Abstract: An ant-pressure surge device mounted in or on a closure member (1) of a check valve to eliminate overpressure and reduce shock waves in a pipeline when the check valve closes. The anti-pressure surge device comprises a fast acting flow relieving valve having a flow path sufficient in the open position to relieve the reverse flow on closure of the check valve closure member and is designed to open when the back pressure shock wave on the downstream side of the valve approaches a predetermined value. A suitable anti-pressure surge device comprises a poppet comprising a piston portion (7) and a sealing element (7A) moveable by the back pressure shock wave against resilient disk springs (10).

Abstract: The fitting, in particular a safety valve, operates according to the relief principle or according to the loading principle. The fitting is opened and closed by a plurality of pilot parts. The pilot parts are connected in series in the control line of the fitting and are each actuated by a pilot valve. The pilot parts open the fitting only when all the pilot parts are in a position which opens the fitting. The fitting closes as soon as even only one of the pilot parts is in a position which closes the fitting.

Abstract: A pilot operated pressure valve which limits the rate of start-up pressure rise (“soft start-up”) and substantially eliminates excessive system pressure spikes. The valve includes an inlet, a hollow cylindrical main body sealingly connected at one end thereof to the inlet, a pilot chamber having a sleeve slidably mounted within the main body and an operating pressure adjustment connected to another end of the main body adjacent another end of the pilot chamber for varying the threshold operating pressure of the valve. A main chamber receives pressurized fluid metered through a main orifice and discharges pressurized fluid through a damping orifice when the main chamber is filled and fluid inlet pressure exceeds the inlet threshold pressure which is just sufficient to open a spring biased pilot ball downstream of the damping orifice.

Abstract: A fluid flow regulator having a chamber comprising a port opening and a tapered pin disposed within the opening, for controllably restricting the cross-sectional flow area through the port. The tapered pin moves relative to the bore of the port that it is disposed in, under the influence of a pressure responsive diaphragm. A spring biases the pin towards the diaphragm. The diaphragm's movement is unaffected by any misalignment of the diaphragm with respect to the tapered pin and port, and the tapered pin's movement is unaffected by any diaphragm movement not in line with the port.

Abstract: The present invention relates to a pilot poppet type pressure control valve capable of discharging a part of a fluid for thereby constantly maintaining a pressure of a high pressure chamber when the pressure of the high pressure chamber exceeds a certain level. In the pilot poppet type pressure control valve according to the present invention, a discharging port capable of discharging a fluid of a high pressure chamber includes an inner diameter which is gradually increased in a downstream direction for preventing an instant pressure decrease based on the opening by a pilot poppet when the pressure of a high pressure chamber exceeds a certain level. Therefore, in the present invention, it is possible to decrease a vibration and noise based on the discharge of a high pressure fluid based on the inventive construction of the discharging port. In addition, it is possible to process the discharging port at one time using a programmed NC lathe.

Abstract: In a hydraulic relief valve having a main poppet draining into a pressure-oil tank hydraulic fluid flowing into a sleeve from a hydraulic pump and a pilot poppet draining into the oil tank the hydraulic fluid upon the occurrence of a high pressure over a pressure value set in a back-pressure chamber of the sleeve, an interference-preventing hole is provided to be formed in an outer periphery of the sleeve to be placed at boundary portions of feedback paths of feedback fluid on the side of the main poppet which is drained past a throttle of the sleeve and feedback fluid on the side of the pilot poppet which is drained past a feedback fluid path formed outside the sleeve.

Abstract: A pilot operated pressure valve which limits the rate of start-up pressure rise (“soft start-up”) and substantially eliminates excessive system pressure spikes. The valve includes an inlet, a hollow cylindrical main body sealingly connected at one end thereof to the inlet, a pilot chamber having a sleeve slidably mounted within the main body and an operating pressure adjustment connected to another end of the main body adjacent another end of the pilot chamber for varying the threshold operating pressure of the valve. A main chamber receives pressurized fluid metered through a main orifice and discharges pressurized fluid through a damping orifice when the main chamber is filled and fluid inlet pressure exceeds the inlet threshold pressure which is just sufficient to open a spring biased pilot ball downstream of the damping orifice.

