, which holds the water against
the plates, and hides the mischief from observation. It is astonishing
to find how much damage is allowed in this way to go on without
attention, until the tops of boilers are corroded so thin that little
holes burst through. These are sometimes found stopped with wooden
pegs or covered by screwed patches of plate, either of which cause
leakage that hastens the mischief, as shown by the sample exhibited.
Boilers exposed to the weather will of course become corroded like
anything else made of iron and not painted; and yet so much mischief
is sometimes caused by leakage beneath improper covering that exposure
may almost be said to be the smaller evil of the two, as it is better
to see what is going on than to rest in false security. No covering
will be found cheaper, or better, in the long run, than a roof, which
prevents the loss of heat by exposure, and yet allows free access to
all the fittings and joints on the top of the boiler.
[Illustration: _Fig. 60._]
Some examples of the evils of covering can be given that have come
under the writer's observation. A set of boilers had been well covered
by arches of brickwork, so built as to keep out all water, and also
set so as to touch the boilers only at intervals, leaving a space
generally of a few inches. After about seven years' working, the whole
of the tops of the boilers were discovered to be dangerously thin, and
had to be renewed. The cause was leakage from the joints of fittings
and seams of the boilers, and the issuing steam had been drawn along
the space between the boilers and the arches, and had escaped at a
place where it had not attracted notice. In another case, a somewhat
similar set of boilers were covered with ashes, to prevent the loss
of heat by radiation; and the rain and the leakage beneath the ashes,
in conjunction with the corrosive matter from the ashes themselves,
thinned the tops of the boilers to a dangerous extent in less than two
years. A sketch of the corrosion caused in this instance by covering
with ashes is shown in Figs. 60 and 61.
[Illustration: _Fig. 61._]
[Illustration: _Fig. 62._]
[Illustration: _Fig. 63._]
Similar mischief has been noticed in boilers covered with sand, as
shown in the sketches Figs. 62 and 63, which represent an instance of
corrosion after eight years' working; although nothing forms a better
covering than sand for preventing loss of heat by radiation. In both
these examples it will be seen that the corrosion has continued until
the thickness of the plate has been so eaten away that a hole has been
burst out at SS. A very good covering is formed by brickwork in cement;
or various cements made for the purpose, which adhere to the surface of
the plate and yet show leakage; or such materials as sacking or felt;
or sheet-iron casing, leaving about 6 inches of air space all round
the boiler. But all these have the great objection that they hide the
boiler from inspection, except by the expensive process of removing
the covering; and in this way dangers that have caused explosion have
remained hidden from observation.
Explosions have also taken place from general corrosion of the surface
of the boilers in the flues. A new boiler which was set on sidewalls
built upon a foundation of porous rock was found to have become
corroded all along the bottom in less than two years, owing to the
dampness which rose from the foundations causing a constant presence
of vapour. The corrosion was peculiar, and more like that found on old
iron left for a long time in a damp place; for the iron plate fell
to pieces when touched, and large flakes could be raised from the
surface, and the greater part of the thickness of the plate could be
removed with the fingers. Somewhat similar corrosion had taken place
in a boiler which exploded at Loughborough in 1863; the bottom of the
shell became rent at the corroded part, and as the fracture continued
spirally round the boiler several times, nearly all the shell was
peeled off in the curious manner shown in Fig. 64. The explosion shown
in Fig. 65, which occurred at Leeds in 1866, also arose from corrosion
of the bottom of the boiler.
[Illustration: _Fig. 64._]
[Illustration: _Fig. 65._]
[Illustration: _Fig. 66._]
The greater part of the corrosion found in the side flues of boilers
is caused by the leakage of seams. Many boilers are emptied for
cleaning as soon as work is over on Saturday night, and long before the
brickwork of the fireplaces and flues has cooled; and consequently,
the boiler, having no water in it, is made much hotter than it ever
is in working, and the seams are injured and sprung and the rivets
loosened by the extra expansion so caused. This is sometimes done
intentionally, in order to loosen the scale by the greater expansion
of the iron than of the scurf. When the boiler is again set to work,
the seams and rivets leak and cause that corrosion which is called
channelling. This has been observed to occur to such an extent that
all the seams in a boiler have been seen thus corroded; and the same
has sometimes been found in all the boilers in a large manufactory.
Specimens of this channelling were exhibited to the meeting. One in
particular, shown in Figs. 66 and 67, deserves attention, as it
shows the effect of a jet of steam and water from the leaking rivet
R, in cutting a series of channels into the plate along the course of
the dotted lines EEE, and producing a hole in the plate at S. This
corrosion had been going on for about four years, but was in a part of
the boiler seldom seen in ordinary examination. Many explosions have
resulted from this form of corrosion; for when a rent is once made, the
fracture continues along the thinned channel of the plate.
[Illustration: _Fig. 67._]
The corrosion most to be dreaded, because most difficult to detect, is
that which takes place where the boiler is in contact with brickwork;
and it is found alike in all forms of boilers set in brickwork. When
found at the part where the side flues are gathered in at the top
against the boiler, it is usually occasioned by the leaking of fittings
or feed pipes, or by rain being allowed to run between the boiler and
the brickwork. More than one explosion has been caused by the droppings
from a roof being allowed to fall upon the tops of the flues. When the
corrosion is found at the point where the bottom flue walls touch the
boiler, it is frequently caused by the leaking of seams that have been
strained by the weight of the boiler; and this often arises from want
of care to replace the brickwork, after repair of the boiler or flues,
in such a position as to take again its proper proportion of the weight
of the boiler. Cases have been met with where the shape of the bottom
of large boilers has been quite altered by such means. The brackets
on the sides of heavy boilers have not only been strained so that the
rivets or bolts have leaked and caused corrosion, but they have also
bent or cracked the side plates of the boiler. The bracket shown at B
in Fig. 53, page 40, made of only an angle iron with a piece of plate
attached, is especially liable to cause injury if the brickwork is not
rebuilt close up to the angle iron, as the leverage is so great. This
is avoided by the better form of bracket shown at C, consisting of an
elbow of flat bar-iron rivetted at top and bottom to the boiler.
[Illustration: _Fig. 68._]
In the old balloon and wagon boilers, the angle where the bottom joined
the sides scarcely ever remained sound for long when in contact with
the brickwork, and many of those that exploded have been found almost
corroded through where they stood upon the brickwork. The explosion
before alluded to and shown in Fig. 7, was caused by corrosion of the
bottom of the boiler where it was set on the brickwork. Many boilers
are so set that the brickwork of the flues is made to follow the shape
of the boiler, with as little space between as possible; but the slight
advantage gained in increased heating effect is far outweighed by the
impossibility of getting into the flues for examination. It is only
by having the flues sufficiently roomy that proper examination can be
made, and that the indications on the brickwork of leaking can be seen
and remedied, and corrosion arrested. A remarkable case of corrosion
occurred in a boiler with an oval shell, set upon a middle wall. The
flues were too narrow for a man to enter, and a leak in the bottom was
only discovered by the boiler nearly running empty while the engine
pumps were standing for a short time. It was subsequently found that
the whole bottom where it rested on the wall was extensively corroded
in a continuous line, and that explosion was only prevented by the
numerous stays across the bottom to compensate for the oval shape. Fig.
68, shows the position and extent of the corrosion, and the plate was
completely in holes at the parts indicated by the black marks. This
corrosion was supposed to have been going on for about three years.
[Illustration: _Fig. 69._]
[Illustration: _Fig. 70._]
It is sometimes asserted that corrosion cannot be the cause of an
explosion, because the corroded place would simply give way and let off
the steam harmlessly, or at least the boiler would not be displaced
from its seating. When the corrosion is only local, and surrounded by
sound plates of sufficient strength to arrest the extension of the
fracture, this may be the case, as in an explosion at Sheffield in
1865, shown in Fig. 69, where a piece of plate was blown out on one
side of the boiler, allowing the steam and water to escape without
displacing the boiler; the thickness of the plate at that part had
been reduced to 1/8th inch by corrosion in about 1-1/2 years, which
had been caused by leakage at the seams from inefficient repair with
bolts instead of rivets, and also from the moisture having been allowed
to be kept against the plate by the brickwork. But even under such
circumstances, if the piece blown out should be from the bottom, the
whole boiler may be thrown a great distance by the reaction of the
issuing steam, as in an explosion at Leeds in 1865, shown in Fig. 70.
If the corrosion extends for any length, the first rent is almost
sure to continue until a complete explosion is the result. Several of
the small models exhibited to the meeting showed the line of fracture
in various cases of explosion. One showed the appearance of a plain
cylindrical boiler after explosion caused by corrosion along the whole
length where it rested on brickwork; this explosion occurred at Wigan
in 1865, and a sketch of it is given in Fig. 71.
[Illustration: _Fig. 71._]
Many explosions of boilers have been caused by accumulation of scurf.
The mischief is not so much from scurf being gradually deposited all
over the interior of the boiler to a dangerous thickness as from the
chips off the sides falling in heaps on the bottom. The plate beneath
this accumulation becomes overheated, because not in contact with the
water, and softens and sinks down into a "pocket," which if unnoticed
will soon burn quite through. If the scurf that has caused the mischief
is thick and hard enough to resist the pressure for a little time,
the hole enlarges, until the scurf suddenly gives way and allows the
contents to issue so violently as to disturb the boiler, or at least
to blow the fire out of the grate. Such was an explosion at Bilston
in 1863, where a large plain cylindrical boiler, 9 ft. diameter, was
heated by three large fires placed side by side along the bottom;
and a large "pocket" burst out over the third grate, and scalded the
attendant to death. A similar pocket in a boiler, 4 ft. 6 ins. diameter,
which exploded at Dudley in 1864, after having been at work six weeks
without cleaning, is shown in the transverse section, Fig. 72. In this
case the scurf had filled up the circle of the boiler to a depth of 3
inches at the bottom, as shown in the drawing, and was of a very hard
description; and the boiler plate was bent out in a gradual curve, and
thinned to about 1/16 inch, the original thickness being 1/2 inch.
[Illustration: _Fig. 72._]
[Illustration: _Fig. 73._]
The whole bottom of a boiler is sometimes injured, and the plates
buckled and the seams sprung, from the accumulation of mud. One case
may be mentioned where the water was very full of mud, and the boilers
were worked day and night during the week but stopped for several hours
on Sunday, during which time the deposit of mud was so thick that it
did not get thoroughly disengaged again from the bottom when the boiler
was set to work, but hardened into a mass. Although many of these
pockets and injuries to the plates may occur without serious damage,
they sometimes cause that first rent which destroys the equilibrium of
the structure and leads to explosion. Some of the specimens of scurf
exhibited to the Meeting show that their thickness is made up of small
chips, carelessly left after cleaning or fallen from the sides of the
boiler, as seen in Fig. 73, or from cotton waste or other matter left
in the boiler and forming a nucleus for the scurf to accumulate upon.
Other specimens show that foreign matter must have been put into the
boiler to stop leaking.
Accumulations of scurf in the feed pipes at the point of entrance into
the boiler have also caused explosion by stopping the supply of water.
The same result is caused by the freezing of the water in the pipes
which are exposed, and each winter one or two boilers are injured or
exploded from this cause, especially small household boilers placed
behind kitchen grates. Scurf cannot be considered so great an evil as
corrosion, since it can be removed, and if this is done in time, the
boiler is restored to its original condition.
The advantage of a pure water, which does not deposit scurf, is so
great for the supply of boilers that it is always worth while to
go to considerable expense for obtaining it; or to take some steps
for purifying the feed water as much as possible. If it is only mud
mechanically suspended, which would deposit by gravity on the bottom
of the boiler, frequent use should be made of the blow-off apparatus.
If the impurity is light enough to be carried to the surface in the
form of scum, the blow-off apparatus should discharge from the surface
of the water as well as from the bottom. If the impurity is chemically
suspended in the water, some one of the many substances which form
the refuse from various manufactures, and which may contain suitable
ingredients, should be used to counteract the effect of the impurity.
Common soda will answer the purpose perhaps better than anything else.
It must not be forgotten however that the blow-off apparatus must
afterwards be used more frequently, to rid the boiler of the foreign
matter, or the mischief will be increased. In marine boilers, constant
attention is necessary to get rid of the saline deposit; and in
stationary boilers using impure water an equally systematic attention
is needed to get rid of the earthy deposit.
* * * * *
Perhaps no cause of explosion is oftener mentioned than shortness
of water, and this is not unfrequently coupled with turning on the
feed suddenly into an overheated boiler. Many explosions have been
attributed to this cause, when closer investigation would have
revealed some far more probable reason. For instance, shortness of
water was stated as the cause of the explosion, at Abercarn in 1865,
of a single-tube boiler with a very large flue tube, which collapsed
upwards from the bottom. The top of the tube and the sides of the shell
had not the slightest mark of overheating, although exposed to the
flame of three furnaces, one of which worked through the tube, and the
others on each side of the shell. In this case the cause of explosion
was clearly the weakness of the tube, and not shortness of water. It
is erroneous to suppose that if a boiler runs dry, or if the feed is
turned into a red-hot boiler, there must necessarily be an explosion.
If a boiler unconnected with any other runs rapidly empty, from the
breaking of the blow-off pipe or any such cause, it will simply get
red-hot and sink out of shape upon the fire, as may often be seen, but
no explosion would happen. If the water only falls gradually, as it
would if the feed were turned off and evaporation continued, the parts
exposed to the fire would get overheated as the water left them. If the
subsidence of the water were very slow, those parts might get red-hot,
and so much softened and weakened as to be incapable of bearing the
pressure, when an explosion would take place, as at Smethwick, in the
present year, where the flues were set above the water line, as shown
in Fig. 74.
[Illustration: _Fig. 74._]
If however the water were turned on again before the overheating had
gone so far, and the feed pipe were, as usual, carried down to nearly
the bottom of the boiler, the water would gradually creep up the heated
sides and cool the plates, the heat of which would not be sufficient
to cause greater evaporation than the ordinary safety valves would
carry off. The danger would not arise so much from the excess of steam
generated by the heat accumulated in the heated plates of the boiler,
as from the injury and strain that would be caused to the plates by
the undue expansion and sudden contraction, especially as this action
would take place on only a portion of the boiler. A singular case,
bearing on this point, may be mentioned. A four-furnace upright boiler,
like that shown in Fig. 44, happened to run so nearly empty, through
the accidental sticking of the self-acting feed apparatus, that the
level of the water sank to the top of the hemispherical end forming
the bottom of the boiler. The feed apparatus then became released of
itself, and, the feed being turned full on, the water gradually rose
until the whole occurrence was only discovered by the leaking at the
seams that had been sprung, which caused so much steam in the flues
as to stop the working of the furnaces. The overheating had been
sufficient to buckle the plates, and in one place a rupture had almost
commenced; but there was no explosion. By way of direct experiment upon
this point, boilers have been purposely made red-hot and then filled
with cold water, without causing explosion.
It has been supposed that boilers sometimes explode from overheating
without the water level being below the usual point, or without
the accumulation of scurf previously alluded to, but simply by the
rapidity of the evaporation from an intensely heated surface causing
such a continuous current of steam as to prevent the proper contact
of the water with the heated plate. Such has been the cause assigned
for the explosion of a three-furnace upright boiler at Birmingham in
1865, shown in Fig. 75. A piece of plate about 3 ft. by 1-1/2 ft. was
blown out of the side, at a place where an enormous flame impinged
continually. The plates had first bulged out, and then given way in the
centre of the bulge, each edge being doubled back and broken off. There
was no positive evidence as to the water supply; but the crown of the
centre tube, which was much above the bottom of the part blown out,
remained uninjured.
A somewhat similar case was that of a large horizontal boiler at
Kidderminster, the tube of which collapsed in 1865, as shown in Fig.
76. It was heated by four furnaces, one of which worked into the tube,
one under the bottom, and one on each side; and all the furnaces worked
into the same end of the boiler. The tube was found to have partially
collapsed at that end, and the top had dropped 11 inches. This was
repaired in the first instance, but was afterwards again found injured
by overheating, although not so seriously. It is very probable that the
extremely rapid ebullition from the sides and bottom, from which the
steam had to pass up the narrow space between the tube and the shell,
produced such a foaming that very little solid water could reach the
top of the tube where it was exposed to extreme heat.
[Illustration: _Fig. 75._]
[Illustration: _Fig. 76._]
Many explosions have been attributed to deterioration of the iron
through long use, as in an explosion at Durham in 1864, and another at
Haswell, near Sunderland, 1865, where the boilers had worked constantly
for 25 and 30 years respectively. When an explosion arises from the
failure of a plate which has not been properly welded in rolling,
there is no question that it was unsound when put in, and escaped
notice; but when the plate that fails is found to be brittle and of
bad iron, the fault is rather attributed to the effect of working than
to original bad quality. Of course this is not always the case, as
the injury done to plates by overheating has been already explained.
Pieces of plate have in some cases been erroneously pronounced to be
deteriorated by work, which have been taken from situations in the
boilers where they were not exposed to any action of fire that could
cause overheating; and therefore in reality the injury could only have
taken place when the boiler was being made, by burning the iron in
bending it to the required shape. A frequent cause of fatal injury to
boilers is injudicious repair, whereby the crossing of the seams is
destroyed, as in the explosion at Wolverhampton in 1865, previously
referred to and shown in Fig. 36. Moreover the edges of the old plates,
already tried by the first rivetting and the subsequent cutting out
of the rivets, are frequently strained again by the use of the drift
to draw them up to the strong new plates; and many a seam rip is thus
started which ultimately causes explosion.
Many explosions have been caused by the want of proper apparatus for
enabling the attendant to tell the height of the water and the pressure
of the steam, and also by the want of sufficient apparatus for supply
of feed water and escape of steam, or by the failure of one or other
of these; but such explosions can only be referred to generally in
the present paper. The mountings on a boiler are usually so open to
observation, and the importance of having them good and efficient is
so universally acknowledged, that much remark is not needed. Mention
has already been made of the sticking of self-acting feed apparatus as
a cause of mischief, and similar failures of floats and gauges have
constantly happened; but this should by no means be considered to
condemn self-acting apparatus, either for assisting in the steadiness
of working, or for giving warning of danger. The apparatus however
should be relied on for assistance only; and an attendant cannot be
called careful who leaves a boiler dependent on such apparatus without
watching. The self-acting principle has been seen by the writer applied
in a novel and useful way in a recording pressure gauge, which proved
the more interesting as it had shown the actual pressure of steam
at the time of the explosion of one of the boilers with which it was
connected.
Among the numerous boiler explosions that have been attributed to
over-pressure through deficient arrangements for escape of steam, in
many cases the safety valves have been placed on the steam pipes in
such a manner that the communication with them was cut off whenever
the steam stop-valve was shut, which is just the time when the safety
valves are most wanted. Safety valves are too often found needlessly
overweighted; and it is believed that many boilers are constantly
worked with safety valves so imprudently arranged and weighted, that
they could not carry off all the steam the boilers would generate
without a very great increase of pressure.
* * * * *
It is concluded that enough has now been said to show that boiler
explosions do not arise from mysterious causes, but generally from some
defect which could have been remedied if it had been known to exist. It
only remains therefore to consider what is the most ready and efficient
way to discover the true condition of a boiler. It has been maintained
that this end is best accomplished by what is called the hydraulic
test, in which a pressure of water is maintained in the boiler for a
given time at a certain excess above the working pressure. This test
is undoubtedly useful so far as it goes, and is perhaps the only one
that can be applied to boilers with small internal spaces, such as
locomotive boilers, not admitting of personal inspection over the whole
of the interior; and it is also admirable for testing the workmanship
of a new boiler. But on the other hand the conditions of a boiler at
work are so different from those which exist during the hydraulic test,
that this alone cannot be depended on; for old boilers have been known
to stand this test to double their working pressure without apparent
injury, although known to be dangerously corroded. The difficulty also
of seeing or measuring the effect of the hydraulic test upon large
boilers set in elaborate brickwork is so great that little practical
benefit has resulted in many cases.
It is believed by the writer that the surest way to ascertain the true
condition of a boiler is to examine it at frequent intervals in every
part, both inside and outside; and as this can only be done when both
the boilers and the flues can be readily entered, it is specially
important that facility for examination should be made a consideration
in selecting a construction of boiler. Permanent safety should be
considered as an element of economy, in addition to its still higher
importance in reference to the preservation of life.
ON THE CONCLUSIONS DERIVED FROM THE EXPERIENCE OF RECENT STEAM BOILER
EXPLOSIONS, BY EDWARD B. MARTEN, MEM. INST. M.E., EXCERPT MINUTES OF
PROCEEDINGS OF THE MEETING OF THE INSTITUTION OF MECHANICAL ENGINEERS,
AT NOTTINGHAM, 3RD AUGUST, 1870, THOMAS HAWKSLEY, ESQ., VICE-PRESIDENT,
IN THE CHAIR. BY PERMISSION OF THE COUNCIL.
The records of Steam Boiler Explosions in recent years are very
numerous, as the increased attention drawn to the subject in this
and other countries has placed far more information at disposal; and
the experience of the last four years, since a former paper was read
by the writer on the subject of boiler explosions, has confirmed the
opinion then expressed, that all boilers, however good in original
construction, are liable in the course of time to get into bad order
and explode. The particulars of the explosions during this period
are given in the Tables appended to the present paper, which show
the number of explosions due to each cause in each class of boiler,
distinguishing those of the United Kingdom from those in foreign
countries. An analysis is also given of the explosions in the last four
years, showing the causes of explosion of each form of boiler; and also
a summary of the causes of explosion under the three general heads
of--(1) faults in construction or repair: (2) faults in working which
creep on insidiously and unnoticed: (3) faults which might be seen and
guarded against by careful attendants. Nearly all of the faults in
these three classes would have been detected by periodical examination.
* * * * *
In the case of Cornish, Lancashire, and other boilers with internal
flues, the faults of construction which have caused explosions have
been weakness in the tubes, combustion chambers, ends, domes, or
manholes; and explosions in these, as in other classes of boilers,
have also resulted from external or internal corrosion, shortness of
water, undue pressure of steam, and scale or mud on the boiler plates.
In plain cylindrical boilers, and others without internal flues,
explosions have resulted from the boiler ends being made flat, and also
from frequent repairs producing seam rips, especially in boilers having
the plates arranged lengthways instead of in rings.
In marine boilers, weak flues and weak ends have also led to explosion,
in addition to the other causes mentioned above.
Locomotive boilers have in two cases exploded in consequence of the
strains thrown upon them by their being used as a frame for the engine.
Other explosions have resulted from want of stays, and from too much
heat impinging on some particular part; and in domestic boilers from
freezing of pipes under pressure.
* * * * *
Altogether the total number of explosions in this country that have
been recorded during the past four years has amounted to 219, which may
be classed under the following heads:--
Faults of construction or repair 95
Faults to be detected only by periodical examination 62
Faults which should be prevented by careful attendants 54
Extraneous or uncertain causes 8
---
Total 219
---
By these 219 explosions 315 persons were killed and 450 injured.
The following are the particulars of the construction of the 219
exploded boilers:--
Cornish, Lancashire, or other boilers with internal flues 84
Plain Cylindrical boilers or others without internal flues 54
Marine boilers 12
Agricultural boilers 11
Locomotive boilers 10
Furnace-upright boilers 8
Crane boilers 6
Rag steamers, &c. 6
Balloon and Elephant boilers 5
Domestic boilers, &c. 16
Not sufficiently described 7
---
Total 219
---
The causes of these 219 explosions may also be classed as follows:--
Worn out, corroded, or burnt plates 89
Undue pressure, overloaded valves, intentional or from carelessness 25
Bad construction, defective fittings or stays, or want of repair 69
Shortness of water, formation of scale or mud, or external flues
set too high 28
Extraneous or uncertain causes 8
---
Total 219
---
Sketches are given of the most instructive examples of boiler
explosions during the last four years, which are sufficient to explain
themselves, with a brief reference to their special features.
* * * * *
[Illustration: _Fig. 1._]
Although the importance of periodical examination as the best safeguard
against explosion is generally admitted, a great number of those who
make or use boilers have not at present sufficient belief in its
importance to adopt this course. Boilers are still constructed or set
in such a manner as to render examination next to impossible; and are
continued to be worked without making it the duty of those who mind
them, or of any one else, to examine every part at frequent intervals;
and hence such explosions have occurred as shown in Fig. 1, No. 12,
1870, in which the original position of the boiler before explosion is
indicated by the dotted lines. It is thought by many steam users that
all has been done which is possible, if their boilers are the best that
can be procured, and are set in the most approved way; and it is taken
for granted that such boilers should last for many years, under the
idea that a good boiler can never explode unless the feed is neglected.
Similar boilers are often referred to as having worked safely for ten
or twenty years, but it is forgotten that they may be exposed to the
insidious action of furrowing on the inside or channelling on the
outside, such as caused the explosions of the originally good boilers
shown in Figs. 2, 3, 4, and 5, Nos. 35, 1870; 50, 1866; 46, 1869; and
25, 1870.
[Illustration: _Fig. 2._]
[Illustration: _Fig. 3._]
Much mischief arises from special classes of boilers, fittings, or
apparatus, being looked upon as promising permanent safety from
explosion; while the inevitable circumstance is overlooked that it is
only so long as everything is maintained in good condition that safety
is insured. An apparatus, for instance, for preventing explosion from
shortness of water or over-pressure, however perfect for any such
object, would be quite inefficient as a safeguard against explosion
from corrosion, furrowing, channelling, or weak construction. It is
curious to note how often it is the case that every other part of an
establishment is subject to severe and perpetual scrutiny, the engines
especially being overhauled with the most scrupulous regularity; while
the boilers, the very source of the power and the heart of the whole
business, are left to themselves for long periods, even for years,
without examination; and it is too often only after bitter experience
that owners have understood the need of this examination. In this, as
in many other matters, experience has shown that there is no royal road
to safety, and that immunity is only secured by unremitting care and
constant watchfulness. It should never be forgotten that even a good
boiler can explode; for however good at the outset, sooner or later
the time must eventually arrive, when such wear and tear will have
taken place as will result in dangerous weakness, unless the boiler is
carefully and systematically attended to. Although a boiler may even
last safely for ten to thirty or more years if worked slowly and with
care, no confidence can be placed in a boiler which has worked so long,
unless it is examined in every part.
[Illustration: _Fig. 4._]
[Illustration: _Fig. 5._]
[Illustration: _Fig. 6._]
[Illustration: _Fig. 7._]
The opinion is more general than many are aware of, that explosions
as a rule are caused by shortness of water and the sudden turning on
of the feed water upon red-hot plates; and the appearances of injury
in the plates from fire, arising in the ordinary course of working,
have been frequently mistaken for signs of overheating from shortness
of water at the time of explosion, as illustrated in Figs. 6 and 7,
No. 24, 1867, and No. 59, 1866. Although boilers do explode from the
softening of the plates by overheating in consequence of shortness
of water, yet it is very doubtful whether the turning on of the cold
water at such a time is ever the cause of explosion. The feed water
being always introduced at the bottom of the boiler, as in Figs. 8, 9,
and 10, cannot be scattered suddenly near the overheated parts, but
must rise gradually up the sides; and the boiler would have gone to
pieces from the giving way of the softened parts long before the water
reached them, as was the case in the explosions shown in Figs. 11 and
12, end of 1868. The experiment of injecting cold water into red-hot
boilers has been carefully tried more than once, without producing any
explosion.
[Illustration: _Fig. 8._]
[Illustration: _Fig. 9._]
[Illustration: _Fig. 10._]
Although it may be too much to suppose that boiler explosions will ever
be entirely prevented, it is important that those who have the care of
boilers should understand better what are the true causes of explosion,
in order that they may know what to guard against in addition to
shortness of water. This better understanding of the subject has been
much retarded by the supposition that the causes of boiler explosions
are beyond the comprehension of the boiler minders; and still more by
the important differences of opinion among those under whom they work.
Much evil has resulted from the promulgation of strongly expressed
views, which have been founded upon facts but of too limited extent,
and such as must become modified by consideration of the facts of
a large number and variety of explosions. Mysterious theories to
account for explosions have been resorted to only from want of clearer
explanations.
