IMPROVEMENTS IN HYDRAULIC VALVES
Year: 1885

page_text: I CHARLES DAVY of 24 Lawson Road, Sheffield in the County of York, Engineer,
do hereby declare the nature of the said invention for "IMPROVEMENTS IN
HYDRAULIC VALVES," to be as follows:-
My Invention relates to improvements in the construction of hydraulic valves,
and particularly the valves used in connection with hydraulic forging presses, such
as that described in the specification of another application for Letters Patent
dated 29th September 1884, N° 12,920.
My Invention relates first to a compound automatic valve for controlling the
admission and exhaust of both high and low pressure water to and from the main
rams in the press, one such valve common to the two ram cases, or one for each
ram case being employed, as preferred.
This improved valve consists of a tubular plug controlling the communication of
the main ram cases with the low pressure main, said plug containing an inner valve
opening in the opposite direction to the main valve or plug and serving to control the
communication, through said tubular main valve or plug, of the high pressure main
with the main ram cases. The main valve or plug, and the casing in which it
works, are of two diameters, an annular chamber being thereby formed around the
plug which is in free communication with the lifting ram cases, or the pipe
supplying high pressure water thereto, so that on admitting high pressure water to
the lifting ram cases it is at same time admitted to the annular chamber around
the valve, which is thereby lifted off its seat by the pressure of water acting in
said annular chamber in order to allow of the water in the main ram cases being
returned through the low pressure main to the air vessel. The pressure exerted in
this annular chamber is sufficient to keep the valve open to the low pressure main
in order to allow the main ram cases to be refilled with low pressure water on the
descent of the main rams.
The small valve seated inside the main valve or plug, opens with the high
pressure, and is loaded by a spring sufficiently to cause the main valve or plug to
be closed by the high pressure water acting on its back or upper end, before said
inner valve will open to allow high pressure water to enter the main ram' cases,
the pressure tending to close the main valve sufficing to keep it closed and prevent
high pressure water leaking into the low pressure main.
The upper or rear side of the main valve may be reduced in area by surrounding,
the valve with a second annular chamber which is in open communication with the
atmosphere so as to minimise the pressure tending to close the main valve and allow

page_text: the pressure exerted in the first mentioned annular chamber to act with greater
effect when (as for instance whilst the press is at rest) the said chamber contains
only low pressure water whereby the main valve will, under ordinary circumstances,
be maintained in its open position.
My Invention relates, secondly, to an improved construction of hydraulic valve,
which construction is applicable for the three valves used for controlling the
admission and exhaust of the water to and from the main and lifting ram cases.
This improved construction of valve is of the "floating" or "pilot" valve type,
that is to say, it is composed of a main valve in the form of a tubular plug and of
an inner or pilot valve situated within the main valve and opening in the same
direction, this inner valve being attached to or formed on the spindle of the main
valve which is allowed a limited play in the main valve in order to cause the latter
to be opened after the pilot valve has been opened by the hydraulic or other gear
used for operating the main valve as described in my aforesaid application. The
main valve is so fitted in its cylindrical guide as to allow a slight leakage of
water to pass to the top side, or a bye-pass is provided for the same purpose in
order to admit sufficient pressure to the upper side of the valve to keep it closed,
this pressure being released when the pilot valve is opened, the main valve being
then in equilibrium and therefore easily lifted.
The present improvement consists essentially in providing a balancing ram and
cylinder at the opposite end of the spindle to that at which the pilot valve is
situated, the said balancing ram being of about the same area as the pilot valve and
its cylinder being in communication with the space at the underside of the valve
by means of a pipe the main and pilot valves being thus both in a condition of
equilibrium.
:
I CHARLES DAVY of 24 Lawson Road Sheffield in the County of York Engineer
do hereby declare the nature of this invention and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:-
'
My Invention relates to improvements in the construction of hydraulic valves,
and particularly the valves used in connection with hydraulic forging presses, such
as that described in the Specification of former Letters Patent dated 29th September
1884 N° 12.920

