IMPROVED APPARATUS FOR PREVENTING EXPLOSIONS OR ACCIDENTS TO STEAM BOILERS
Year: 1871

page_text: LETTERS PATENT to Arthur Milsom Birchall, of Preston, in the
County of Lancaster, Tobacco Manufacturer, for the Invention of
66 IMPROVED APPARATUS FOR PREVENTING EXPLOSIONS OR ACCIDENTS TO STEAM
BOILERS."
Sealed the 6th June 1871, and dated the 5th April 1871.
PROVISIONAL SPECIFICATION left by the said Arthur Milsom
Birchall at the Office of the Commissioners of Patents, with his
Petition, on the 5th April 1871.
I, ARTHUR MILSOM BIRCHALL, of Preston, in the County of
Lancaster, Tobacco Manufacturer, do hereby declare the nature of the
said Invention for "IMPROVED APPARATUS POR PREVENTING EXPLOSIONS OR
ACCIDENTS TO STEAM BOILERS," to be as follows:―
My Invention consists in an improved apparatus for discharging
steam and water or steam into the furnace of a steam boilers, and thereby
putting out the fire when the water has got down to a dangerous level,
which I effect in the following manner :—I fix a pipe so that one end
communicates with the inside of the boiler and below the working level

page_text: of water.
The other end is outside the boiler to which is fixed a
chamber, the top of which is capable of being removed. This chamber
contains a disc of a composition of metals which melts at the temperature
of steam, which, by preference, I make of "two parts of bismuth, onc
part of lead, and one part of tin." The communication between the
boiler and the above chamber is made so as to be closed by a valve
when required, which valve is closed when the top of the chamber is
removed. Into this chamber is attached another pipe, to the end of
which is secured (and closed by) the before-mentioned disc plate of
composition metals, the other end descends "over" and is open to the
fire. When the boiler is at work and the water is at a level above the
bottom of the first-mentioned pipe such pipe is wholly or partialy filled
with water, which pipe is carried above to such a height that the heat
in the chamber is not sufficient to melt the disc plate contained therein:
On the water falling below the level of the lower end of the pipe com-
municating with the boiler the water previously contained in it descends
and allows steam, "which is usually under such circumstances super-
heated," or heated water, to take its place, which immediately coming
in contact with the disc plate at the top end of the inner pipe in tho
chamber melts such disc plate and descends on to the fire of the boiler
"putting it out," and thereby preventing explosion or accident.
When this takes place and the shortness of water discovered the valve
should be closed and the water got up to the ordinary working level,
this being accomplished another disc can be inserted, the chamber
closed, the valve opened, and the apparatus is again ready for acting
should another shortness of water take place.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Arthur Milsom Birchall in the Great Scal Patent
Office on the 2nd October 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ARTHUR 30
MILSOM BIRCHAL, of Preston, in the County of Lancaster, Tobacco
Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of April, in the year of our
Lord One thousand eight hundred and seventy-one, in the thirty-fourth, 35

page_text: year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Arthur Milsom Birchall, Her special licence
that I, the said Arthur Milsom Birchall, my executors, administrators,
and assigns, or such others as I, the said Arthur Milsom Birchall, my
exccutors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVED
APPARATUS FOR PREVENTING EXPLOSIONS OR ACCIDENTS TO STEAM BOILERS," upon
the condition (amongst others) that I, the said Arthur Milsom Birchall,
my executors or administrators, by an instrument in writing under or
their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
"
NOW KNOW YE, that I, the said Arthur Milsom Birchall, do
hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
My Invention is specially adapted to steam generators, to which if
applied any explosion or accident arising therefrom in consequence of
deficiency of water is rendered nearly impossible, for on the water falling
to a low level the steam or steam and water through the aid of the said
Invention is allowed to play freely on the fire or fires of such steam
generator, thus causing them to be imediatly extinguished; but should
the fireman be present at the time he is enabled to attend to the
requirements of the said Invention and can restore it to its working
order in a few minutes.
Hereunto I annex a Sheet of Drawings in the several Figures of
which similar parts are marked by corresponding letters of reference.
Fig. 1 is a sectional clevation of my apparatus; Fig. 2 is a front view
of the same; Fig. 3 plan of top, with cap removed; Fig. 4 section of
internally fixed boiler shewing my apparatus in position, and the water
at the proper working level; Fig. 5 section of an externally fixed boiler
shewing my apparatus in position, and in operation extinguishing the
fires, the water in the boiler being at a low level.

