Abstract: A rigid piston assembly for use in a conventional flush valve includes a rigid piston and a solenoid configured to fixedly engage within the valve body. A flush valve for a plumbing fixture as well as a method of retrofitting a piston valve into a diaphragm flush valve body which includes a rigid piston and solenoid configuration.

Abstract: A system for monitoring flush valves includes a plurality of flush valves arranged in at least one restroom, each flush valve including a communication device configured to transmit flush valve data, and at least one controller arranged in a first flush valve and in communication with each other flush valve. The at least one controller is configured to determine a static pressure within the first flush valve, detect a second pressure within the first flush valve, determine that the second pressure is less than the static pressure, in response to determining that the second pressure is less than the static pressure, compare the second pressure with at least one other pressure associated with at least one other flush valve, and determine that the first flush valve is in need of servicing or replacement based on comparing the second pressure with the at least one other pressure.

Abstract: A system for hydraulically managing fluid pressure between selected set points includes a pilot control system operably coupled to a main valve. The pilot control system includes at least one fluid conduit, a variable orifice assembly, and a control pilot valve apparatus. Fluid is passed through a fixed orifice and into a first chamber of the control pilot valve apparatus. Fluid is passed through the variable orifice of the variable orifice assembly and into a second chamber of the control pilot valve apparatus. The main valve is hydraulically opened or closed in response to a pressure differential between the first and second chambers of the control pilot valve apparatus so as to manage fluid pressure downstream of the main valve between the selected upper and lower set points.

Abstract: A system for hydraulically managing fluid pressure between selected set points includes a pilot control system operably coupled to a main valve. The pilot control system includes at least one fluid conduit, a variable orifice assembly, and a control pilot valve apparatus. Fluid is passed through a fixed orifice and into a first chamber of the control pilot valve apparatus. Fluid is passed through the variable orifice of the variable orifice assembly and into a second chamber of the control pilot valve apparatus. The main valve is hydraulically opened or closed in response to a pressure differential between the first and second chambers of the control pilot valve apparatus so as to manage fluid pressure downstream of the main valve between the selected upper and lower set points.

Abstract: An adjustable hydraulically operated pressure management control pilot assembly has first and second diaphragm assemblies which define two fluid pressure chambers. Varying the pressure between these two fluid chambers modulates the control pilot assembly between adjusted low and high set points, which can be used to control high and low pressures downstream of a pressure reducing valve of a water supply system.

Abstract: A pilot-controlled valve arrangement having at least one valve mechanism mounted in a valve housing for multi-stage switching of a compressed air flow between a feed pressure connection and a working line connection wherein a throttled compressed air flow can be switched in at least one switching stage by a throttle, wherein the pneumatic pilot control has a first control piston mounted in a first control chamber implemented in the valve housing and having a coaxial recess for forming a second control chamber in which a second control piston is mounted, so that an additive control pressure application to the control chambers generates a telescope-like deployment of a ram extending from the second control piston for generating a multi-stage switching stroke for the valve mechanism, in order to implement the throttled compressed air flow in at least one switching stage of the valve mechanism present between the closed and the open valve setting.

Abstract: Apparatus to regulate fluid flow are disclosed. The apparatus includes an example regulator valve and an example automatically-adjusting or self-adjusting amplifier valve to maintain fluid flow during low downstream demand fluid flow conditions, and to maintain the operational accuracy and stability of the regulator valve during higher downstream demand fluid flow conditions.

Abstract: A system for hydraulically managing fluid pressure between selected set points includes a pilot control system operably coupled to a main valve. The pilot control system includes at least one fluid conduit, a variable orifice assembly, and a control pilot valve apparatus. Fluid is passed through a fixed orifice and into a first chamber of the control pilot valve apparatus. Fluid is passed through the variable orifice of the variable orifice assembly and into a second chamber of the control pilot valve apparatus. The main valve is hydraulically opened or closed in response to a pressure differential between the first and second chambers of the control pilot valve apparatus so as to manage fluid pressure downstream of the main valve between the selected upper and lower set points.