[Illustration: _Fig. 11._]
[Illustration: _Fig. 12._]
[Illustration: _Fig. 13._]
[Illustration: _Fig. 14._]
Before considering in detail the causes of explosion, it is necessary
to recall to mind that beyond question there is sufficient accumulated
force in any working boiler to cause all the violent effects of an
explosion, if this force be suddenly liberated. In Figs. 13 and 14,
No. 18, 1869, and No. 63, 1866, are shown the violent effects of the
rupture of vessels employed for steaming rags, which were filled with
steam only. In ordinary boilers however there is present, besides the
steam, a quantity of water heated much beyond the atmospheric boiling
point; and when rupture takes place and the pressure is suddenly
relieved, part of this water evaporates, and keeps up the supply of
steam to continue the rupture and destruction. The explosion of a
boiler differs from the discharge of electricity or lightning, which
cleaves the air and instantly leaves a vacuum; it also differs from
the discharge of detonating compounds which act suddenly and leave a
vacuum; but it more nearly resembles the discharge of gunpowder, which
burns sufficiently slowly to keep up a continuous pressure behind a
projectile until it leaves a gun; and each cubic foot of water in a
boiler working at 60 lbs. pressure has been shown to produce in steam
an explosive effect equal to one pound of gunpowder. None of the
elaborate but unlikely theories of decomposed steam, or of electric
accumulations, suppose a force so fitted to cause destruction as that
contained in the highly heated water existing in all working boilers.
* * * * *
The following appear to be the general results to be derived from the
experience of the explosions in this country during the last four years.
[Illustration: _Fig. 15._]
[Illustration: _Fig. 16._]
First as to faults of construction which fall under the department
of the boiler maker or repairer. One of the most apparent causes of
explosion in stationery boilers is the loss of strength occasioned by
frequent repair, not only from the injury done to the old plates by
removing rivets, but from the want of bond in the new work. This has
lead to many of the explosions of the Plain Cylindrical boilers, such
as are shown in Figs. 15, 16, and 17, No. 45, 1869, No. 32, 1870, and
No. 20, 1870. Where the plates are arranged longitudinally instead
of in rings, the danger is increased, as there is less chance of a
dangerous rip being arrested by a crossed joint. So great a number of
boilers with continuous longitudinal seams, especially in the North,
have worked for twenty or thirty years, that it can hardly be supposed
they are any weaker than the boilers made in rings; but they are more
liable to explode, for if a seam rip occurs, it more easily extends
along the seam, and leads to the general break up of the boiler, shown
in Fig. 18, No. 59, 1869.
[Illustration: _Fig. 17._]
[Illustration: _Fig. 18._]
Perhaps no boilers have worked for a greater number of years than
the Plain Cylindrical boilers, many specimens being in existence and
apparently in good order which were put to work fifty or sixty years
ago. When such boilers have been too much or injudiciously repaired,
they are treacherous and uncertain; but their rupture and explosion
occur not so much on account of fault of shape, as from the simple
reason that like willing horses they are easily overworked. The grates
are usually twice as large as the fair proportion to the heating
surface, producing the double evil of forcing more heat through the
iron plates over the fire than they can transmit without injury, and
allowing a great amount of heat to pass away to the chimney without
useful effect. Careful experiment shows that nearly as good duty can
be obtained with the plain cylindrical boiler as with any other form,
provided the rate of combustion is in fair proportion to the extent
of heating surface in the boiler. The circumstance that many plain
cylindrical boilers have exploded is not sufficient to condemn this
make of boiler, which is the cheapest, simplest, and most easily set.
If the number of explosions alone were to be taken as the guide, it
would lead to the condemnation of the Cornish and Lancashire boilers,
from the experience of the past four years. But in case of both plain
cylindrical and other forms of boilers, most of the dangers admit of
remedy, and can be guarded against by frequent examination.
[Illustration: _Fig. 19._]
[Illustration: _Fig. 20._]
Five very fatal explosions have occurred of boilers heated by Puddling
and Mill Furnaces, leading in some cases to the supposition that this
form of boiler is more liable to explosion than others. They were not
adopted however in the iron-making districts without great care and
consideration, and there does not seem ground for attributing special
danger to them. The causes of the five explosions referred to of these
boilers were manifest, and would have led to the explosion of any form
of boiler; the loss of life however was great, because the situation
of the boilers was among a large number of workmen. The steam power
required in ironworks so far exceeds that in any other trade, that
an ironwork is half composed of boilers; the workmen are necessarily
within the range of explosion of many boilers, and hence the great loss
of life when such an accident occurs. The explosions of such boilers
shown in Figs. 19 and 20, No. 24, 1868, and No. 31, 1868, were from
external and internal corrosion respectively of the bottoms, rendering
them too weak to bear the ordinary pressure.
[Illustration: _Fig. 21._]
[Illustration: _Fig. 22._]
[Illustration: _Fig. 24._]
Those shown in Figs. 21 and 22, No. 23, 1870, and No. 53, 1869, were
from the collapse of the central tubes, which were weakened by external
and internal corrosion respectively. In Fig. 24, No. 35, 1868, the
shell was in bad order from over work and receiving too much heat from
four large furnaces, one of these especially causing a constant mass of
flame to impinge upon a single plate, which resulted in a seam rip.
[Illustration: _Fig. 23._]
[Illustration: _Fig. 25._]
[Illustration: _Fig. 26._]
[Illustration: _Fig. 27._]
The greatest number of explosions and the greatest loss of life and
personal injury have been in the case of Cornish and Lancashire
boilers, or others with internal flues. In the county of Cornwall
itself there have been many explosions, as often from the rupture of
the shell, Fig. 23, No. 58, 1869, as from the collapse of the tube,
Fig. 25, No. 35, 1869. The temporary patching on some of these old
boilers was most extensive, Fig. 26, No. 52, 1869, and the only wonder
really was that they held together as long as they did. The belief that
shortness of water is the only cause which can lead to the collapse of
tubes is so strong, that the boiler minders have often been condemned
almost unheard in cases of explosion, as if there were no room for
doubt that their neglect was the cause. Explosions from weakness of
tubes are not however confined to Cornwall, as for example in Fig.
27, No. 42, 1868, where the flue was oval and very weak: although it
was supposed that shortness of water caused the accident, from the
idea that nothing else could account for it. The strain caused by the
varying temperature of the internal tubes in Cornish or Lancashire
boilers, and the difficulty of staying their flat ends so as to make
them sufficiently secure without being too rigid to allow for the
expansion of the tubes, render them liable to corrosion or "furrowing"
in particular lines of strain, the destructive action of which is
very rapid; while the large quantity of brickwork around the outside,
necessary to form the external flues, also renders them liable to
corrosion in the parts most difficult of access. In this favourite
form of boiler therefore careful and frequent examination in every part
is more needed than in boilers of simpler form and setting; and the
increasing number of explosions among these boilers seems to establish
that they are only trustworthy if frequently examined and kept in
perfect order.
[Illustration: _Fig. 28._]
[Illustration: _Fig. 29._]
[Illustration: _Fig. 30._]
Several instances have occurred of explosion of Portable Crane Boilers.
Their small size has led to their condition being disregarded, under
the idea that scarcely any pressure could burst them. In practice it
is found however that they are often exposed to greater pressure than
other boilers, because the fire is large and quick in proportion to
their size; and they often have to stand for a considerable time with
the steam up, and their exposed position and long intervals of rest add
to the chances of corrosion, as shown by the example in Fig. 28, No.
14, 1869. The large manholes without strengthening rings, that are so
often put in these boilers, have been the cause of explosions such as
that shown in Fig 29, No. 57, 1866.
[Illustration: _Fig. 31._]
The same remark applies to some of the portable or agricultural
boilers which have exploded, such as those shown in Figs. 30 and 31,
No. 43, 1868, and No. 12, 1869.
Much mischief is often caused by bad imitation of well planned boilers.
Thus in boilers of the Cornish form, the ends are made sometimes so
rigid as to give no allowance for the expansion of the tube, and the
result is such continued strain as to cause constant leaking and the
consequent risk of fracture. In furnace boilers the tops of the crowns
of the inside tubes are often made flat, as in Fig. 37, instead of
being domed; or the inside tube is of undue size, as in Fig. 21, No.
23, 1870, see page 73. Furnace boilers have been made with the omission
of the stays that are so peculiarly necessary in that form, whereby
both ends have been left free to bulge outwards with the pressure, as
in Fig. 32.
[Illustration: _Fig. 37._]
[Illustration: _Fig. 32._]
[Illustration: _Fig. 33._]
[Illustration: _Fig. 34._]
[Illustration: _Fig. 35._]
Cornish boilers are often altered to the plain cylindrical form,
without compensation being made for the loss of strength caused by
the removal of the tube; this has led to such explosions as shown in
Fig. 33, No. 47, 1869, where two tubes where taken out, and Fig. 34,
No. 42, 1867, where one tube was taken out. One of the most frequent
and serious causes of loss of strength is the repairing of externally
fired boilers. Not only are the patches sometimes only bolted on in a
temporary manner, as in Fig. 35, No. 29, 1869, but even where they are
rivetted on there is an entire want of bond or crossed joint, as in the
case of the exploded boilers shown in Figs. 15, 16, and 17, see page
70 and 71, No. 10, 1869, and Fig. 36.
[Illustration: _Fig. 36._]
[Illustration: _Fig. 38._]
An attempt is made in Fig. 38 to show the effect of wear and tear
of boiler plate in an ordinary upright furnace boiler, such as is
shown in Fig. 37. The external surface is exposed to intense heat
and consequently expands, while the internal surface is kept cool by
contact with the water and expands to a much less degree. The continued
repetition of this process produces the same effect of cracking the
surface as that seen in the anvil blocks of steam hammers; and the
strength of the plate is reduced in proportion to the destruction of
the continuity of its surface. The deleterious effect of this process
is much increased if the boiler is subject to alternate heating
and streams of cold air on opening the fire-doors. To avoid it the
flame should have room to spread over as large a surface as possible,
without impinging on one particular point, and the firing should be
as regular as possible; and hence the greater freedom from injury in
boilers mechanically fired or heated by gas. The above action is quite
distinct from the overheating of the plates that occurs when no water
is in contact with them, which simply softens them and reduces their
strength, as in Fig. 39. It is believed that many boilers suffer from
overheating without being short of water: and an attempt is made to
show this action in such an upright boiler as is represented in Fig.
37, page 78, by the enlarged section of the side shown in Fig. 40.
The flame is shown impinging on a limited surface, as before, and
the steam rises so rapidly from the inner surface as to maintain a
continuous stratum of steam between the iron and the water, and the
plate consequently becomes overheated at that part. When the intense
flame subsides by an alteration of the working of the furnace, the
stream of steam diminishes, and the water returns and suddenly cools
and contracts the plate, but often not before it has commenced to get
out of shape. This has perhaps led to the explosion shown in Fig. 59,
No. 37, 1868, page 82. The same thing may happen to the crowns of tubes
of internally fired boilers when over fired, as in Fig. 41. Success
has attended the use of internal linings to boilers, arranged so as
to ensure a rapid circulation over the most heated parts, and also to
catch all the mud and loose scale.
[Illustration: _Fig. 39._]
[Illustration: _Fig. 40._]
[Illustration: _Fig. 59._]
[Illustration: _Fig. 41._]
[Illustration: _Fig. 42._]
[Illustration: _Fig. 43._]
[Illustration: _Fig. 44._]
In order to enable boiler minders to make proper periodical
examinations, it is necessary that care should be taken to arrange
both the boilers and the flues with that view; and this can be done
without materially injuring the efficiency of the boiler. Ordinary
plain cylindrical boilers can be entered easily, as in Fig. 42; and
although the small spaces between the tubes and the shells of Cornish
and Lancashire Boilers, as shown in Fig. 43, render the complete
examination troublesome, there is no difficulty in seeing those parts
most likely to need examination, such as the crowns of the tubes and
the end plates and angle iron. It is in the external flues that greater
accommodation is needed, as in many cases these are so narrow that the
boiler is quite inaccessible without pulling down the brickwork, as in
Figs. 44 and 45. The loss of heating effect caused by the use of wider
flues is so little, that it is far outweighed by the greater security
obtained from the more efficient examination that is thereby rendered
practicable. The flues of the plain cylindrical boiler are easily
made wide enough for a man to pass through them. The flues of Cornish
and Lancashire boilers should be made as shown in Figs. 46 and 47, so
that a man can enter them without such inconvenience as in Fig. 48.
One point of danger being the use of wide mid-feather walls, on which
corrosion is apt to take place, these should be narrowed and the weight
of the boiler supported on side brackets; the top of the mid-feather
and side walls can then be constructed with sight holes as at A A in
Figs. 49 and 50, so as to give the means of examining the plates near
each seam by simply removing loose bricks.
[Illustration: _Fig. 45._]
[Illustration: _Fig. 46._]
[Illustration: _Fig. 47._]
[Illustration: _Fig. 48._]
[Illustration: _Fig. 49._]
[Illustration: _Fig. 50._]
[Illustration: _Fig. 51._]
[Illustration: _Fig. 52._]
[Illustration: _Fig. 53._]
[Illustration: _Fig. 54._]
[Illustration: _Fig. 55._]
The explosions of fourteen Domestic or Heating-Apparatus Boilers are
included in the list of explosions, Table III; and some notice is
required to be taken of these, because they have led to the loss of the
lives of those who could not be expected to know their construction or
how to guard against accident; and as these boilers are seldom seen or
examined after they are once set, they should be the more carefully
constructed. In one or two cases these boilers were of a rectangular
shape, as in Fig. 51, No. 41, 1868, ill adapted to bear internal
pressure, and yet placed in connection with cisterns in the roofs of
lofty houses, so as to expose them to a hydrostatic pressure almost
up to their bursting strength without any addition of steam pressure.
The most usual cause of explosion is the lighting of the fire during
frosty weather in a house that has been left vacant, so that steam
pressure accumulates in the boiler whilst the exit is frozen up, as was
the case in Fig. 52, No. 6, 1870. The cast-iron boilers commonly used,
Fig. 53, end of 1869, are capable of bearing but little pressure; and
the wrought iron boilers, as in Fig. 54, No. 7, 1870, are found often
so badly welded as to be but little stronger; but even if they were as
strong as they could be made, the stoppage of the pipes by ice would
lead to explosion. Steam pressure may be guarded against by a safety
valve; but as this may become set fast in a little time, it would
be far better to avoid all chance of steam accumulation by such an
arrangement as that shown in Fig. 55, where the circulating boiler is
placed within an open-topped boiler behind the kitchen fire, and only
receives its heat through the hot water surrounding it, and therefore
cannot itself become sufficiently hot to generate steam.
* * * * *
[Illustration: _Fig. 56._]
A few remarks may be useful as to those faults arising in working
which fall under the department of the boiler minders. Not a few of
the explosions during the last four years have occurred from acts of
simple carelessness, such as where a blow-off pipe was left open,
so that the boiler was nearly emptied of water while at work; or in
another case where two boilers were fed at the same time through a
common pipe without a back valve, and the water from one "kicked" over
into the other. Undue pressure has been allowed to accumulate by safety
valves being tied down, as in the agricultural boiler, Fig. 56, No. 16,
1867; or by an extra weight being put upon the safety valve, as in an
instance where three bricks were fastened to the lever and the fires
were lighted earlier than usual, under the idea that an accumulation
of steam could be raised during the night to make a good start in the
morning. Another explosion was caused by working a boiler at more than
three times its proper pressure to meet a temporary emergency. In not a
few cases of explosion there was no pressure gauge on the boiler, or
the gauge was out of repair in consequence of being placed on the steam
pipe, so that it vibrated with every stroke of the engine; as in the
examples shown in Figs. 24 and 16, No. 35, 1868, No. 32, 1870, pages 70
and 74.
[Illustration: _Fig. 57._]
Corrosion has been the direct cause of many of the explosions. In one
or two cases the corrosion was known to exist, but the renewal of the
boiler was too long delayed, as in Fig. 57, No. 8, 1869, in others it
took both owners and minders by surprise, as in Fig. 1, No. 12, 1870,
page 63. It is said that to produce rapid rusting of iron there must be
present oxygen, water, and carbonic acid; and as all these are present
in a boiler flue when there are leaks, it is not surprising that so
many cases occur of explosions from corrosion.
* * * * *
Much mischief is often done by the injudicious use of compositions in
the boiler that are designed to prevent incrustation, especially where
there is no blow-off cock or where its use is neglected. A hard deposit
on the boiler plates is, in the writer's opinion, not so injurious as
the soft and muddy deposit produced by the use of such compositions.
A hard scale is equivalent to thickening the plate; and although this
is sufficiently mischievous, the injury to the plates is much more
rapid when a thicker but spongy deposit entirely prevents contact of
the water and impedes the transmission of the heat. An attempt to
illustrate this is given in Fig. 58, which is an enlarged view of a
portion of such a boiler as is shown in Fig. 37. The money spent in
boiler compositions would be better applied in securing a supply of
proper water, or in filtering and purifying the water before it enters
the boiler.
[Illustration: _Fig. 58._]
The writer has had to mention only faults in boilers; but it is not
to be inferred that all boilers are working in actual danger. A very
small percentage perhaps are so; but without periodical examination
no one can feel sure of the condition of any boiler. It is not likely
that explosions in future will be from exactly the same causes as those
now described, because the known faults will be avoided. For instance
no new Balloon, Wagon, or Butterley boilers are now made; and the
peculiar faults and the weakness of the tubes in Cornish and others of
the better classes of boilers are now so well known as to be generally
avoided; and as information spreads, many evils will become things of
the past.
As periodical examination has been so strongly advocated, it might seem
natural to desire that it should be enforced by government authority;
but this is by no means recommended. A select parliamentary committee
has been recently investigating the subject, with a view to ascertain
whether that would be desirable, but has adjourned for the session
without coming to any decision on this point. Even if a perfect
system of government inspection could be contrived and perfectly
administered, it would have the effect of taking the responsibility
from the owners, who are the natural guardians of the safety of their
boilers. Although the loss of 70 lives per annum by boiler explosions
is sufficiently deplorable, the deaths by railway accidents are more
than three times that number; yet very little inspection of railways
is held to be necessary, and that inspection takes place chiefly before
the commencement of working or after accidents. A coercive system
may introduce more evils than it cures, especially as at present so
much difference of opinion exists respecting the causes of boiler
explosions. In the opinion of the writer, far more real good arises
from the calm discussion of the facts and from the spread of correct
information by such societies as this Institution, than from enforcing
by law any action which is not perhaps believed by the majority of
steam users to be at all necessary or useful. It has been at times
suggested to increase the power and responsibility of coroners in
holding inquests upon those killed by boiler explosions, by requiring
them to obtain scientific evidence and to insist that the causes of
the explosions shall be added to the verdicts of juries. But it is
believed that this would only encumber an important institution,
because a jury who might well decide whether a person had been killed
by any criminal carelessness would not be a suitable tribunal to
decide between possibly conflicting scientific evidence; and also,
as an inquest may result in a verdict of manslaughter, the eliciting
of information on such an occasion is checked by the natural fear of
inadvertently involving some one in so serious a charge. The public
at large, and steam users generally, would gain more information and
guidance from the scientific evidence itself than from the verdict
of a coroner's jury; and it is believed much good has resulted in
preventing locomotive boiler explosions by publishing the reports of
the government inspecting engineers, who have gained their knowledge
of the facts in conversation with all those concerned, and have added
recommendations which have been promptly acted upon.
The writer's object has been that the boilers found most convenient and
best suited for the different purposes for which they are used should
be made to work with safety, rather than that reliance should be placed
upon the qualities of any particular kind of boiler or fittings. No
form of boiler at present admits of absolute reliance upon its freedom
from risk.
The following general conclusions appear to arise from the
consideration of the records of boiler explosions.
1. That the force accumulated in an ordinary boiler is enough to
account for the violence of an explosion.
2. That no form of boiler, however well constructed and fitted, is free
from the liability to explosion, if allowed to get out of order; and
that boilers which bear the hydraulic test may still be dangerous.
3. That the condition of a boiler can be satisfactorily ascertained
only by periodical examinations, and that no boiler should work without
being thoroughly examined at short intervals.
4. That the cost of periodical examination is so little as to be far
outweighed by the greater security obtained; and that the settings of
all boilers should be constructed with a view to facilitate examination.
5. That the surest way to make systematic examination general is to
spread as widely as possible correct information as to the facts and
ascertained causes of boiler explosions, and to inform boiler owners
and minders what dangers to guard against; and that this is preferable,
and more likely to lessen explosions than enforcing any system of
inspection by legal enactment.
TABLE I.
_Summary of Records of Steam Boiler Explosions_
_up to 30th June, 1870,_
_showing Description of Exploded Boilers._
+------------------++-----------------------++-----------------------+
| Description of || Explosions up to June || Explosions in the 4 |
| Boiler. || 1866. || years from June 1866 |
| || || to June 1870. |
+ |+--------+--------+-----++--------+--------+-----+
| ||English.|Foreign.|Total||English.|Foreign.|Total|
+==================++========+========+=====++========+========+=====+
|Marine || 57 | 203 | 320 || 12 | 64 | 76 |
+------------------++--------+--------+-----++--------+--------+-----+
|Cornish, || 140 | 1 | 141 || 84 | 3 | 87 |
|Lancashire, or || | | || | | |
|others with || | | || | | |
|internal flues || | | || | | |
+------------------++--------+--------+-----++--------+--------+-----+
|Locomotive || 91 | 29 | 120 || 10 | 68 | 78 |
+------------------++--------+--------+-----++--------+--------+-----+
|Plain Cylindrical || 114 | 2 | 116 || 54 | 3 | 57 |
|externally fired || | | || | | |
+------------------++--------+--------+-----++--------+--------+-----+
|Balloon, || | | || | | |
|Haystack, Wagon, || 62 | 2 | 64 || 5 | 2 | 7 |
|Butterley, || | | || | | |
|British-Tube || | | || | | |
|Elephant, or || | | || | | |
|Trevithick || | | || | | |
+------------------++--------+--------+-----++--------+--------+-----+
|Portable, || | | || | | |
|Agricultural, || 28 | 1 | 29 || 17 | 17 | 34 |
|Upright, Crane, || | | || | | |
|or very small || | | || | | |
+------------------++--------+--------+-----++--------+--------+-----+
|Heating, Kitchen, || 14 | .. | 14 || 22 | 14 | 36 |
|Domestic, Rag || | | || | | |
|Steamers, &c. || | | || | | |
+------------------++--------+--------+-----++--------+--------+-----+
|Furnace-upright || 10 | .. | 10 || 8 | .. | 8 |
+------------------++--------+--------+-----++--------+--------+-----+
|Not sufficiently || 203 | 29 | 232 || 7 | 175 | 182 |
|described to be || | | || | | |
|classified || | | || | | |
+==================++========+========+=====++========+========+=====+
|Totals || 719 | 327 |1046 || 219 | 346 | 565 |
+------------------++--------+--------+-----++--------+--------+-----+
TABLE I (continued)
+------------------++--------------------------+
| Description of || Total Explosions |
| Boiler. || up to June, 1870. |
| |+--------+--------+--------+
| ||English.|Foreign.| Total. |
+==================++========+========+========+
|Marine || 69 | 327 | 396 |
+------------------++--------+--------+--------|
|Cornish, || 224 | 4 | 228 |
|Lancashire, or || | | |
|others with || | | |
|internal flues || | | |
+------------------++--------+--------+--------+
|Locomotive || 101 | 97 | 198 |
+------------------++--------+--------+--------+
|Plain Cylindrical || 168 | 5 | 173 |
|externally fired || | | |
+------------------++--------+--------+--------|
|Balloon, || | | |
|Haystack, Wagon, || 67 | 4 | 71 |
|Butterley, || | | |
|British-Tube || | | |
|Elephant, or || | | |
|Trevithick || | | |
+------------------++--------+--------+--------+
|Portable, || | | |
|Agricultural, || 45 | 18 | 63 |
|Upright, Crane, || | | |
|or very small || | | |
+------------------++--------+--------+--------+
|Heating, Kitchen, || 36 | 14 | 50 |
|Domestic, Rag || | | |
|Steamers, &c. || | | |
+------------------++--------+--------+--------+
|Furnace-upright || 18 | .. | 18 |
+------------------++--------+--------+--------+
|Not sufficiently || 210 | 204 | 414 |
|described to be || | | |
|classified || | | |
+==================++========+========+========+
|Totals || 938 | 673 | 1611 |
+------------------++--------+--------+--------+
TABLE II.
_Summary of Records of Steam Boiler Explosions_
_up to 30th June, 1870,_
_showing Causes of Explosions._
+-----------------++------------------------++------------------------+
|Cause of || Explosions up to June || Explosions in the 4 |
|explosion. || 1866. ||years from June 1866 to |
| || || June 1870. |
| |+--------+--------+------++--------+--------+------+
| ||English.|Foreign.|Total.||English.|Foreign.|Total.|
+=================++========+========+======++========+========+======+
|Worn out, || 92 | 53 | 145 || 89 | 5 | 94 |
|corroded, or || | | || | | |
|burnt plates || | | || | | |
+-----------------++--------+--------+------++--------+--------+------+
|Undue pressure, || 132 | 5 | 137 || 25 | 6 | 31 |
|overloaded || | | || | | |
|valves, || | | || | | |
|intentional or || | | || | | |
|from carelessness|| | | || | | |
+-----------------++--------+--------+------++--------+--------+------+
|Bad || 136 | 108 | 244 || 69 | 8 | 77 |
|construction, || | | || | | |
|weak tubes, || | | || | | |
|defective || | | || | | |
|fittings or || | | || | | |
|stays, or want || | | || | | |
|of repair || | | || | | |
+-----------------++--------+--------+------++--------+--------+------+
|Shortness of || 106 | 8 | 114 || 28 | 2 | 30 |
|water, formation || | | || | | |
|of scale or mud, || | | || | | |
|or external || | | || | | |
|flues set too || | | || | | |
|high || | | || | | |
+-----------------++--------+--------+------++--------+--------+------+
|Extraneous || 6 | 3 | 9 || 2 | .. | 2 |
|causes, || | | || | | |
|lightning, fire, || | | || | | |
|gas, &c. || | | || | | |
|-----------------++--------+--------+------++--------+--------+------+
|Too uncertain to || 247 | 150 | 397 || 6 | 325 | 331 |
|be classified || | | || | | |
|=================++========+========+======++========+========+======+
|Totals || 719 | 327 | 1046 || 219 | 346 | 565 |
+-----------------++--------+--------+------++--------+--------+------+
Table II (continued)
+-----------------++------------------------+
|Cause of || Total Explosions up to |
|explosion. || June 1870. |
| || |
| |+--------+--------+------+
| ||English.|Foreign.|Total |
+=================++========+========+======+
|Worn out, || 181 | 58 | 239 |
|corroded, or || | | |
|burnt plates || | | |
+-----------------++--------+--------+------+
|Undue pressure, || 157 | 11 | 168 |
|overloaded || | | |
|valves, || | | |
|intentional or || | | |
|from carelessness|| | | |
+-----------------++--------+--------+------+
|Bad || 205 | 116 | 321 |
|construction, || | | |
|weak tubes, || | | |
|defective || | | |
|fittings or || | | |
|stays, or want || | | |
|of repair || | | |
+-----------------++--------+--------+------+
|Shortness of || 134 | 10 | 144 |
|water, formation || | | |
|of scale or mud, || | | |
|or external || | | |
|flues set too || | | |
|high || | | |
+-----------------++--------+--------+------+
|Extraneous || 8 | 3 | 11 |
|causes, || | | |
|lightning, fire, || | | |
|gas, &c. || | | |
|-----------------++--------+--------+------+
|Too uncertain to || 253 | 475 | 728 |
|be classified || | | |
|=================++========+========+======+
|Totals || 938 | 673 | 1611 |
+-----------------++--------+--------+------+
TABLE III.
_Analysis of Steam Boiler Explosions in the United Kingdom_
_during the Four years ending 30th June, 1870,_
_showing the Causes of Explosion of Boilers of different descriptions._
A = Faults in construction or repair.
B = Faults which should be detected by periodical examination.
C = Faults which should be prevented by careful attendants.
D = Causes extraneous or uncertain.
E = number of Explosions.
K = number of persons Killed.
I = number of persons injured.
CORNISH, LANCASHIRE, _or other Boilers with internal flues_.
_E_ _K_ _I_
{Weak Tubes 26 17 41
{Weak combustion chambers 5 8 7
A {Weak ends 3 10 10
{Weak dome 1 0 0
{Weak manhole 1 1 1
{Bad repair 3 5 2 _E_ _K_ _I_
------------ 39 41 61
B {External Corrosion 18 42 101
{Internal Corrosion 6 4 5
------------ 24 46 106
{Shortness of Water 14 11 23
C {Scale of mud 3 1 0
{Undue Pressure 4 14 4
------------ 21 26 27 _E_ _K_ _I_
------------ 84 113 194
PLAIN CYLINDRICAL, _or other Boilers without internal flues_.