page_text: A in Figs. 1 and 2 is an elbow stand pipe screwed firmly to the front
of the boiler by the screws a, a; to this is attached stand pipe B, to the
top of which is affixed valve box G with screwed cover E; D is a pipe
screwing into the valve seat II, H, and the opposite end, as will be seen,
on Figs. 4 and 5, decends through the boiler imediatly over the fire,
the end of the pipe being open to the fire. On the top end of the valve
scat H, I, is screwed a box cap which is formed so as to receive a disc
plate of metal, which will melt at or near to the temperature of steam,
the metal being composed of bismuth, lead, and tin. This box cap and
disc plate closes the upper end of the before-mentioned pipe D. The
connection between the pipes B and D is closed when occasion requires
by a valve marked F, F, (or when preferred) by two or more known as
"mushroom valves." The valve box cover E, when screwed down,
and
presses on the upper ends of the guide wings J of the valve F, F,
keeps it open, thus leaving a free communication for the water between
the boiler and the chamber K, K, in the valve box cap, and covers the
before-mentioned disc plate.
It will be observed that while the water remains at its proper level,
the apparatus being outside the boiler and exposed to the atmosphere,
the water in it is rendered much cooler than the water and steam insido
the boiler, but when the water falls to the low level indicated in Fig. 5,
that is, below the bottom of pipe B, the apparatus becomes charged with
steam, the heat from which melts the disc plate c in chamber K, K,
thus allowing the steam to escape down the pipe D and on to the fire as
shewn in Fig. 5, calling the fireman's attention to the fact, if he is at
hand, or if not, extinguishing the fire, thus preventing any explosion or
accident to the boiler. When the disc has melted and the steam is
playing on the fire the fireman turns on the feed water to the boiler,
after which he removes the cover E, in doing which he allows the
valve F, F, to closc, shutting off the steam or steam and water from
playing on the fire. After the water has regained the ordinary working
level a fresh dise plate e is fixed in the appratus, the valve box cover E
screwed down to its place during the operation; the valves F, F, are
opened, and the apparatus is again in order and ready to act on the
water falling to the low level. All this is accomplished without its
being necessary to stop the engine, which the boiler has to supply.
Having fully described the nature of my Invention, and the way
it is worked, I wish it to be understood that I do not confine myself

page_text: to the precise details I have had occasion to describo and illustrate, as
many variations can and may be made in detail without deviating from
the principles herein contained; but what I claim as substantialy mino
as herein secured is,―
First. The vertical stand pipes, either placed in front of the boiler or
on the top, or wherever placed, in connection with steam boilers and
used for the purposes herein set forth and illustrated.
Second. The valve box G containing a valve or valves in connection
with and for the purposes herein set forth and illustrated.
Third. The valve box cover and its action upon the valve or valves
in opening such valve or valves, substantialy as herein set forth.
Fourth. The disc plate and method of securing the same, substantialy
as herein set forth and illustrated.
In witness whereof, I, the said Arthur Milsom Birchall, hereunto
set my hand and seal, this Twenty-eighth day of September,
in the year of our Lord One thousand eight hundred and seventy-
onc.
Witness,
0
JOHN LEWIS,
ARTHUR MILSOM BIRCHALL. (L.S.)
Engineer & Patent Agent,
Preston,
Lancashire.