Abstract: A valve of the invention includes a valve body having an inlet, an outlet, and a flow passage connecting the inlet and outlet, the inlet, the outlet and the flow passage being in general axial alignment within the valve body. A valve seat surrounds the flow passage and a valve closure member is movable towards and away from the valve seat to close and open the valve respectively. The valve closure member is a poppet-type closure member axially mounted to a stem. The stem has a plurality of pistons spaced apart along the length thereof, and the valve body has a plurality of cylinders fixed relative thereto, the pistons each being slidable in a respective cylinder. The valve closure member is movable by varying the pressure in the cylinders. Preferably each of the cylinders has an outlet port through a wall thereof which is exposed when the closure member has moved towards or into a fully open position, pressure within said cylinders dissipating through those outlet ports when the outlet ports are exposed.

Abstract: A flow control valve comprising a housing, in turn comprising a substance inlet opening and a substance outlet opening and a substance channel extending between the substance inlet and outlet openings. The valve further comprises: a piston carried by the housing and movable relative thereto; a first biasing member biasing the piston towards a first piston postion in which the piston seals the substance channel; a guide channel carried by the housing; and a valve actuator movable along and whithin the guide channel between first and second actuator positions.

Abstract: A seat member forms a bleed chamber between a spool and the seat member and has a bleed port communicated with a low pressure side. The spool is seatable against a seat of the seat member, which is formed around the bleed chamber, to disable substantial communication between the bleed chamber and a supply port, which supplies oil to the bleed chamber. An opening and closing valve plug is seatable against another seat of the seat member, which is formed around the bleed port, to close the bleed port. A push member is placed between the spool and the valve plug. When a solenoid actuator applies a drive force to the valve plug, the push member is driven by the valve plug to directly push the spool and thereby to lift the spool away from the seat of the seat member.

Abstract: A metering faucet assembly includes a metering cartridge valve assembly and a separate mixing control valve having a mixing valve stem that is offset relative to a valve actuator for the cartridge valve assembly and coupled to the valve actuator by a coupling mechanism that allows both the mixing valve and the cartridge valve assembly to be operated by a common operating handle. The coupling mechanism includes a slip gear mechanism that allows reciprocating movement of the operating member of the cartridge valve assembly to operate the cartridge valve and rotational movement of a mixing valve stem to operate the mixing valve. The slip gear mechanism provides an end of travel limit for the mixing valve stem and allows adjustment in the temperature limit of the hot or cold water in the mix.

Abstract: A cartridge relief valve uses a piston design. The piston replaces a tube used in prior art relief valves. The piston makes the inventive relief valve easier to manufacture and more stable than prior art relief valves. This is due to the fact that, for a given size valve, the diameter of the piston is smaller than the diameter of the tube that it replaces. Furthermore, the diameter of the pilot seat of the inventive relief valve is also smaller than the diameter of the pilot seat of many prior art valves.

Abstract: A valve assembly having a valve body, a piston, a modulating plug, a valve cover adjoining the valve body, and a throttling member. The valve body has an inlet and outlet port, a partition with a valve seat separating the valve body into a first and second flow passage. The piston has a throughbore including an orifice, reciprocably mounted in the valve body and movable between a first and second position. The modulating plug, in abutting contact with the piston and reciprocably mounted in the valve body, gradually moves between an open position, permitting a main fluid flow, and a closed position engaging the valve seat, blocking the main fluid flow. The throttling member is adapted to insure a gradual alteration of the cross-section of the orifice upon piston movement. A method of gradually opening the valve assembly modulating plug is also set forth.

Abstract: An improved control valve in combination with a pressurized water closet having a housing, a spool rotatable within the housing, a valve stem threading engaging the spool but fixed from rotating relative to the housing and a needle valve extending from the valve stem and into the housing orifice, creating a self cleaning valve adjustable by rotating the spool, which adjusts the depth of the needle valve in the orifice, and thus adjusting the effective opening of the orifice.