Abstract: A pilot operated safety relief valve (14) having a main piston valve member (26). A dome chamber (42) is provided in the valve body (18) over piston valve member (26) and a cap (44) forms a closure for dome chamber (42). A pilot valve (46) is mounted on the cap (44) and has a diaphragm actuated fluid inlet sensing tube (60) received within a bore (30) of the piston valve member (26). Inlet fluid pressure is communicated through bore (61) of sensing tube (60) to the inlet fluid sensing chamber (84) on the outer side of diaphragm (65). Exhaust chamber (56) is positioned between dome chamber (42) and inlet sensing chamber (84). Adjustment spring (67) continuously urges O-ring (72) in dome chamber (42) to a seated position on seat (70). An annular clearance (78) is provided between sensing tube (60) and piston (26) for providing a restricted fluid flow between dome chamber (42) and the inlet (20).

Abstract: A valve assembly for a hydraulic discharge device and including a piston displaceable in a bore of a housing of the discharge device against a biasing force and having an outer surface, which sealingly engages an inner wall of the housing bore and blocks a channel opening into the bore so that the piston functions as a slide valve for this channel, the valve assembly further including a valve seat which, together with the piston, forms a seated valve.

Abstract: An improved slow opening gas valve providing for continuous gradual and smooth opening of the gas valve includes an expansible auxiliary chamber connected to an expansible control chamber by a metering orifice. The expansible auxiliary chamber slows expansion of the expansible control chamber, thereby slowing opening of the gas valve and allowing gas to ignite at a lower pressure with a much less audible sound. The gas valve is provided with a normally closed valve member for controlling flow of gas through the gas valve and a diaphragm forms a movable wall of the expansible control chamber that is operable upon expansion of the chamber to move the valve member to an open position. The expansible auxiliary chamber also comprises a movable diaphragm to control the opening of the gas valve and provide gas flow gradually and smoothly.

Abstract: A pilot operator and a relief valve are provided in the same housing. The pilot-operating mechanism is contained partially within the main closure element of the valve and partially within the valve cap. Inlet pressure to the valve is communicated to the pilot via an access passage extending through the main closure element. In response to high-pressure flow from the inlet, a pilot piston moves a spacer rod through the passage and into engagement with a spring-loaded vent closure. The piston-induced movement of the rod opens the vent to relieve the pressure behind the main closure element, which in turn permits the main closure element to open and relieve the inlet pressure through the valve outlet. Opening of the main closure element terminates flow through the access passage. When the inlet pressure is sufficiently reduced, the pilot piston is unseated by the spring force re-opening the access passage to allow the pressure behind the main closure element to increase and close the main closure element.

Abstract: A pilot operated pressure valve which limits the rate of pressure rise and substantially eliminates excessive system pressure spikes, the valve including an inlet, a hollow cylindrical main body sealingly connected at one end thereof to the inlet, a pilot chamber having a sleeve slidably mounted within the main body and an operating pressure adjustment connected to another end of the main body adjacent another end of the pilot chamber for varying the operating pressure of the valve. A main chamber receives pressurized fluid metered through a main orifice and discharges pressurized fluid through a damping orifice when the main chamber is filled and fluid inlet pressure exceeds a preselected inlet pressure level sufficient to open a spring biased pilot ball downstream of the damping orifice. The inlet will open an exit port upstream of the main orifice for discharging pressurized fluid from the valve back to a supply tank when inlet pressure exceeds the operating pressure.

Abstract: A gas purge valve comprising a valve housing that has a valve inlet and major and minor valve outlets, a valve partition mounted in the housing divides the housing into a first chamber communicating with the valve inlet and a second chamber that communicates with the minor valve outlet. A restrictive flow passage is defined in the housing that effects communication between the first and second chambers and has a through flow rate less than that of the minor valve outlet. A minor valve closure device is provided for closing the minor valve outlet to liquid outflow. A differential pressure responsive device mounted in the partition member and displaceable in response to a pressure differential between the chambers and a major valve outlet obturating device responsive to displacement of the differential pressure responsive device into the opening of the major valve outlet when the pressure differential exceeds a predetermined magnitude.

Abstract: A pilot operated pressure valve which limits the rate of pressure rise and substantially eliminates excessive system pressure spikes, the valve including an inlet, a hollow cylindrical main body sealingly connected at one end thereof to the inlet, a pilot chamber having a sleeve slidably mounted within the main body and an operating pressure adjustment connected to another end of the main body adjacent another end of the pilot chamber for varying the operating pressure of the valve. A main chamber receives pressurized fluid metered through a main orifice and discharges pressurized fluid through a damping orifice when the main chamber is filled and fluid inlet pressure exceeds a preselected inlet pressure level sufficient to open a spring biased pilot ball downstream of the damping orifice. The inlet will open an exit port upstream of the main orifice for discharging pressurized fluid from the valve back to a supply tank when inlet pressure exceeds the operating pressure.

