IMPROVED Low WATER APPARATUS TO ACT ON THE SAFETY VALVES OF 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
"IMPROVED Low WATER APPARATUS TO ACT ON THE SAFETY VALVES OF
STEAM BOILERS."
Sealed the 1st August 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 Lan-
caster, Tobacco Manufacturer, do hereby declare the nature of the said
Invention for "IMPROVED LOW WATER APPARATUS TO ACT ON THE SAFETY
VALVES OF STEAM BOILERS," to be as follows:
My Invention consists of an improved low water apparatus in con-
nection with the ordinary steam pressure or safety valve. In the inside
of the boiler I fix a water float by lever and fulcrum or other means.
This float on the falling of the water to a low level opens a small valve
and admits the steam into a cylinder or on to a diaphragm, whereby a
force is exerted against one or more levers or other equivalents, or
directly on the weight of some safety valves, if thought desirable, thus
:

page_text: having the effect of lifting the load from off the safety valve and allow
the steam to escape from the boiler. On the water regaining its proper
level the float will close the small valve, and the blowing off of steam
stopped, the high-pressure steam valve being quite unencumbered and
free to act.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Arthur Milsom Birchall in the Great Seal Patent
Office on the 2nd October 1871.
TO ALL TỌ WHOM THESE PRESENTS SHALL COME, I, ARTHUR
MILSON BIRCHALL, 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 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
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the 1
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 LOW
⚫ WATER APPARATUS TO ACT ON THE SAFETY VALVES OF 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 ascertained in and
by the following statement:-

page_text: My Invention consists of an improved low water valve in connection
with the ordinary steam pressure or other valve.
Hereunto I annex a Sheet of Drawings which shews my Invention in
connection with a dead weight safety valve, I shew it by preference to
this valve, "but I can apply it to open any description of valve.".
A, A, in my Drawings represents a portion of an ordinary boiler "in
section"; B, B, the top plates of such boiler; C, C, main steam passage
to safety valve; D, D, the stand pipe firmly fixed to the top of boiler
plates B. On the top of such pipe and connected to same is a piston
E, E, in cylinder F, F. In the centre of this cylinder I cast a plate G, G,
which rests upon several stops a, a, cast upon the upper side of piston E.
There is a guide pipe b, b, on the upper side of this cylinder, plate G,
made to fit easily on to the steam passage pipe d which is cast to the
piston, on which is check ring e or other equivalent, this is to prevent
the cylinder F under extreme pressure from being lifted off the piston E.;
H, H, are a number of holes inserted round the cylinder, and are below
the packing ring when the cylinder is at rest. When however steam
enters and lifts the cylinder these holes come above the packing ring,
and allows the steam to escape. and prevents the cylinder from being
lifted too high. The lower end of the cylinder has a cup flange N cast
on it to guide the steam upward when escaping through the series of
holes H. all round such cylinder; J is an ordinary water float connected
to end of lever K by rod f, this lever is fulcrumed to bracket L at g,
at the other end of such lever K is a balance weight M. The valve h
is made with three wings of Y shape, so that the escape of steam may
be gradually increased as the valve opens. The first escape for a short
time being sufficient to sound the whistle I without lifting the cylinder,
and thereby giving warning to the fireman or other attendant, so that
by instant attention to its requirements he may prevent any loss of
steam. The valve h is likewise connected to lever K by stalk i. This
valve and seat are fitted into a passage; cast in stand pipe D, this
passage goes through piston E into space o, between plate G in cylinder F,
and the upper side of piston E; l, l, is a valve for testing the accurate
working of the apparatus; P, P, are a number of wings cast on the
cylinder so as to carry the weights up when the cylinder is raised, but
allowing the weights to hang free when the cylinder is down.
.
The action of the apparatus is as follows:-When the float for want
of water falls to low water level "it" by means of rod and lever K,

page_text: opens valve h, thus admitting steam by passage j to space o between
piston top and cylinder plate G, which having a great area has an
increased force corresponding to the difference between the area of
valve h and piston E, by which means the cylinder F is raised and
coming in contact with the weights of the high-pressure valve lifts 5
such valve and gives a vent for the escape of the steam equivalent to
the area of the steam pipe C. (By preference) I line my cylinders with
brass and use brass piston rings.
Having now described my Invention and its action it may be as well
to say in conclusion that I do not confine myself to the precise arrange-
ments in detail, as it is posible to alter the arrangement to suit the
different kinds "or makes" of valves without deviating from the
principle contained herein, but what I claim as my Invention and
secured by these Presents "is,"—
1
First. The stand pipe D, piston E, and cylinder F, substantialy as 1
and for the purposes herein set forth and illustrated.
Second. The valve h connected to lever K balance and float, sub-
stantialy as and for the purposes herein set forth and illustrated.
Third. The testing valve substantialy as and for the purposes hercin
set forth and illustrated.
Fourth. The general arrangement of the several parts of this apparatus
and its application for opening any other description of valve, sub-
stantialy as and for the purposes herein set forth and illustrated.
2
In witness whereof, I, the said Arthur Milsom Birchall, hereunto
set my hand and seal, this Twenty-eighth day of September, in 2
the year of our Lord One thousand eight hundred and seventy-
one.
ARTHUR MILSOM BIRCHALL. (L.S.)
Witness,
JOHN LEWIS,
Engineer and Patent Agent,
Preston,
Lancashire.