_E_ _K_ _I_
{Weak flat ends 8 9 12
{Weak manhole 1 0 2
{Frequent repair producing }
A { seam rip in boilers with } 15 18 28
{ plates arranged lengthways}
{Do. with plates arranged in }
{ rings } 8 11 25
------------ 32 38 67
B {External Corrosion 11 5 19
{Internal Corrosion 5 5 6
------------ 16 10 25
{Shortness of Water 2 1 0
C {Scale 1 1 0
{Undue pressure 3 4 3
------------ 6 6 3
------------ 54 54 95
------------
MARINE BOILERS.
_E_ _K_ _I_
{Weak flues 3 6 3
A {Weak ends 2 6 5
{Bad material 1 3 _E_ _K_ _I_
------------ 6 15 9
B {External Corrosion 2 10 3
{Internal Corrosion 3 1 4
------------ 5 11 7
C Shortness of water 1 11 7
------------ 1 11 7
------------ 12 37 23
LOCOMOTIVE BOILERS.
A Boiler used as frame for engine 2 1 2
------------ 2 1 2
B {External Corrosion 2 1 4
{Internal Corrosion 2 0 3
------------ 4 1 7
{Broken connecting-rod }
D { pierced boiler } 1 2 1
{Dome caught by railway bridge } 1 1 0
{Uncertain causes } 2 0 4
------------ 4 3 5
----------- 10 5 14
AGRICULTURAL BOILERS.
A Weak manhole 1 1 4
------------ 1 1 4
B {External Corrosion 2 3 3
{Internal Corrosion 1 1 7
------------ 3 4 10
C {Shortness of water 1 0 0
{Undue pressure 6 15 15
------------ 7 15 15
----------- 11 20 29
FURNACE UPRIGHT BOILERS.
{Too much flame on one part 1 2 0
A {Frequent repair producing }
{ seam rip } 1 13 2
------------ 2 15 2
B {External Corrosion 2 13 11
{Internal Corrosion 2 15 6
------------ 4 28 17
C Shortness of Water 2 3 8
------------ 2 3 8
----------- 8 46 27
ELEPHANT BOILERS.
A Weak ends or want of stays 1 2 2
------------ 1 2 2
B External Corrosion 1 0 4
------------ 1 0 4
----------- 2 2 6
CRANE BOILERS.
_E_ _K_ _I_
A Weak manhole 3 7 3 _E_ _K_ _I_
------------ 3 7 3
B External Corrosion 1 4 2
------------ 1 4 2
C Shortness of water 2 2 0
------------ 2 2 0
----------- 6 13 5
RAG STEAMERS, &C.
{Weak manhole 3 2 5
A {Bad material 1 1 5
{Want of stays 1 1 0
------------ 5 4 10
C Undue Pressure 1 2 6
------------ 1 2 6
----------- 6 6 16
FEED-WATER HEATERS.
D Uncertain causes 2 0 6
------------ 2 0 6
----------- 2 0 6
DOMESTIC BOILERS.
A Weak shape 3 4 7
------------ 3 4 7
B Corrosion 2 0 5
------------ 2 0 5
C Undue Pressure from }
freezing of Pipes } 9 7 9
------------ 9 7 9
----------- 14 11 21
BALLOON BOILERS.
B External Corrosion 2 1 2
------------ 2 1 2
C Undue Pressure 1 1 0
------------ 1 1 0
----------- 3 2 2
BOILERS OF UNCERTAIN DESCRIPTION.
A Weak manhole 1 0 0
------------ 1 0 0
{Steam entered through blow- }
{ off pipe from another boiler} 1 1 2
C { while cleaning }
{Steam pipes broken 2 4 3
{Shortness of Water 1 1 4
------------ 4 6 9
D Uncertain causes 2 0 3
------------ 2 0 3
----------- 7 6 12
----------
_E_ _K_ _I_
TOTALS 219 315 450
TABLE IV.
_Summary of causes of the Steam Boiler Explosions comprised in Table
III._
+-----------------------------------+-----------+---------+---------+
| | E | K | I |
| | Number |Number of|Number of|
|Causes of Explosion. | of | persons | persons |
| |Explosions.| Killed. |Injured. |
+-----------------------------------+-----------+---------+---------+
|A Faults in construction or repair | 95 | 128 | 167 |
+-----------------------------------+-----------+---------+---------+
|B Faults which should be detected }| 62 | 105 | 185 |
| by periodical examination }| | | |
+-----------------------------------+-----------+---------+---------+
|C Faults which should be prevented}| 54 | 79 | 84 |
| by careful attendants }| | | |
+-----------------------------------+-----------+---------+---------+
|D Extraneous or uncertain causes | 8 | 3 | 14 |
+===================================+===========+=========+=========+
|Totals | 219 | 315 | 450 |
+-----------------------------------+-----------+---------+---------+
BRIEF ABSTRACTS
FROM REPORTS ON
STEAM BOILER EXPLOSIONS,
PRESENTED TO THE
MIDLAND STEAM BOILER INSPECTION & ASSURANCE Co.,
BY
EDWARD BINDON MARTEN,
CHIEF ENGINEER TO THE COMPANY.
_Description is shortened as much as possible, and facilitated by
slight sketches, showing the position of the fragments or line of
fracture, and the general construction of the Boilers._
REPUBLISHED BY THE PERMISSION OF THE COMPANY.
STOURBRIDGE: B. BROOMHALL, PRINTER, HIGH STREET.
1869.
BOILER EXPLOSIONS IN 1866.
_No. 1. Nottingham. January 1st. none injured._
Locomotive, 110 lbs., standing with steam up near a platform. All but
the fire box was blown away, the main portion being thrown a distance
of 400 yards. The first rent took place at a longitudinal seam of
the barrel where grooving had gone on very rapidly, which was not
discovered when examined and tested a short time before.
_No. 2. Walsall. (Fig. 1.) January 2nd. 2 injured._
[Illustration: _Fig. 1._]
Butterley, 26ft. 6in. long, and 9ft. diameter. The wagon-shaped top to
the fire place was 8ft. 6in. long, and was attached to the bell-mouth
of the internal tube, which then continued circular to the back of the
boiler. The tube was 3ft. 6in. diameter. All the plates were about
7/16ths inch thick, and although the boiler was an old one, they were
nowhere reduced in thickness by wear. The usual pressure of steam
was 18 lbs., and a self-registering gauge showed that at the time of
explosion it did not exceed 20 lbs.
The top of the fire grate on the right side rent longitudinally,
and the upper part of the shell consisting of four rings of plates,
and also the top of the fire place opened out and blew away to a
considerable distance.
The front end also blew away. The bell-mouth of the tube was blown to
the front, and the tube which remained in the back part of the shell
collapsed upwards.
The cause of the explosion was most likely the intrinsic weakness of
boilers of this shape, especially over the fire, where the top is only
retained in its shape by numerous stays. The boiler had been very
frequently repaired, at this the weakest place, and its strength had
been thus so reduced as to make it unable to bear even a few pounds
more than the ordinary working pressure.
The whistle was found to have been gagged by hemp, carefully inserted,
so that there is ground for supposing there had been intentional unfair
usage.
_No. 3. Blyth. (Fig. 2.) January 8th. 1 killed 1 injured._
[Illustration: _Fig. 2._]
Marine, 20ft. long, and 5ft. diameter, with internal fire place and
return flue, 14 lbs. There were altogether three rents in the tube over
the fire, as a small band was held in its place by a stay from the tube
to the shell. The escaping contents scalded those near, but no damage
was done to anything but the boiler.
The cause was stated to be shortness of water. There was no water gauge.
_No. 4. London. January 9th. 1 killed._
One tube Cornish, 28ft. long, 6ft. 6in. diameter, with one tube 3-6
diameter, 3/8 inch plates, 45 lbs.
The tube collapsed in an incline direction from weakness without
strengthening rings.
The appearance after explosion was nearly the same as that shown in
sketch given at No. 12 explosion.
_No. 5. Glasgow. (Fig. 3.) January 13th. 4 killed, 4 injured._
[Illustration: _Fig. 3._]
Two tube Cornish, 22ft. 3in. long, and 7ft. 7in. diameter, 3/8 inch
plates, tubes 2ft. 7in. diameter, 40 lbs.
About 8ft of the back portion of the shell was torn off, leaving the
tubes and ends intact.
The cause of the explosion was considered to be excessive pressure, but
how accumulated did not transpire.
It is most natural to expect that there must have been corrosion under
the bottom to cause the first rent.
_No. 6. Coatbridge. January 17th. 1 injured._
Cornish. No details have been obtained.
_No. 7. York. (Fig. 4.) January 18th. 1 killed, 2 injured._
[Illustration: _Fig. 4._]
Agricultural, 8ft. 2in. long, 3ft. 6in. diameter in the barrel, 5/16ths
inch plates, internal fire box, 2ft. 4in. wide, 2ft. 4in. high, and
2ft. 10in. deep. From the back of this fire box, two 12-inch tubes
passed to an internal chamber at the back of the barrel. From this
again passed nine 3-3/4 inch tubes to an exterior smoke-box fixed over
the fire door. The boiler was fitted with one spring safety valve,
which was screwed down tight, but there was no pressure gauge. The
front plate was intended to be bolted on so that the fire-box and tubes
could be taken out for cleaning, but it had been rivetted, leaving no
means of cleaning, and it was nearly full of scurf.
The crown plate of fire-box which was too flat and unstrengthened, rent
at the front and along both top edges, and was driven into the fire.
The boiler was thrown backwards and reared against a wall, resting on
the front right hand corner.
The cause of the explosion was that the very dirty state, caused
overheating where the water was not in proper contact with the plates,
and the defective construction did not admit of proper cleaning. The
mountings were insufficient for the proper protection of the boiler.
_No. 8. Durham. (Fig. 5.) January 29th. 1 killed, 3 injured._
[Illustration: _Fig. 5._]
Plain Cylinder Boiler with hemispherical ends, 30ft. long and 6ft.
diameter, 3/8 inch plates, 30 lbs. It was the second from the engine
in a bed of five, and had been at work three years, then remained idle
for eight years, working again fourteen years. The boiler was mounted
with two safety valves 3-7/8 and 4 inches diameter, a float and alarm
whistle. The boiler had been more than once repaired over the fire with
several new plates. One seam over the fire had been observed to leak
about a week before the explosion, but not seriously, and had been
caulked. The boiler had just been started after cleaning. Six months
before explosion, the boiler had been tested to 69 lbs.
About 5 feet of the front end of the boiler opened out flat, and was
thrown to the rear about 60 yards; the front hemispherical end was
liberated and thrown 20 yards also to the rear and right hand. The back
part of the boiler was thrown in a mass, and after bounding twice,
lodged at a distance of 230 yards.
The cause of the explosion appeared to be from the failure of a seam
over the fire place in a plate deteriorated by age, and overheated
through a deposit of scurf and mud.
_No. 9. Birmingham. (Fig. 6.) February 7th. 1 killed, 4 injured._
[Illustration: _Fig. 6._]
Plain Cylindrical Boiler, with hemispherical ends, 23ft. long, and 5ft.
diameter, 3/8 inch plates, 50 lbs. It was set so as to be fired under
the bottom if required, but the grate was seldom used. The principal
heat was supplied from a mill furnace, the neck of which was at the
left hand of the back, and the flame was carried by a wheel flue round
the front of the boiler to the stack on the right hand side of the
back. The boiler was fitted with a 4-3/4-inch safety valve, and also a
float, but it was suspected that the latter had broken from the rod.
A horizontal seam about the middle of the left hand side had given way,
and the upper portion of the 3rd and 4th rings of plates had spread out
like a lid without being detached from the boiler. The front end became
detached and was thrown some distance to the front.
The cause of explosion was, that the left side of the boiler became
overheated, and so much softened, that it first bulged outwards with
the ordinary working pressure, and then rent open. The overheating was
most likely the result of shortness of water, but it might possibly
have been in consequence of the intense heat of a mill furnace
impinging on a small area so near the water line, leading to such rapid
ebullition as to prevent sufficient contact of the water to keep the
plates cool.
_No. 10. Dunse. February 14th. 1 injured._
Locomotive. It exploded while standing in a shed, but no particulars
have been obtained.
_No. 11. Middlesbro'. February 26th. 1 injured._
Marine, in a small tug boat, but no details have been obtained.
_No. 12. Gainsbro' (Fig. 7) February 26th. 1 injured._
[Illustration: _Fig. 7._]
One Tube Cornish, 21ft. long, 5ft. diameter, with one tube 2ft. 11in.
diameter, plates 3/8 inch, 64 lbs. There were no strengthening rings on
the tube. The boiler was second-hand, and had only worked a part of a
day at its new position when it exploded.
The tube collapsed from weakness without strengthening rings.
_No. 13. Redruth. (Fig. 8.) March 3rd. 1 killed._
[Illustration: _Fig. 8._]
One Tube Cornish, 31ft. 9in. long, and 5ft. 9in. diameter, tube 3ft.
8in. diameter, 3/8 inch plates, 40 lbs.
The tube had been repaired with a bolted patch on the left side the
day before the explosion, and it is presumed it was slightly out of
the circular shape, as it collapsed sideways, the top being thrown up
above its proper height. There was no evidence of shortness of water.
The tube without strengthening rings was too weak to sustain the
ordinary working pressure.
_No. 14. London. March 5th. 7 injured._
Cornish, at 27 lbs., but as the boiler was not injured, it is only
noticed as an explosion, because of the imprudence of placing fittings
in such dangerous positions. The boiler was beneath a work room, and
the lever of the safety valve became displaced, allowing the valve to
blow out, and the escaping steam rushed into the room above and scalded
seven men very badly.
_No. 15. Manchester. March 6th. 1 killed._
This was a Boiler with two internal fireplaces, connected into one flue
at the back.
The crowns of both furnaces were collapsed, and slightly rent, and the
escaping steam and water scalded the attendant.
The water was 8 or 9 inches below its proper level, allowing the
furnace crowns to become overheated and unable to bear the working
pressure.
Each furnace had been fitted with a fusible plug, but they proved
inefficient.
_No. 16. Norwich. (Fig. 9.) March 13th. 1 killed, 1 injured._
[Illustration: _Fig. 9._]
This was a very small boiler, 8ft. long, and 3ft. 2-1/2in. diameter,
with two small tubes. It was fired externally.
The dome was blown off and the rents continuing, the top opened out on
each side, and the upper portion of both back and front was bent back.
The dome cut away the whole of the top plate, and so much reduced the
strength that it would not bear the ordinary working pressure.
_No. 17. Dudley. (Fig. 10.) March 19th. none injured._
[Illustration: _Fig. 10._]
Plain Cylinder Boiler, 36ft. long, 5ft. 6in. diameter, 60 lbs. It had
frequently been repaired over the fire, so that the longitudinal seams
ran for several plates without break of joint. A patch had been put on
a few days before explosion, and as the rivet holes had badly fitted,
there had been much strain caused by drifting, and the rivets were much
distorted.
A longitudinal seam gave way over the fire, when two rings of plates
opened out, rending the transverse seams at each side until completely
separated, and fell in two parts at a distance of about 100 yards in
front of the boiler. The front end was liberated and fell in one piece
about 100 yards beyond the two pieces of the shell. The main body of
the boiler was driven back a few yards and rolled over so as to be
upside down, but was little injured.
The frequent and badly executed repair over the fireplace, had so
weakened the structure as to make it unable to bear the very high
ordinary pressure. This frequent repair over the fireplace had been
made necessary by very hard firing and deposits of scurf from muddy
water, preventing the proper contact of the water with the plates.
_No. 18. Liverpool. March 22nd. 1 killed._
This was a small Boiler to supply steam for some steam winches on board
a steam boat, and exploded from the overheating of the upper tubes
through shortness of water, or from over pressure in consequence of
having only one safety valve.
_No. 19. Leeds. (Fig. 11.) March 27th. 2 killed, 18 injured._
[Illustration: _Fig. 11._]
Two Tube Cornish, 24ft. 6in. long, 6ft. 6in. diameter, tubes 2ft. 6in.
diameter, 3/8 inch plates, 54 lbs., fitted with steam gauge, blow-off
cock, 1-1/2 inch dead weight safety valve, loaded to 54 lbs., and 4-3/8
inch lever safety valve, loaded to 62 lbs., and had been at work about
five years.
Nearly the whole of the two back rings of the shell were torn off and
opened out, and the boiler was turned partly round, and moved upon its
seat sideways and forwards.
There was extensive corrosion at the under side of the back of shell,
where the first rent took place, caused by the leaking of the joints
and seams.
_No. 20. Swansea. (Fig. 12.) April 4th. 5 killed, 4 injured._
One Tube Cornish Boiler, 30ft. long, and 7ft. diameter, tube slightly
oval about 4ft. diameter, 7/16 inch plates, 43 lbs., fitted with 3-1/2
inch safety valve, which is much too small for such a boiler, glass
water gauge, two gauge cocks, and pressure gauge.
The tube collapsed from end to end. The front end was blown out with a
short length of the tube attached, and was driven against a wall about
30 yards to the front. The main body of the shell, and the back end,
with the collapsed tube within it, were driven back against another
wall, about the same distance away. Very great damage was done to the
surrounding property.
[Illustration: _Fig. 12._]
The cause of the explosion was the weakness of the tube of so large a
diameter, without strengthening rings, which made it unable to bear the
ordinary working pressure. It is very probable, however, that at the
time of the explosion, the pressure was considerably more than usual
during the stoppage of the engine, and the confusion caused by a man
becoming entangled in the machinery.
_No. 21. Morpeth. April 10th. 1 killed._
Plain Cylinder Boiler, 34ft. long, and 5ft. diameter, 3/8 inch plates
placed lengthways, 33 lbs.
The explosion took place at a seam in the front part of the bottom
of the boiler just over the fire. This rupture allowed the sides to
expand, until the boiler was completely destroyed and torn into seven
pieces.
The cause of the explosion was supposed to be the defective state of
the seams over the fire, which, being placed longitudinally, were in
the weakest position.
_No. 22. Shiffnal. (Fig. 13.) April 21st. none injured._
[Illustration: _Fig. 13._]
Two Tube Cornish, 15ft. long, 6ft. diameter, tubes 1ft. 8in. diameter,
3/8 inch plates, 40 lbs. The heat was supplied by two furnaces, one of
which played into each tube.
The left hand tube collapsed from shortness of water, and tore away
from the angle iron in the front plate, and allowed the contents to
issue violently and scatter the brickwork, but the boiler was not
disturbed.
_No. 23. Burnley. April 26th. 2 killed, 2 injured._
Small internally fired Boiler, 5ft. high, 2ft. 4in. diameter, and was
intended to work at 70 lbs. The fittings were defective, the spiral
spring of the safety valve being most easily altered, so as to cause
over pressure. The manhole was not strengthened by any ring, and the
first rents commenced at that point.
The cause of the explosion was over pressure and defective construction.
The sketch at No. 57 explosion in this year, is of a similar boiler
which exploded from nearly similar causes.
_No. 24. Bilston. (Fig. 14.) May 13th. none injured._
Balloon or Haystack Boiler, about 16ft. diameter, 5/16 inch plates, and
worked at very little above atmospheric pressure.
The boiler was chiefly used to store water during the time another
boiler by the side of it was emptied. When the water was required to
refill the other boiler, a fire was lighted under the balloon, and
sufficient steam generated to drive the water from it into the other
boiler. The safety valve never being used, it had become fast, and as
a little more steam than usual had accumulated, the bottom gave way,
and the reaction of the issuing contents made the boiler rise from its
seat, and it fell on its side at some distance away flattened by the
fall.
[Illustration: _Fig. 14._]
_No. 25. Westbromwich. (Fig. 15.) May 25th. none injured._
[Illustration: _Fig. 15._]
One Tube Cornish Boiler, 15ft. long, and 4ft. 6in. diameter, taper
tube, 2ft. 9in. diameter in front, and 2ft. diameter at back, 3/8 inch
plates, 40 lbs. The boiler rested on two walls forming the bottom flue.
There was a safety valve, a glass water gauge, a pressure gauge, and
two fusible plugs upon the tube.
Two longitudinal rents took place on the under side of the shell,
allowing two strips, forming the central part, to open out by the
continuation of the fracture, until they were blown to a considerable
distance. The tube with the front end, and one ring of the shell were
thrown to the front, while the back end was thrown to the rear, the
smallest end of the tube having torn away from the back.
The shell was deeply corroded where it rested on the side walls of
the bottom flue, and the strength of the boiler was thereby so much
reduced, that it was unable to bear the ordinary working pressure.
_No. 26. Halifax. (Fig. 16.)_ _May 26th. 1 killed._
[Illustration: _Fig. 16._]
One Tube Cornish, 24ft. 6in. long, and 5ft. diameter, taper tube,
slightly oval in the front, 2ft. 8in. diameter, and 2ft. diameter at
the back, 3/8 inch plates. The boiler was fitted with glass water
gauge, float, self-acting feed apparatus, and safety valve loaded to 52
lbs., and also a mercury gauge.
The tube collapsed over the fire, a rent taking place in the second
ring of plates. The issuing steam and water caused the death of a man
in front, but the shell of the boiler was not injured or moved.
The cause of the explosion was shortness of water, and as the glass
gauge was set unusually low, the man in charge may have been deceived.
The oval shape of the fireplace, and the laminated iron, as shown in
the fracture, rendered the tube peculiarly liable to collapse.
_No. 27. Durham. May 26th. 1 killed._
Plain Cylinder Boiler, 34ft. long, 5ft. diameter, 3/8 inch plates, 45
lbs., fitted with two 5-inch safety valves, and 2 floats.
The boiler was torn in two pieces, that were thrown to a considerable
distance. The first rent had taken place immediately over the fire.
The cause of the explosion was the weakening of the shell by frequent
repair over the fire, rendered necessary by the deposit from the muddy
water preventing proper contact of the water with the plates.
_No. 28. Durham. May 27th. 1 killed._
Plain Cylinder Boiler, 32ft. long, 6ft. diameter, 3/8 inch plates, 35
lbs., fitted with two safety valves, two floats, and two alarm whistles.
The boiler was lifted from its seat, and one end was separated and
thrown to a considerable distance.
The cause of the explosion was weakening of the shell from repair a few
days before, and perhaps over pressure, as the gauge was found some
time after, and indicated that the pressure had at some time exceeded
80 lbs.
_No. 29. Redruth. May 28th. 1 killed, 4 injured._
One Tube Cornish, 30ft. 8in. long, 6ft. 8in. diameter, tube, 4ft.
diameter, 7/16 inch plates, 40 lbs.
The tube collapsed, and rent, and the issuing steam and water scalded
those near, as it was too weak to bear the ordinary working pressure.
_No. 30. Leicester. (Fig. 17.) May 31st. 1 killed, 1 injured._
[Illustration: _Fig. 17._]
Plain Cylinder Boiler, with dished ends, and only 4ft. 2in. long, and
2ft. 6in. diameter, 1/4 inch plates. It was most inefficiently mounted,
the safety valve was only 1-5/8-inch diameter, and of such faulty
construction, that it would not open under a pressure of 162 lbs. There
was no steam gauge or float, and the gauge cocks were defective. There
was no means of putting water in the boiler when there was a pressure
of steam. The manhole was very large for so small a boiler.
Four rents started from the manhole and continued along the top of the
boiler and round the end seams. A tongue-shaped strip of the top plate
was attached to the back end plate; two strips about a foot wide on
either side were blown away. The boiler had been turned nearly round
in its flight, and fell with the back about 12 feet from the original
position of the front.
The boiler was worked until it was nearly dry, and, during a temporary
stoppage of the engine, an accumulation of steam caused a greater
pressure than the boiler could bear.
_No. 31. Newcastle. June 7th. none injured._
Marine Boiler in a Tug Boat.
The boiler was blown completely out of the vessel, and the greater part
of it fell into the water, and a large piece alighted on a crowded
quay, but without doing any damage.
The cause of the explosion was supposed to be over-pressure during a
temporary stoppage of the engine.
_No. 32. Barnard Castle. (Fig. 18.) June 11th. 2 injured._
[Illustration: _Fig. 18._]
Agricultural, of about 7 horse power. The barrel of the boiler was
6ft. 1in. long, 2ft. 5in. diameter; the fire-box end was 3ft. wide,
and 2ft. 4in. deep; the fire-box was 2ft. 5-1/2in. wide, and 2ft. 7in.
high, and 1ft. 9-1/2in. deep, with 23 tubes passing from it through the
barrel to the smoke box and chimney. The boiler was fitted with a 2in.
safety valve, which was intended to blow at 45 lbs., but as there was
no ferrule, it is supposed to have been screwed down to a much greater
pressure.
The upper portion of the shell over the fire-box rent through the
manhole, and allowed the shell to open out and fall on each side. A
large portion of the front plate was also torn off.
The cause of the explosion was the weakness of the manhole, which was
not strengthened by any ring, and also excessive pressure from want of
proper safety valve.
_No. 33. Breage. June 11th. 1 killed._
Cornish Boiler, 36ft. 6in. long, and 6ft. diameter, 3/8 inch plates, 45
lbs.
The tube collapsed and rent, and the issuing contents caused the death
of the attendant.
The weak tube of such large diameter, was unable to bear the ordinary
working pressure, having no strengthening rings.
_No. 34. Nottingham. June 19th. 2 killed, 4 injured._
Locomotive, 1/2 inch plates, 140 lbs.
The explosion occurred at the left hand side of the ring of plates
in the barrel next the fire-box, and below the foot-plate. The rent
tore along the edge of the lap and into the next ring of plates. The
reaction of the issuing contents threw the engine off the rails.
The cause of the explosion was partial corrosion at the point of
rupture and strain of the plates, as the boiler itself formed part of
the frame of the engine.
_No. 35. Richmond. June 26th. 2 injured._
Locomotive, being tried for the first time. The funnel came in contact
with a bridge, and the dome was also torn off.
_No. 36. Gainsbro' June 29th. none injured._
No details have been obtained.
_No. 37. Durham. July 2nd. 4 killed._
Plain Cylindrical Boiler, 30ft. long, and 6ft. diameter, 3/8 inch
plates, 28 lbs. It had been repaired a short time before the explosion,
with 5 new plates.
The boiler was torn up into several pieces, but the main portion
remained flattened out on the seating, while some smaller pieces were
sent 250 yards away.
The cause of the explosion was the deterioration of the boiler, and its
frequent repair over the fireplace.
_No. 38. Liverpool. June 12th. 4 injured._
Elephant Boiler, 20ft. long, and 4ft. diameter, 3/8 inch plates, and
worked at low pressure. The bottom shell had a tube through its whole
length.
A rent took place in the lower part of the fireplace, and extended
along the bottom, and the reaction of the issuing contents caused the
top to rear up.
The cause of the explosion was supposed to be that the bottom plates
were worn too thin to bear the ordinary pressure.
_No. 39. Sheffield. July 4th. none injured._
Two Tube Cornish Boiler, externally fired, 30ft. long, and 6ft.
diameter, 3/8 inch plates, 40 lbs.
The second seam over the fire gave way, and the plate sank down upon
the fire.
The cause of the explosion was the deterioration of the seams over
the fire, in consequence of the deposit of scurf which could not be
properly cleared off owing to the internal tubes.
_No. 40. Oldham. July 14th. none injured._
Boiler, with two internal furnaces, 9ft. 6in. long, and 2ft. 11in.
diameter, 3/8 inch plates, uniting into one tube beyond. The furnace
crown collapsed near the front of the boiler.
There was an extra weight upon the safety valve, and the steam valve
was left closed, so that more pressure accumulated than the boiler
could bear.
_No. 41. Oxford. July 23rd. 3 injured._
Rag Boiler, not used for the generation of steam. It was a plain
cylinder, with hemispherical ends, about 16ft. long, and 7ft. diameter.
There was a neck at each end upon which the boiler revolved, and
through one of these the steam was admitted to a pressure of 30 lbs.,
in order to assist in cleaning the rags. There was a large manhole for
filling and emptying.
The boiler rent in the middle, and each half was blown to some distance.
The manhole was so large, that the strength of the boiler was too much
reduced, and the constant strain of revolving caused a central seam to
give way at the ordinary pressure.
The sketch to No. 63 is of a similar boiler.