Abstract: A pump assembly (33) including a cartridge valve assembly (39) having a poppet member (69) biased toward a closed position (FIG. 4) when a pilot portion (51) is closed, under the influence of an electromagnetic actuator (53), so that flow entering an inlet port (65) flows out an outlet opening (61). When the actuator (53) is not energized (FIG. 1), a pilot poppet (89) and armature (93) are biased to an open position (FIG. 5) by a pilot spring (94), so that fluid in the inlet port (65) flows through an orifice (71) in the poppet member (69) and through the pilot portion (51) to a system reservoir (R), creating a pressure differential across the poppet member (69), and opening a tank port (67). Flow is then from the inlet port (65) to the tank port (67), thus operating in a "bypass" mode. Under excessive inlet pressure, the pilot portion (51) also serves a pressure relief function.

Abstract: The fire-extinguishing device proposed includes a container, holding a gas under pressure, and a fusible hollow element designed to actuate the device. The fusible hollow element is connected to the extinguishant container in such a way that it is acted on by the compressed gas in the container. A pressure regulator is fitted between the extinguishant container and the fusible hollow element. The pressure regulator enables the device to be operated using CO.sub.2 for instance as the extinguishant, even in situations in which the ambient temperature varies widely. The fusible hollow element can also be designed as a feed line for the extinguishant. Also proposed is a valve for a fire-extinguishing device of this kind.

Abstract: A pressure regulator for supplying water to an associated watering system for poultry or the like includes a top works structure and a bottom works structure which are formed of few parts, which are easy to manufacture and assemble together. The top works structure includes a cover seated within a cover and a reference spring assembly which includes a reference spring and a diaphragm membrane. The reference spring assembly can be adjusted to vary the outlet pressure of the regulator. The bottom works structure includes a body having an inlet through which water flows into the regulator from a supply and an outlet through which water flows out from the regulator to the associated watering system. A structure is provided for substantially isolating said diaphragm from water pressure in said regulator during flushing of the regulator and the associated watering system and during conditions of higher-demand for water.

Abstract: A pressure compensation valve is constructed with a valve establishing and blocking a communication between an inlet port and an outlet port, a pressure receiving chamber, a piston driven by a load pressure within the pressure receiving chamber and shifting the valve in blocking direction, an intermediate pressure receiving chamber communicated with the inlet port via a first conduit and pushing the valve in blocking direction by the pressure therein, and a pressure variable relief valve for relieving a pressurized fluid in the intermediate pressure chamber to the outlet port via a second conduit.

Abstract: A cartridge valve for installation in a manifold having a receiving cavity which includes an inlet port and an outlet port. The cartridge valve includes a cavity adaptor for engaging the cartridge valve with the receiving cavity in the manifold, a cage assembly which includes a floating cage body within a portion of the cavity adaptor, and a control device which controls the flow through the cartridge valve. The cavity adaptor has walls defining a primary bore and the cage body has walls defining a second bore. The cavity adaptor and the cage body are sized and dimensioned so that an interior dimension of the cavity adaptor is greater than an exterior dimension of the corresponding portion of the cage body. The dimensional difference between the interior surface of the cavity adaptor and the exterior surface of the cage body defines a radial passage. A knob assembly associated with the cartridge valve includes a split collet which is positively retained on a handle portion.

Abstract: A valve assembly used in combination with a pressurized-fluid source having a high-pressure side and a low-pressure side and a load has a pressure-actuated flow regulating valve having a housing and a valve body movable in the housing and defining therein a pump compartment connectable to the high-pressure side of the source and a load compartment connectable to the load. The body is movable between a front position permitting free flow from the pump to the load compartment and a rear position limiting such flow. The valve body is formed with a throughgoing bypass passage having one end open into the load compartment and an opposite end. A spring braced between the valve body and the housing urges the valve body forwardly along an axis toward the load compartment. A relief valve in the housing connected to the opposite bypass passage end and to the low-pressure side of the source relieves pressure in the load compartment when pressure in the load compartment exceeds a predetermined limit.

