IMPROVEMENTS IN COMPOUND MAINTAINING PRESSURE APPARATUS FOR GAS VAPOUR OR OTHER FLUIDS
Year: 1883

page_text: LETTERS PATENT to James Cambell Stevenson of 11 Alice Street, Liverpool,
in the County of Lancaster, Engineer for an Invention of IMPROVEMENTS
IN COMPOUND MAINTAINING PRESSURE APPARATUS FOR GAS VAPOUR OR
OTHER FLUIDS
PROVISIONAL SPECIFICATION left by the said James Cambell Stevenson
at the Office of the Commissioners of Patents on the 14th May 1883.
JAMES CAMBELL STEVENSON, of 11 Alice Street, Liverpool, in the County of
Lancaster, Engineer, " IMPROVEMENTS IN COMPOUND." MAINTAINING PRESSURE
APPARATUS FOR GAS VAPOUR OR OTHER FLUIDS
This invention has reference to apparatus for maintaining a constant (or an
approximately constant) pressure of gas or other fluid by the use of floats within a
casing having inlet and outlet passages.
According to one arrangement for maintaining a constant (or approximately
constant) pressure of gas the casing provided with inlet and outlet passages or
branches is of cylindrical form. The said passages or branches project into the
casing parallel with its axis (which is. vertical when the apparatus is in working
position) and are of sufficient length to prevent water or other sealing liquid with
which the casing is charged, and wherein the floats work, from passing into the
main.
Over the inlet branch pipe is a cap valve suspended to one end of a lever the
fulcrum of which is formed by a rod attached to a float resting on the water in
the outer casing. At the other extremity the lever is connected by a pivotted rod
to a hollow cylindrical float so arranged that the pressure of the entering gas may
slightly raise this float thus closing the cap valve to the regulated pressure.
Outside the above mentioned hollow cylindrical float is another and similar
float that I call a compound maintaining float; a sufficient annular space is left
between these two floats for a pipe or communication extending from the outlet
branch. The arrangement is such that should a sudden rush of fluid occur in the
main thereby causing the first or inner cylindrical float to rise so high as to close
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page_text: .
the cap valve, thus causing a momentary stoppage of the gas then the compound
or outer float will come into action and allow gas to pass through the other pipe or
communication into the outlet branch.
By this arrangement the gas pressure is less liable to fluctuations than when a
single float is used.
It will be understood that the inlet and outlet branches or pipes are within the
inner float and that the second outlet branch establishes communication between
the two. hollow cylindrical floats and the outlet main. The cylindrical floats
resemble gas bolders, and the water or other liquid seal is such as to prevent
escape of gas otherwise than through the outlet branches or pipes. The outer
casing is provided with a lid and the necessary guides and charging inlet and
overflow.
It will be obvious that apparatus of the kind above described may be constructed
in modified forms adapted for use with different fluids and under various conditions
without departure from the essential features of my invention
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Cambell Stevenson in the Great Seal Patent Office on the
14th November 1883.
JAMES CAMBELL STEVENSON of 11. Alice Street Liverpool in the County of
Lancaster Engineer. "IMPROVEMENTS IN COMPOUND MAINTAINING PRESSURE
APPARATUS FOR GAS VAPOUR OR OTHER FLUIDS."
This invention has reference to apparatus for maintaining a constant (or an
approximately constant) pressure of gas or other fluid by the use of floats within a
casing having inlet and outlet passages.
According to one arrangement for maintaining a constant (or approximately
constant) pressure of gas the casing provided with inlet and outlet passages or
branches is of cylindrical form. The said passages or branches project into the
casing parallel with its axis (which is vertical when the apparatus is in working
position) and are of sufficient length to prevent water or other sealing liquid with
which the casing is charged and wherein the floats work from passing into the
main.
Over the inlet branch pipe is a cap valve suspended to one end of a lever the
fulcrum of which is formed by a rod attached to a float resting on the water in
the outer casing. At the other extremity the lever is connected by a pivotted rod
to a hollow cylindrical float so arranged that the pressure of the entering gas may
slightly raise this float thus closing the cap valve to the regulated pressure.
Outside the above mentioned hollow cylindrical float is another and similar float
that I call a compound maintaining float; a sufficient annular space is left between
these two floats for a pipe or communication extending from the outlet branch.