_No. 42. Tunstall. (Fig. 19.) July 28th. 2 killed, 7 injured._
[Illustration: _Fig. 19._]
Boiler, 36ft. 6in. long, and 8ft. 9in. diameter, 7/16 inch plates,
with flat back and hemispherical front end, 36 lbs. A tube 3ft. 3in.
diameter, passed from the back end nearly to the front, and returned
to the back end, but of 6 inches less diameter and then passed to an
iron chimney. The fire grate was beneath the hemispherical end.
The angle iron of the flat back end gave way, and separated from the
shell and with the tubes attached was blown to a good distance, and the
reaction drove the shell far in the opposite direction.
The cause of the explosion was the bad construction of the boiler, as
the back end was quite unsupported, as there were no stays, and the
bend of the tubes was not attached to the shell.
An adjoining boiler which was being cleaned inside by two men, was
rolled off its seat by the force of the explosion.
_No. 43. Widnes. August 2nd. 2 killed, 6 injured._
Plain Cylindrical Boiler, with flat ends, 23ft. long, 5ft. 3in.
diameter, 3/8 inch plates, 40 lbs.
Both the flat ends were blown out, and the first ring of plates at the
front end torn off.
The cause of the explosion was the weakness of the flat ends without
stays.
_No. 44. Sunderland. August 7th. 1 killed, 3 injured._
Locomotive, 13ft. 4in. long, 3ft. 11in. diameter, with 140 2-in. tubes.
The fire-box was 4ft. 5in. long, 3ft. 6in. broad, and 5ft. deep, and
made of copper, 1/2 inch thick, 100 lbs. It was fitted with two 4-in.
safety valves, and a steam gauge.
The fire-box gave way about the middle of the left side, 2ft. 6in.
below the water line, where corroded to 1/8 inch, and the issuing water
and steam scalded those near.
_No. 45. Runcorn. (Fig. 20.) August 22nd. 3 killed, 5 injured._
[Illustration: _Fig. 20._]
Marine Multitubular, 5ft. 8in. long, and 6ft. 6in. diameter, with two
internal tubular furnaces, which joined to an internal chamber of large
size, and small tubes passed to a smoke box and chimney in the front
over the fire doors. Both ends were flat.
The flat back end was insufficiently stayed, and was blown completely
out and torn into two pieces, the lower portion remaining in the
vessel, and the upper part falling in the water, and the reaction of
the issuing contents caused the boiler to be thrown on to the side of
the quay.
_No. 46. Hull. (Fig. 21.) August 25th. 1 injured._
[Illustration: _Fig. 21._]
One Tube Cornish, 24ft. 3in. long, and 6ft. diameter, taper tube 3ft.
5in. diameter, for about 7ft. 6in. in length, and 2ft. 6in. diameter
for the rest of the length, 33 lbs.
The tube was much corroded, and the fireplace gave way on left side,
and was so much torn, that the plates were forced out of the front.
_No. 47. Morecombe. August 27th. 3 killed, 1 injured._
Marine, of the usual construction, and had been tested to 60 lbs.
It gave way at the lower portion of the back, and the issuing steam and
water scalded those near.
A seam rent, 6ft. 6in. long, had not been detected by testing.
_No. 48. Tuddenham. August 29th. 2 killed, 2 injured._
Agricultural. It burst during a temporary stoppage from accumulation of
steam, causing undue pressure.
_No. 49. Glasgow. August 31st. 3 killed, 6 injured._
Upright Boiler, 36ft. high, 5ft. 6in. diameter, 7/16 inch plates, 45
lbs.
The bottom gave way from shortness of water, and the main bulk of the
boiler was thrown straight up into the air to a great height, but
descended again on its seating.
_No. 50. Chatham. (Fig. 22.) September 7th. 2 killed, 30 injured._
[Illustration: _Fig. 22._]
Two Tube Cornish, 22ft. long, 7ft. 6in. diameter, with tubes, 3ft.
diameter, 7/16 inch plate, 60 lbs.
Some rents took place at the under side of the shell, allowing the
central portion to open out and blow away. The portion containing the
dome was thrown to the left, and the other to the right. The front
end, with 3 rings of the shell, with the tubes and back end, were but
little moved from their original position. The tubes were dented in on
the top and bottom, by the fall of some large coping stones upon them,
but the crowns of the furnaces were uninjured, and there was no sign of
shortness of water or overheating.
Extensive corrosion on the under side of the shell, where it rested on
the brickwork, had so reduced the strength, that it was unable to bear
the working pressure.
In the sketch the fragments are drawn so as to show their position when
in the boiler.
_No. 51. Newark. September 21st. none injured._
One tube Cornish. The tube collapsed from shortness of water, and the
escape of the steam and water blew off the door frame.
_No. 52. Ashton. September 23rd. 1 injured._
Plain Cylindrical Boiler, 7ft. long, and 2ft. diameter, 3/8 inch
plates, 30 lbs.
The upper part of the boiler at the first ring of plates was torn off,
and the front end was blown out.
Extensive external corrosion, where the plates rested against the
brickwork, rendered the boiler too weak to bear the ordinary pressure.
_No. 53. Norwich. (Fig. 23.) September 25th. 7 killed._
[Illustration: _Fig. 23._]
One Tube Cornish, 20ft. long, 4ft. 6in. diameter, tube 2ft. 6in.
diameter, 3/8 inch plates, 100 lbs. It was double-rivetted, and the
crown of tube was strengthened with angle iron. The shell was formed
of six rings, each of two plates alternately jointed top and sides.
The third ring from the front had stripped off, and was thrown to the
right and forwards against a wall. The line of rent was confined to the
plates forming the ring, which was an outer one, and covered the two
adjoining rings in the laps, the rent being from the edge of the inner
lap to the nearest rivets. The first rent had taken place in the solid
iron, about 1 inch from the rivets of a seam on one side, and from this
the rent had extended along the seams on either side, and of course
the whole ring soon tore off when the equilibrium was destroyed by the
first rent.
The fittings of the boiler were sufficient, except that there was only
one safety valve, and that was so constructed that it could only open a
very little way.
The cause was a defect in the iron at the point of the first rent, and
accumulated pressure during the time of standing.
_No. 54. Macclesfield. September 25th. none injured._
Multitubular Boiler, with large internal fireplace, 60 lbs.
The furnace crown became overheated from shortness of water, and was
crushed down and torn across two seams. The boiler was lifted from its
seat and thrown back against a stone wall.
_No. 55. Chelmsford. October 5th. 1 killed, 7 injured._
Agricultural, 45 lbs., and had only just been set to work.
The crown plate to the fire-box was so deeply corroded from long wear
that it gave way, and the issuing contents scalded those near.
_No. 56. Greenwich. (Fig. 24.) October 8th. 2 killed, 2 injured._
Marine, 16ft. long, slightly oval, front end flat, 8ft. 6in. wide,
7ft. 10in. high, and the dimensions of the back hemispherical end were
2ft. less each way, 3/8 inch plates, 26 lbs. There were two internal
fireplaces, of irregular shape, uniting at the back into one flue of
similar shape, which did not come to the front, but passed through the
steam space, and out at the top of the boiler.
While the vessel was waiting to start, with steam up, the wing furnace
of the starboard boiler collapsed on the wing side, as shown by the
dotted lines, and allowed the steam and water to escape into the stoke
hole.
[Illustration: _Fig. 24._]
The side of the furnace next the shell was rent along the edge of a
longitudinal seam in a line, which was slightly nicked in the caulking.
This rent extended about 5ft. 6in. from the front, and then at a cross
seam it went along the line of rivets from the crown to the bottom of
the furnace. Beyond this cross seam the furnace was collapsed, until it
nearly touched the other side of the furnace, and the bulge died away
towards the back end. There was also a rent in the lower part of the
front of the shell, as shown in dotted line.
The cause of the explosion was the weakness of the shape of the flue,
which was not stayed to the shell. It had evidently gradually been
giving way some time before the explosion, and eventually collapsed at
nearly the ordinary pressure. Symptoms of the same alteration of shape
were noticed in the corresponding flue of the other boiler.
_No. 57. Liverpool. (Fig. 25.) October 9th. 7 killed, 1 injured._
Crane Boiler, 5ft. 6in. high, and 2ft. 6in. diameter, with internal
conical fire-box, with two cross tubes and a chimney at the top, 1/4
inch plates, 75 lbs.
The outer shell of the boiler was rent into many pieces, leaving the
central conical fireplace intact. The nature of the rents showed that
the plate round the manhole, which was unstrengthened by a ring, had
first given way, and all the other fractures had led away from that
point. This is confirmed by the fact, that the manlid was thrown a good
distance, with force enough to make its way through the timber walls
of a cabin. The front plate divided into many pieces, and scattered
right and left, while the back plate was thrown through a cabin in the
opposite direction to the manhole.
[Illustration: _Fig. 25._]
The central flue showed a slight indication of overheating, but the
construction was such that the upper portion passed through the steam
space, and was always exposed to the action of the fire, without the
protection of the contact of water. The manhole without a ring on its
edge to strengthen the plate, and held in by two clamps, which caused
additional strain when carelessly screwed up, was by far the weakest
place. The engine was standing after a short time of working, and as
the safety valve was very defective, and could be screwed down until
tight, against almost any pressure, it is most probable that the
pressure mounted much higher than usual, when the weakest part gave
way, and led to the sudden tearing up and scattering of the whole
fabric.
Faulty construction of both boiler and fittings, rendered it unable to
bear that accumulated pressure, which the safety valve ought to have
made impossible.
_No. 58. Durham. October 13th. 1 killed._
One Tube Cornish, 14ft. long, 6ft. diameter, internal flue 3ft. 3in.,
by 2ft. 10in., 3/8 inch plates, 27 lbs., standing on three saddles,
with a bearing surface of 3ft. by 4 inches.
A portion of plate 20in. by 18in., at the bottom of the boiler, was so
corroded that it was blown out, and the issuing contents scalded a man
to death.
_No. 59. Bristol. (Fig. 26.) November 1st. 7 killed._
[Illustration: _Fig. 26._]
Two Marine Boilers exploded simultaneously. They were 16ft. long,
6ft. 6in. diameter at the flat front ends, and somewhat less at the
hemispherical back ends. Each had two internal fireplaces, united in
one flue, which returned nearly to the front and passed up through the
steam space, and out at the top of shell into the funnel. The central
fireplaces were not circular, and the outside fireplaces and the return
flues were still more distorted, but the weakness of the shape was
somewhat compensated for by stays between the tubes, and from the tubes
to the shell. The mountings to the boiler were of the ordinary kind and
efficient.
The under sides of the shells were so deeply corroded that they were
rent longitudinally for their whole length, allowing the sides to
open out and tear away from the front ends. Each shell fell at a
considerable distance. The furnaces, with parts of the front ends
attached, fell into the water, but except one of the side flues that
was a little collapsed, they were uninjured. Small pieces of the front
ends were thrown to a great distance. The sides of the vessel were so
completely blown out that she sank.
The corrosion was no doubt caused by the leakage of the vessel, keeping
the shells of the boilers constantly wet.
_No. 60. London. (Fig. 27.) November 3rd. none injured._
[Illustration: _Fig. 27._]
Agricultural, barrel was 3ft. 9in. long, and 2ft. 6in. diameter, 70
lbs. From the internal fire-box the heat passed through a number of
1-inch tubes to the front smoke box and chimney.
During a stoppage for breakfast, the fire-box end was torn from the
barrel, and from the position of those fragments that could be found,
the boiler appeared to have turned over. Part of the fire-box was sent
through the stage upon which the boiler was travelling, and the barrel
with the tubes remaining in it, first struck a rail which caused it to
be dented in, and then rebounded to a point about 100 yards from its
original position.
Enough of the fragments were not recovered from the river to trace the
cause of the explosion, but it is presumed that, although when the
boiler was left, only 20 lbs. pressure was shown by the gauge; the fire
door being left closed, the pressure must have risen to a point much
above the working pressure, and to more than the boiler could bear.
_No. 61. Bilston. (Fig. 28.) October 1st. none injured._
One Tube Cornish, 22ft. long, 6ft. diameter, tube 4ft. 6in. diameter,
3/8 inch plates, 12 lbs. There was an unusually large dome at the back
end, 5ft. diameter, and the whole of the shell was cut out from under
it, so that the construction was peculiarly weak.
[Illustration: _Fig. 28._]
The boiler had been off for cleaning, and steam was being got up in the
night, and it was said that an extra pressure was caused by the stop
valve being left closed, but it could not have been very great, or the
large tube would have collapsed.
The dome was split in two, in the line marked in the sketch, owing to
the extreme weakness of the shell at the juncture of the dome, and the
shell was a little ruptured on each side of it, and so large a rent was
suddenly made, that the contents of the boiler passed harmlessly into
the air, without moving the boiler on its seat.
_No. 62. Preston. (Fig. 29.) November 11th. 1 killed, 1 injured._
[Illustration: FRONT VIEW. BACK VIEW.
_Fig. 29._]
One Tube Cornish, 16ft. 3in. long, and 5ft. 8in. diameter, tube 3ft.
1in. diameter, 7/16 inch plates, 60 lbs.
The tube collapsed from end to end, from over-pressure, as the man in
charge had fastened 3 bricks to the lever of the safety valve causing
27 lbs. extra pressure, under the impression that he could thus
accumulate a quantity of steam during the night, to be available on
commencing work on the morrow.
_No. 63. Tamworth. (Fig. 30.) November 20th. none injured._
[Illustration: _Fig. 30._]
Revolving Steam Chamber, 12ft. 6in. long, and 5ft. diameter, 12 lbs.
The manhole was large, to facilitate filling and emptying, and was
rectangular and unstrengthened on the edges, and measured 3ft. 6in. in
length, and 1ft. 6in. in width, and the lid fitted on the inside and
was held by clamps.
The boiler was much out of repair, and a crack shown in sketch, from
one corner of the manhole to the commencement of the hemispherical end
was only temporarily prevented from leaking by a screw-patch, which did
not restore the strength.
The explosion happened when in revolving, the manlid was downwards, and
the lid was driven nearly through the floor, and the shell was rent
from opposite corners of the manhole, and blown through the roof.
The large manhole cut away nearly all the strength on one side, and
the fastenings of the lid were not contrived to compensate at all for
the loss of strength. The constant strain when revolving, also tended
to weaken it. These two causes together were sufficient to account for
the explosion, at the usual working pressure of 12 lbs., although it is
possible that it might have been increased to 35 lbs., as that was the
pressure in the boiler supplying the steam, although the pressure was
regulated by a check valve.
This explosion (and also No. 41 in this year) clearly show that a mere
vessel of steam not exposed to the fire, or any chance of overheating
of the plates, can burst and cause very great destruction, although
there could be no sudden _increase of pressure_ which is so often
supposed necessary to account for the havoc caused by explosions.
_No. 64. Manchester. November 26th. none injured._
This Boiler was 28ft. long, 7ft. diameter, made of 7/16 inch plates,
and worked at 50 lbs. pressure, with two internal fireplaces united
into one tube beyond.
The sides of the oval chamber forming the junction of furnaces and
tube, crushed inwards, being of such a weak shape as to be unable to
resist the ordinary working pressure.
_No. 65. Hull. (Fig. 31.) December 1st. 3 killed, 2 injured._
[Illustration: _Fig. 31._]
Agricultural, 7ft. 6in. long, and 3ft. 8in. diameter, 1/4 inch plates,
35 lbs., fire-box 2ft. long, and 2ft. 10in. broad. Two 11-1/2-inch
tubes led to an internal chamber at the other end of the boiler, and
three 8-1/4-inch tubes led back again to an external smoke box and
chimney fixed over the fire door.
The bottom of the right hand side lower tube was forced upwards, and
rent along to within 12 inches of the fire-box.
The tubes were so corroded from leakage of patches, that they were
unable to bear the slight increase of pressure during a short stoppage.
_No. 66. Glasgow. December 4th. 2 killed, 6 injured._
Two Tube Cornish, 22ft. long, and 7ft. 6in. diameter, tubes 3ft.
diameter, and strengthened with rings in the approved manner.
The second from the back of the seven rings, was ruptured at the bottom
and torn off by a rent through the line of rivets on each side, and
the boiler was thrown from its seat, and turned completely over, so as
to lie in a contrary direction to what it was before.
Extensive corrosion, from leaking of the seams beneath the brickwork,
where hidden from view, was the cause of explosion.
_No. 67. Willenhall. December 7th. none injured._
Plain Cylinder, with hemispherical ends, 9ft. long, 3ft. 3in. diameter,
20 lbs.
The boiler was rent all along one side, and the reaction of the issuing
contents caused it to be thrown some yards away, and one of the ends
became altogether detached, and flew to a considerable distance.
The plates were so thinned by corrosion, that they gave way on a very
slight increase of pressure during a temporary stoppage of the engine.
_No. 68. Glasgow. December 12th. 1 killed, 1 injured._
This Boiler was 14ft. long, with hemispherical ends, and 7ft. diameter,
30 lbs.
The cause of the explosion was over-pressure and thinness of plates,
wasted by corrosion.
_No. 69. Manchester. (Fig. 32.) December 15th. 5 injured._
[Illustration: _Fig. 32._]
Two Tube Cornish, 24ft. long, 6ft. 6in. diameter, tubes 2ft. 8in.
diameter, 7/16 inch plates, 50 lbs. The boiler was fired in each of the
tubes in the ordinary way, and also the heat from two furnaces passed
from the back, one on each side of the outside shell.
Both the internal furnaces collapsed, until the crowns almost touched
the fire bars, as shown in dotted lines, but without fracture. The back
of the shell, on the right side, had evidently been overheated, and had
rent along the centre of a bulge, and this rent had extended along the
line of rivets of the transverse seam on each side, allowing two rings
of the plates of the shell to open out flat as shown. There was a bulge
on the plate, on the right side of shell, corresponding with the one
which parted on the opposite side.
The cause of the explosion was overheating of the plates from shortness
of water.
_No. 70. Aberdeen. December 24th. 1 injured._
No particulars have been obtained.
BOILER EXPLOSIONS IN 1867.
_No. 1. Hull. January 2nd. 1 killed, 1 injured._
A small Boiler to heat a bath. It exploded, causing great damage,
because the connecting pipes were frozen. All such boilers should have
a proper safety valve.
_No. 2. Durham. (Fig. 1.) January 2nd. 3 killed, 3 injured._
[Illustration: _Fig. 1._]
Plain Cylinder, 33ft. long, 6ft. diameter, 33 lbs. pressure. Only
set two days, but was old and deteriorated, and had worked before at
another place. It had been turned 1/4 round, and old fitting-holes
stopped. First rent was supposed to be in a seam at front end, over the
fire. Main portion of shell was driven back, and front end forward, and
torn in its flight. The cause of explosion was, that the seam in front
was overheated and injured, and also incautious working without a steam
gauge.
_No. 3. Sheffield. (Fig. 2.) January 2nd. 1 killed, 4 injured._
[Illustration: _Fig. 2._]
One Tube externally fired, 30ft. long, 6ft. 6in. diameter, with dished
ends. Tube 2ft. 9in. diameter, slightly oval. Pressure 60 lbs. Tube
collapsed sideways from end to end, because it was not strengthened
by hoops or other means, which were the more needed, because it was
slightly oval, and the longitudinal seams were nearly in one line.
_No. 4. Preston. January 3rd. 1 killed._
Boiler for heating apparatus. Fire was lighted without noticing that as
there was no safety valve, and that all escape of steam was prevented
by the connecting pipes being frozen.
_No. 5. Westerham. January 5th. 1 killed._
Cast-iron Boiler for heating water for a horse shower bath, fixed
behind an ordinary fireplace. Burst and caused great damage, owing to
the pipes being frozen. There was no safety valve.
_No. 6. Barr. January 9th. 1 killed, 3 injured._
Kitchen Boiler, which burst because the supply pipes were stopped by
frost, and there was no safety valve.
_No. 7. London. January 11th. 1 killed._
Cornish, 12ft. long, 4ft. 6in. diameter, tube 2ft. 4in. diameter,
pressure 40 lbs. Small piece of plate was blown out near the bottom,
and the boiler was displaced by the reaction of issuing contents. The
cause of explosion was extensive external corrosion on the lower part.
_No. 8. Preston. January 16th. none injured._
Kitchen Boiler. Burst and did great damage, because pipes were frozen
preventing escape of steam. There was no safety valve.
_No. 9. Brechin. January 23rd. 1 killed._
Kitchen Boiler. Fire had been out some days, and the boiler burst soon
after re-kindling it and did much damage, because the supply pipes were
stopped by frost, and there was no safety valve for escape of steam.
_No. 10. Sunderland. (Fig. 3.) January 26th. 3 injured._
[Illustration: _Fig. 3._]
Plain Cylinder, 30ft. long, 6ft. 2in. diameter. Pressure 30 to 35 lbs.
Rent into four pieces, which were flattened out and scattered on to
other boilers, but are arranged in sketch so as to show their original
position in the boiler. It had worked a very long time, and was
overheated and injured along the fractured line.
_No. 11. Exeter. (Fig. 4.) January 30th. 2 killed, 2 injured._
Elephant Boiler, 16ft. long, 5ft. diameter, tubes 1ft. 10in. diameter,
45 lbs. pressure. Flat end blew out, throwing boiler upwards by
reaction, but shell and tubes were not injured. The flat end was not
sufficiently stayed, having only one stay-rod to the centre, the bolt
of which was broken.
[Illustration: _Fig. 4._]
_No. 12. Glasgow. February 8th. 1 killed, 4 injured._
Small Boiler to 6-horse power engine. Gave way at centre of furnace,
and water forced out at both ends, and it was suspected that the water
was low.
_No. 13. Sheffield. (Fig. 5.) February 11th. 4 injured._
[Illustration: _Fig. 5._]
Cornish, about 30ft. long. Tubes 3ft. unstayed. Tube collapsed
sideways, and was rent from grate bars to end, without injuring front
plates or shell. It was said to be short of water, but most likely the
true cause was the weakness of the tube.
_No. 14. Manchester. February 15th. none injured._
Two flued, 28ft. long, 6ft. 9in. diameter, slightly oval; plates 3/8
inch; tube 2ft. 8in. diameter, pressure 45 lbs. Shell had once been
externally fired. Rent along the seams which were in one line, and a
large piece of the plate blew away, leaving tubes uninjured. The cause
of explosion was defective form and worn out state of shell.
_No. 15. Weymouth. (Fig. 6.) March 12th. 1 killed, 3 injured._
[Illustration: _Fig. 6._]
Agricultural, 45 lbs. pressure. Fire-box blew off, and the outer shell
separated from it. The cause of explosion was over-pressure from the
safety valve being screwed down.
_No. 16. Lynn. (Fig. 7.) March 19th. 8 killed, 4 injured._
[Illustration: _Fig. 7._]
Agricultural, 45 lbs. pressure. Fire-box and tubes blew out. The cause
of explosion was over-pressure, as the safety valve was tied down with
string.
_No. 17. Blackbraes. March 23rd. 3 killed, 1 injured._
Colliery Boiler, 30 lbs. pressure. Rent in two while the engine was
standing, but no details obtained.
_No. 18. Barnsley. (Fig. 8.) March 29th. 2 killed, 2 injured._
[Illustration: _Fig. 8._]
Small plain Cylinder, with ends nearly flat, 4ft. 7in. long, 2ft. 4in.
diameter, plates 3/16 inch. No emptying plug or feed-pipe, and only a
very small hand-hole. Front end attached by slight angle iron, which
gave way, leaving the shell unmoved. The cause of explosion was the
internal corrosion of front end owing to very bad water being used. The
plates were reduced to a knife edge in line of fracture.
_No. 19. Cornwall. (Fig. 9.) April 10th. 1 killed, 1 injured._
[Illustration: _Fig. 9._]
Cornish, one tube 32ft. long, 6ft. diameter, tube 3ft. 10in. diameter,
plates 3/8 inch, pressure 25 to 40 lbs. It was 20 years old, but just
repaired and reset. Furnace tube failed and collapsed from one end to
the other, except about 4 feet of front, owing to its weakness, being
unstrengthened by hoops or cross tubes.
_No. 20. Belfast. (Fig. 10.) April 20th. 1 killed, 2 injured._
[Illustration: _Fig. 10._]
Plain Cylinder, 6ft. long, 2ft. 5in. diameter, plates 1/4 inch,
pressure 90 lbs. The end blew out from excessive pressure, as the
escape from the safety valve was prevented by a plug in the exit pipe.
_No. 21. Birmingham. (Fig. 11.) May 9th. 2 injured._
[Illustration: _Fig. 11._]
Plain Cylinder, 3ft. 2in. long, 1ft. 8in. diameter, plates 5/16 inch,
pressure 30 lbs. Workmanship and material very inferior. Piece of top
ripped out from manhole and allowed manlid to blow out through manhole.
The cause of the explosion was, the large manhole and over-pressure.
The safety valve was too small, and very roughly made.
_No. 22. Hartlepool. (Fig. 12.) May 10th. 1 killed, 1 injured._
[Illustration: _Fig. 12._]
Locomotive, 130 lbs. pressure. Barrel blown away and broken to pieces,
leaving fire and smoke boxes. The cause of explosion was supposed to be
the strain on the boiler caused by its being made a stay to the frame
without allowance for expansion, and thereby weakening a horizontal
seam.
_No. 23. Newark. (Fig. 13.) May 18th. 4 injured._
[Illustration: _Fig. 13._]
Cornish, one tube 20ft. 6in. long, 5ft. 4-1/2in. diameter, tube 3ft.
diameter, plates 3/8 inch, pressure 64 lbs. The ends came out and tube
collapsed for its full length, every joint being broken. The cause of
explosion was bad construction and workmanship, and tube too weak for
pressure.
_No. 24. Tamworth. (Fig. 14.) June 4th. 2 killed._
[Illustration: _Fig. 14._]
Two tube, externally fired, 30ft. long, 7ft. diameter, tubes 2ft. 4in.
diameter, pressure 50 lbs. Two plates lately put in bottom gave way,
and shell rent along bottom and opened out, dividing into several
pieces, which were scattered to great distances, but are arranged in
sketch so as to show their original position. The cause of explosion
was too frequent repair over the fireplace, and external firing.
_No. 25. Dudley. (Fig. 15.) July 10th. 1 killed, 2 injured._
[Illustration: _Fig. 15._]
Balloon, 22ft. diameter, pressure 5 lbs. Bottom blew out and was torn
in pieces. Main portion of shell fell over on to another boiler. The
cause of explosion was deep corrosion along the bottom where it rested
on the brickwork.
_No. 26. Batley. (Fig. 16.) July 11th. 3 killed, 3 injured._
[Illustration: _Fig. 16._]
One tube Cornish, 26ft. long, 8ft. 10-1/2in. diameter, tube 5ft.
diameter, for 8ft. 6in. of front end, tapering to 4ft. diameter at
back, pressure 30 lbs. Rent along bottom, allowing central ring of
plates to open out. The whole boiler was thrown some distance by the
reaction of issuing contents. The cause of explosion was corrosion at
mid-feather wall, the plates being little thicker than paper.
_No. 27. Rotherham. (Fig. 17.) July 13th. none injured._
[Illustration: _Fig. 17._]
Two tube Cornish, 31ft. long, 7ft. diameter, tube 2ft. 7in., tapering
to 2ft., pressure 55 lbs. Left hand tube collapsed, and about the
centre of collapse, plate was torn in two pieces from seam to seam. The
cause of explosion was overheating, because the water was being let low
before all the fire was out.
_No. 28. Bilton. (Fig. 18.) July 24th. 1 injured._
[Illustration: _Fig. 18._]
Locomotive. Side-plate in the upper part of high top fire-box blew
away. The cause of explosion was most likely the boiler being made the
frame of the engine without allowance for expansion.
_No. 29. Ecclesfield. August 5th. 1 killed, 2 injured._
Full particulars were not obtained, but the steam and hot water were
allowed to come in from a neighbouring boiler through the blow-off pipe
while the men were cleaning.
_No. 30. Belfast. (Fig. 19.) August 27th. 7 killed, 3 injured._
[Illustration: _Fig. 19._]
Cornish, 18ft. long, 4ft. 9in. diameter, tube 1ft. 6in. diameter,
plates 3/8 inch, pressure 50 lbs. There were no stays. End plate blew
out while being caulked at a jump joint in back angle iron. The cause
of explosion was bad construction and want of stays, and also want of
proper care in working.
_No. 31. Plashetts. September 2nd. 2 injured._
Locomotive, but no details obtained.
_No. 32. Ashton. September 9th. none injured._
Two flued, 40 lbs. pressure. The cast-iron mouth-piece of manhole
fractured from insufficient strength, and allowed lid and upper flange
to blow off.