Abstract: A pressure limiting valve with rates of flow of more than 8,000 l/min exhibits a valve casing comprising a control piston and valve piston. These valve casings are arranged inside the casing so as to be movable against corresponding springs, whereby the control piston and valve piston are separate units. The valve piston is arranged so as to be movable against an adjustment screw that is supported on the control piston side and has a through-bore that has a smaller diameter than the blind bore of the control piston. This special design of the valve ensures a uniform opening and reclosing of the pressure limiting valve for the described rates of flow, whereby suitable sealing rings consisting of Teflon are used in the area of the valve piston.

Abstract: A pressure limiting valve with high flow rates, but in particular with a good adaptability to the respective conditions, is constructed so that the control piston and the valve piston are coordinated with separate valve cases, whereby these valve cases are connected to each other by way of a plug-in fitting which can be screwed into the valve case of the valve piston and has on the opposite side a standardized plug connection. In the center of this plug-in fitting is provided a center bore, so that the plug-in fitting which has a corresponding opening or blind hole on both sides permits the pressure medium to flow through. The blind hole in the valve piston itself is again connected via a through-bore to the compensation chamber on the opposite side, whereby the diameter of this through-bore is smaller than that of the blind hole of the control piston.

Abstract: A high-speed solenoid valve apparatus has a body, and a high-speed solenoid valve section and a logic valve section disposed in the body. The high-speed solenoid valve section includes a solenoid valve outlet port communicating with a body outlet port, a solenoid valve sleeve including a solenoid valve inlet port, and a spool for opening and closing a communication path between the solenoid valve inlet port and the solenoid valve outlet port.

Abstract: A pressure control valve is provided comprising an inlet bore, an annular channel and a control spool. So as to obtain a low control deviation and good stability an annular channel is provided at the outlet side of the valve. The axial extension of said annular channel is smaller than the outlet flow area formed by said bores.

Abstract: A pressure relief valve (1) has a relief piston (5) for a large stream of oil and a precontrol piston (11) for a small stream of oil for influencing the point of actuation of the reliefing piston. Both pistons (5 and 11) are part of seat valves. The pressure relief valve is to be constructed so that the maximum pressure adjusted at high oil viscosity declines. In that way, the hydraulic apparatus containing the pressure relief valve is protected against overloading at low temperatures. For that purpose, the precontrol piston (11) has a bushing-shaped extension (26) that projects into a drilled hole (25) that is connected with an outlet (23). Furthermore, a ring surface (A1) is provided at the precontrol piston (11) that acts in the direction of opening. By means of the extension (26), a pressure-regulating section (27) that is dependent upon viscosity comes into play that generates a dynamic pressure that acts upon the ring surface (A1) when the oil is cold.

Abstract: In a pressure control valve having a valve body (1), a pilot poppet (7) is so mounted in the body (1) as to permit/prevent communication between a low-pressure relief port (12) and a back-pressure chamber (5), while moderated and stabilized in its opening operation so as to realize a steady relief flow of the valve, which flow depends on relief-flow properties of a relief poppet (4) so provided as to permit/prevent communication between: a pressure supply port (2); and a relief port (3). A piston poppet (8) is slidably mounted in the relief poppet (4) to extend to the back-pressure chamber (5). A cross-sectional area of the piston poppet (8) is larger than an opening area of a seat portion (6a) of a passage (6) in which the pilot poppet (7) is inserted.

Abstract: A hydrostatic transmission is provided of the type including a pump (15), a motor (17), and a pintle assembly (35) defining high (61) and low (63) pressure fluid conduits. In communication with the conduits, the pintle assembly includes a pair of acceleration valves (85, 89), each of which comprises a differential area piston. Adjacent each acceleration valve is a pilot valve means (95) disposed in a pilot bore (105) and including a valve member (115) operable, in response to system pressure in excess of the pressure relief setting of a spring (117) to relieve fluid pressure in a chamber (101), such that the acceleration valve (85) is biased toward an open position (FIG. 5) relieving fluid pressure spikes from the high pressure conduit (61) to the low pressure conduit (63).