Abstract: The invention relates to a subcutaneous valve having opening pressure that can be adjusted non-invasively from the outside, said valve comprising a body presenting a chamber with a cylindrical inside side wall, an inlet duct and an outlet duct for cerebospinal fluid both opening out in said side wall, a valve member such as a ball placed at the inside end of said inlet duct, a spring blade fitting closely to the side wall of said chamber and urging the valve member against its seat, and a moving member controlled from the outside and provided with means for locking it in a determined position, the length of the spring blade acting on the valve member being determined by the position of said moving member. The valve is remarkable in that said moving member is constituted by a resilient flexible arcuate blade fitting closely to the cylindrical inside wall of said chamber. The valve is applicable to the treatment of hydrocephalus.

Abstract: A cartridge relief valve uses a piston design. The piston replaces a tube used in prior art relief valves. The piston makes the inventive relief valve easier to manufacture and more stable than prior art relief valves. This is due to the fact that, for a given size valve, the diameter of the piston is smaller than the diameter of the tube that it replaces. Furthermore, the diameter of the pilot seat of the inventive relief valve is also smaller than the diameter of the pilot seat of many prior art valves.

Abstract: A solenoid valve has a solenoid, a control valve having a spool, a seat member having an oil hole whose one end communicates with a control pressure chamber between the seat member and the spool, a supply passage through which a second supply port communicates via a control orifice with the control pressure chamber and a drain passage through which the other end of the oil hole is able to communicate with the second drain port. A second orifice or a slit, whose cross sectional opening area is smaller than that of the control orifice, is formed in the supply passage at a periphery of the seat member that comes in contact with the spool so that a flow amount of the oil supplied to and ejected from the control pressure chamber through the supply and drain passages after the spool contacts the seat member is smaller than that before the spool contacts the seat member.

Abstract: A hydraulic valve control arrangement is provided with a control line of a control cylinder, the control line being connected to a first oil volume, with a first control piston having a first control face and operatively connected to the first oil volume, and with a plunger piston which is arranged between the first control piston and an outlet valve and has a second control face and which is operatively connected to a second oil volume. A first control edge is provided between the control cylinder and the first control piston. The control edge switches a first throughflow connection between the first oil volume and the second oil volume operatively connected to a third control face of the first control piston.

Abstract: A unitary diaphragm assembly for use primarily in conventional flush valves. The diaphragm assembly has a flexible diaphragm which includes a sealing portion and a mounting portion at the outer peripheral edge. A flow ring is positioned adjacent the sealing portion of the diaphragm. An elongated barrel member extends from the diaphragm in a longitudinal direction and includes a plurality of radial guides positioned circumferentially around the outer surface of the barrel member along a portion of the length of the barrel member. The diaphragm defines an orifice having a ring portion that flexes when a pressure difference is applied across the orifice thereby increasing the flow rate across the diaphragm. The orifice has a smaller diameter at a first end relative to a second end of the orifice. A method of compensating for a pressure difference across the diaphragm is also disclosed.

Abstract: A rack and pinion power steering system 10 is provided and includes a variable orifice valve 22 which controls the flow of fluid in and out of a hydraulic cylinder 20. Variable orifice valve 22 is communicatively coupled to a source of pressurized fluid 30 by use of a conduit 42 and an electronically controlled valve assembly 38. The pressurized fluid received through conduit 42 controls the operation of valve 22. Based upon the pressure of the received fluid, valve 22 selectively increases and decreases the volume of fluid flow in and out of cylinder 20, thereby causing cylinder 20 to have enhanced damping characteristics during certain vehicle operating conditions (e.g., during relatively high vehicle speed operating conditions).

Abstract: An input/output port 1 of a hose rupture control valve unit 100 is attached to a bottom port of a hydraulic cylinder 102, and an input/output port 2 is connected to one of actuator ports of a control valve 103 via an actuator line 105. The valve unit comprises a poppet valve body 5 serving as a main valve, a first spool valve body 6 serving as a pilot valve operated with a pilot pressure supplied as an external signal and having a pilot variable throttle portion 6a to operate the poppet valve body 5, a second spool valve body 50 operated with a pilot pressure and having a sub-variable throttle portion 50a to control a sub-flow rate, and a small relief valve 7 having the function of an overload relief valve.

