ROBINET DE COUPURE SUR TUYAUX D'ADDUCTION DE POMPES HYDRAULIQUES

CLOSE-OFF VALVE FOR SUCTION PIPES IN HYDRAULIC PUMPS

Abrégé anglais

ABSTRACT OF THE DISCLOSURE
A close-off valve for suction pipes to establish
communication between a source of pressure and a
consumer of pressure, such as a hydraulic pump.
The valve makes it possible to disconnect the
consumer in a simple and reliable manner, that
is without leakage of the pressure, in addition
to which it allows a liquid, such as oil, in certain
quantities to flow through the valve above the valve
disc, when the latter assumes the position in which
it closes the outlet of the valve. For this purpose
the valve comprises a solenoid valve which controls
a flow of pressurized air to the valve housing in
order to actuate the valve disc closing off said
communication. In addition, the valve is arranged
with through-passage means above said disc in order
to allow passage-through of a certain amount of liquid,
when the valve disc is in its closing position.

Revendications

The embodiments of the invention in which an
exclusive property or privilege is claimed are defined as
follows:-
1. An improved close-off valve for suction pipes
between a reservoir and a hydraulic pump, said pump compri-
sing a hydraulic piston system, a main passageway adapted to
selectively connect with said reservoir, a tilting disc
for operating said hydraulic piston system for generating a
flow of a hydraulic fluid from the reservoir through the
said main passageway to said pump, a thrust bearing support-
ing said tilting disc, and a bypass passageway provided in
the pump housing and passing across said tilting disc and
said thrust bearing to allow passage through of a small
amount of oil, said small amount of oil being sufficient to
lubricate and cool the pump, said close-off valve comprising
a valve housing, a spring-loaded piston movably mounted in
said valve housing and operatively connected to a rod, a
valve disc supported by said rod, a solenoid valve control-
ling the movement of said valve disc, said valve disc
arranged to be moved into abutment against a valve seat for
the purpose of shutting off the connection of said reservoir
to said main passageway of the pump, the improvement com-
prising a cavity in said valve housing between said reser-
voir and said valve seat, said cavity being in continuous
communication with the reservoir and with said bypass
passageway regardless of the position of said valve disc for

allowing oil to flow from the reservoir around said thrust
bearing and said tilting disc and further through said
bypass passageway to lubricate said thrust bearing of the
pump and said tilting disc to cool the pump even when said
valve disc is in the closed position.
2. An improved valve as claimed in claim 1,
comprising a valve operating cavity between said piston and
a shoulder formed in the interior of said valve housing,
said solenoid valve controlling the air flow to said valve
operating cavity in order to displace said piston against
the action of said spring in order to lift said valve disc
for the purpose of opening said communication.
3. An improved valve as claimed in claim 1,
comprising a valve operating cavity formed between one end
wall of said valve housing and said piston, said solenoid
valve arranged to control an air flow to said valve opera-
ting cavity for the purpose of forcing said piston against
the action of said spring to a position, wherein said valve
disc abuts against said valve seat, thus interrupting
communication through said close-off valve.