_No. 33. Blackburn. October 4th. 4 injured._
Water Heater, made of large bottle-shaped pipes placed in the flue. The
force of explosion caused the neighbouring boilers to be unseated. No
details have been obtained as to the cause of the explosion.
_No. 34. London. (Fig. 20.) October 7th. 1 killed._
[Illustration: _Fig. 20._]
One tube Cornish, 11ft. long, 4ft. diameter, plates 3/8 inch, tube 2ft.
1-1/2in. diameter, pressure 50 lbs. Gave way underneath. Top thrown
upwards. Front part and tube thrown to the front. The cause of the
explosion was extensive corrosion at the bottom where it touched the
walls.
_No. 35. Preston. October 31st. none injured._
Cornish, 26ft. long, 5ft. 6in. diameter, tube 2ft. 11in. diameter,
plates 3/8 inch. Pressure 30 lbs. Tube collapsed for want of proper
strengthening hoops, blowing out back end, and throwing boiler forward.
_No. 36. Durham. (Fig. 21.) November 3rd. 1 killed, 1 injured._
[Illustration: _Fig. 21._]
Plain Cylinder, 19ft. long, 6ft. diameter, pressure 40 lbs. It was 36
years old, and iron deteriorated and also much patched. The cause of
explosion was over-pressure for so old a boiler.
_No. 37. Bradford. (Fig. 22.) November 6th. 2 killed, 3 injured._
[Illustration: _Fig. 22._]
Agricultural, wagon-shaped, 6ft. 5in. long, 3ft. high, 2ft. 4in. wide,
plates 3/8 inch, pressure 50 lbs. Upper portion of barrel blew off. The
cause of the explosion was over-pressure from locked safety valve and
defective construction.
_No. 38. Sheffield. (Fig. 23.) November 7th. 1 injured._
[Illustration: _Fig. 23._]
Plain Cylinder, 12ft. 3in. long, 3ft. 11in. diameter, pressure 20
lbs., flat front, and round back end. Main portion thrown back and
front forward. Front torn all round the root of angle iron, and stay
rivets drawn through flat end. The cause of explosion was weakness of
construction of flat end, and bad safety valve, which could have been
loaded to 60 lbs.
_No. 39. Langley Mill. (Fig. 24.) November 11th. 3 killed, 10 injured._
[Illustration: _Fig. 24._]
Plain Cylinder, 40ft. long, 5ft. diameter, plates 7/16 inch, pressure
45 to 50 lbs. Parted at third seam, and front thrown forward and
main portion backwards. The cause of explosion was a seam-rip of old
standing near patch at place of first rupture.
_No. 40. Bradford. (Fig. 25.) November 14th. 4 killed, 3 injured._
[Illustration: _Fig. 25._]
Breeches tube 25ft. 6in. long, 7ft. 6in. diameter, plates 7/16 inch,
pressure 30 lbs. Front end and fire-grate tubes and taper junction
were thrown to the front in one piece. Main shell not injured. Back
part of tube remained in boiler. Bottom part of taper junction where
flattened to receive the two fire tubes, collapsed upwards. The cause
of explosion was the want of proper stays or strengthening tubes, and
consequent weakness. There was only one safety valve of small size.
_No. 41. Chippenham. (Fig. 26.) November 21st. 3 killed, 2 injured._
[Illustration: _Fig. 26._]
One tube Cornish, 11ft. long, 5ft. diameter, pressure 44 lbs. Tube gave
way at an old crack at back of strap-plate and partially collapsed.
_No. 42. Dudley. (Fig. 27.) November 27th. 1 killed._
[Illustration: _Fig. 27._]
Plain Cylinder, 25ft. long, 6ft. diameter, plates 7/16 inch, pressure
50 lbs. Had been a one tube Cornish, but tube had been taken out,
leaving flat ends. Back end was blown out. Main shell thrown forwards.
The cause of explosion was weakness of construction in not sufficiently
strengthening the flat end to compensate for loss of tube.
_No. 43. Shields. (Fig. 28.) December 7th. none injured._
[Illustration: _Fig. 28._]
One tube Cornish, 28ft. long, 6ft. diameter, tube 4ft. diameter, plates
3/8 inch. Pressure 28 lbs. Tube collapsed for the whole length, but no
particulars of the cause obtained.
_No. 44. Belfast. December 14th. 2 killed._
Some repair had been done to a Boiler, and a blank flange used to stop
off the steam was being removed without shutting the stop-valves to the
other boilers, and the joint blew out when the bolts were loosened.
_No. 45. Manchester. (Fig. 29.) December 23rd. 6 killed, 4 injured._
[Illustration: _Fig. 29._]
One tube Cornish, 18ft. long, 6ft. diameter, tube 3ft. 2in. diameter,
plates 3/8 inch. Pressure 25 lbs. Rent along bottom, and two rings
of plates blown away, but tube and ends not much injured. The cause
of explosion was extensive corrosion on the part resting on the
mid-feather wall.
_No. 46. Barnsley. (Fig. 30.) December 28th. 1 killed._
[Illustration: _Fig. 30._]
Balloon, 11ft. 6in. diameter, and 11ft. 6in. high, plates 3/8 inch.
Bottom domed up 3ft. 6in. over fire; ordinary pressure 8 lbs. Boiler
had worked two days at 25 lbs. pressure, but safety valve loaded to 16
lbs. The cause of explosion was undue pressure for an old boiler of
such weak shape.
_No. 47. Leeds. (Fig. 31.) December 30th. 2 injured._
[Illustration: _Fig. 31._]
Two tube Cornish, 22ft. long, 7ft. 2in. diameter, tubes 2ft. 7in.
diameter, pressure 15 lbs. Rent along bottom, and shell blown away,
leaving tubes and ends nearly uninjured. The cause of explosion was,
that the bottom was corroded to a knife edge all along the mid-feather
wall.
_No. 48. Shields. (Fig. 32.) December 31st. 2 killed, 1 injured._
[Illustration: _Fig. 32._]
Plain Cylinder, 30ft. long, 4ft. 6in. diameter, plates 3/8 inch,
pressure 29 lbs. Rent over fire near where a new plate had lately been
put in. Front part of shell opened out and rent, and back end blew away
in one piece. The cause of explosion was deterioration from 20 years'
wear, and bad management.
BOILER EXPLOSIONS IN 1868.
_No. 1. Newcastle. (Fig. 1.) January 13th. none injured._
[Illustration: _Fig. 1._]
One of three. Plain Cylinder, 27ft. long, 5ft. diameter, 3/8 inch
plates, 35 lbs. pressure. The boiler was much torn up, and all the
fragments thrown to the front of their original position. The cause of
the explosion was that the boiler was very old and much deteriorated,
so that it was unable to bear the ordinary pressure. The longitudinal
arrangement of the plates, and the entrance of the feed directly on the
bottom, no doubt contributed to the weakness.
_No. 2. Glasgow. January 27th. 1 killed, 5 injured._
One of four. Kier or steam chamber, and not used for generating steam.
It was 8ft. 6in. high, 6ft. 6in. diameter, 7/16 inch plates, 40 lbs.
pressure. It was rent from top to bottom, owing to inferior iron and
workmanship.
_No. 3. Sheffield. (Fig. 2.) January 28th. 1 killed._
[Illustration: _Fig. 2._]
One of four. One tube Cornish, 26ft. 4in. long, 6ft. 6in. diameter.
Tube 3ft. 9in. diameter, 3/8 inch plates, 15 lbs. pressure. The dotted
line shows outside shell of boiler. The tube collapsed from end to end
while the steam was being raised, owing to the weakness of so large a
tube without strengthening rings.
_No. 4. London. (Fig. 3.) January 29th. 1 killed._
[Illustration: _Fig. 3._]
One tube Cornish, 18ft. 3in. long, 4ft. 10in. diameter, 3/8 inch
plates. Tube 3ft. diameter, 5/16 inch plates. In sketch the external
shell is shown in outline to allow the tube to be seen. The tube
collapsed owing to shortness of water, and rent open at one seam,
allowing the contents to issue violently, although the boiler itself
was not disturbed.
_No. 5. Bolton. (Fig. 4.) January 31st. 1 injured._
[Illustration: _Fig. 4._]
Locomotive, 90 lbs. Sketch shows interior view of fire-box with front
removed. The left side of the copper fire-box burst inwards owing to
the plate in line of fracture being corroded to less than 1/8 inch.
_No. 6. Stoke. (Fig. 5.) February 6th. none injured._
[Illustration: _Fig. 5._]
One of three. One tube Cornish, with two external fire grates with a
water tube over each fire. It was 30ft. 2in. long, 6ft. diameter. Tube
3ft. diameter, 3/8 inch plates, 40 lbs. pressure. External shell is
shown in dotted lines to allow of the tubes being seen. The tube had
formerly been placed rather higher in the boiler. The tube collapsed
sideways, having become overheated from shortness of water. The boiler
itself was but little disturbed.
_No. 7. Kelso. (Fig. 6.) February 11th. none injured._
[Illustration: _Fig. 6._]
One tube Cornish, 9ft. 9in. long, 4ft. 6in. diameter. Tube 2ft. 3in.
diameter, 5/16 inch plates, 30 lbs. pressure. The boiler rent open at
the bottom, and was thrown a considerable distance by the reaction
of the issuing contents. The plates along the bottom were reduced by
corrosion to 1/16 inch where in contact with the brickwork, so that the
boiler was unable to bear the usual working pressure.
_No. 8. Durham. (Fig. 7.) February 12th. 2 killed, 1 injured._
[Illustration: _Fig. 7._]
One of four. External shell is shown in dotted lines in sketch, to
allow the tubes to be seen. It was 20ft. long, 7ft. diameter, 40 lbs.
pressure. The two internal fire grates in the flues were 2ft. 8in.
diameter, which joined at the back with a central return flue to a
chimney passing out of the top of the boiler. The sides of flues were
flattened to allow them to be packed closer together, and especially
the central return flue, which was flattened on both sides, and thus
rendered so weak that the left side collapsed and allowed the contents
of the boiler to issue, blowing out the grate on the left side.
_No. 9. Halifax. (Fig. 8.) March 3rd. none injured._
[Illustration: _Fig. 8._]
Plain Cylinder, with flat ends, 18ft. 6in. long, 3ft. 11in. diameter,
3/8 inch plates, 50 lbs. pressure. The back end gave way at the root
of the angle iron all round, and was thrown 60 yards to the rear. The
boiler was forced forward, and tilted up by the reaction of the issuing
contents, and forced through a wall. The cause of explosion was the
want of sufficient stays to the flat end.
_No. 10. Newcastle. (Fig. 9.) April 4th. 1 killed, 4 injured._
[Illustration: _Fig. 9._]
One of four. Plain Cylinder, 28ft. long, 6ft. diameter, 3/8 inch
plates, 30 lbs. pressure. The boiler was much torn and scattered,
and much damage was done. The plates were improperly arranged
longitudinally. The boiler gave way at a patch lately put on, and had
become so deteriorated by nearly 30 years' wear, that it was unable to
bear the usual pressure.
_No. 11. Aberdeen. April 7th. 1 killed._
Two tube Cornish, 6ft. diameter. Few particulars have been obtained.
The upper part of front end was blown out and did considerable damage.
Most likely this was for want of proper stays.
_No. 12. April 15th. 1 injured._
One of four. One tube Cornish, 15ft. long, 4ft. 7in. diameter. Tube
2ft. 8in. diameter, 1/4 inch plates, 60 lbs. pressure. The tube
collapsed and rent open near the bridge, owing to its weakness with
such thin plates and no strengthening rings.
_No. 13. Cornwall. May 1st. 1 killed._
No details obtained. One tube Cornish. Tube collapsed, owing to its
weakness without strengthening rings.
_No. 14. Cornwall. May 9th. none injured._
Few particulars obtained. One tube Cornish, 34ft. long. Tube 4ft.
diameter, 3/8 inch plates, 40 lbs. pressure. Tube collapsed owing to
its weakness without strengthening rings.
_No. 15. Oldham. May 11th. 1 killed, 1 injured._
A very small plain cylinder, 3ft. 5in. long, 1ft. 8in. diameter, 1/4
inch plates, 45 lbs. pressure. It burst at a faulty place at the lower
part of the back, on the left hand side, allowing the hot water to
issue, but the boiler was not much disturbed.
_No. 16. Bristol. May 11th. 1 killed._
Marine. Single internal fire grate, with small return tube, 7ft. 9in.
long, 5ft. 4in. diameter, 3/8 inch plates, tube 2ft. 7in. diameter, 1/4
inch plates, 62 lbs. pressure. Tube collapsed and rent open owing to
its weak, corroded, and deteriorated condition, and the contents issued
so violently, as to cause much damage to the boat.
_No. 17. Hull. (Fig. 10.) May 12th. 2 killed, 2 injured._
[Illustration: _Fig. 10._]
One of two. Plain Cylinder, 4ft. 9in. long, 3ft. diameter, 1/4 inch
plates, 25 lbs. pressure. This was a second-hand boiler, and rent into
several pieces just after being put to work, owing to its having become
thinned to 1/8 inch by corrosion.
_No. 18. Coatbridge. May 15th. 1 injured._
Plain Cylinder, flat ends, 15ft. long, 5ft. diameter, 3/8 inch plates,
30 lbs. pressure. The back end blew out and caused considerable
damage, and the boiler was thrown some distance. The end was very
insufficiently stayed.
_No. 19. Gravesend. (Fig. 11.) May 28th. 2 killed._
[Illustration: _Fig. 11._]
One of two. Marine, 13ft. 5in. long, 7ft. 2in. diameter, 5/16 inch
plates, 25 lbs. pressure. The fire was in two internal furnace tubes
united at the back, and the flame was returned to the front by four
smaller tubes. The furnace tubes were of exceedingly weak shape as
the sides followed the curve of the shell, but were not attached to
it by proper stays, so that the left hand tube collapsed upwards, and
one seam rent open and allowed the contents to violently escape. It
is probable there may have been greater pressure than usual at the
time, but the furnaces without stays were unsafe, even at the ordinary
pressure.
_No. 20. Durham. (Fig. 12.) June 8th. 2 killed._
[Illustration: _Fig. 12._]
One of eight. Plain Cylinder, 30ft. long, 6ft. diameter, 3/8 inch
plates, 35 lbs. pressure. The plates were arranged longitudinally.
Boiler had worked 27 years, and was much deteriorated, and gave way at
an old fracture over the grate, and was torn into 4 pieces, which were
thrown a great distance.
_No. 21. Huddersfield. (Fig. 13.) June 20th. 1 killed, 6 injured._
[Illustration: _Fig. 13._]
One tube Cornish, 24ft. long, 6ft. diameter. Tube 3ft. 3in. diameter,
3/8 inch plates, 40 lbs. pressure. The seams were arranged diagonally,
but the rents had not followed the seams, but had torn the plates. The
shell gave way where extensive corrosion had reduced the plates to 1/8
inch in thickness, and all the shell was blown off, and the tube thrown
over and turned end for end.
_No. 22. June 22nd. none injured._
Two tube Cornish, 27ft. long, 7ft. 6in. diameter. Tube 3ft. diameter,
7/16 inch plates, 70 lbs. pressure. Left hand tube collapsed from end
to end owing to its weakness without strengthening rings.
_No. 23. Halifax. July 9th. 6 injured._
Two tube Cornish, 20ft. long, 6ft. 3in. diameter. Tube 2ft. 3in.
diameter, 3/8 inch plates, 55 lbs. pressure. The shell was blown
completely off, leaving the tubes and ends intact. The bottom was
extensively corroded, so that the strength of the boiler was so reduced
as not to be able to bear the usual pressure.
_No. 24. Wrexham. (Fig. 14.) July 9th. 2 injured._
[Illustration: _Fig. 14._]
Two Furnace Upright, 22ft. high, 8ft. 10in. diameter, 3/8 inch plates,
14 lbs. pressure. Small piece was blown out of the bottom, and the
issuing contents disturbed the brickwork surrounding the boiler. The
plate was corroded to a knife edge in the line of fracture, from the
leaking of the adjacent blow-pipe joint.
_No. 25. Dundee. July 13th. 1 killed, 1 injured._
Two tube Cornish, 28ft. 6in. long, 7ft. diameter, 3/8 inch plates. Tube
2ft. 2in. diameter, 7/16 inch plates, 40 lbs. pressure. Both furnaces
collapsed, and ruptured from overheating through shortness of water.
_No. 26. Halifax. July 14th. 3 injured._
Locomotive, 10ft. 9in. long, 4ft. diameter, 1/2 inch plates, 130
lbs. pressure. Nearly all the barrel was blown away. The inside was
very much corroded, and there was a deep furrow at the line of first
rupture, caused by the alteration in form of the boiler in the strain
of working. This is usually obviated by substituting butt for lap
joints, so that the pressure does not tend to alter the circular shape
of barrel.
_No. 27. Limerick. July 21st. 2 killed, 1 injured._
Locomotive. Few particulars are obtained. The connecting rod broke, and
the loose end attached to the crank pierced the boiler, and allowed the
contents to issue and scald those near.
_No. 28. Hanley. (Fig. 15.) July 31st. 1 killed._
[Illustration: _Fig. 15._]
One of three. Plain Cylinder, 36ft. 9in. long, 5ft. diameter, 3/8 inch
plates, 50 lbs. pressure. The boiler parted at a seam over the fire
bridge. The front end was thrown upwards and to a considerable distance
to the front. The back part of the boiler was forced backwards. The
first rent took place at a seam-rip at the ruptured seam, and the
boiler exploded while the fire was being drawn in order to repair the
faulty place.
_No. 29. Easter Ross. August 8th. 2 killed, 3 injured._
Agricultural. It exploded while travelling, by its own steam power. The
engine had stuck fast, and extra pressure of steam was raised to try
and extricate it. The boiler was torn in pieces, and scattered to a
great distance.
_No. 30. Bilston. (Fig. 16.) August 17th. 1 killed._
[Illustration: _Fig. 16._]
One of two. Plain Cylinder, 30ft. long, 5ft. diameter, 3/8 inch plates,
46 lbs. pressure. The boiler gave way on the side where the plates were
overheated by the water being too low, and the front part of the shell
was flattened out and thrown some distance to the rear, as its course
was influenced by its remaining attached to the rest of the boiler as
by a hinge; while the front end was rent into several pieces, and the
back end was thrown also to the rear and rolled down a declivity into a
stream.
_No. 31. Liverpool. (Fig. 17.) August 20th. 7 killed, 5 injured._
[Illustration: _Fig. 17._]
Two Furnace Chimney Boiler, 42ft. 4in. high, 6ft. 9in. diameter,
1/2 inch plates, 50 lbs. pressure. Nearly half the bottom plate was
blown out, and the issuing contents found their way into the furnace
and increased the damage. The line of rupture near where it joined
the shell was corroded almost to a knife edge, which so reduced its
strength as to make it unable to bear the usual working pressure of
steam, in addition to that of the column of water in the boiler.
_No. 32. Accrington. August 31st. 1 killed._
A Kier or Steam Bleaching Chamber, somewhat like No. 2, and not used
for generating steam, 9ft. high, 8ft. diameter, 1/2 inch plates, 50
lbs. pressure. The bottom blew out, and the shell was torn to pieces.
The cause of explosion was weakness of the ruptured end, and want of
care in working.
_No. 33. Birmingham. September 11th. 1 killed, 1 injured._
Two tube Cornish. The manlid was wrongly fixed outside with internal
clamps. It was being screwed up tighter to stop leaking when the bolt
broke, and the lid came off and allowed the contents of the boiler to
escape.
_No. 34. Greatbridge. (Fig. 18.) September 21st. none injured._
[Illustration: _Fig. 18._]
One of four. One tube, externally fired, 18ft. 6in. long, 6ft. 6in.
diameter. Tube 3ft. diameter, 1/2 inch plates, 40 lbs. pressure. In
sketch the shell is shown in dotted lines to allow the tube to be
seen. The tube collapsed from end to end and ruptured at two seams,
and the contents issued so violently as to knock down the brickwork
and displace the boiler. The tube was in a very weak and corroded
condition, and unable to bear the usual working pressure.
_No. 35. Moxley. (Fig. 19.) September 28th. 13 killed, 2 injured._
[Illustration: _Fig. 19._]
One of four. Four Furnace Upright, 22ft. high, 10ft. 6in. diameter,
7/16 inch plates, 40 lbs. pressure. The boiler was rent into nine
pieces, one of which was not found. The dotted line in sketch shows the
outline of the boiler before explosion, and the fragments are arranged
as nearly as possible in their original position. The first rent was at
a seam-rip opposite the largest furnace, from whence the rupture opened
in every direction. This seam-rip must have existed some time before
explosion, and must have extended from rivet to rivet, until the boiler
was so much weakened as to be unable to bear the usual pressure.
_No. 36. Winsford. September 30th. 1 killed._
Plain Cylinder. Few particulars obtained. The end over the fire burst
open and allowed the contents to escape. A thick accumulation of scale
on the bottom had caused the plate to become overheated by preventing
proper contact of the water.
_No. 37. Elsecar. (Fig. 20.) October 2nd. 2 killed._
[Illustration: _Fig. 20._]
One of four. Two Furnace Upright, 21ft. high, 7ft. diameter, 7/16 inch
plates, 58 lbs. pressure. A large piece of plate was blown out of the
side of the boiler, and the reaction of the issuing contents threw
the boiler over on to its side. The plate was said to be overheated
from shortness of water, but as the centre tubes were uninjured,
the ruptured plate may have become overheated from the intense heat
impinging on one place, causing so rapid a generation of steam as to
prevent proper contact of water.
_No. 38. Glasgow. October 12th. 1 killed, 1 injured._
Plain Cylinder, 39ft. long, 5ft. diameter, 3/8 inch plates. A small
piece of plate about one-and-half-feet area blew out of the bottom,
and the contents issued so violently as to do much damage, although
the boiler itself was not otherwise injured. The ruptured plate was
corroded, to 1/16 inch thickness by the leaking of seams, caused by the
feed water entering close to the bottom of the boiler.
_No. 39. Swansea. October 13th. 2 killed, 1 injured._
One of twenty-four. One tube Cornish, worked by two furnaces, 23ft.
long, 6ft. 6in. diameter. Tube 3ft. 9in. diameter, 1/2 inch plates, 40
lbs. pressure. The tube was divided by a wall down the middle. The tube
collapsed sideways. It was said that one side was overheated through
shortness of water, but it is more than probable the explosion was
owing to the weakness of so large a tube without strengthening rings.
_No. 40. Preston. October 16th. 2 injured._
This was an arrangement of pipes, called an "Economiser," placed in the
flues of a set of boilers for heating the feed water. It was shattered
into fragments, causing considerable damage. As the whole apparatus was
said to be in proper order, the explosion had been attributed to coal
gas in the flues, and some peculiarities in the ruptured pipes bear out
the supposition.
_No. 41. London. (Fig. 21.) October 19th. 6 injured._
[Illustration: _Fig. 21._]
Kitchen Boiler, for supplying hot water to the top of a lofty house.
It was rectangular, 3ft. 6in. wide, 2ft. 6in. high, and 1ft. deep. The
front was blown out and caused considerable damage. The boiler was of
most weak shape, and although no pressure of steam was intended, it
appeared to have been overlooked that the column of water to the top of
the house would give sufficient pressure to make such a boiler unsafe.
_No. 42. London. (Fig. 22.) October 30th. 2 killed, 10 injured._
[Illustration: _Fig. 22._]
One tube Cornish, 15ft. long, 5ft. diameter, 3/8 inch plates, 50 lbs.
pressure. Tube oval at fire end, 2ft. 11in. wide, 2ft. 6in. high.
Circular beyond bridge, tapering to 2ft. diameter at back end. In
sketch outside shell is shown in dotted lines to allow tube to be seen.
The front of the tube burst beneath the fire bars, and rent upwards.
Tube collapsed beyond bridge and rent open at each side, but remained
intact over the fire. The oval part of the tube was of so very weak a
shape, that it burst open, and the collapse of the back part followed
as a consequence.
_No. 43. Birmingham. (Fig. 23.) December 2nd. 1 injured._
[Illustration: _Fig. 23._]
Small Portable Boiler, 4ft. 9in. high, 2ft. 3in. diameter, 1/4 inch
plates, 40 lbs. pressure. The shell was rent completely off. The
explosion arose from the large size of the manhole, which had no guard
ring on the edge, and the lid had strained it and caused several
cracks, and at last forced itself through the boiler, and the rents
spread in every direction, and caused the break up of the boiler.
_No. 44. Newcastle. (Fig. 24.) December 11th. 3 killed, 3 injured._
[Illustration: _Fig. 24._]
Marine Upright, 13ft. 3in. high, 6ft. 6in. diameter, 1/2 inch plates.
Internal fire-box 8ft. 6in. high, 6ft. diameter at bottom, 5ft. 3in.
diameter at the top, 3/8 inch plates, 50 lbs. pressure. In the sketch
the shell is shown in dotted lines to allow the internal fire-box to
be seen. The boiler was rent into many pieces, many of which were lost
in a river, so that a satisfactory conclusion as to the cause of the
explosion was impossible. The boiler was not very firmly stayed, and it
is supposed that it was weakened by corrosion round the fire doors.
_No. 45. Hartlepool. December 29th. 1 injured._
Marine, with 3 internal fireplaces joined at the back. The back of the
junction tube gave way at a place deeply corroded, and allowed the
contents of the boiler to escape.
* * * * *
NOTE.--Two more illustrations may be given which are not sufficiently
important to include in the above list.
* * * * *
_Willenhall. (Fig. 25.) December 24th. none injured._
[Illustration: _Fig. 25._]
One of two. Plain Cylinder, 25ft. 6in. long, 5ft. 6in. diameter, 3/8
inch plates, 30 lbs. pressure. The water was allowed to get low, and
the overheated plates opened and allowed the steam to escape harmlessly.
_Stoke. (Fig. 26.) December 9th. none injured._
[Illustration: _Fig. 26._]
One of eight. Four Furnace Upright, 22ft. high, 9ft. diameter, 7/16
inch plates, 45 lbs. pressure. The water was allowed to get so low
that the shell was overheated and rent, and the side tube slightly
collapsed, and the injury was not discovered until the feed water had
risen up to the rupture, when it ran into the furnaces without causing
any violent explosion, although cold water had been put into a red hot
boiler.
* * * * *
STOURBRIDGE:
PRINTED BY R. BROOMHALL, HIGH STREET.
BOILER EXPLOSIONS IN 1869.
_No. 1. Chesterfield. (Fig. 1.) January 14th. 4 killed, 2 injured._
[Illustration: _Fig. 1._]
One of two. One tube Cornish, 26ft. 6in. long, 6ft. diameter, tube
3ft. 3in. diameter, 3/8 inch plates, 45 lbs. pressure. The gauge glass
was broken and the float was either out of order or unobserved, as the
water was allowed to get 9 inches below the usual level, so that the
crown of the furnace became overheated and collapsed, and rent open
where a patch had been put on some little time before.
_No. 2. Manchester. (Fig. 2.) January 22nd. none injured._
[Illustration: _Fig. 2._]
Locomotive. The barrel was 10ft. 6in. long, 4ft. diameter, 7/16 inch
plates, 130 lbs. pressure. The engine was 14 years old, and had lately
been tested to 180 lbs. hydraulic pressure. The seams near the bottom
were so deeply "furrowed" or corroded just above the lap joint in a
continuous line that they rent open.
_No. 3. Greatbridge. (Fig. 3.) January 26th. 1 killed, 1 injured._
[Illustration: _Fig. 3._]
One of two. Plain Cylinder, with flat ends, 22ft. long, 4ft. 3in.
diameter, 3/8 inch plates, 60 lbs. pressure. There had formerly been
a tube with internal furnace, and this had been removed without
sufficient stays to compensate for the loss of strength. The plates
were arranged in the weakest way with seams in one line from end to
end, and the strength of the boiler had been further reduced by very
frequent patching. Fracture commenced about the centre of the long seam
under the dome, which had gradually ripped from rivet to rivet, until
unable to bear the ordinary pressure. The boiler exploded because it
was completely worn out, and shows how treacherous and uncertain a
boiler becomes by constant patching and alteration. See also No. 45.
_No. 4. Rotherham. (Fig. 4.) January 27th. 1 injured._
One of five. Plain cylinder, with dished ends, 36ft. long, 4ft. 6in.
diameter, 3/8 inch plates, 55 lbs. pressure. It had worked about 8
years, and was much patched over the fire end, and had lately been put
into what was supposed to be thorough repair. As there was no need of
an inquest the wreck was quickly cleared and some of the fragments
cut up, but enough particulars were obtained to give some idea of the
nature of the explosion.