Abstract: A unitary diaphragm assembly for use primarily in conventional flush valves. The diaphragm assembly has a flexible diaphragm which includes a sealing portion and a mounting portion at the outer peripheral edge. A flow ring is positioned adjacent the sealing portion of the diaphragm. An elongated barrel member extends from the diaphragm in a longitudinal direction and includes a plurality of radial guides positioned circumferentially around the outer surface of the barrel member along a portion of the length of the barrel member. The diaphragm defines an orifice having a ring portion that flexes when a pressure difference is applied across the orifice thereby increasing the flow rate across the diaphragm. The orifice has a smaller diameter at a first end relative to a second end of the orifice. A method of compensating for a pressure difference across the diaphragm is also disclosed.

Abstract: A system for decelerating a linearly displaceable valve undergoing a closing motion is disclosed. The system includes a housing, a first hydraulic fluid chamber provided in said housing, and a slave piston for displacing the valve in response to the supply of hydraulic fluid to the first hydraulic fluid chamber. Deceleration of the valve may be accomplished by selectively throttling the release of hydraulic fluid in the first chamber to a second chamber. The hydraulic pressure in the second chamber opposes the closing motion of the valve, thereby slowing it gently for a valve seating event. Progressive throttling is used to maintain nearly constant hydraulic pressure in the second chamber during the seating event. The progressive throttling may be accomplished by selection of an appropriate throttling orifice size and shape, as well as an appropriate throttling profile for the orifice.

Abstract: A unitary diaphragm assembly for use primarily in conventional flush valves. The diaphragm assembly has a flexible diaphragm which includes a sealing portion and a mounting portion at the outer peripheral edge. A flow ring is positioned adjacent the sealing portion of the diaphragm. An elongated barrel member extends from the diaphragm in a longitudinal direction and includes a plurality of radial guides positioned circumferentially around the outer surface of the barrel member along a portion of the length of the barrel member. The diaphragm defines an orifice having a ring portion that flexes when a pressure difference is applied across the orifice thereby increasing the flow rate across the diaphragm. The orifice has a smaller diameter at a first end relative to a second end of the orifice. A method of compensating for a pressure difference across the diaphragm is also disclosed.

Abstract: A hose rupture control valve unit includes a housing provided with two input/output ports. One input/output port is directly attached to a bottom port of a hydraulic cylinder, and the other input/output port is connected to one of actuator ports of a control valve via an actuator line. Within the housing, there are provided a poppet valve body serving as a main valve, a spool valve body serving as a pilot valve which is operated with a pilot pressure supplied as an external signal from a manual pilot valve, thereby operating the poppet valve body, and a small spool having the function of an overload relief valve. The above construction reduces the number of components arranged in a flow passage through which a hydraulic fluid passes at a large flow rate, and hence a pressure loss. A further reduction in overall size and production cost of the valve unit is achieved.

Abstract: In an own-medium controlled magnetic valve (2) actuatable by an electromagnetically controlled pilot vale (46) for controlling liquids, having a main valve member (50) in the form of a differential piston and means to suppress pressure surges during the closure of the main valve (12) implying the cooperation of an overflow channel (68, 80, 82) with a limited passage cross section between both sides of the main valve member (50). The overflow channel consists at least partly of an elastic-walled choke channel (80) which can be increasingly narrowed by squeezing during the closure of the main valve (12). This ensures that the closing movement takes place rapidly and with enduring precision despite gentle closing.

Abstract: A multi-speed slit valve apparatus and method of actuating a slit valve apparatus at least at two distinct speeds is provided. The slit valve apparatus includes a pneumatic cylinder 210 having a primary channel 254, 266 and auxiliary channel 258, 270 at each end, wherein the auxiliary channels 258, 270 have a cross sectional area smaller than that of the primary channels 254, 266. A piston 226 defining a front volume 240 and a back volume 242 is disposed in the cylinder 210 and is reciprocally actuated by a compressed fluid such as air. At a predetermined stage during the cylinder's out-stroke and in-stroke the primary channels 254, 266 become sealed from the front and back volumes 240, 242, respectively, such that during the remainder of the stroke the fluid is biased to exhaust through the auxiliary channels 258, 270.