Abstract: A metering valve adapted to operate a seat on a side of an actuator port by means of a poppet section of a main poppet arranged in a valve casing to selectively communicate the actuator port to a tank passage. The main poppet is formed with a pressure chamber on a side thereof opposite to the poppet section. The pressure chamber has a pressure receiving area substantially equal to that of the seat. Also, the main poppet is formed with a through-hole constantly communicated to the actuator port and a pilot chamber to which pilot pressure for moving the main poppet in a direction of opening the seat is applied. Thus, the metering valve is capable of stably accomplishing its control irrespective of a variation of pressure on the side of the actuator port.

Abstract: The present invention provides a pilot operated pressure reducing valve in which the pilot liquid (generally the pilot fluid) is taken from the low pressure side, wherein two pilot liguid connections (or conduits) from the low pressure side to the pilot valve are provided which the separate from each other. The one connection takes the pilot liquid (or fluid) from the control area of the control spool while the other connection takes the pilot liquid (or fluid) from outside the control range (or area) of the control spool. A check valve is provided to seperate said two connections and closes to the low pressure side. Thus, even for large volume flows and large pressure differentials, between the high pressure side and the low pressure side, good control- and stability characteristics are obtained.

Abstract: A bidirectional cartridge valve comprises a generally cylindrical valve housing including an end port and a side port each opening into an axial, cylindrical bore defining a valve chamber. A flow control element is movable in the valve chamber between a valve open position to open a flow path between the two ports and a valve closed position to block the flow path between the two ports. The flow control element includes a first passage provided with a first check valve connecting the end port with the valve chamber and a second passage with a second check valve connecting the side port with the valve chamber. A cylindrical pilot seat in the chamber includes a partial, axial bore defining a pilot chamber and an opening through the seat connecting the valve chamber with the pilot chamber. A third passage is provided through the valve housing, provided with a third check valve, connecting the pilot chamber to the side port.

Abstract: To reduce the noise on response of a pressure-limiting valve, downstream of the valve seat an annular space, an annular gap and a further annular space are provided. This flow-off system gives a reduction of the noise level. Moreover, in pressureless circulation the flow resistance of the valve is low because the annular gap is freed by the piston.

Abstract: An electrically controlled, proportional, pressure relief valve (100/200) used to control the maximum allowable pressure in a hydraulic line (3), whose pressure is used to control, for example, the relative up-and-down positioning and speed of movement of a combine header (1) on an agricultural combine, in which the effective maximum pressure of the pilot valve of the relief valve is controlled by a solenoid (113/213). The distal tip of the armature (114/214) of the solenoid bears against a movement and force translating drive pin (112/212), which in turn bears against a ball (110; FIG. 2) or a poppet pin (210; FIG. 3). The effective maximum pressure permitted by the relief valve is linearly varied by the applied voltage/current to the solenoid coil (115/215).

Abstract: A metering valve adapted to operate a seat on a side of an actuator port by means of a poppet section of a main poppet arranged in a valve casing to selectively communicate the actuator port to a tank passage. The main poppet is formed with a pressure chamber on a side thereof opposite to the poppet section. The pressure chamber has a pressure receiving area substantially equal to that of the seat. Also, the main poppet is formed with a through-hole constantly communicated to the actuator port and a pilot chamber to which pilot pressure for moving the main poppet in a direction of opening the seat is applied. Thus, the metering valve is capable of stably accomplishing its control irrespective of a variation of pressure on the side of the actuator port.

Abstract: There is disclosed a pilot operated valve which includes a valve body, a main valve having a main valve member controlling fluid communication between an inlet port and an outlet port, a pilot valve including a vent passage sensing downstream pressure to open and close the main valve member as the sensed pressure is above or below a predetermined pressure, and selectively operable override means to suspend pilot operation of the valve. The override means may be means to occlude the vent passage and thus close the main valve, means to open the vent passage to atmosphere and thus open the main valve, or means to bypass the main valve.

Abstract: A pressure regulator comprises a housing (1) defining first and second chambers separated by a movable partition (4,5), the first chamber being provided with an inlet port (2) facing towards and sealingly closeable by a rigid central portion (5) of the partition at a position remote from its centroid and an outlet port (3), and the second chamber being vented (7) to a reference pressure, the regulator including means (8) extending between the housing and the central portion (5) of the partition to define a pivot axis for the partition extending between its centroid and the position of the inlet port (2). The partition (4,5) may be a tilting diaphragm or a piston (D) with a peripheral sealing element (S). The pivot axis for the partition may be defined by a fixed pivot pin (20), or by projections (8) extending across the first chamber to abut the partition (4,5).