[Illustration: _Fig. 4._]
The first rent must have taken place in the bottom seams over the fire,
where weakened by frequent repair.
_No. 5. Durham. (Fig. 5.) February 2nd. 1 killed, 4 injured._
[Illustration: _Fig. 5._]
One of twelve. Plain cylinder, 13 years old, 30ft. long, 6ft. diameter,
3/8 inch plates, 35 lbs. pressure. The plates were arranged lengthways,
so that the seams were in continuous lines from end to end. This has
often been mentioned as giving far less strength than where the plates
are placed in rings. There had been considerable repair at various
times, and just previous to explosion the boiler had been placed as
was supposed in thorough repair, and some new plates had been put
over the fireplace. The first rent appears to have taken place where
one of these plates joined the old work. The rent quickly extended
along a straight seam, and the boiler was blown into three pieces.
The explosion was simply caused by the boiler having been weakened by
frequent repair until unable to bear the ordinary working pressure.
Externally fired boilers, when so frequently patched become treacherous
and uncertain, and more especially so when the seams run from end to
end. See No. 59.
_No. 6. South Wales. February 12th. 2 injured._
This was a colliery boiler. Very few particulars were obtained. The
roof of the engine house was blown off, the boiler was torn from its
fittings and turned right round, and knocked down three walls and fell
in an upright position.
_No. 7. Cornwall. (Fig. 6.) February 15th. none injured._
[Illustration: _Fig. 6._]
One of four. One tube Cornish, 37ft. 6in. long, 7ft. diameter. Tube
4ft. 4in. diameter, 7/16 inch plates, 40 lbs. pressure.
The tube collapsed for the whole length beyond the bridge, and the back
end of boiler was blown out. The portion of tube over the fire was left
intact, and the fusible plug was uninjured. The cause of the explosion
was the weakness of the tube of such large diameter and so great
length. See No. 57.
_No. 8. Yarmouth. (Fig. 7.) February 23rd. 3 injured._
[Illustration: _Fig. 7._]
Marine, 17ft. long, and 15ft. high, 3/8 inch plates, 15 lbs. pressure.
The top was blown off, the plates having been extensively corroded.
The boiler had also been much weakened by altering it from a round to a
flat top without sufficient stays.
_No. 9. Drogheda. March 3rd. 2 injured._
The roof of a shed was blown off, but no particulars have been obtained.
_No. 10. West Bromwich. (Fig. 8.) March 9th. 3 injured._
[Illustration: _Fig. 8._]
One of two. Plain cylinder, 25ft. long, 4ft. 6in. diameter, 3/8 inch
plates, 42 lbs. pressure. The boiler had been very frequently repaired,
and a seam gave way where a large patch had just previously been put
on over the fire, in doing which the rivet holes of the old work had
evidently been cracked, rendering the boiler unable to bear the usual
working pressure. See No. 45.
_No. 11. Cornwall. March 18th. none injured._
One tube Cornish. The tube collapsed from want of water.
_No. 12. Broseley. (Fig. 9.) April 1st. 1 killed, 4 injured._
[Illustration: _Fig. 9._]
Multitubular, 9 years old, 8ft. 6in. long, barrel 6ft. long, and 2ft.
4in. diameter, 5/16 inch plates, 50 lbs. pressure. The cylinder was
attached to right side of the top of the boiler over the fire box, and
on the other side there was a very large manhole, the edges of which
were corroded, and so strained and cracked by the screwing up of the
manlid, as to be unable to bear the working pressure. The rent started
in all directions from the manhole allowing the boiler to split up into
three pieces. See Nos. 18 and 36.
_No. 13. Cornwall. April 11th. none injured._
One tube Cornish--but no particulars.
_No. 14. Barking. (Fig. 10.) April 19th. 4 killed, 2 injured._
[Illustration: _Fig. 10._]
Portable Crane, 8 years old, 8ft. 3in. high, 4ft. 4in. diameter, with
internal fire box, 6ft. high and 3ft. 6in. diameter, and chimney
passing out at the top, 5/16 inch plates, 40 lbs. pressure. The
internal fire box crushed in sideways, and the shell was rent into
several pieces. The attachment of the fire box to the shell was made
by bending the plates, as shown in enlarged sketch, and this is not so
rigid as double angle iron and had evidently strained the chimney tube.
This weakness had been so increased by deep corrosion just at the bend
of the plates that it had given way. The havoc and loss of life was far
greater than would have been supposed possible from so small a boiler,
but similar cases are mentioned in No. 43, 1868, and No. 57, 1866.
_No. 15. Durham. (Fig. 11.) April 23rd. none injured._
[Illustration: _Fig. 11._]
One of two. Plain cylinder, with plates arranged lengthways, 30ft.
long, 6ft. diameter, 3/8 inch plates, 9 lbs. pressure. A seam gave
way on the right side over the fire and immediately rent along the
straight seam from end to end, and the boiler was thrown in one mass a
great distance to the left. The boiler was very old and much weakened
by frequent repair, and at the time of explosion was being imprudently
worked at twice its usual pressure for a temporary purpose. See No. 59.
_No. 16. Bury. (Fig. 12.) April 29th. none injured._
[Illustration: _Fig. 12._]
Double Furnace, internally fired, 28ft. long, 7ft. diameter, 7/16 inch
plates, 55 lbs. pressure. Furnace tubes 7ft. long, 3ft. diameter, 3/8
inch plates. The crown of the left hand furnace collapsed and the right
hand furnace was slightly altered in shape, as if from overheating
by shortness of water, although the true cause was supposed to be
the thickening of the water by use of anti-incrustation composition,
preventing proper contact of the water with the plates.
_No. 17. Liverpool. (Fig. 13.) May 12th. 1 killed, 1 injured._
[Illustration: _Fig. 13._]
Plain cylinder, 10ft. long, 3ft. diameter, 3/8 inch plates, 50 lbs.
pressure. The ends were flat made of plates, with turned edges, and
there was such extensive corrosion on the inside of the bend that the
back end came out and was blown 30 yards to the right and rear, the
rest of the boiler being thrown to the front. The front plate had been
repaired with angle iron where similarly corroded, and the shell was
also much patched. The fractured edges were not 1/16 inch thick, so
that the boiler was not fit to carry any pressure with safety.
_No. 18. Abingdon. (Fig. 14.) May 13th. 2 killed, 2 injured._
[Illustration: _Fig. 14._]
Revolving Rag boiler, 16ft. long, 6ft. diameter, 7/16 in. plates. There
was no fire applied to the boiler itself, but it received steam through
one end from other ordinary boilers at 50 lbs. pressure. There were two
large rectangular manholes for putting in and taking out the rags, with
cast iron frames and lids, attached by bolts with large nuts or clamps.
The explosion appeared to have taken place when, in revolving, the
manlids were approaching the bottom, and the first part to give way was
at one of the manholes where the frame was previously broken. The cause
of the explosion was the weakness of the manholes, which were very
large, and both in the same line, and the attachment of the lids was
insecure, as the bolts did not go through the lids, or in any way help
to compensate for the large portion of the plate cut away. The boiler
was only supported at each end, and had to act as a hollow girder to
bear not only its own weight but the repeated shocks of the heavy
material inside falling over and over in addition to the pressure. See
Nos. 41 and 63, 1866.
_No. 19. Glasgow. May 19th. 1 killed, 1 injured._
Two tube Cornish. One of the tubes collapsed for a length of 8 feet
having become overheated through shortness of water.
_No. 20. Durham. (Fig. 15.) May 29th. 3 injured._
[Illustration: _Fig. 15._]
One of ten, 16 years old, Plain Cylinder with plates arranged
lengthways, 34ft. long, 5ft. 6in. diameter, 7/16 inch plates, 50 lbs.
pressure. The boiler gave way at one of the long straight seams near
the bottom, and rent into five pieces, which were scattered to wide
distances, but are so drawn in sketch as to show whereabouts in the
boiler they came from. The boiler had been weakened by frequent repair
until unable to bear the ordinary pressure. See No. 59.
_No. 21. South Wales. (Fig. 16.) May 31st. 5 killed, 4 injured._
[Illustration: _Fig. 16._]
One of three, very old, plain Cylinder, with flat ends, 34ft. long,
6ft. diameter, 3/8 inch plates, 40 lbs. pressure. There had formerly
been a tube through the boiler, and when this was taken away new flat
ends had been put in without sufficient stays to compensate for the
loss of the tube. The front end was blown out, and the reaction sent
the boiler upwards and broke it into three pieces. See No. 47.
_No. 22. Bingley. (Fig. 17.) June 9th. 15 killed, 33 injured._
[Illustration: _Fig. 17._]
Two tube Cornish, 16ft. long, 6ft. 9in. diameter, 7/16 inch plates,
50 lbs. pressure. Tubes 2ft. 6in. diameter. The bottom was so much
corroded that it rent open, and the boiler was torn to pieces which
were scattered to wide distances. The boiler had been much neglected
and badly used, and the safety valve was insufficient, of bad
construction, and overloaded, and the alarm whistle was gagged.
_No. 23. Cornwall. June 14th. 1 injured._
Cornish, but no particulars have been obtained.
_No. 24. Durham. (Fig. 18.) June 16th. 3 killed, 1 injured._
[Illustration: _Fig. 18._]
One of three. Plain Cylinder, with plates arranged lengthways, 30ft.
long, 6ft. 6in. diameter, 3/8 inch plates, 28 lbs. pressure, 25 years
old.
A seam gave way over the fire where there had been frequent repair,
and the boiler was rent into two pieces, which were thrown to some
distance. See No. 59.
_No. 25. Airdrie. June 23rd. 2 killed, 3 injured._
Two tube Cornish, 35ft. long, 6ft. diameter. Tube 3ft. 2in. diameter
over fire, and 2ft. diameter beyond, 50 lbs. pressure. The tube
collapsed over the fire, having been very much weakened by frequent
repair.
_No. 26. Nuneaton. (Fig. 19.) July 5th. 3 injured._
[Illustration: _Fig. 19._]
Plain Cylinder, 25ft. long, 4ft. 6in. diameter, 7/16 inch plates, 25
lbs. pressure. The plates along the line of rupture were corroded to
1/16 inch, and in some places much less, so that the boiler was quite
unfit for the ordinary working pressure.
_No. 27. Birmingham. (Fig. 20.) July 6th. 1 injured._
[Illustration: _Fig. 20._]
Small Plain Cylinder, 5ft. long, 2ft. 2in. diameter, 1/4 inch plates,
25 lbs. pressure. Both sides of the boiler were corroded nearly through
so that the strength was entirely gone, and it rent in two at the
ordinary pressure.
_No. 28. Wishaw. July 9th. 2 killed, 2 injured._
One of six. Breeches Tube. The tube or combustion chamber collapsed,
having become overheated through shortness of water.
_No. 29. Kidderminster. (Fig. 21.) July 16th. 1 killed, 4 injured._
[Illustration: _Fig. 21._]
Plain Cylinder, 21ft. long, 4ft. 6in. diameter, 3/8 inch plates, 50
lbs. pressure. The boiler was very old and very much corroded. It had
slightly rent open at some former time, and a most wretchedly made
patch, shown in enlarged sketch, had been put on to stop leaking, made
of thin sheets of iron inside and out and pasteboard between, held
together by 36 slight bolts. Of course this patch did not restore the
strength of the boiler, and it soon leaked badly, and the leaking
hastened the corrosion of the plate below, until it was nearly eaten
away, and quite unfit to bear the working pressure.
_No. 30. Leeds. July 19th. 4 injured._
One of three, 12 years old. Two tube Cornish, 32ft. long, 7ft. 6in.
diameter. Tube 2ft. 10in. diameter, 3/8 inch plates, 45 lbs. pressure.
The right hand tube collapsed from end to end sideways, and ruptured
in the furnace, and part of the tube was blown out. The cause of the
explosion was simply the weakness of the tube without strengthening
rings.
_No. 31. South Wales. (Fig. 22.) July 19th. 1 killed._
[Illustration: _Fig. 22._]
One of two. Plain Cylinder, 32ft. long, 5ft. diameter, 3/8 inch plates,
40 lbs. pressure. It gave way where deeply corroded on the inside.
_No. 32. Burslem. (Fig. 23.) July 22nd. 1 killed, 3 injured._
[Illustration: _Fig. 23._]
One of six. Plain Cylinder, 36ft. long, 6ft. diameter, 3/8 inch plates,
50 lbs. pressure. Although the boiler was not an old one, it had been
much repaired at the seams with strap plates. It was said that the
water was very bad, and deposited much mud, which allowed the seams to
get overheated and injured. The seam which rent was an original one,
and no doubt was ripped as the others had been before repair, and that
this rip extended from hole to hole until a rupture at the ordinary
pressure was the result.
_No. 33. Preston. August 4th. 1 killed._
Locomotive. In shunting the engine was dragged under a bridge that was
not intended for locomotives to pass, and the dome was knocked off.
_No. 34. London. (Fig. 24.) August 11th. 3 killed._
[Illustration: _Fig. 24._]
Marine, 8ft. long, 5ft. 6in. diameter, 3/8 inch plates, 80 lbs.
pressure. The flat front end gave way at the angle iron all round,
allowing the front with tubes attached, and the shell to be thrown in
opposite directions.
The front being flat was very weak, and depended for its strength on
gusset stays and small bolts connecting the back of the combustion
chamber and the round end of the shell. These stays were very
defective and insufficient, and the angle iron was bad and not welded
into one ring, and the boiler was therefore unfit to bear the ordinary
pressure, and gave way at the weakest place.
_No. 35. Cornwall. (Fig. 25.) August 16th. none injured._
[Illustration: _Fig. 25._]
One tube Cornish, 32ft. long, 6ft. 6in. diameter. Tube 4ft. diameter,
7/16 inch plates, 40 to 50 lbs. pressure. There was no steam gauge.
The tube collapsed from end to end, both ends being torn, but the
boiler was not moved from its seat. The fusible plug was uninjured. The
cause of the explosion was the weakness of the large tube. See No. 57.
_No. 36. Leicester. (Fig. 26.) September 1st. 1 injured._
[Illustration: _Fig. 26._]
Upright, 5ft. 6in. high, 4ft. diameter, 7/16 inch plates, 40 lbs.
pressure. The top of the boiler was blown out. The rent commenced in
the manhole, which was unguarded by a ring, and cracks two inches long
had existed before explosion. See Nos. 12 and 18.
_No. 37. Preston. (Fig. 27.) September 3rd. 1 killed, 1 injured._
[Illustration: _Fig. 27._]
One of two. Two tube Cornish, 30ft. long, 7ft. 2in. diameter. Tube
2ft. 8in. in furnaces, and 2ft. 4in. beyond, 3/8 inch plates, 50 lbs.
pressure.
The left furnace crown collapsed and ruptured, and the right furnace
crown was slightly altered in shape. The two boilers were connected by
one feed pipe without back valves, so that the water from this boiler
was forced into the other and allowed the tubes to be overheated.
_No. 38. Liverpool. (Fig. 28.) September 8th. 1 killed, 1 injured._
[Illustration: _Fig. 28._]
One tube Cornish, 22ft. 6in. long, 6ft. diameter, 3ft. tube, 7/16 inch
plates, 55 lbs. pressure.
The tube collapsed over the fire. It was so much thinned by corrosion,
and so many of the rivet heads were eaten off, that there was not
strength left to bear the ordinary pressure.
_No. 39. Boxmoor. (Fig. 29.) September 10th. 1 killed, 4 injured._
[Illustration: _Fig. 29._]
One of three. One tube Cornish, 27ft. 3in. long, 5ft. diameter. Tube
2ft. 10in. over furnace, and 2ft. 8in. beyond, 3/8 inch plates, 40 lbs.
pressure. One ring of plates was blown out of the back end of shell.
There was such extensive external corrosion on the seating at the
bottom that the boiler was unable to bear the working pressure.
_No. 40. Hull. (Fig. 30.) September 16th. 1 killed, 1 injured._
[Illustration: _Fig. 30._]
Breeches Tube, 13 years old, 30ft. long, 7ft. diameter. Furnace tube
2ft. 10in. diameter. Main tube 3ft. 5-1/2in. diameter, and originally
made to work at 20 lbs. pressure, but working lately at 45 lbs. The
main tube collapsed. The boiler was not adapted for the pressure at
which it was worked, and the tube was much weakened by the overheating
caused by a thick incrustation of scale, and was not strengthened by
any rings or stays, and was of very weak construction as the plates
were arranged lengthways.
_No. 41. South Wales. (Fig. 31.) September 26th. 1 killed, 1 injured._
[Illustration: _Fig. 31._]
One of two, 20 years old. Plain Cylinder, 36ft. long, 6ft. 6in.
diameter, 9/16 inch plates, 35 lbs. pressure.
The plates and rivet heads were very much reduced in thickness by
internal corrosion, and in many places were only 1/8 inch or less.
_No. 42. Warrington. October 6th. 2 killed, 6 injured._
One of seventeen. Two tube Cornish, 22ft. long, 7ft. 6in. diameter.
Tube 2ft. 6in. diameter, 7/16 inch plates, 45 lbs. pressure.
The left hand tube collapsed. The blow-off cock was left open until the
water was so low as to allow the tube to be overheated.
_No. 43. Rowley. (Fig. 32.) October 13th. none injured._
[Illustration: _Fig. 32._]
Plain Cylinder, with flat ends, 15ft. long, 3ft. 10in. diameter, 3/8
inch plates, 25 lbs. pressure.
The back end ripped all round the angle iron, and was blown out, and
the rest of the boiler was thrown forward a considerable distance.
There had once been an internal tube, and when this was taken out the
flat end had no stay, and was unfit to bear the usual pressure. See No.
47.
_No. 44. Newcastle. (Fig. 33.) October 14th. 2 killed, 5 injured._
[Illustration: _Fig. 33._]
Plain Cylinder, with plates arranged lengthways, 29ft. long, 6ft.
diameter, 3/8 inch plates, 25 lbs. pressure.
Although only 3 years old the boiler had always given trouble, and had
been very frequently repaired. Some new plates had just been put in the
bottom, and as the primary rent was in the old plates adjoining them,
it is most likely they had caused seam rips in the old metal.
The frequent repair had reduced the strength until unequal to bear the
ordinary pressure. See No. 59.
_No. 45. Greatbridge. (Fig. 34.) October 18th. 2 killed, 2 injured._
[Illustration: _Fig. 34._]
One of eight, 15 years old. Plain Cylinder, 40ft. long, 6ft. diameter,
1/2 inch plates. The boiler had originally carried 60 lbs., but lately
only 40 lbs. The boiler had been worked very hard, and had been so
often repaired, that many of the seams were continuous for a long
distance without break of joint, so that its strength was reduced until
unable to bear the ordinary pressure.
The treacherousness and uncertainty of boilers with one patch over
another has often been pointed out, as in Nos. 3, 4, 10, and 32.
_No. 46. Acorington. (Fig. 35.) October 19th. 2 killed, 3 injured._
[Illustration: _Fig. 35._]
One tube Cornish, 14ft. 6in. long, 5ft. diameter. Tube 2ft. 10in.
diameter, 7/16 inch plates, 40 lbs. pressure usually, and sometimes 60
lbs. One ring of plates was blown out of shell.
The boiler was so very badly corroded at the bottom, that the edges of
the rent were quite sharp like a knife, and the boiler was therefore
unable to bear the usual working pressure. The flues were too narrow to
enter for proper inspection, and the bearing surfaces were too wide and
retained moisture against the plates.
_No. 47. Lydney. (Fig. 36.) October 28th. 1 killed._
[Illustration: _Fig. 36._]
One of four. Plain Cylinder with round front and flat back end, 36ft.
long, 6ft. diameter, 7/16 inch plates, 20 lbs. pressure.
The flat end was blown out, the rent extending all round the angle iron.
There had originally been a breeches tube in the boiler with a strong
stay to the front end, but when this was taken out no stays were put
to the flat end to compensate for the loss of their support. The angle
iron attaching the flat end was made in four pieces instead of being
welded, and it was reduced to 3/16 inch thick by external corrosion, so
that it was not strong enough to bear the ordinary working pressure.
The extreme imprudence of altering boilers without due care to preserve
their strength has been often pointed out. See Nos. 21 and 43.
_No. 48. Newcastle. (Fig. 37.) October 29th. none injured._
[Illustration: _Fig. 37._]
One of six. Plain Cylinder, with plates arranged lengthways, 40ft.
long, 5ft. 3in. diameter, 40 lbs. pressure.
The boiler gave way at the fire end, and divided in two, and both
pieces were blown to a great distance. The boiler was old and had been
much repaired, and the seams running from end to end made it very weak,
but the immediate cause of the rupture was supposed to be shortness of
water and consequent overheating of the plates. See No. 59.
_No. 49. Stockport. October 30th. 1 killed._
[Illustration: _Fig. 38._]
One of eight. Two tube Cornish, 30ft. long, 7ft. 4in. diameter. Tube
2ft. 11in. diameter, 3/8 inch plates, 50 lbs. pressure.
The crown of the right hand tube became overheated from shortness of
water, and bulged down and rent half round at the second seam of rivets.
_No. 50. Durham. (Fig. 38.) November 2nd. 1 injured._
[Illustration: _Fig. 39._]
One of four. Plain Cylinder, with the plates arranged lengthways, 38ft.
long, 6ft. 6in. diameter, 3/8 inch plates, 35 lbs. pressure. A seam
over the fire slightly to the right side gave way where there had been
frequent repair to stop leaking. At the part which gave way there had
formerly been a side fire, which had perhaps damaged the seams. This
boiler was known to have been in bad condition and needing repairs. See
No. 59.
_No. 51. Sheerness. (Fig. 39.) November 3rd. 11 killed, 7 injured._
[Illustration: _Fig. 40._]
One of three. Marine, 15ft. 6in. long, 6ft. diameter. Furnace Tube 2ft.
4in. diameter, 5/8 inch plates, 80 lbs. pressure.
The left hand tube collapsed and ruptured, and the contents issued at
the front and scalded all near. The right hand tube was also slightly
out of shape on the top.
The cause of the collapse was, that the water had been allowed to get
below the crowns of the furnaces. There was no means of ascertaining
how the shortness of water occurred, as all were killed who had the
opportunity of knowing.
_No. 52. Cornwall. (Fig. 40.) November 25th. 1 injured._
[Illustration: _Fig. 41._]
One of five, 30 years old. One tube Cornish, 36ft. long, 7ft. diameter.
Tube 3ft. 10in. diameter, 7/16 inch plates, 40 lbs. pressure.
The shell was rent into several large pieces and thrown to some
distance. The tube was also thrown out and broken, chiefly by its fall
and striking against walls.
The boiler was corroded very badly on the seating, which must have been
known, as there were numerous small screw patches to prevent leaking at
the corroded places. The shell was in such bad condition, that it was
quite unfit to bear the ordinary working pressure. See No. 58.
_No. 53. Bilston. (Fig. 42.) December 3rd. 8 killed, 1 injured._
[Illustration: _Fig. 42._]
One of three. Four Furnace Upright, 20ft. high, 10ft. diameter. Centre
tube 10ft. high, 4ft. 6in. diameter, side tubes 2ft. diameter, 3/8 inch
plates, 35 lbs. pressure.
The central tube collapsed, and the bottom part was blown out, and
allowed the contents of the boiler to issue from the bottom into the
culvert leading to the stack, and into the necks of the furnaces from
which it was heated. The reaction sent the boiler up to a great height,
and it divided into eleven fragments, which were very widely scattered.
Comparatively little damage was done to the furnaces and premises, only
the brickwork surrounding the boiler being thrown down.
Although it had only worked a short time at this place, it was very
old, and the central tube was corroded until only 1/8 inch thick in
many places, and many of the rivet heads were quite eaten away. It was
altogether so worn out that it was quite unfit to work at any pressure.
_No. 54. Cornwall. (Fig. 43.) December 6th. none injured._
[Illustration: _Fig. 43._]
One tube Cornish, 32ft. long, 6ft. diameter. Tube 4ft. diameter, 7/16
inch plates, 40 to 50 lbs. pressure. The tube collapsed from end to
end, and the front portion was blown out with the front end, and the
back end was left attached to the shell, and but little moved from its
seat.
The cause was doubtless the weakness of such a large tube.
This is the third explosion at this engine. One of the previous
explosions is described at No. 35.
_No. 55. Stonehaven. December 9th. 2 injured._
Locomotive, but no particulars have been obtained.
_No. 56. Cornwall. (Fig. 44.) December 10th. none injured._
[Illustration: _Fig. 44._]
One tube Cornish, 26ft. long, 6ft. 6in. diameter, tube 3ft. 10in.
diameter, 3/8 inch plates, 40 lbs. pressure. The tube collapsed and
ruptured in the central part from weakness.
_No. 57. Cornwall. (Fig. 45.) December 11th. none injured._
[Illustration: _Fig. 45._]
One tube Cornish, 32ft. long, 6ft. 6in. diameter. Tube 4ft. diameter,
3/8 inch plates, 60 lbs. pressure.
It was an old boiler, and some of the plates of the tube were thinned
by corrosion, but it had only just been put to work at this place, and
burst the first day of working.
The tube collapsed beyond the bridge, and the back part with the back
end plate was blown out to a great distance. The front end was also
ruptured, and the whole boiler was sent forwards. The tube over the
fire had not collapsed. The cause of explosion was the weakness of such
a large tube without strengthening rings.
Many similar boilers have exploded in the same way from the same cause,
as described in Nos. 28, 30, 35, 40, 54, and 56.
_No. 58. Cornwall. (Fig. 46.) December 14th. 2 killed._
[Illustration: _Fig. 46._]
One tube Cornish, 26ft. 8in. long, 6ft. diameter. Tube 3ft. 10in. at
front end, and 3ft. beyond, 7/16 inch plates, 40 lbs. pressure.
The shell was rent into several pieces, which were scattered to wide
distances. The tube was also thrown to a great distance, but was
uninjured. The boiler was 36 years old. The shell was very badly
corroded, and temporarily repaired with screw patches to stop leaking,
so that the boiler was unfit to bear the usual pressure. See No. 52.
_No. 59. Durham. (Fig. 47.) December 29th. 2 killed, 1 injured._
[Illustration: _Fig. 47._]
One of three. Plain Cylinder, with plates arranged lengthways, 47ft.
long, 6ft. diameter, 3/8 inch plates, 30 lbs. pressure. It gave way at
the seams over the fire, where the edges of the plates had been injured
by injudicious and excessive repairing and caulking. The pieces were
sent to great distances. The weakness of boilers with seams from end
to end in continuous lines has often been pointed out. Eight of the
exploded boilers this year, Nos. 5, 15, 20, 24, 44, 48, 50, and 59, and
many others in former years were of the same objectionable construction.
* * * * *
The following, not being steam boilers, are not included in the list,
but the details may be useful.
* * * * *
_Oldbury. March 10th. 4 killed._
[Illustration]
Tar still, 10ft. high, 7ft. diameter, with round top and domed bottom,
3/8 inch plates, and not intended to work at any pressure. The vapour
passing away became congealed, and stopped up the small exit pipe, and
pressure accumulated sufficiently to burst the weak shaped vessel.
The bottom came completely out and was left upon the fire, while the
top ascended to a great height and fell a long distance away. The loss
of life was owing to the material igniting and suffocating those who
were thrown down by the explosion.
_Greatbridge. December 29th. 2 killed._
[Illustration]
Tar still, 12ft. high, 12ft. diameter, 3/8 inch plates, and not used at
any pressure usually.
The upper part separated from the bottom, rending in the angle iron all
round. The angle iron near the outlet pipe was corroded nearly away,
as shown in enlarged sketch, and the rivet heads were eaten completely
off.
It was supposed that the intense frost, during a long stoppage for
holidays, had caused the worm to be stopped up and pressure to
accumulate, as in the one previously described. But it is perhaps more
probable that the vessel gave way because it was corroded so thin in so
important a part as the angle iron. The explosion was very slight, the
damage and loss of life being from the fierce fire which immediately
succeeded it.
_Darlington. August 26th. 2 injured._
Domestic. Rectangular, and made of wrought iron. The front blew out.
It was said that all the communication pipes were shut, and therefore
steam accumulated until the weakest part gave way.
_Manchester. December 29th. 1 killed, 1 injured._
[Illustration]
The sketch is to a much larger scale than the others.
