Improvements in Hydraulic Valves, more particularly relating to the Control of Large Volumes of Liquids at High Pressures.
Year: 1898

page_text: Date of Application, 11th Nov., 1898-Accepted, 1st Apr., 1899
COMPLETE SPECIFICATION.
Improvements in Hydraulic Valves, more particularly relating to the
Control of Large Volumes of Liquids at High Pressures.
I, GEORGE CROYDON MARKS, of 18, Southampton Buildings, Chancery Lane,
London, W.C., Consulting Engineer (being a communication from abroad by
Harry Samuel Bickerton Brindley, of 3, Awoicho, Akasaka, Tokio, Japan,
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:.
This invention relates to hydraulic valves for controlling the admission and
exhaust of water or other liquids, and its object is to provide simple and easily
manipulated exhaust and controlling valves which allow the induction and eduction
of the fluid under pressure without shock to the machine or pipes and without
interfering with the rapidity of action.
The invention consists generally in governing the opening and shutting of the
main admission and exhaust valves by pilot valves controlling small ports or
passages passing through the main valves, and, further, in arranging these main
valves of two diameters, so that the operation of the pilot valves, in conjunction
with the specially placed ports and passages hereinafter described, will cause a
rapid opening of the main exhaust or admission valve but a slow closing of the
same to prevent shock, the whole device being operated by the movement of a
single hand lever.
The mode of carrying the invention into effect is illustrated in the accompanying
sheet of drawings as follows:-
Figure 1 is a vertical transverse section through the main valve its ports and
passages and its controlling pilot valve.
Figure 2 is a vertical transverse section at right angles to Figure 1 showing
the main admission and exhaust valves and the inlet and outlet passages.
Figure 3 is a plan of the valve box and mechanism.
Referring to the drawings: the main admission valve A is constructed of two
diameters as shown; one, the larger diameter, forming a piston sliding in a
chamber X, the other, the smaller diameter, forming the valve face at its bottom
end and sliding with suitable packings within a portion of the valve casing as
shown. The valve face formed at the bottom portion of A controls the passage of
the pressure liquid from the supply pipe F through the short port from Yinto
the pipe or conduit J communicating with the machine to be operated. The
piston of the valve A when in the position shown has a space Z between it and the
valve chest to permit of cushioning and at its upper side has another space which
communicates through the valve by the ports r s with a chamber Y communicating
with the supply pipe F and also communicates by the passage e with the chamber.
of a pilot valve c. Attached to the piston portion of the valve A is a spindle.
passing through a cover E on the top of the valve chest and suitably packed and
this spindle is controlled by an external spring in such a manner that normally
the admission valve A is lifted up from its seat. The pilot valve c controls the
passage of liquid from the chamber in which it works through the passage d into