Description

1148059
The invention generally relates to an improvement
in close-off valves in suction lines of the kind comprising
a valve housing in which a spring-loaded piston is movably
mounted. The rod of the piston supports a valve disc which
is arranged to move into a position in engagement with a
valve seat for the purpose of shutting-off a suction line.
The purpose of the invention is to provide a
close-off valve, which is arranged, while shutting-off a
flow of a medium, such as a hydraulic fluid from the source
to the consumer, e.g. a hydraulic pump, to allow a small
flow of the hydraulic fluid, thus effecting lubrication and
to some extent cooiing of the hydraulic pump when the latter
is running idle, that is when the valve disc is in its
position abutting against its valve seat to close-off the
main passageway through the valve.
More precisely, the invention is an improved
close-off valve for suction pipes between a reservoir
and a hydraulic pump, said pump comprising a hydraulic
piston system, a main passageway adapted to selectively
connect with said reservoir, a tilting disc for operating
said hydrauiic piston system for generating a flow of a
hydraulic fluid from the reservoir through the said main
passageway to said pump, a thrust bearing supporting said
tilting disc, and a bypass passageway provided in the
pump housing and passing across said tilting disc and said
thrust bearing to allow passage through of a small amount
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11~805~
of oil, said small amount of oil being sufficient to lub-
ricate and cool the pump, said close-off valve comprising
a valve housing, a spring-loaded piston movably mounted in
said valve housing and operatively connected to a rod, a
valve disc supported by said rod, a solenoid valve control-
ling the movement of said valve disc, said valve disc
arranged to be moved into abutment against a valve seat for
the purpose of shutting off the connection of said reservoir
to said main passageway of the pump, the improvement compr-
ising a cavity in said valve housing between said reservoirand said valve seat, said cavity being in continuous
communication with the reservoir and with said bypass
passageway regardless of the position of said valve disc for
allowing oil to flow from the reservoir around said thrust
bearing and said tilting disc and further through said
bypass passageway to lubricate said thrust bearing of the
pump and said tilting disc to cool the pump even when said
valve disc is in the closed position.
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~8~)59
The invention will be described in closer
detail in the following with reference to the
accompanying drawings, wherein
Fig. 1 illustrates a first embodiment
of the valve in accordance with the invention, when
connected to a hydraulic pump,
~ig. 2 illustrateæ a modified embodiment
of the valve of the invention, and
Fig. 3 illustrates the valve in accordance
with the invention arranged in a hydraulic pump and
connected in a hydraulic circuit.
Fig. 1 illustrates in a cross-sectional view
a valve 1 in accordance wlth the invention when
connected 'o a hydraulic pump 2. The supply of
hydraulic fluid to the pump 2 is controlled by
the valve 1. ~he valve 1 comprises two parts 3 and 4
forming a housing in which a plston 5 i8 movably
mounted. The piston 5 has an extension 6 which
supports a vaive disc 7. ~he piæton 5 iæ movable
in a chamber 8 and this movement of the piston 5
causes displacement of the valve disc 7 in a cavity 9.
On the inner face of the housing 3, 4 is arranged a
shoulder 10, whereby a cavity 11 is formed between
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li~8059
the ~iston 5 and the shoulder 10, into which cavity,
e.g. compressed air may be supplied from a line 12
while being controlled by a solenoid valve 13. ~he
solenoid valve 13 is of a well known type and
therefore need not be described in closer detail here.
The piston 5 is actuated by a spring 14
which tends to urge the piston 5 to a position
wherein the valve disc 7 abuts against its seat and
in which the inlet (the pipe socket 15) is closed.
Consequently, hydraulic fluid is prevented from
flowing through the outlet 16. Pressurized air may be
fed through the line 12 into the cavity 11, resulting
in displacement of the valve disc 7 to the position
indicated in dash-and-dot lines, whereby the main
passageway through the valve 1 is opened.
In the embodiment illustrated, the valve 1
is connected to a hydraulic pump 2, which in the manner
indicated is provided with a pipe 17 to connect it to
a reservoir container (reference numeral 27 in Fig. 3)
holding a hydraulic fluid. The hydraullc pump lncludes
a thrust bearing 18 and a tilting disc 19 and when said
bear~ng and said disc are made to rotate, as they are
when the hydraulic pump is in operation, a partial
vacuum is generated forcing hydraulic fluid to flow
from the line 17 through a channel 31 to the cavity 20
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11481;~59
occupied by details 18, 19, and further through a line
21 in the pump unit 22 to the outlet line 23 to be
supplied to the valve 1. In the open position of
the valve 1, hydraulic fluid i9 sucked down into
the outlet 16, whereas when the valve i~ closed,
the flow of fluid from the line 23 will be through
the pipe socket 15. This means that lubrication of
the hydraulic motor is provided not only during the
pump operation but also while it is running idle. In
~0 addition, thls continual flow of lubricating medium
i8 sufficient to lower the temperature of the pump
to some extent in addition to which the lubrication
has the positive effects of not only preventing
overheating of the pump but al~o of giving noiseless
operation thereof.
Fig. 2 shows a modified embodiment according
to which a spring 24 tends to move the piston 5 to the
open position shown by the position of the valve disc 7,
indicated in dash-and-dot lines. In this ca3e shutting
of the valve 1 thus i9 effected with the aid of
pressurized air which is forced from the line 12 into
an upper ca~ity 25 formed in.the valve housing 26,
Also in this case oil or some other hydraulic fluid
is allowed to flow through the line 23 both when the
valve 1 i9 in its open and in its closed positions
in the manner explained above.

~148C~59
Fig. 3 sho~ the valve 1 and the pump 2
when inserted in a hydraulic pipe system including
a reservoir container 27 and communicating lines
17, 23 between the pump and the container 27 as well
as between the pump 2 and the valve 1. In addition,
this drawing figure indicates the provision of a
line 28 from the valve 1 to the container 27 and a
line 29 from the pump to the consumer of the
hydraulic fluid under pressure a~ well as the
provision of a return pipe 30 from this consumer.
In addition, the drawing flgure 6uggests a system
designed to feed compressed air with the aid of the
solenoid valve.
The invention is not limited to the embodi-
ments shown and described in the aforegoing but
modifications are possible within the scope of the
appended claims. It goes without sayine that the
valve could be used in other positions and appli-
cations than those suggested herein, partioularly
when it is desired to be able to close off a flow
of liquid from a pump or similar means to remove
the pump for repair,s~vice or exchange.
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