page_text: The arrangement is such that should a sudden rush of fluid occur in the main
thereby causing the first or inner cylindrical float to rise so high as to close the
cap valve, thus causing a momentary stoppage of the gas then the compound or
outer float will come into action and allow gas to pass through the other pipe or
communication into the outlet branch.
By this arrangement the gas pressure is less liable to fluctuations than when a
single float is used.
It will be understood that the inlet and outlet branches or pipes are within the
inner float and that the second outlet branch establishes communication between
the two hollow cylindrical floats and the outlet main. The cylindrical floats
resemble gas holders and the water or other liquid seal is such as to prevent escape
of gas otherwise than through the oulet branches or pipes. The outer casing is
provided with a lid and the necessary guides and charging inlet and overflow.
It will be obvious that apparatus of the kind above described may be constructed
in modified forms adapted for use with different fluids and under various conditions
without departure from the essential features of my invention.
Referring to the accompanying sheet of drawings Fig. 1 is a sectional elevation
of an apparatus according to my invention, for maintaining a constant (or an
approximately constant) pressure of gas or other fluid, the section being taken in
the line A. B. of Fig. 3. Fig. 2. is a sectional elevation in line C. D. of Fig. 4.
Fig 3. is a sectional plan taken in line E. F. of Fig. 1 Fig. 4 is a plan with the
top of the inner cylindrical float N. removed to shew the lever more distinctly.
The arrangement shewn is one suitable for maintaining a constant (or an
approximately constant) pressure or flow of fluids, such as illuminating gas.
G. is the inlet branch, H is a cap valve suspended by a link to one end of a lever J.
the fulcrum of which is formed by a rod or support K attached to a float L which
rests on water or other sealing liquid (and is line sectioned for clearness in Figs. 1.2..
and 3) contained in an outer cylindrical casing M., at its other extremity the
lever J is connected by a pivotted rod or link to a hollow cylindrical float N
which is so arranged that the pressure of the entering gas may slightly raise the
float N thereby depressing that end of the lever J to which the cap valve H is
attached, thus partially submerging it in the sealing liquid, thereby closing the gas
inlet until the regulated pressure is again obtained.---Outside the float N. is
another and similar cylindrical float O. of larger diameter, this I call a compound
maintaining float.--An annular space is left between the two floats N. O. sufficient
to admit a pipe P. or communication extending from the outlet branch Q.-
With this arrangement in the event of a quantity of gas being suddenly required
as for example, supposing the apparatus to be attached to the inlet branch of a gas
engine, instead of the inner float N. descending rapidly allowing a quantity of gas
to enter the apparatus from the main thus causing a temporary reduction therein
the compound float O. which is weighted to the required pressure simply lowers
without interfering with the inlet or cap valve H. which when the pressure gets
below the set standard opens and allows the gas to flow in.--Should a sudden
rush of gas occur in the main by the closing of a number of outlet branches (not
attached to the apparatus) thereby causing the inner cylindrical float N. to rise so
high as to close the cap valve H. thereby causing a momentary stoppage of the
gas then the compound float O comes into action and allows gas to pass through
the outer pipe or communication P. into the outlet branch Q as before described.
With this arrangement the gas pressure is less liable to fluctuations than when
a single float is used and my invention is specially applicable to mains when gas
engines are supplied from the same pipe.
It will be understood by reference to the drawing that the inlet and outlet
branches or pipes G. Q project into the float L which is formed with cylindrical
holes which are respectively sufficiently large to receive the outlet branch Q and
for the cap valve H to work in; also that the second outlet branch P. establishes
communication between the two hollow cylindrical floats O. N. and the outlet
main Q. These floats O. N are each provided with guides or steady pins R. R.

page_text: It will be understood from the arrangement of the apparatus as before described
that the wasting away of the water to a certain extent will not materially affect
the working of the apparatus, and that it is not absolutely necessary that the
water or sealing agent should be kept at a fixed height.
The outer casing M. is provided with an overflow branch S. placed somewhat
lower than the tops of the branches G. Q. P. and a suitably formed lid T which
has a supply branch or inlet U. In the centre of lid T. a receptacle V. is
provided with a loose bottom W which acts as a guide for the compound float. O.
and which may be lifted out for inserting circular balance weights on the top of
the float O. In apparatus of large capacity instead of the simple lever for raising
or lowering the cap valve H I use a combination of levers such as is well known
for procuring a parallel motion.
Having thus described the nature of the said invention and the manner in
which it is to be carried into practical effect,. I desire to have it understood that
what I consider to be novel and therefore claim as secured to me by the Letters
Patent hereinbefore in part recited is :-
First. In apparatus for maintaining a constant (or an approximately constant)
pressure of fluid the use of a compound maintaining float and communi-
cation pipe applied and operating substantially as and for the purpose
hereinabove described with reference to and illustrated in the drawings.
Second. The use in combination with the inlet G and outlet. Q of the floats
N & L lever J and cap valve H substantially as hereinbefore described and
illustrated in Figs 1 to 4 inclusive of the drawings.
Third The combination of parts constituting the improved apparatus for
maintaining constant (or approximately constant) pressure of Buid, the
whole constructed, arranged and operating substantially as described and
shewn.
In witness whereof, I, the said James Cambell Stevenson have hereunto set
my hand and seal, this Twelfth day of November in the year of our Lord
One thousand eight hundred and eighty three.
JAMES CAMBELL STEVENSON (L.S.)