Domestic, 14in. wide, 11in. high, and about 10in. deep, made of cast
iron 1/4 inch thick. It had close top and two circulating pipes to warm
a bath about 10ft. above it. The supply cistern was about 17ft. above
the boiler. The front was blown out into the kitchen. It was said that
the pipes were frozen, and that steam pressure had thus accumulated.
The boiler was of a treacherous material and weak shape, and unfit to
bear safely the 7 lbs. pressure the column of water from the cistern
would give. The fire also acted on the sides of the boiler without any
intervening brickwork. If a closed top boiler is used, there should be
a dead weight safety valve to prevent pressure. A far safer plan is to
have the kitchen boiler with open top and the circulating heater within
it, so that it can never get overheated, as it only obtains its heat
from the water in the open boiler.
* * * * *
_R. Broomhall, Printer, Stourbridge._
BOILER EXPLOSIONS IN 1870.
_No. 1. Newcastle. (Fig. 1.) January 7th. 3 killed, 1 injured._
[Illustration: _Fig. 1._]
One of five. Cornish, 13 years old, 30ft. long, 6ft. 6in. diameter.
Tube 3ft. 3in. diameter, 3/8 inch plates, 30 lbs. pressure. Tube
collapsed sideways from weakness, and the front part and the front
plate were blown out, carrying the attendants into a deep and swollen
river which ran close in front of boilers.
_No. 2. South Wales. (Fig. 2.) January 15th. 1 killed, 4 injured._
[Illustration: _Fig. 2._]
Plain cylinder, very old, 32ft. long, 5ft. diameter, 7/16 inch plates,
30 lbs. pressure. Externally corroded to 1/16 inch, and gave way near
a seam, the front being thrown forward into a house, and the back
end 150 yards to the rear, carrying away the stack. It had been badly
repaired with bolted patches which had hastened corrosion, and as it
was known to be nearly worn out, it was to have been replaced in a few
days.
_No. 3. Worksop. (Fig. 3.) January 28th. 2 killed._
[Illustration: _Fig. 3._]
Domestic, 2ft. wide, 1ft. 10in. high, and 7in. deep, 3/8 inch plates,
with badly welded joints. The circulating pipes to cistern, 15ft.
above, were frozen, and steam pressure accumulated and blew out the
front.
_No. 4. Ipswich. (Fig. 4.) February 4th. 1 killed._
[Illustration: _Fig. 4._]
One of three. Cornish, 7 years old, 24ft. long, 5ft. diameter. Tube
3ft. diameter, 7/16 inch plates, 65 lbs. pressure. The boiler was good
and well fitted, but an accumulation of salt on tube caused overheating
and rupture of 3rd seam.
_No. 5. Sheffield. (Fig. 5.) February 8th. 2 killed, 6 injured._
[Illustration: _Fig. 5._]
One of three. Rag Boiler, 2 years old, 11ft. diameter, 9-1/2ft. deep,
7/16 inch plates. Steam was supplied from the engine exhaust, and was
usually about 10 lbs. pressure, but as the boilers from which the steam
was originally supplied worked at 60 lbs., it is possible this was
sometimes exceeded. The vessel was of very weak shape for even 10 lbs.
pressure.
_No. 6. Derby. (Fig. 6.) February 14th. 1 killed, 2 injured._
[Illustration: _Fig. 6._]
Domestic, 1ft. high, 1ft. wide, 8in. across top, and 12in. across
bottom, made of cast-iron, 7/16 inch thick. The fire had been let out
sometime, and the circulating pipes to cistern 16ft. above were frozen,
and on lighting fire steam was formed for which there was no escape,
and the boiler was shattered.
_No. 7. Sheffield. (Fig. 7.) February 14th. 2 killed, 1 injured._
[Illustration: _Fig. 7._]
Domestic, used for warming rooms above, 2ft. 6in. wide, 2ft. high, 9in.
across top, and 13in. across bottom, 3/8 inch plates. The circulating
pipes to cistern, 12ft. above, were frozen, and steam was formed for
which there was no vent, and boiler was rent open. The joints were so
badly welded that they soon gave way, and little damage was done to
property.
_No. 8. Walsall. (Fig. 8.) February 19th. none injured._
[Illustration: _Fig. 8._]
One of two. Plain cylinder, 12 years old, 30ft. long, 7ft. diameter,
1/2 inch plates, 50 lbs. pressure. The seams and plates were
overheated by shortness of water, and gave way at ordinary pressure.
It is supposed the water "kicked" into the other boiler, as there was
no back valve to prevent this whenever one boiler happened to be fired
a little harder, and consequently at slightly higher pressure than the
other. There was no damage except to the boiler.
_No. 9. Birmingham. (Fig. 9.) February 25th. none injured._
[Illustration: _Fig. 9._]
Cornish, 5 years old, 32ft. long, 7ft. diameter. Tube 2ft. 4in.
diameter, 7/16 inch plates, 30 lbs. pressure. Cracked along the
bottom of front end where internally "furrowed." The boiler was not
disturbed, but as the water escaped into an iron furnace the bricks
were scattered, but little damage done. The boiler was intended for two
tubes, and therefore there was a large part supported only by stays,
allowing of a slight movement with varying pressure which facilitates
the corrosion in certain lines of strain called "furrowing." In this
case they were so close to the angle iron and filled with scale that
they were difficult to detect.
_No. 10. Cornwall. (Fig. 10.) March 17th. 5 injured._
[Illustration: _Fig. 10._]
Upright Boiler, 2 ft. high, 1ft. 9in. diameter, 1/4 inch plates. It
gave way where deeply corroded externally round the bottom angle iron.
The top was blown through the roof and did considerable damage, the
bottom being left in the grate.
_No. 11. Sheffield. (Fig. 11.) March 27th. 1 injured._
[Illustration: _Fig. 11._]
Agricultural or Contractor's Engine, 9ft. 2in. long, 2ft. 6in.
diameter, 3/8 inch plates, 30 lbs. pressure. The heads of stays on each
side were corroded outside and drew through the holes, allowing the
angles of fire box to open. Boiler was not disturbed and no damage was
done.
_No. 12. Portsmouth. (Fig. 12.) March 29th. 3 killed, 1 injured._
[Illustration: _Fig. 12._]
One of two. Cornish, 9 years old, 22ft. long, 6ft. diameter. Tube 3ft.
diameter, 3/8 inch plates, 40 lbs. pressure. Gave way at mid-feather
wall where corroded to 1/32 inch, at a place where flues were too
narrow to enter. Two rings of plates were torn out and blown into an
adjoining street, while the reaction of the escaping contents forced
the boiler into a building in a very singular manner, doing very great
damage. This case is of peculiar interest, because although the cause
of explosion was so plain to see, all the old theories of decomposition
of steam, and ignition of hydrogen, were revived, and it was even
stated that "a bad boiler could not explode, as the corroded part would
give way, and allow the steam to escape harmlessly," and any cause
seemed to be considered more probable than the plain and simple one,
that it was corroded to the thickness of card board. Like many other
examples this explosion shows that however well a boiler is tended, it
should be examined in the flues to make sure that it is safe.
_No. 13. Manchester. March 30th. 2 killed, 3 injured._
Underground. Some alterations were being done to some brick arching,
which fell upon and broke steam pipes, and the escape of steam
suffocated those near.
_No. 14. Warrington. (Fig. 13.) April 13th. 6 killed, 3 injured._
[Illustration: _Fig. 13._]
Lancashire, used for evaporation only, 24ft. 6in. long, 8ft. diameter,
3/8 inch plates, and usually worked with little or no pressure.
The boiler was very old and much patched, and incapable of bearing the
15 lbs. pressure which was temporarily put upon it.
_No. 15. Scotland. April 18th. none injured._
Plain cylinder, said to have exploded from shortness of water, but no
particulars have been obtained.
_No. 16. Cornwall. (Fig. 14.) April 18th. 1 killed, 1 injured._
[Illustration: _Fig. 14._]
One of two. Cornish, very old, 34ft. long, 6ft. diameter. Tube 3ft.
10in. diameter, 3/8 inch plates, 50 lbs. pressure. The tube collapsed
and the front part was blown out, and the boiler was forced back a
little. It was said to have been short of water, but the weakness of a
tube of such large diameter was most likely the true cause.
_No. 17. Wellington. (Fig. 15.) April 22nd. none injured._
[Illustration: _Fig. 15._]
One of two. Balloon, very old, 11ft. high, 9ft. 6in. diameter, 3/8 inch
plates, 5 lbs. pressure. The bottom was corroded externally to 1/8
inch, and temporarily repaired with screw patches, and was so reduced
in strength that it gave way at the ordinary pressure.
The top was blown about 20 yards away, but little damage was done.
_No. 18. Cornwall. May. none injured._
Cornish, 30ft. long, 6ft. diameter. Tube 3ft. 6in. diameter, 40 lbs.
pressure. Boiler gave way under bottom where corroded very thin, but
little damage was done.
_No. 19. Darlaston. (Fig. 16.) May. none injured._
[Illustration: _Fig. 16._]
Cornish, 15ft. long, 4ft. 3in. diameter. Tube 1ft. 6in. diameter, 7/16
inch plates, 40 lbs. pressure. Tube collapsed and ruptured, having been
softened by overheating through shortness of water. Very little damage
was done.
_No. 20. Westbromwich. (Fig. 17.) May 12th. 2 killed._
[Illustration: _Fig. 17._]
One of three. Plain cylinder, 5 years old, 34ft. long, 6ft. diameter,
7/16 inch plates, 45 lbs. pressure. Gave way by the rent of a ripped
seam over the fire, which had been repeatedly temporarily patched
without restoring the strength or stopping the rip. Three rings were
torn out of the middle, while the front end was blown into the bed room
of a house, and the back part of the boiler was thrown across a canal
through two walls into a distant street. Great damage was done.
_No. 21. Dublin. (Fig. 18.) May 18th. 3 killed, 6 injured._
[Illustration: _Fig. 18._]
Cornish. Second-hand, but just started at this place, 26ft. long, 6ft.
diameter. Tube 3ft. diameter, 3/8 inch plates, 40 lbs. usual pressure.
Tube collapsed from end to end. The pressure at time was supposed to
be 70 lbs., and as there was no evidence of shortness of water, it is
presumed the tube gave way from weakness. The boiler was moved forward
about 20 feet, but much damage was done to premises.
_No. 22. Bury. (Fig. 19.) May 25th. none injured._
[Illustration: _Fig. 19._]
Domestic Saddle, 5ft. long, 3ft. high, 2ft. 6in. wide, 3/8 inch plates,
15 lbs. pressure, the cistern being 30ft. above. There were no stays
between the inner and outer shell, and the space between them was too
small to allow proper circulation of water to keep the plates from
overheating, so that it was hardly fit for its ordinary pressure, and
the top was blown off.
_No. 23. Kidsgrove. (Fig. 20.) May 26th. 13 killed, 9 injured._
[Illustration: _Fig. 20._]
One of three. Four Furnace Upright, 12 years old, 17ft. 6in. high, 9ft.
diameter. Centre tube 5ft. 9in. diameter, 3/8 inch plates, 40 lbs.
pressure. The centre tube was much corroded on the inside and collapsed
inwards from consequent weakness, allowing the contents to issue at the
bottom of the boiler, and the reaction sent the whole boiler high up
into the air, and on to a roof causing great damage.
_No. 24. Lowestoft. (Fig. 21.) May 27th. 2 killed._
[Illustration: _Fig. 21._]
Crane or Donkey boiler on board a vessel. About 6ft. high, and 3ft.
diameter, 25 lbs. pressure. The internal fire box collapsed from the
softening of the plates through shortness of water, the blow off pipe
having been left open too long. Little or no injury was done to the
ship.
_No. 25. Birmingham. (Fig. 22.) June 2nd. 2 killed, 1 injured._
[Illustration: _Fig. 22._]
Cornish, 6 years old, 21ft. long, 6ft. diameter. Tube 3ft. diameter,
3/8 inch plates, 40 lbs. pressure. The tube was so much weakened by
cracks and by being out of true circle, that it collapsed from end to
end at the ordinary working pressure.
_No. 26. Wigan. (Fig. 23.) June 6th. none injured._
[Illustration: _Fig. 23._]
One of two. Cornish, 28ft. 7in. long, 5ft. 4in. diameter. Tube 3ft.
diameter, slightly oval, 3/8 inch plates, 50 lbs. pressure. Tube
collapsed over the fire and ruptured from weakness. The boiler was not
moved and the damage was not great.
_No. 27. Bury. June 9th. 1 injured._
Lancashire. The plates were reduced to 1/16 inch by external corrosion,
so that the boiler was not able to bear the ordinary pressure, but no
details have been obtained.
_No. 28. Workington. (Fig. 24.) June 9th. 7 injured._
[Illustration: _Fig. 24._]
One of two. Cornish, nearly new, 16ft. long, 5ft. diameter, 3/8 inch
plates, 45 lbs. pressure. Three plates over fire collapsed from
overheating through shortness of water.
_No. 29. Nottingham. (Fig. 25.) June 13th. 3 injured._
[Illustration: _Fig. 25._]
Ten years old. Plain cylinder, with flat ends, 10ft. long, 2ft.
diameter, diagonal seams, 1/4 inch plates, 25 lbs. pressure. The whole
shell was blown 80 yards to the front, and the chimney and engine house
much damaged. It was much corroded and badly patched, so as to be unfit
to carry pressure.
_No. 30. Blackburn. (Fig. 26.) June 17th. 2 killed, 1 injured._
[Illustration: _Fig. 26._]
Sixteen years old. Galloway, 26ft. long, 7ft. diameter, 3/8 inch
plates, 56 lbs. pressure. There was a combustion chamber between the
furnace tubes and the main tube, and this had been lately repaired
insecurely, and gave way and burst upwards. The boiler was not moved,
but the contents issued so violently that a good deal of damage was
done to surrounding premises.
_No. 31. Glasgow. (Fig. 27.) June 17th. none injured._
[Illustration: _Fig. 27._]
Crane Boiler, about 2 years old, 7ft. high, 4ft. diameter, 3/8 inch
plates, 50 lbs. pressure. The internal fire box collapsed and the
external shell was blown to pieces. There was no sign of shortness
of water, but it is supposed that the fire box was not circular, and
therefore too weak to bear the ordinary pressure.
_No. 32. Bilston. (Fig. 28.) June 21st. 2 killed, 6 injured._
[Illustration: _Fig. 28._]
One of seven. Plain cylinder, 30 years old, 30ft. long, 8ft. 3in.
diameter, 1/2 inch plates, 35 lbs. pressure. It gave way over fire
place, where it had been weakened by frequent repair, which had caused
a seam rip near a patch. The fragments were widely scattered, and
much damage was done to the premises. The insecurity of boilers so
frequently repaired with patch upon patch has been often pointed out.
_No. 33. Darlington. (Fig. 29.) June 24th. 2 injured._
[Illustration: _Fig. 29._]
One of twelve. Two Furnace Upright, about 2 years old, 20ft. high,
8ft. diameter, 7/16 inch plates, 30 lbs. pressure. The water was
allowed to run so low that the plates softened by the overheating, and
a small piece was blown open and threw down the brickwork.
_No. 34. Dudley. (Fig. 30.) June 25th. 2 injured._
[Illustration: _Fig. 30._]
One of two. Balloon, 34 years old, 12ft. diameter, 10ft. high, 3/8
inch plates, 7 lbs. pressure. There were no stays, and the boiler was
of very weak shape, and as the boiler it worked with was loaded to 15
lbs., it is presumed this also was exposed to that pressure, and burst
in consequence. It gave way at the angle at front over the fire, and
was thrown over the engine house.
_No. 35. Manchester. (Fig. 31.) June 27th. 2 killed, 1 injured._
[Illustration: _Fig. 31._]
One of four. Galloway, 4 years old, 32ft. long, 8ft. diameter, 7/16
inch plates. Tube 2ft. 10in. diameter, originally intended for 40 lbs.,
but worked at 65 lbs. pressure. The left hand tube collapsed sideways,
having been very much weakened by internal corrosion.
_No. 36. July 2nd. 1 injured._
Marine. One of the oval tubes collapsed. The boiler was worked at
a higher pressure than it was capable of bearing safely, but no
particulars have been obtained.
_No. 37. Scotland. July 3rd. 2 killed, 3 injured._
Plain Cylinder, 3 years old, 20ft. long, 4ft. diameter, 25lbs.
pressure. It was so corroded inside about the water line from bad
water, that it gave way at the ordinary pressure. The boiler was thrown
160 yards from its seat.
_No. 38. July 29th. none injured._
Cornish, 26ft. long, 5ft. 9in. diameter, tube 3ft. 6in. diameter, 7/16
inch plates, 35 lbs. pressure. The boiler rent open where externally
corroded to 1/32 inch, and 3 widths of plates were torn away.
_No. 39. Nottingham. August 12th. none injured._
Tubulous Boiler, quite new, made entirely of tubes. One tube gave way
at defective weld, but no other damage was done.
_No. 40. Leicester. (Fig. 32.) August 13th. 4 killed, 5 injured._
[Illustration: _Fig. 32._]
Upright Boiler, nearly new, 10ft. high, 5ft. diameter, with internal
fire box, 1/2 inch plates, 45 lbs. pressure. The shell was rent into
many pieces, which were widely scattered, doing much damage. The safety
valve was defective and incapable of relieving the pressure, and the
spring indicated wrongly, so that a much higher pressure was used than
the boiler could bear safely.
_No. 41. Newcastle-on-Tyne. (Fig. 33.) Sep. 14th. 5 killed, 20 injured._
One of two. Plain Cylinder, with plates arranged lengthways, 17 years
old, 27ft. long, 6ft. diameter, 3/8 inch plates, 30lbs. pressure,
mechanically fired. It had just been extensively repaired over the
fire, but it gave way at the back end, where a plate had been put in
some time before, and it is supposed that a seam rip or injury to
the old plate, not visible outside or in, was then set up, which was
perhaps increased by the strain of late repairs and gave way as soon as
steam was again raised to working pressure. See No. 55 this year and
many others in past years of similar construction.
[Illustration: _Fig. 33._]
_No. 42. Nottingham. (Fig. 34.) September 15th. 1 killed._
[Illustration: _Fig. 34._]
Tubulous, or all tubes, 1-1/2 years old, 100 lbs. pressure. Steam was
being raised with too little water in the boiler, so that the tube
became overheated and incapable of bearing pressure, and rent open, and
as the boiler was in a small space the steam suffocated the attendant,
but the boiler was not disturbed or the premises injured.
_No. 43. Tunstall. (Fig. 35.) September 17th. 3 killed, 1 injured._
One of four. Plain Cylinder, 8 years old, 36ft. long, 5ft. diameter,
3/8 inch plates, 50 lbs. pressure. It gave way at fifth seam, where
a seam rip, caused by bad repair, had so far weakened it that it was
unable to bear the usual pressure, and the ends were blown in opposite
directions.
[Illustration: _Fig. 35._]
_No. 44. Exeter. (Fig. 36.) September 27th. 1 killed._
[Illustration: _Fig. 36._]
Lancashire, 2 years old, 31ft. long, 7ft. diameter, tube 2ft. 10in.
diameter, with 56 Field tubes in each, 3/8 inch plates, 45 lbs.
pressure. The right hand tube collapsed and ruptured from softening of
plates through shortness of water. The fire was blown out and set the
premises on fire and much damage was done.
_No. 45. Cardiff. October 1st. 1 killed, 2 injured._
Locomotive, 4-1/2 years old, 14ft. long, 4ft. diameter, 7/16 inch
plates, 120 lbs. pressure. The fire box was reduced to 1/32 inch by
corrosion, and unable to bear the usual pressure and rent open, and the
escaping contents rushed out at the fire doors and injured those near.
_No. 46. Liverpool. (Fig. 37.) October 4th. 4 killed, 4 injured._
[Illustration: _Fig. 37._]
Plain Cylinder, 6ft. 6in. long, 3ft. 6in. diameter, 3/8 inch plates,
80 lbs. pressure. The plates were corroded both inside and out, and
in some places reduced to less than 1/16 inch in thickness, and it
was quite unfit to bear the ordinary pressure. The damage to the
surrounding property was very great although the boiler was so small.
The shell of the boiler was thrown across a street into an upper room
of the house opposite.
_No. 47. Bathgate. October 14th. 2 injured._
Rag Boiler. The boiler became exposed to higher pressure than it was
intended to bear. The boiler house was destroyed, but no particulars
have been obtained.
_No. 48. Walsall. (Fig. 38.) October 19th. 1 killed, 2 injured._
[Illustration: _Fig. 38._]
Cornish, 7 years old, 13ft. 3in. long, 5ft. 6in. diameter, tube 3ft.
6in. diameter, 3/8 inch plates, and supposed to work at 30 lbs.
pressure. The gauge was so out of order that it only indicated half
the real pressure. The tube was not in good condition and had leaked
very much and was quite unfit for the pressure of 60 lbs. to which
the valve was loaded. The tube collapsed beyond the bridge, and the
contents issued at the back and drove the boiler forward 30 feet and
into a workshop.
_No. 49. Soho. (Fig. 39.) October 19th. 1 killed, 1 injured._
[Illustration: _Fig. 39._]
One of four. Lancashire, 23ft. long, 7ft. diameter, tube 2ft. 6in.
diameter, 30 lbs. pressure, usually, but 15 lbs. at time of explosion.
The left side of left tube collapsed and rent owing to shortness of
water.
_No. 50. North Wales. (Fig. 40.) October 19th. 1 killed, 8 injured._
[Illustration: _Fig. 40._]
One of two. Cornish, 26ft. long, 5ft. 6in. diameter, tube 3ft.
diameter, 7/16 inch plates, 23 lbs. pressure. The bottom was so thinned
by external corrosion that it was not able to bear the usual pressure
and rent open. The boiler was turned upside down, and the house much
injured.
_No. 51. Berwick. (Fig. 41.) October 21st. 1 killed._
[Illustration: _Fig. 41._]
Cornish, 12ft. long, 4ft. 3in. diameter, tube 2ft. 4-1/2in. diameter,
3/8 inch plates, 32 lbs. pressure. The tube collapsed, having become
overheated through shortness of water.
_No. 52. Sheffield. (Fig. 42.) October 26th. 1 killed, 1 injured._
[Illustration: _Fig. 42._]
Locomotive, 11 years old, 9ft. 6in. long, 4ft. diameter, 1/2 inch
plates, 80 lbs. pressure. The top plate over fire box was blown off,
having given way along a "furrow" caused by corrosion in a line of
strain owing to position of stays. It was in a part of the boiler where
it is not usual to find it, and as it could not be seen, it increased
until unable to bear the usual pressure.
_No. 53. Darlaston. (Fig. 43.) October 27th. 3 injured._
[Illustration: _Fig. 43._]
Plain Cylinder, 22ft. long, 4ft. diameter, 7/16 inch plates, 25 lbs.
pressure. The water was allowed to get so low that the sides were
softened by overheating, and rent open. The boiler was not moved and
only a few bricks were disturbed.
_No. 54. Cornwall. (Fig. 44.) October 27th. 1 killed._
[Illustration: _Fig. 44._]
One of three. Cornish, 12 years old, 36ft. long, 6ft. diameter, tube
3ft. 9in. diameter, 3/8 inch plates, 38 lbs. pressure. The tube
collapsed from end to end, the front and central parts being blown
out. The shell and back of tube were thrown in one piece to the rear,
and much damage was done. It was supposed to have been short of water,
because the tube had collapsed, but it is more likely it collapsed
because of its weakness without strengthening rings. A tube in this
boiler collapsed in a similar way about 5 years previously.
_No. 55. Newcastle. (Fig. 45.) November 17th. 1 killed, 2 injured._
One of seven. Plain Cylinder, with plates arranged lengthways, 30 years
old, 26ft. long, 6ft. diameter, 3/8 inch plates, 35 lbs. pressure,
mechanically fired. Gave way at a seam on the right hand side of the
fire place, where the insertion of a new plate had caused injury to the
old plate, and it divided into two parts which were sent in different
directions. The uncertainty and treacherousness of these straight
seamed boilers has often been pointed out. See No. 41, and many
examples in former years.
[Illustration: _Fig. 45._]
_No. 56. South Wales. November 19th. none injured._
Cornish, 7ft. diameter, tube 4ft. diameter, 40 lbs. pressure. Tube
collapsed from weakness.
_No. 57. Shields. (Fig. 46.) November 24th. 1 killed, 2 injured._
[Illustration: _Fig. 46._]
One of two. Marine, second hand when put in 3 years since. Return tube
12ft. 4in. long, slightly oval, 6ft. diameter at front, and 5ft. 6in.
at back; tube, oval, 3ft. 10in. wide, and 3ft. deep, 5/16 inch plates,
25 lbs. pressure. The tube collapsed. It was in such a corroded and
cracked condition, and so badly repaired, with screw patches, that it
was unable to bear the ordinary pressure.
_No. 58. Manchester. (Fig 47.) December 2nd. 3 injured._
[Illustration: _Fig. 47._]
One of two. Balloon, used for evaporating only, nearly new, 9ft. high,
and 9ft. diameter, 1/2 inch plates, not usually worked at any pressure.
The top was thrown 60 yards away, and the bottom left on furnace. The
boiler was temporarily exposed to pressure which it was too weak a
shape to bear.
_No. 59. Bilston. (Fig. 48.) December 2nd. 1 killed, 2 injured._
[Illustration: _Fig. 48._]
Plain Cylinder, 5 years old, 14ft. 9in. long, 4ft. 9in. diameter, 3/8
inch plates, 30 lbs. pressure. The water was allowed to get so low that
the sides became softened by overheating and rent open, and blew the
fire upon those near, but without disturbing the boiler or brickwork.
_No. 60. Hanley. (Fig. 49.) December 16th. 1 killed, 5 injured._
[Illustration: _Fig. 49._]
One of two. Balloon, 30 years old, 15ft. diameter, 3/8 inch plates,
worked at 20 lbs. pressure. It rent in two and threw down the engine
house and chimney. The boiler was not intended to work at more than 5
lbs. pressure, and was quite unable to bear the extra pressure to which
it was exposed.
_No. 61. Leeds. (Fig. 50.) December 24th. 1 injured._
[Illustration: _Fig. 50._]
Domestic, wrought iron, welded, 13-1/2 inches wide, 12 inches high. The
house had been empty, and the pipes to cistern, 26 feet above, had
frozen, and when a fire was lighted the accumulated pressure, having no
escape, forced out the front.
_No. 62. Leamington. (Fig. 51.) December 25th. none injured._
[Illustration: _Fig. 51._]
Domestic Saddle, wrought iron welded, 1ft. 9in. long, and the same
width and height. The circulating pipes were stopped by ice, and the
accumulated pressure forced down the underside and rent open the joint.
The building was injured.
_No. 63. Morley. (Fig. 52.) December 25th. none injured._
[Illustration: _Fig. 52._]
Domestic Saddle, wrought iron welded, 2ft. 6in. long, 1ft. 6in. wide
and high. The circulating pipes being stopped by ice the accumulated
pressure forced out the plate on the under side. The building was
injured.
_No. 64. Liverpool. (Fig. 53.) December 25th. 2 injured._
[Illustration: _Fig. 53._]
Domestic, 1ft. 8in. wide and high, 1ft. deep, 1/2 inch cast iron. The
circulating pipes were stopped with ice, and the accumulated pressure
forced out the front, and did great damage to the house.
_No. 65. London. (Fig. 54.) December 25th. 1 killed._
[Illustration: _Fig. 54._]
Domestic, wrought iron, 1ft. 3in. wide, 1ft. 4in. high, 6in. deep, 3/8
inch thick. The circulating pipes to the cistern about 30ft. above were
stopped with ice, and the accumulated pressure rent the boiler in the
welded joints, and did great damage to the house.
_No. 66. Dukinfield. (Fig. 55.) December 26th. none injured._
[Illustration: _Fig. 55._]
Domestic, cast iron, 3/8 inch thick, 1ft. 3in. wide, 1ft. deep. The
circulating pipes were frozen, and the pressure accumulated and rent
the boiler to fragments and did great damage to the room.
_No. 67. Northallerton. (Fig. 56.) December 29th. 1 injured._
[Illustration: _Fig. 56._]
Locomotive, 20 years old, 12ft. 9in. long, with plates arranged
lengthways, 3ft. 8in. diameter, 3/8 inch plates, 80 lbs. pressure.
The barrel appears to have given way on the under side near fire box,
and opened out and rent into fragments. As the pieces containing
the probable first rent were missing, nothing positive could be
ascertained. It may have contributed to the rupture that the engine
drew from the fire box instead of from the frame.