Abstract: A power tong assembly wherein a safety latch mechanism includes a power part equipped with two outlet side connections, one of which is connected to a control part for controlling the opening cross section of the tank side connection. The power part has a control element in the form of a piston-shaped valve body with equal sized surfaces on both end faces subject to the pressure of the working medium and with a bore running in the direction of the valve body movement. This bore has a conical extension of its inlet flow end. This blocks the direct connection of the supply with the return to the tank.

Abstract: A compact pressure-limiting valve is provided for optional attachment to a water-conducting device which for this purpose comprises a flange which matches the connecting flange of the pressure-limiting valve and which can be closed with a closure-plate when the pressure-limiting valve is not required. A compact unit providing high response speed of the pressure-limiting valve is achieved by a particular relative arrangement of the main piston and the pilot valve piston and by short and loss-free flow connections in the interior of the pressure-limiting valve. In spite of the high response speed and the compact constructional form the pressure-limiting valve is distinguished by a large flow cross-section for levelling pressure peaks.

Abstract: A valve for periodically opening and closing a flow path 11 leading to a suction source for predetermined periods is disclosed. The valve comprises a body 12 defining a first flow passage 13 and a further flow passage 23 therethrough. In body 12 there is mounted a fluid pressure operable closure member 16 for periodically opening and closing flow passage 13. Actuating means driven by water wheel 17 and which includes a variable volume chamber 21, a stopper 19 for an equalization port 20 in chamber 21 and a gear train 18 is adapted periodically to vary the pressure in chamber 21 acting on closure member 16 in response to fluid flow past water wheel 17.

Abstract: A hydraulic cylinder usable as a shock-absorbing trim and tilt cylinder for adjusting the position of an outboard motor or outdrive unit of a boat, is provided with a piston including pilot-operated valve means which stepwise responds at a precisely setable pressure, to pressures resulting from impact of an outboard motor or outdrive unit upon an obstacle, the valve means then departing as a poppet-type relief valve to allow the outboard motor or outdrive unit to return to operative position following the impact. The hydraulic cylinder is provided with an integral conduit formed by milling a groove or slot from a point adjacent its mounting end to the point adjacent its rod end, and fastening a cover over the groove.

Abstract: This invention relates to a coupling connector attachable to and detachable from a respirator mask. The connector comprises a chamber which is arranged to be in communication with the mask in the attached position, a tube for connection to a source of pressurized breathing gas, a valve to admit or interrupt the gas flow, a pressure gauge device sensing the relative pressure prevailing within the chamber, and means of positively interlinking the said valve with the pressure gauge device.According to the invention the connector has a feeler which is released or inserted depending on whether it is attached to the mask or not, said feeler being associated with the interlinkage means via means modifying the mode of operation, which are arranged to establish an operational mode under negative pressure or overpressure automatically depending on whether the feeler is free or inserted.The connector is intended for respirator devices shut off in the open circuit condition.

Abstract: A pilot operated relief valve is disclosed which includes a first control space operatively connected to the inlet fluid channel, and a second control space operatively connected to the outlet fluid channel. In one embodiment, each control space is connected to a relief outlet by means of an adjustable valve, whereby the valve is adapted to operate as a pressure relief valve in either flow direction. In another embodiment, one of the control spaces is connected to the opposite channel by means of a one-way check valve, so as to function as a makeup fluid supply valve upon the pressure in the opposite channel reaching a predetermined low level.

Abstract: In a demand valve for breathing apparatus gas flow is controlled by a main valve disc in accordance with the pressure in a control chamber. Gas vents from the control chamber through a bleed orifice at a rate dependent upon the deflection of a diaphragm sensitive to respiration and which controls the spacing of a spring arm from the bleed orifice. The arm has a set spacing from the orifice such as to provide "positive pressure" operation of the valve when the valve is connected into the inlet of an associated breathing mask. A lever on the valve contacts the mask inlet and acts through a pin to bias the arm to its "positive pressure" setting through a second spring arm. When the valve is disconnected the lever drops to allow the two arms to relax so that the first arm moves closer to the control chamber bleed orifice and thereby shuts off gas flow past the main valve disc.

