AN IMPROVED REGULATING VALVE FOR RAILWAY BRAKES WORKED BY FLUID PRESSURE
Year: 1881

page_text: LETTERS PATENT to George. Westinghouse, junior, of Canal Road, King's
Cross, in the County of Middlesex, for an Invention of "AN IMPROVED
REGULATING VALVE FOR RAILWAY BRAKES WORKED BY FLUID PRESSURE."
PROVISIONAL SPECIFICATION left by the said George Westinghouse, jr.,
at the Office of the Commissioners of Patents on the 8th August 1881.
GEORGE WESTINGHOUSE, junior, of Canal Road, King's Cross, in the County of
Middlesex. "AN IMPROVED REGULATING VALVE FOR RAILWAY BRAKES WORKED
BY FLUID PRESSURE."
For working brakes on a railway train by fluid pressure the engine driver
usually employs a regulating valve, by which he can either admit Huid under
pressure into the pipe which conveys it along the train, or he can more or less
relieve the pressure in the train pipe. My Invention relates to the construction
and arrangement of a regulating valve for this purpose in a compact and convenient
form, giving facilities for delicate regulation. The valve box has two nozzles, one
connected to the main reservoir or supply of fluid under pressure, and the other
connected to the train pipe: Between the compartments of the valve box with
which these nozzles communicate there is a partition having a check valve opening
towards the main supply nozzle. In the compartment with which the train pipe
nozzle communicates, which compartment is bored cylindrical, there is a piston
having through it a hole fitted with a check valve, which is loosely connected to
the check valve previously mentioned. Behind the piston there are apertures
opening to the outer air when compressed air is the fluid employed for working
the brakes, but which should open into a return pipe or exhaust pipe when liquid
under pressure or steam is employed. Against the stem of the piston butts one
end of a helical spring, the other end of which butts against the boss of a hand
lever. This boss has on it a screw thread fitting an internal thread in the cover of
the valve box. The handle is provided with a spring catch lever having at its end

page_text: teeth which take into teeth on a ring fixed around the exterior of the valve box.
When the driver desires to admit fluid under pressure into the train pipe he
releases the spring catch and turns the handle round, so as to screw its boss
inwards. He thus compresses the spring and it urges the piston forwards, opening
the check valve first mentioned, whereby fluid passes into the train pipe until the
pressure on the face of the piston is sufficient to overcome the force of the spring
behind it, in which case the piston retreats, closing the check valve and so cutting
off the supply. When the driver desires to reduce the pressure in the train pipe
he turns the handle in the opposite direction and the force of the spring being
thus relieved the piston retreats. The second check valve, being connected to the
first check valve which has become seated, is withdrawn from its seat by the
retreat of the piston, and thereupon fluid escapes through the piston until the
pressure in the train pipe, acting on the face of the piston, is so far reduced that
the spring can cause the piston to advance again, seating the check valve on the
piston and so preventing farther escape. Thus according to the extent to which
the driver turns the handle and fixes it by letting go the spring catch, the pressure
in the train pipe is regulated and maintained to balance or nearly so the force of
the spring as determined by the position of the handle. When the valve is used
for compressed air it is of advantage to fix in front of the piston a flexible
diaphragm in order to prevent leakage past the piston when it becomes worn.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said George Westinghouse, jr., in the Great Seal Patent Office on the
30th January 1882.
GEORGE WESTINGHOUSE, junior, of Canal Road, King's Cross, in the County of
Middlesex. AN IMPROVED REGULATING VALVE FOR RAILWAY BRAKES WORKED
BY FLUID PRESSURE."
For working brakes on a railway train by fluid pressure the engine driver
usually employs a regulating valve, by which he can either admit fluid under
pressure into the pipe which conveys it along the train, or he can more or less
relieve the pressure in the train pipe. My Invention relates to the construction
and arrangement of a regulating valve for this purpose in a compact and convenient
form, giving facilities for delicate regulation.
•
Fig. 1 is a longitudinal section, and Fig. 2 is a front view of the valve box. It
has two nozzles A, which is connected to the main reservoir or supply of fluid
under pressure, and B, which is connected to the train pipe. These nozzles open
from two compartments of the valve box separated by a partition having a valve C,
which is pressed to its seat by a spring c. Attached to the valve is another
valve D, the attachment consisting of a cross pin d, which has certain freedom in
the hole of the stem D through which it passes. The valve D seats on a holé in
the centre of a piston E, which may have in front of it a flexible diaphragm F
secured at its outer edge between the two parts of the valve box which are screwed
together. The compartment of the valve box on the other side of the piston E
communicates with the outer air by passages G, there being free passage to this
compartment when the valve D is unseated by the hole through the piston and
cross holes e. The stem of the piston E has a shoulder, against which butts one
end of a spring H, whose other end butts against a plug k which is screwed into
the lever handle K. The boss of this handle has on it a screw thread L working in
an internal thread of the valve box. The handle K is provided with a spring catch
lever M, the lower end of which has teeth that can engage with teeth cut in the
periphery of a ring N that is clamped between the two parts of the valve box, the
lever K being held in any desired position by the engagement of the spring catch
with these teeth. When the driver desires to admit fluid under pressure into the
train pipe, he turns the handle K, so that its boss screws inward, pressing the
piston E forwards. The valve D is thus firmly seated, but the valve O is forced
from its seat, and fluid under pressure entering by the nozzle A passes the valve O
and flows by the nozzle B to the train pipe. When the driver desires to let fluid
escape from the train pipe and thereby reduce the pressure in the pipe he turns the
handle K in the opposite direction, unscrewing its boss and so relieving the pressure
of the spring H on the piston E. The pressure of the fluid in the train pipe acting
on the piston E forces it back, and the valve C being seated, the pin d holds the .
valve D while the piston retreats from it, and thereupon fluid from the pipe flows
by the nozzle B past the valve D through the piston and the lateral apertures e
and escapes by the passages G. When the pressure in the pipe is so far reduced
by escape of fluid that the force of the spring H overcomes the pressure on the
piston E the piston automatically advances so as to close the valve D and prevent
farther escape from the pipe. As the driver, by turning the handle K more or less,
can more or less relieve the spring H, he can delicately regulate the pressure in
the train pipe, and can thus cause the brakes to be applied with greater or less
rapidity and force as circumstances may require. The diaphragm F may obviously
be dispensed with if the packing of the piston E be sufficiently tight to prevent

page_text: leakage past the piston; the diaphragm is useful when compressed air is the fluid
employed, but when steam or a liquid under pressure is used the diaphragm F
should be dispensed with and the passages G should be connected to a return pipe.
The valves C and D are preferably loosely connected, as shewn, to allow for slight
inequalities of workmanship.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I claim the use of a regulating valve for railway brakes
worked by fluid pressure, constructed and operating as herein described with
reference to the accompanying Drawings.
In witness whereof, I, the said George Westinghouse, junior, have hereunto
set my hand and seal, this Twentieth day of December, in the year of
our Lord One thousand eight hundred and eighty one.