The Stourbridge Observer, Cradley Heath, Halesowen & District Chronicle.
Stourbridge, West Midlands, England, 1875-01-09 00:00:00

THE EXPLOSION OF HOUSEHOLD
BOILERS.
The Times has published the following letter

Sir,—May I request you, in the interest of public
safety, to afford me space for a few lines on the subk ct
of household boiler explosions? Few winters, if at all
frosty, come round without bringing with them several
of these explosions, which too frequently are attended
with serious consequences. Within the last few days
the public papers have reported two of these disasters,
one that occurred at Chorley on the night of Sunday,
the 27th December, whereby three persons were very
severely injured, and another which occurred at a
workhouse at Preston on the morning of Monday,
December 28, whereby one lad was killed and two
others injured, the lad who was killed being reported
to have been found after the explosion buried under a
heap of debris, frightfully mangled, scalded, and quite
dead. It is highly probable that other explosions have
occurred which have not as yet been brought under
public notice.
The cause of household boiler explosions is simple,
and their prevention easy. They are not due to the
thaw but to the frost. They do not arise from asudden
generation of steam through the boiler being boiled
sky during the frost and then, when overheated, being
subjected to the introduction of cold water on the oc-
currence of the thaw. To throw light upon this sub-
ject the Manchester Steam Users' Association insti.
tuted some experiments in the year 1867, making some
household boilers redhot, and then injecting cold water,
when no explosion resulted, though the experiment
was repeated again and again. Household boilers on
the circulating principle have, as a rule two pipes con-
necting them to an overhead cistern. Through one of
these pipes there is a down current, and through the
other an up-current. As long as these pipes are free
they form two n atural safety-valves, and no accumulation
of pressure can occur. When, however, the thorough-
fare through the pipes is choked the conditions are alto-
gether altered. Sometimes stop-taps are placed in the
circulating pipes, and these may be inadvertently
closed. Under these circumstances, there being no
outlet, the pressure within the boiler accumulates, and
in short time with a brisk fire generates an explosion.
Such explosions may occur at any time of the year,
whether winter or summer, and several have come under
my notice. One such occurred at a first-class Loudon
west-endhotel, and a second at a London west-end club,
both in the month of October, long before the frost
had set in. In frosty weather the circulating pipes
are apt to become choked with ice, which bottles
up the pressure within the boiler just as securely as
if the thoroughfare were cut off by means of stop-
taps, when, as just stated, the pressure having no
outlet, goes on accumulating till it bursts the boiler
and leads to an explosion. The simple cause of house-
hold boiler explosions, therefore, is a gradual accumu-
lation of pressure through stoppage of the outlets.

Iters, I are

To prevent this accumulation of pressure all that is
needed is to fix a small reliable safety-valve to the
boiler. The Manchester Steam Users' Association
drew up a report on the subject some years sinoe, ac-
companied with a drawing of a simple and inexpen-
sive safety-valve speeially adapted for household
boilers, and sent the report to the public papers for
general circulation, while the subject has since
been called attention to by the Association every
winter. This safety-valve is of pendulous dead weight
construction. It has no lever, joiat, fang, or spindle
to become corroded or to stick fast. The bearing por-
tion of the valve is spherical, and is kept on its seat
simply by dead weight, while the surface on which
it rests is little wider than a knife edge. No
trriginality is claimed with regard to the-construc-
tion of this valve. Its application is simply an adap-
tion in miniature of a valve that has been extensively
used for years on large steam-engine boilers. It can
be made by any one who has the requisite skill. A
good valve of this class, adapted for household
boilers, may be bought for 10s. 61., so that it is by no
means expensive. An inferior one may be ;got for
something less. The main difference between the two
is this—that the better one has the bearing portion of
the valve made in a separate piece from the outer
shell which weights it, so that it can be got up more
truly. The inferior one is made all in one piece, and
is apt to leak. Leakage at the valve involves empty-
ing the overhead cistern, and withdrawing the fire,
in otaler to effect repairs. The in convenience which
this occasions would con vinee those who experience
it that the better valve is the cheaper of the two.
Hundreds of these valves are at work, and I have
not been able to leara that any of them have stuck
fast. I have had one at work under my own eye for
the last three years. ~It has given no trouble, and i
perfectly free in acti n. In the first instance, how-
ever, having one of th valves of the inferior type, eon-
aiderable ineonveniene was'experienced from leakage,
but since it was exchanged for one of the better sort
there has been no difficulty whatever. A more detailed
description of the construction of this valve, accom-
panied with explanatory drawings, was given in the
Association's last monthly Report, printed for circu-
lation among the members. A copy of this, may be
had gratuitously on application by parties desirous of
further information, ~,

Circulating boilers for supplying baths with hot
water, as well as for warming and ventilating and
other purposes, are now of such very general adoption
that the question of their safety becomes of interest to
almost every householder.
Pending the fixing of a reliable safety-valve, it is
desirable to open the hot and cold water taps in the
circulating pipes to see if the water runs freely. If it
does not do so, the fire should not be lighted. The
precaution of opening the taps is more especially
necessary on re-lighting a fire after the boiler has been
standing idle for a day or so. This suggestion, how-
ever, is not intended as a substitute for a safety-valve,
but simply as an intermediate precaution. Where
there are no taps for testing the freedom of the circu-
lation no fire can be lighted under a circulating boiler
in frosty weather without great danger. In many
cases, the stoppage for a single night is sufficient to
choke the outlets with ice.--I am, Sir, yours faith-
fully, LAVINGTON E. FLETCHER,
Chief Engineer to the Manchester Steam
• 'Users' Association.
41, Corporation-street, Manchester.
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