Abstract: A hydraulic fuse closes flow of hydraulic fluid in a hydraulic line upon loss of downstream fluid pressure. The hydraulic fuse includes a housing having an upstream opening and a downstream opening and a poppet slidably mounted within the housing for opening and closing fluid flow between the upstream and downstream openings. A spool is slidably mounted within the poppet for opening and closing fluid flow between first and second ends of the poppet. The spool includes a head which is positioned within the poppet and a rod which extends outwardly from the second end of the poppet and into the housing. When downstream pressure is lost, differential pressure acting on the first and second ends of the poppet will move the poppet to close fluid flow.

Abstract: Method and apparatus for controlling fluid leakage from sections of a pressurized fluid system adapted to provide fluid at line pressure to equipment associated therewith includes means for sensing first and second conditions indicative of non-use and of a usage demand respectively of the equipment and for generating a signal indicative of one of the conditions and control unit means for selectively isolating and effecting communication between line pressure of the fluid system and the system section in response to the condition-indicating signal. According to a first embodiment, the first non-use and second usage demand conditions are constituted by respective lower and higher rates of fluid flow through the section of the fluid system in which leakage is to be controlled. According to a second embodiment of the invention, the first non-use and second usage demand conditions are constituted by support and non-support of the equipment respectively or non-movement and movement of the equipment respectively.

Abstract: A pilot operated relief valve is disclosed which includes a first control space operatively connected to the inlet fluid channel, and a second control space operatively connected to the outlet fluid channel. In one embodiment, each control space is connected to a relief outlet by means of an ajustable valve, whereby the valve is adapted to operate as a pressure relief valve in either flow direction. In another embodiment, one of the control spaces is connected to the opposite channel by means of a one-way check valve, so as to function as a makeup fluid supply valve upon the pressure in the opposite channel reaching a predetermined low level.

Abstract: A flow control valve comprising spool means and overload relief valve means built in the spool means. A filter is disposed on the upstream side of the relief valve means. When a hydraulic oil is passed through the filter, foreign materials are removed from the oil and the pulsation of the oil is inhibited or eliminated.

Abstract: A cross line relief valve mechanism includes a pair of opposed relief valves contained in a bore connecting the service passages of a control valve. A high pressure condition in one of the service passages acts directly on the main poppet of one of the relief valves causing it to become unseated and communicating the high pressure condition to a zone in the bore between the two relief valves. The high pressure condition in this zone acts on the pilot poppet of the other relief valve causing it to open which results in the unseating of the main poppet in that relief valve. The high pressure condition in one of the service passages thus results in the opening of both valves so as to allow high pressure fluid to flow from one service passage to the other in order to obtain a balanced condition.

Abstract: A valve device is provided for use in a pressurized hydraulic fluid path, for example the hydraulic path of a hydraulic leg of a mine roof support which is required to yield under two different sets of conditions. The valve device has a port 15 for connection to the pressurized hydraulic fluid path, a bleed valve 25 being arranged to permit hydraulic fluid to bleed from the path at a first rate when the pressure in the path exceeds the first limit, for example to permit the hydraulic leg to collapse at a very slow rate, for example as a mine roof converges. There is also a dump valve 20 arranged to permit hydraulic fluid to flow from the path at a second greater rate, for example if a rock burst occurs. Although the dump valve 20 reacts to high pressure surges of fluid, it does not react to low pressure surges because a non-return valve device 30 traps on one side of the dump valve hydraulic fluid which is at a pressure in the region of the first limit.

Abstract: A valve device for controlling and monitoring an operating pressure in a hydraulically operated consumer arrangement, such as a tool chuck or head stock of a machine tool, includes a pressure reducing valve coupled to the consumer device and a servo valve connected to the pressure reducing valve for adjusting the operating pressure to a maximal allowable value. The servo valve is in turn connected to a flow monitoring device which upon reduction of operating pressure in the consumer device generates an electrical signal which is used for shutting off the consumer device.

Abstract: A pilot-controlled pressure limiting valve with a feeding function for pressure medium to be replenished comprises a main control spool movable between a pressure chamber and a high pressure inlet and being formed with a control edge to control communication between the inlet and a low pressure outlet; an annular piston slidably surrounds the main spool and in the closing position of the spool rests on a stationary abutment in the range of the low pressure outlet; the other face of the annular piston cooperates with a stop flange on the main spool so that when pressure medium is fed into the low pressure outlet the annular piston engages the stop flange and moves the main spool in opening direction so as to establish communication between the outlet and the inlet.