page_text: the conduit feeding the machine and this valve c is operated by a cam upon a
shaft K arranged transversely below the end of the spindle which protrudes through
the valve casing as clearly shown in Figure 1. it is preferred to arrange the
guide stem 6 on the upper portion of the valve c of a smaller diameter than the
guide stem a on the lower portion, so that the pressure in the valve chamber may
normalty keep closed the said valve.
.
The exhaust valve B is also arranged of two diameters, the larger diameter
working in a chamber X¹ and the smaller diameter being formed at its lower end
as a valve and closing when in a shut position the exhaust passage G but when
open allowing this passage to communicate with the conduit J. The smaller
diameter of the valve B is suitably packed and slides in a valve chest as shown,
and, in this case also, an air cushioning space or chamber Z' is formed underneath
the passage of the valve and a space is left above the valve which communicates by
a port e with a second pilot valve chamber. A second pilot valve is constructed
in a precisely similar manner to the first pilot valve, that is to say, with guide
stems of two diameters, and this second pilot valve when lifted allows the space
above the piston of the valve B to communicate by a passage el and passages d'
with the exhaust pipe G. Again, in this exhaust valve ports sr lead through the
main valve from a chamber 1¹ communicating with the conduit J and this exhaust
valve B is normally lifted up by a spindle passing through the valve cover E¹,
suitably packed and held by an external spring. A cam placed upon the trans-
verse shaft K also controls the lifting of the second pilot valve. A hand lever L
is attached to the transverse shaft and it is evident that the relation of the cams
controlling the pilot valves to this lever can be so arranged that its rotational
motion will control the eduction and induction of the working fluid from the
source of supply to the machine and exhaust in the manner now to be described.
Consider the hand lever L to be in such a position that both pilot valves are
closed and that the pressure from the accumulator or pumps supplying the liquid
is conveyed through the passage F into the chamber Y. The pressure therefore
passes through the ports rs in the admission valve A into the chamber X and
acting upon the piston portion of the said admission valve forces down the valve
face at the bottom to close the passage from F to the conduit J. Similarly the
exhaust valve B closes the passage from the supply conduit J to the exhaust
pipe G by the pressure from the fluid passing to the machine in the conduit J
acting through the passages s¹ r¹ upon the top of the piston.
open no
It is
Let the lever L, however, be moved a sufficient distance to bring a cam into
operation and lift the stem a of the admission pilot valve c opening the said
valve, then the pressure which has accumulated over the piston portion of the
valve A passes by the passage e through the pilot valve box and passages d into
the conduit J and the area of the passages e d are purposely made larger than
the passages s or r so that during the whole time the pilot valve c
pressure can accumulate over the piston of the main admission valve.
evident now that as the pressure is removed from the top of the piston the spring j
will open the valve A allowing the liquid to pass through the admission pipe F
into the supply conduit J. If the exhaust valve B has not already been closed by
an existing pressure in the conduit J then the liquid will pass through the
pipes into the space above the piston of the exhaust valve and immediately
close it.
To close the admission valve the lever L is put into the position f allowing the
pilot valve c to come to its seat and then when it is desired to exhaust, the lever L
is pushed over in the same direction to the position g. The second pilot valve
is then immediately opened and allows the water pressure accumulated over the
piston of the exhaust valve B to pass by the passage e¹ through the second pilot
valve box into the passage d' leading into the exhaust pipe G. It is evident then
that the spring acting on the spindle attached to the head of the valve will lift
it up allowing the fluid to exhaust from the supply conduit J. It will thus be seen
that the operations of admitting the fluid, closing the admission valve, and opening

page_text: the exhaust valve, may be all performed easily and without shock by the movement
of a single lever.
The applicant is well aware that the general principle of raising a large valve
by means of a pilot valve is not new but what he considers as novel is the
particular construction of the main and pilot valves with their ports and passages
permitting a rapid opening and slow closing without shock, thus obviating the
trouble common in machines working under an accumulator load. The novel
arrangement also permits of accurate adjustment and allows the valves to work in
any position independent of gravity. The whole action is controlled by a single
lever.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. In hydraulic controlling valves the provision of admission and exhaust
valves of two diameters normally held open by spring or like attachments but
closed by the passage of the pressure fluid through the said valves into chambers
over their larger diameters, and operating these valves by closing in or releasing
the pressure in these chambers by pilot valves controlled from a single lever.
2. In hydraulic controlling valves arranged as claimed in Claim 1 providing
a space between the valve casing and the larger diameter of either admission
or exhaust valves so that slow closing ensues by the air cushion thus formed all as
a means for preventing shock in the working pipes.
3. In hydraulic controlling valves as claimed in Claim 1 arranging the admission
and exhaust valves so that they are opened in one direction by a spring or like
attachment and closed in the other direction by liquid pressure and their respective.
pilot valves with stems of two diameters so that they are closed in one direction
by liquid pressure and opened in the other mechanically by a cam or the like all
as a means of allowing the valves to work in any position independent of gravity.
4. The improved hydraulic controlling valve mechanism substantially as herein-
before described with reference to the accompanying drawings.
1141
1000
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street Birmingham, Agents.