_No. 68. London. (Fig. 57.) December 29th. none injured._
[Illustration: _Fig. 57._]
Domestic, Saddle, wrought iron, welded, 1ft. 6in. long, 1ft. 2in. wide,
and 1ft. high, 3/8 inch thick. The circulating pipes to cistern 25ft.
above were frozen, and the accumulated pressure forced the crown out of
under side of boiler, and caused great damage to premises.
_No. 69. London. December 30th. none injured._
Domestic, the circulating pipes were frozen, and the accumulated
pressure caused the boiler to rent open, but little damage was done.
_No. 70. Burton. Date not ascertained. 1 killed._
Plain Cylinder, underground, internally corroded until too weak to bear
ordinary pressure.
* * * * *
_R. Broomhall, Printer, Stourbridge._
BOILER EXPLOSIONS IN 1871.
_No. 1. Tranmere. (Fig. 1.) January 1st. 1 injured._
[Illustration: _Fig. 1._]
Domestic. Cast-iron, 1ft. 4in. wide, 1ft. high, and 11in. deep. The
circulating pipes being frozen the pressure accumulated, and rent the
boiler into pieces, doing great damage.
_No. 2. Rochdale. (Fig. 2.) January 2nd. 1 injured._
[Illustration: _Fig. 2._]
Plain cylinder, 11ft. long, 3ft. 1in. diameter, 3/8 inch plates, 25
lbs. pressure. Ruptured at a bad patch over grate, around which were
many old cracks, and the rent passed along the bottom, and through the
unguarded manhole, and round several of the transverse seams, dividing
the boiler into 4 or 5 pieces, which were widely scattered, but are
arranged in sketch near their original position.
_No. 3. January 2nd. none injured._
Cornish, 32ft. long, 6ft. 6in. diameter, 3/8 inch plates, 30 lbs.
pressure. Tube ruptured at first seam over the fire from weakness
caused by internal corrosion.
_No. 4. Middlesbro. (Fig. 3.) January 4th. 1 killed._
[Illustration: _Fig. 3._]
Domestic, 1ft. 3in. wide, 1ft. high, 11in. deep, 5/16 inch thick. The
circulating pipes being frozen, the pressure accumulated and rent the
boiler open, doing considerable damage.
_No. 5. Stirchley. (Fig. 4.) January 9th. 1 killed, 4 injured._
[Illustration: _Fig. 4._]
One of five, about 30 years old. Lancashire, 18ft. 2in. long, 7ft.
6in. diameter. Tubes 2ft. diameter, 3/8 inch plates, 12 lbs. pressure.
Ruptured at corroded steam pipe joint at top of front end, and the
rent followed along the angle ring of shell which was also corroded,
and then along the seams of some plates in the bottom, placed
longitudinally, allowing the top of the boiler to open up like a lid,
without moving it much out of its original position.
_No. 6. Cornwall. January 12th. 1 killed._
Cornish, 30ft. long, 6ft. diameter, 7/16 inch plates, 35 lbs. pressure.
The ball weight of the safety valve was unusually near the steam pipe,
and it is supposed that the boy who was scalded having put his dinner
on the pipe to warm, it slipped between the ball and pipe; and that in
trying to extricate it he lifted the valve which was held open by the
"pasty" wedged under the ball.
_No. 7. Dalry. January 13th. 3 injured._
One of two, 25 years old. Plain cylinder, 24ft. long, 4ft. diameter,
5/16 inch plates, 30 lbs. pressure. Gave way at a ring seam where much
corroded near the back end, which was blown to the rear, the front end
being thrown considerably forwards, and the shell was torn into many
fragments which damaged the engine house, and so injured the other
boiler that it also was rent into pieces and thrown some distance
away. One safety valve was made to serve for the two boilers, and the
connecting valve being shut there was no escape from this boiler, so
that the bursting pressure soon accumulated. A similar boiler attached
to the same engine exploded in April, 1870, and is mentioned as No. 15
in the "records" of that year.
_No. 8. S. Wales. January 15th. none injured._
Plain cylinder, 5 years old, 35ft. 6in. long, 4ft. 10in. diameter, 1/2
inch plates, 55 lbs. pressure. Some plates over the fire became red hot
from the accumulation of scale some inches thick upon them and gave
way, and the reaction of the issuing contents sent the boiler some
distance and did much damage.
_No. 9. Manchester. January 16th. 1 injured._
Plain cylinder, flat ends, very old, 8ft. 4in. long, 3ft. diameter, 3/8
inch plates, 50 lbs. pressure. The front plate was blown out, and the
boiler was thrown backwards for some distance. The boiler was corroded
until too weak to bear the ordinary pressure.
_No. 10. Sunderland. January 17th. 1 killed, 1 injured._
Marine. The steam expansion joint was placed between two opposite
curves in the pipe, and one end drew out when first under pressure.
_No. 11. Leslie. January 26th. 2 killed._
Cornish, 10ft. long, 4ft. diameter. Tube 2ft. 4in. diameter, plates
5/16 inch, 40 lbs. pressure. Gave way at bottom where it rested on the
brickwork, the plates being completely eaten away by external corrosion.
_No. 12. Gateshead. (Fig. 5.) January 27th. none injured._
[Illustration: _Fig. 5._]
Domestic, 3ft. high, 2ft. wide, and 1ft. 1in. deep, 3/8 inch plates.
The circulating pipes being frozen, the pressure accumulated, and rent
the boiler open doing great damage.
_No. 13. Bradford. (Fig. 6.) February 1st. 1 killed._
[Illustration: _Fig. 6._]
Plain cylinder, 5 years old, flat ends, 7ft. 5in. long, 3ft. 4in.
diameter, 3/8 inch plates, 45 lbs. pressure. The safety valve was
loaded to 70 lbs., and this pressure was too great for the insufficient
stay to the flat end, which was blown out, the boiler being thrown
backwards.
_No. 14. Dover. February 5th. 1 killed._
Marine, 70 lbs. pressure. The boiler was not moved from its place, and
the damage appeared to have been slight, but no particulars have been
obtained.
_No. 15. Newcastle. (Fig. 7.) Feb. 10th. none injured._
[Illustration: _Fig. 7._]
One of three, 3 years old. Chimney, 27ft. high, 5ft. diameter. Tube
2ft. 9in. diameter, 3/8 inch plates, 25 lbs. pressure. Collapsed about
half-way up the tube from overheating through shortness of water.
_No. 16. Birmingham. (Fig. 8.) February 15th. 3 injured._
[Illustration: _Fig. 8._]
One of two, 1 year old. Portable upright, 6ft. high, 3ft. diameter,
7/16 inch plates, 25 lbs. pressure. There was but one safety valve,
and that was on the other boiler. The junction valve between the
boilers was closed, when left for the night, without the fire being
properly put out, and there being no outlet for the steam the pressure
accumulated, and the boiler ruptured at the unguarded manhole and rent
into fragments, much damaging the closely packed houses near.
_No. 17. Stockton. March 8th. none injured._
Locomotive. The connecting rod broke and pierced the boiler, allowing
contents to issue violently. A similar case was mentioned as No. 27,
July 21st, 1868, and others have occurred in previous years.
_No. 18. Bradford. (Fig. 9.) March 9th. 1 killed, 1 injured._
[Illustration: _Fig. 9._]
One of six, 3 years old. Lancashire, 27ft. long, 7ft. diameter. Tubes
2ft. 8in. diameter, slightly oval, 7/16 inch plates, 60 lbs. pressure.
The left hand tube collapsed downwards from overheating through
shortness of water. The boiler was not moved, and little damage was
done to premises.
_No. 19. Glasgow. March 11th. 3 killed, 3 injured._
Rag Boiler. The screws of the manlid were loosened before the steam was
exhausted, and the issuing contents scalded those near.
_No. 20. Wootton Bassett. (Fig. 10.) March 11th. 2 killed, 1 injured._
[Illustration: _Fig. 10._]
Cornish, 12ft. long, 4ft. 8in. diameter. Tube 2ft. 3in. diameter,
3/8 inch plates, 72 lbs. pressure. Tube collapsed downwards from
overheating through shortness of water. This was the second time the
tube had collapsed, although the boiler had only worked 18 months.
_No. 21. Newcastle. (Fig. 11.) March 16th. 1 killed._
[Illustration: _Fig. 11._]
Plain cylinder, flat ends, 16ft. long, 3ft. 6in. diameter, 5/16 inch
plates, 25 lbs. pressure. There being no stays to support the flat ends
the varying pressure caused a slight movement backward and forward
(sometimes called "drum-head" motion), which facilitated corrosion in
certain lines of strain, and produced a "furrow" at the front near the
bottom, which rent open. The boiler was not moved, and little damage
was done to the premises.
_No. 22. Brigg. (Fig. 12.) March 17th. 1 killed, 1 injured._
[Illustration: _Fig. 12._]
One of five, 5 years old. Plain cylinder, 68ft. long, 4ft. 4in.
diameter, plates 5/16 inch full, 65 lbs. pressure. Heated by gas. Rent
at fourth seam, the front end being thrown a great distance forward,
and the back end to the rear, displacing the other 4 boilers. The
ruptured seam was next to a patch where the cutting out of the old
rivets and putting in of new had caused a seam-rip.
_No. 23. S. Wales. (Fig. 13.) March 18th. none injured._
[Illustration: _Fig. 13._]
One of two, 36 years old. Lancashire, 30ft. long, 9ft. diameter. Tubes
3ft. diameter, 1/2 inch plates, 22 lbs. pressure. The boiler was rent
into 3 pieces. Five rings of the back part were torn off and thrown to
the rear. Four rings in the middle were opened out flat and fell across
the other boiler, and the remaining part of the shell with the tubes
were left on the seating. The boiler was old and much patched, and was
corroded too thin to bear the usual pressure.
_No. 24. Lynn. (Fig. 14.) March 23rd. 2 killed._
Cornish, 10 years old, 7ft. 3in. long, 3ft. 2in. diameter. Tubes 1ft.
10in. diameter, 3/8 inch plates, 36 lbs. pressure. The tube ruptured at
the last ring of plates, and was forced inwards, allowing the contents
to issue at the back. The boiler was slightly thrown forward. It was
only used occasionally, but was so much reduced by internal corrosion
as to be unable to bear the usual pressure.
[Illustration: _Fig. 14._]
_No. 25. Northwich. (Fig. 15.) May 3rd. 1 killed, 1 injured._
[Illustration: _Fig. 15._]
Marine, 7 years old, 9ft. 2in. long, 6ft. 1in. diameter. Furnace
tube 2ft. diameter, and 3 inch small tubes, 3/8 inch plates, 81 lbs.
pressure. There were two bands as clips round the outside of boiler.
Gave way at a seam where some new bottom plates had been inserted,
and where the old plate was so thinned by internal corrosion as to be
unable to bear the usual pressure. A small plate was blown out and
shattered into three pieces, and the boiler was turned end for end.
_No. 26. Barnstaple. May 9th. 1 killed._
Revolving Rag boiler of plain cylindrical shape, with three filling
holes. The steam was supplied from other boilers. The central lid was
unscrewed, without trying, by a small hole for the purpose, whether
there was any pressure, and the lid came off, and the contents issued
and scalded the attendant.
_No. 27. Leamington. (Fig. 16.) May 18th. 1 killed, 2 injured._
[Illustration: _Fig. 16._]
Portable multitubular, 9 years old, 8ft. 6in. long, 2ft. 6in. diameter,
5/16 inch plates, 50 lbs. pressure. The safety valve was fastened down
by a nail (A) between the lever and the cover, and in consequence the
pressure accumulated to more than the boiler could bear, and it was
rent into many pieces, which were widely scattered.
[Illustration]
_No. 28. May 20th. none injured._
Portable vertical, of peculiar construction, with return down flue
tubes, 6ft. high, 4ft. 6in. diameter, 3/8 inch plates, 35 lbs.
pressure. The shell was torn off, the bottom having given way through
weakness, from want of proper stays, from the crown of the fire box to
top of the boiler.
_No. 29. Hull. (Fig. 17.) May 22nd. 3 killed, 1 injured._
[Illustration: _Fig. 17._]
Lancashire, 22ft. 6in. long, 7ft. 6in. diameter. Tubes 2ft. 10in.
diameter, 3/8 inch plates, 70 lbs. pressure. The tube was somewhat
corroded on the top, and gave way over the fire from weakness.
_No. 30. Bath. May 25th. 1 killed, 1 injured._
Revolving Rag boiler of plain cylindrical shape, but revolving on
trunnions, in the opposite direction to No. 26, 12ft. high, 6ft.
diameter, 9/16 inch plates, 50 lbs. pressure. The steam was supplied
from another boiler. The cover at one end was insecurely fastened and
was blown off.
_No. 31. Oakengates. (Fig. 18.) June 6th. none injured._
[Illustration: _Fig. 18._]
One of two, 20 years old. Balloon, 14ft. diameter, 3/8 inch plates, 6
lbs. pressure. The pressure was allowed to far exceed the proper height
during a temporary stoppage of the engine, and the bottom was rent off,
and the top thrown some distance, but very little damage was done.
_No. 32. Wellingbro'. (Fig. 19.) June 17th. 1 killed, 2 injured._
[Illustration: _Fig. 19._]
Cornish, 28ft. long, 6ft. diameter. Tube 3ft. diameter, 3/8 inch
plates, 40 lbs. pressure. Tube collapsed from weakness, and partly tore
away from the back end, and the reaction from the issuing contents
forced the boiler back a long way.
_No. 33. Tunstal (Fig. 20). June 28th. 8 killed, 20 injured._
[Illustration: _Fig. 20._]
Cornish, 43ft. long, 6ft. 6in. diameter, 7/16 inch plates. Tube 3ft.
diameter, 3/8 inch plates, 50 lbs. pressure. The tube collapsed
sideways from end to end through weakness, being without strengthening
hoops, and with continuous longitudinal seams. The back end and part of
the tube were thrown to the rear, and the rest of the boiler was thrown
to the front, and separated into several fragments.
_No. 34. Glasgow. July 9th. 3 killed._
The lid of a steam valve was being removed while under pressure, and
the steam escaped and scalded those near.
_No. 35. Rotherham. (Fig. 21.) July 11th. none injured._
[Illustration: _Fig. 21._]
Cornish, 10 years old, 7ft. long, 6ft. 6in. diameter. Tube 3ft. 3in.
diameter, 3/8 inch plates, 45 lbs. pressure. Gave way where much
corroded by the damp brickwork of the central wall, and the back ring
of plates was torn out, and the boiler turned up on end, and much
damage was done to the premises.
_No. 36. July 17th. none injured._
Cornish, 16 years old, 12ft. long, 4ft. diameter, 7/16 inch plates, 48
lbs. pressure. Gave way at the bottom and rent open, a belt of plates
being blown away to some distance. The bottom had been extensively
corroded, by the boiler being left exposed to wet for many years before
it was set at this place, rendering it unfit to bear the usual pressure.
_No. 37. Cumnock. (Fig. 22.) July 28th. 1 injured._
[Illustration: _Fig. 22._]
One of five, about 20 years old. Plain cylinder, 20ft. long, 4ft.
diameter, 5/16 inch plates, 45 lbs. pressure. The boiler had been much
patched and altered, and was in very poor condition, and unfit to bear
safely the ordinary pressure. Rupture commenced near the feed pipe,
and ran along one side and then round each end, both of which were
liberated and thrown far away, the barrel of the boiler spreading out
on to the neighbouring boilers, one of which was much injured.
_No. 38. Shields. (Fig. 23.) August 1st. 1 killed, 7 injured._
Multitubular, 10 years old, 7ft. long, 3ft. 6in. diameter, 5/16 inch
plates, 50 lbs. pressure, but valve loaded to 80 lbs. Rupture commenced
at the unguarded manhole, and the shell was rent into several pieces
which were much scattered. The safety valve was defective, and the
boiler had been much weakened by many patches, and was in poor
condition and unable to bear the pressure at which it was worked at the
time of explosion.
[Illustration: _Fig. 23._]
_No. 39. Wakefield. August 3rd. 1 killed, 1 injured._
One of five. Rag boiler, 5 lbs. pressure from the exhaust steam of an
engine. The manhole was of very large size and insecurely fastened, and
was blown off.
_No. 40. Cornwall. (Fig. 24.) August 17th. 2 killed._
[Illustration: _Fig. 24._]
Cornish, 30ft. long, 6ft. 3in. diameter. Tube 4ft. 3in. diameter,
18 lbs. pressure. Ruptured near brickwork at the bottom where much
corroded externally, and one ring of plates was rent open. The boiler
was displaced, and the premises were greatly damaged.
_No. 41. Shields. August 26th. none injured._
Chemical pan, 12ft. long, 5ft. 6in. diameter, 3/8 inch plates. The end
was blown off, the rivets not being strong enough for the pressure of
35 lbs. as supplied from the boilers.
_No. 42. Blackburn. (Fig. 25.) August 29th. 1 killed, 2 injured._
[Illustration: _Fig. 25._]
Lancashire, 26ft. long, 6ft. 6in. diameter. Tubes 2ft. 9in. diameter,
3/8 inch plates, 60 lbs. pressure. The left hand tube collapsed from
overheating through shortness of water, and the contents issued
violently and scalded those near.
_No. 43. Hereford. August. 2 injured._
Chemical boiler, Plain cylinder, 12ft. 6in. high, 4ft. 6in. diameter,
3/8 inch plates, with cast-iron hemispherical ends with manhole in
each. The pressure of 34 lbs. was obtained from another boiler. The
bottom end gave way where the casting was defective, a piece was blown
out, and the reaction of the issuing contents projected the boiler
through the roof, through which it again descended and did much damage.
_No. 44. Cardiff. (Fig. 26.) September 1st. 2 killed, 2 injured._
[Illustration: _Fig. 26._]
Marine. Multitubular, 6ft. long, 6ft. diameter, 60 lbs. pressure. The
under side of fire box gave way at the front rivets, the heads of which
were corroded, and a tongue of plate was torn upwards, allowing the
contents to issue so violently, that those near were carried overboard
and drowned.
_No. 45. Gresley. (Fig. 27.) September 2nd. 7 injured._
[Illustration: _Fig. 27._]
One of six, 2 years old. Plain cylinder, 40ft. long, 5ft. diameter, 3/8
inch plates, 50 lbs. pressure. This case was peculiar, as the back part
of the boiler was found a long way to the front, and the front end in
the rear. An accumulation of scale caused pocket to form, and a hole
to burn through the bottom over the grate, allowing the contents to
issue so violently that the boiler was sent over end for end, when the
front end was knocked off and thrown to the rear, and the contents then
issuing more violently, the reaction sent the rest of the boiler in one
piece a great distance to the front, where it fell, and was crushed
nearly flat and broken into several fragments.
_No. 46. Cornwall. (Fig. 28.) September 16th. 4 injured._
[Illustration: _Fig. 28._]
One of two, 18 years old. Cornish, 32ft. 9in. long, 6ft. 6in. diameter.
Tube 4ft. diameter, 3/8 inch plates, 45 lbs. pressure. The tube
collapsed from end to end, dropping together like an old sack, and
cracking at the edges. A small piece at the front end was blown out.
The cause was supposed to be shortness of water as there was no gauge
glass, but it was far more likely the weakness of so large a tube
without strengthening hoops. The pressure was doubtless more than
usual, as the engine had made a temporary stand. A similar collapse
took place in the next boiler in December, 1869, and is described as
No. 57 in the "records" of that year.
_No. 47. Hull. (Fig. 29.) September 22nd. 2 injured._
[Illustration: _Fig. 29._]
Vertical, with fire box of peculiar corrugated construction, 7ft. 6in.
high, 3ft. diameter, 50 lbs. pressure. Gave way round the bottom of
fire box where much corroded and rent open, and the reaction of the
issuing contents carried the whole boiler to a considerable distance.
The pressure gauge had been removed, and the safety valve did not act
freely, and the pressure accumulated to more than the boiler could bear.
_No. 48. Grindleton. (Fig. 30.) September 26th. 1 killed._
[Illustration: _Fig. 30._]
Lancashire, 3 years old, 20ft. long, 7ft. diameter. Tube 2ft. 2in.
diameter, 3/8 inch plates, 60 lbs. pressure. The boiler gave way at the
second ring of plates from the back end, at the side where externally
corroded to a knife edge, by brickwork made damp by being next the side
of a hill. The rents extended round the boiler, and it was turned
nearly bottom upwards, and the shell opened out in the curious way
shown in the sketch.
_No. 49. Bradford. October 9th. none injured._
One of three. Portable, multitubular, 8ft. long, 2ft. 6in. diameter,
80 lbs. pressure. There was no safety valve, dependence being placed
on that of the boiler to which it was connected. Steam was got up
without opening the connecting steam cock, and the consequent excessive
pressure forced off the front end.
_No. 50. Tipton. October 17th. none injured._
One of twenty, 22 years old. One tube worked by two furnaces, 36ft.
long, 6ft. 3in. diameter. Tube from end to left side 2ft. 8in.
diameter, 1/2 inch plates, 30 lbs. pressure. The tube collapsed from
overheating through shortness of water, and cracked at the edges and
allowed the contents to escape without any violence.
_No. 51. Bury. October 21st. 2 killed, 1 injured._
A wall fell upon and broke the steam pipes, and the escaping steam
scalded those near.
_No. 52. October 25th. 2 injured._
Chemical boiler. Plain cylinder, 9ft. 3in. long, 6ft. diameter, 3/8
inch plates. The back end was blown out, and the boiler moved forward
a few yards, and the premises were much injured. The outlet pipes were
choked up, and more pressure accumulated than it was capable of bearing.
_No. 53. Chesterfield. (Fig. 31.) October 25th. none injured._
Plain cylinder, 6ft. 6in. long, 2ft. 2in. diameter, 5/16 inch plates,
80 to 100 lbs. pressure. The manhole was weak and unguarded with a
strengthening ring, and ruptured and allowed the lid to blow out. The
rents spread along a part where strength was much reduced by the rivets
being countersunk to make room for attachments. The safety valve was
defective and overloaded, and there was no gauge, and the boiler was
unfit to bear the pressure to which it was exposed.
[Illustration: _Fig. 31._]
_No. 54. Northwich. October 28th. 1 killed, 1 injured._
Chemical. The cover was unscrewed before the pressure was off, and the
contents blew out violently and scalded those near.
_No. 55. Bowling. (Fig. 32.) October 30th. 1 killed, 1 injured._
[Illustration: _Fig. 32._]
One of two, 17 years old. Marine, 12ft. 7in. long, 6ft. 3in. diameter.
Tube 4ft. wide, 2ft. 9in. high, 16 lbs. pressure. The tube was much
weakened by corrosion and screw-patching and collapsed upwards, with
the slightly increased pressure of a temporary stoppage of the engine.
_No. 56. Bilston. October. none injured._
Chemical, 9ft. long, slightly oval, 4ft. greatest diameter, 3/8 inch
plates, 2 lbs. pressure. Although not at work, it is supposed that
a gas was gently passing off through a small pipe, 30ft. long, to a
receiver which was under repair, and that this gas being accidentally
lighted, communicated through the pipe with that in the boiler and
exploded it. One end was blown off, the rupture passing completely
round through the solid plate.
_No. 57. Newcastle. (Fig. 33.) November 5th. none injured._
[Illustration: _Fig. 33._]
Cornish, 25ft. long, about 6ft. diameter. Tube 3ft. 6in. diameter, 3/8
inch plates, 30 lbs. pressure. Tube collapsed from overheating through
shortness of water.
_No. 58. Gravesend. (Fig. 34.) November 8th. 2 killed._
[Illustration: _Fig. 34._]
One of two. Marine, 16ft. 6in. long, 8ft. 4in. diameter. Tube of
irregular shape, about 2ft. 10in. high, 3/8 inch plates, 27 lbs.
pressure. The gauge was so much out of order, that it only showed 24
lbs. under a real pressure of 80 lbs. The safety valve was defective
and overloaded, and the pressure was sufficient to collapse and rupture
the side flue, and the contents rushed out at the front.
_No. 59. Bilston. (Fig. 35.) November 12th. none injured._
[Illustration: _Fig. 35._]
One of four. Cornish, about 20 years old, 26ft. long, 6ft. 6in.
diameter, 7/16 inch plates, 40 lbs. pressure. Tube 3ft. 9in. diameter
had been made in two parts, joined in the centre by a narrow plate 3/8
inch thick, and it collapsed at this joint, so that the top met the
bottom, and thus so retarded the issue of the contents after being set
in motion, that a shock was produced, which blew out an end and half
the tube in opposite directions. The shell was left resting in its
seat, and little damage was done to premises. The tube had much the
appearance of collapse from shortness of water, but the most probable
cause was that it was too weak without strengthening hoops to bear the
ordinary pressure with safety.
_No. 60. Diss. (Fig. 36.) November 11th. 2 killed._
[Illustration: _Fig. 36._]
Portable, multitubular, about 10 years old, 8ft. 3in. long, 2ft.
7in. diameter, 3/8 inch plates, 30 lbs. pressure. The bottom of the
smoke box was reduced by external corrosion to less than 1/16 inch in
thickness, and was consequently unable to bear the ordinary pressure,
and a piece was blown out, and the reaction of issuing contents
displaced the boiler a little and much damaged the premises.
_No. 61. Rotherham. November 18th. 1 killed._
The screws of a manhole were loosened while the pressure remained in
the boiler, and the lid was blown off.
_No. 62. Newcastle. November 25th. 1 killed._
One of twelve. Chimney, 28ft. high, 6ft. diameter. Tube 2ft. 5in.
diameter, 3/8 inch plates, 25 lbs. pressure. The blow pipe was left
open while some men were inside repairing, and the steam and water from
the blow-off of another boiler in the same pipe was forced in upon them.
_No. 63. Cradley. December 8th. 1 injured._
Locomotive, 11ft. long, 3ft. diameter, 3/8 inch plates, 95 lbs.
pressure. The pressure amounted to about 134 lbs. during a temporary
effort to get up a steep curved incline, and the fire box was forced
inwards and the outside shell outwards, and the stays drawn, but little
other damage was done.
_No. 64. Middlesbro'. (Fig. 37.) December 13th. 1 injured._
Locomotive, 18ft. 6in. long, 4ft. diameter, 7/16 inch plates, 120
lbs. pressure. Gave way under bottom of barrel where "furrowed" by
the combined action of corrosion and the strain upon the plates, by
attachment to the frame of the engine.
[Illustration: _Fig. 37._]
_No. 65. Westbromwich. (Fig. 38.) December 28th. 1 injured._
[Illustration: _Fig. 38._]
One of five, 23 years old. Balloon, 16ft. diameter, 3/8 inch plates,
5 lbs. pressure. It ruptured at the back where the plates in contact
with brickwork were reduced by external corrosion, and the bottom was
forced down upon the grate, and the top rolled over on to its side. The
boiler was not being used, although connected with the other at work.
The strain upon the bottom was increased by the boiler being over full
and nearly to the brim. Those near were drenched with nearly cold water
from it when it upset.
_No. 66. Glasgow. (Fig. 39.) December 30th. 11 killed, 30 injured._
Portable upright, about 8 years old, 11ft. 4in. high, 4ft. diameter,
3/8 inch plates, 100 lbs. pressure. The internal portion gave way
where attached to the fire holes and collapsed inwards, and the
reaction of the issuing contents forced the boiler up some distance
on to the top of a house. The safety valve did not act properly, and
the pressure appears to have accumulated to more than the boiler could
bear, during a temporary stoppage of the engine.
[Illustration: _Fig. 39._]
* * * * *
_R. Broomhall, Printer, Stourbridge._
[Transcriber's note:
Some of the figures are out or order, as in the original.
Several (apparently) missing punctuation marks have been added to
improve readability.
The word 'guage' appears several times. It has been changed to 'gauge'
in each location.
Italics are rendered between underscores e.g. _italics_.
Small caps are rendered as ALL CAPS.
The following table lists other changes made by the transcriber.]
+-----------------------------+
| Transcriber's Change table |
+----+-----------+------------+
|page|as printed | changed to |
+----+-----------+------------+
| 95| Uudue | Undue |
| 105| Fig. 5. | Fig. 6. |
| 110| to to | to |
| 110| place | placed |
| 143| he | The |
| 172| reqair | repair |
| 195| discribed | described |
| 216| reqaired | repaired |
| 221| diamer | diameter |
| 250|consderable|considerable|
+----+-----------+------------+
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