CERTAIN IMPROVEMENTS ADAPTED TO THE PREVENTION OF STEAM BOLLER EXPLOSIONS
Year: 1857

page_text: LETTERS PATENT to John Brown, of Golds Green, West Bromwich, in
the County of Stafford, Mill and Forge Manager, for the Invention of
"CERTAIN IMPROVEMENTS ADAPTED TO THE PREVENTION OF STEAM BOLLER
EXPLOSIONS."
Sealed the 11th August 1857, and dated the 8th June 1857.
PROVISIONAL SPECIFICATION left by the said John Brown at the
Office of the Commissioners of Patents, with his Petition, on the
8th June 1857.
I, JOHN BROWN, of Golds Green, West Bromwich, in the County of
Stafford, Mill and Forge Manager, do hereby declare the nature of the said
Invention for CERTAIN IMPROVEMENTS ADAPTED TO THE PREVENTION OF STEAM
BOILER EXPLOSIONS," to be as follows:-
To the inside of a boiler I suspend a rod, which forms the fulcrum of a
lever, to one end of which lever is attached the ordinary float, and to the
other end a balance weight. Upon this last-mentioned end of the lever rests
the foot of a valve rod or stalk, which passes upwards through a steam pipe
secured to the boiler; at the upper end of which valve rod is the safety
valve resting in a seating at the top of the steam pipe. The safety valve can,
of course, be weighted to any degree required to govern the pressure in the
boiler. As the level of the water in the boiler falls, the float falls with it,
raising the opposite. end of the lever upon which the valve röd rests, and

page_text: opening the valve at the top, when the steam shall exceed the required
pressure, allows a sufficient escape. Thus the safety valve is made to be the
indicator of low water.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Brown in the Great Seal Patent Office on the
4th December 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
BROWN, of Golds Green, West Bromwich, in the County of Stafford, Mill
and Forge Manager, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of June, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twentieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said John Brown, Her special license that I, the said John Brown, my
executors, administrators, and assigns, or such others as I, the said John
Brown, my executors, 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 "CERTAIN IMPROVE-
MENTS ADAPTED TO THE PREVENTION OF STEAM BOILER EXPLOSIONS," upon the
condition (amongst others) that I, the said John Brown, by an instrument
in writing under my hand and seal, should particularly describe and ascer-
tain 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.
..
per-
NOW KNOW YE, that I, the said John Brown, do hereby declare the
nature of my said Invention, and in what manner the same is to be.
formed, to be particularly described and ascertained in, and by the following
statement, reference being had to the Drawings hereunto annexed, and to the
letters and figures marked thereon, that is to say:-
.
My Invention has reference to an improved construction of safety valve,
by which I propose to withdraw the steam from near the middle or any part
below the crown of a boiler, instead of taking it from the top of the boiler in
the ordinary manner. I attach to the inside of the top of a boiler a rod of

page_text: any requisite strength, which rod hangs suspended in the boiler, and forms a
fulerum upon which I pin a lever; to one arm of this lever is connected a
common float, such as is ordinarily used in steam boilers, and to the opposite
end of the lever is hung a balance weight, so that .when the boiler has
sufficient water this apparatus may.be in a state of equipoise. A steam pipe,
which may be of cast iron, is also secured to the top of the boiler in a line
parallel with the fulcrum rod already described. The steam pipe rises some
short distance out of the crown of the boiler, and descends into it to a depth
of about one-half the distance from the crown of the boiler to the.line of full
water in the boiler, that is to say, to a depth of about one-fourth the diameter
of an ordinary cylindrical boiler. A stalk or valve rod passes up through the
steam pipe, and on the top of this valve rod the valve rests in its seating,
upon which any given weight is placed, the weights being enclosed so that
no undue interference with them can be exercised. The stalk-or-valve rod
which passes through the steam pipe almost touches the balance arm of the
lever, so that when the water falls in the boiler, the float falling with it
as a necessary consequence, the balance arm of the lever rises, and in
doing so affects the stalk or valve rod, raising the valve, and allowing an
escape of steam; the steam thus allowed to escape entering the steam pipe
at or near the bottom is, therefore, drawn from the surface of the water,
instead of being taken from the crown or upper part of the boiler. This
will be better understood by a reference to the accompanying Drawing, in
which (A) represents in section an ordinary cylindrical boiler, and (B), a
common steam valve, which I may employ, if I please, in connection with
my safety valve, and which being of the description well known and in
general use, I of course do not claim and need not further particularize, or I
can use two of my own valves on the same boiler for additional security;
(C) is the fulcrum rod; (D), the lever; (E), the float; (F), the balance
weight; (G), the steam pipe, to which is attached the strap (H), which is
merely for the purpose of steadying the fulcrum rod (C); (I), the stalk or
valve rod; (K), the valve; (L, L, L), the weights enclosed in the case (M).
It is evident that as the water falls in the boiler the consequent sinking of
the float (E) will raise the opposite end of the lever (D), until the part (D')
will in time operate upon the stalk or valve rod (I), raising it as the water
continues to fall, opening the valve, and allowing an escape of steam, which,
entering the escape pipe at the points (N), is drawn from about the middle
of the boiler instead of the top. The parts marked (O, P, Q,) represent a
second fulcrum rod, lever, and float, which I propose to employ in connection
with those already described, should I deem it desirable to do so.

page_text: Having thus described the nature of my said Invention, and in what
manuer the same is to be performed, I wish it to be understood that I do
not confine myself to these precise details; but that which I claim and desire
to have secured to me by the herein-before in part recited Letters Patent is,
the application of the several parts particularly described and shewn in the
Drawing, or the mere equivalents of such parts, adapted to the purpose of a
safety valve which shall allow the steam to escape from a point below the
crown of the boiler, as herein more fully set forth and specified.
In witness whereof, I, the said John Brown, have hereunto set my hand
and seal, this First day of December, in the year of our Lord One
thousand eight hundred and fifty-seven.
JOHN BROWN. (L.S.)