page_text: Reference is to be had to the accompanying drawings forming part of this
Specification.
My Invention relates first to a compound automatic valve for controlling the
admission and exhaust of both high and low pressure water to and from the main
rams in the press, one such valve common to the two ram cases, or one for each
ram case being employed as preferred.
This improved valve is represented in vertical section in figure 1 and consists of
a tubular plug w, contained in a suitable casing w' said plug closing against a seat
at the lower part of the casing and controlling the communication of the main ram
cases with the low pressure main n. This plug w is of two diameters and is fitted
to slide in a corresponding bushing w² provided with suitable cup leather or other
packings w. Between the plug and bushing an annular chamber w' is formed
which is in free communication by a pipe w with the lifting ram cases or the pipe
supplying high pressure water thereto, so that on admitting high pressure water to
the lifting ram cases it is at same time admitted to the annular chamber w' whereby
the plug w is lifted from its seat to allow the water in the main ram cases to return
through the low pressure main n to the air vessel.
This annular chamber is of such area that the pressure exerted therein is
sufficient to keep the valve w open to the low pressure main in order to allow the
main ram cases to be refilled with low pressure water on the descent of the main
rams.
Within the tubular plug w is seated an inner valve w opening in the opposite
direction to the plug or valve w and controlling the communication through the
tubular valve w of the high pressure main q with the main ram cases.
This inner valve we opens with the high pressure and is loaded by a spring w
sufficiently to cause the plug w to be closed (by the high pressure water from
main q acting on the back or upper end of plug w) before the inner valve we will
open to allow the high pressure water to enter the main ram cases.
The pressure
which tends to close the plug w suffices to keep it closed and prevent high pressure
water leaking past it into the low pressure main n.
The spring w is contained in a chamber within plug w and is compressed
between the end of said chamber and a flanged head attached to the rod w³ of
valve we, the spring being confined in the chamber by a lining w10 to which the
head w is attached.
The area of the upper or rear side of the plug w although always greater than
the orifice of its seat, may be less than that shown in figure 1. by surrounding the
plug with a second annular chamber (as shown in figure 2) which is in free com-
munication by a hole w with the atmosphere, so as to minimise the pressure
tending to close the plug w on to its seat and allow the pressure exerted in the first
mentioned annular chamber w to act with greater effect when it contains only low
pressure water (as for instance whilst the press is at rest) whereby the plug w will
under ordinary circumstances be maintained in its open position.
My invention relates secondly to an improved construction of hydraulic valve
which construction is applicable for the three valves used for controlling the
admission and exhaust of the water to and from the main and lifting ram cases.
This improved construction of valve which is represented in vertical section in
figure 3 is of the "floating" or "pilot" valve type that is to say, it is composed of
a main valve in the form of a tubular plug x and of an inner or pilot" valve y
seated within the main valve and opening in the same direction.
"
The main valve or plug x slides within a suitably packed guide cylinder or
bushing x closed at the upper part, in which the plug x works as a piston in a
cylinder, the plug x being so fitted therein as to allow a slight leakage of water to
pass to the top side of the plug (or a bye pass being provided for the same
purpose) in order to admit sufficient pressure to the upper side of the plug x to
keep it closed down on its seat, this pressure being released when the pilot valve
is opened, the plug a being then in equilibrium and therefore easily lifted.

page_text: The pilot valve y is attached to or formed on the end of the spindle y' which is
provided with wings y having a limited play in the plug in order to cause the
fatter to be raised from its seat after the pilot valve y has been opened by the motion
of said spindle y¹ produced by the hydraulic gear described in the Specification of
my previous Patent or by other gear. The special feature of improvement in the
construction of these valves consists in providing a balancing ram y³ working in a
cylinder y at the opposite end of the spindle to that at which the pilot valve y is
situated, the said balancing ram being of about the same area as the pilot valve
and its cylinder being in communication by a pipe y with the space at the under-
side of the valve; the plug x and valve y being thus both in a condition of
equilibrium. In the drawing, the motion is imparted to the spindle y¹ for opening
valves x, y, in the order above mentioned and for closing them in the opposite
order, by an auxiliary piston acting on a lever ² connected to the spindle y¹,
the said piston working in a cylinder and being acted on by fluid pressure
derived from the air vessel (or it may be from an independent source or by steam
power).
Having now particularly described and ascertained the nature of this
invention and in what manner the same is to be performed I declare that what
I claim is
1st The compound automatic valve herein described and represented in figures 1
and 2 consisting of a tubular plug valve controlling the communication of the
pressing ram cases with the low pressure main and surrounded by an annular
chamber wherein high pressure water acts to open the tubular valve, an inner
spring-loaded valve-opening in the opposite direction to the tubular plug valve and
controlling the communication of the high pressure main with the pressing ram
cases, the parts being constructed, combined and arranged to operate automatically
substantially in the manner and for the purpose specified.
2nd The combination with the "floating" or "pilot" valve represented in figure 3
(composed of a balanced tubular plug valve and an inner or "pilot" valve combined
to operate in the manner described) of a balancing ram and cylinder in communi-
cation with the space in front of the valve, said ram and cylinder being of such an
area and so applied as to counter-balance the pressure on the face of the "pilot"
valve substantially as specified.