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 control for a poppet valve providing improved load drift control is disclosed. The control includes a valve member operably moveable between a closed position and a range of open positions for allowing flow from an associated poppet control chamber, and a sealing element disposed between a first cavity portion in communication with the control chamber and a second cavity portion for preventing leakage around the valve member therebetween. The sealing element is supported by structure which maintains the sealing element in close alignment with a bore in which the valve member is supported, the sealing element in several embodiments being integrally formed with the bore and in other embodiments being self aligning with the bore.

Abstract: A poppet adapted for movement in a passage extending between an inlet port and a control chamber of a poppet valve for controlling a fluid flow rate into the control chamber from the inlet port responsive to changes in a fluid flow rate from the control chamber, the poppet including at least one metering port positioned for communicating with the control chamber, a conduit connecting the metering port with an opening positioned for communicating with the inlet port for the flow of the fluid from the inlet port to the metering port, and at least one flow increasing element communicating with the conduit positioned to be covered by an inner sidewall when the poppet is within a predetermined range of displacement from a closed position toward the control chamber, the flow increasing element being increasingly exposed to the control chamber when the poppet is displaced toward the control chamber beyond the range, and the flow increasing element cooperating with the metering port when the poppet is at a predetermi

Abstract: A hydraulic control valve (10; 110) which acts as a hydraulic flow amplifier. An obturator (34; 134) is slidable towards and away from a valve seat (36; 136) to controllably vary throughflow from an inlet (S; P) to an outlet (T; S). The obturator (34; 134) is mounted on a piston (30; 130) which is slidable in dependence on the excess of the difference between inlet and outlet pressures over control pressure in a control chamber (42; 142). The control chamber (42; 142) is fed with hydraulic fluid bled from the source (S; P) via a controlled leak (48+50; 148+150) which is self-regulating in dependence on throughflow-controlling movement of the piston/obturator (34/30; 134/130) in a sense which provides negative feedback. The control chamber (42; 142) is drained through a fluid conduit (54; 154) incorporating an externally-controllable fluid flow restriction (56; 156) which serves as the control input to the control valve (10; 110).

Abstract: An improved pop-up irrigation sprinkler with integral flow control valve, and an improved separate flow control valve, defined by a dual flowpath for pilot flow within the flow control valve; a stem-flushing feature using an interrupter disc (54) mounted on a piston (48), providing a flowpath for a brief hydraulic flushing cycle after a momentary interruption of flow; a direct acting hydraulic pilot valve (92) to permit hydraulic control of an electric type sprinkler or a separate flow control valve; an improvement of the bearing guide (80) by the addition of a resilient barrier seal (84) to prevent seizing of the stem to the bearing guide when fully extended, the seal maintaining a close fit to the stem and yet being sufficiently resilient to permit the flushing of the stem; and a variable orifice in the inlet to the bonnet chamber to retard the initial opening rate of the valve.

Abstract: A flow amplifying poppet valve has a main poppet for controlling fluid flow from an inlet port to an outlet port of a main fluid passage. The position of the main poppet is controlled by controlling the pressure in a first control chamber adjacent the main poppet with a second stage poppet of a two-stage pilot valve disposed within a pilot passage communicating the first control chamber with the outlet port. The position of the second stage poppet is controlled by controlling the pressure in a second control chamber adjacent the second stage poppet with a pilot stage poppet that has a frusto-conical section urged into sealing engagement with the second stage poppet by a spring. A device selectively exerts a control force to move the first stage poppet in a valve opening direction to establish a variable flow control orifice between the frusto-conical section and the second stage poppet.

Abstract: A firefighting nozzle includes a nozzle body having a having a centrally formed jet orifice at its outlet end. An annular fog spray opening concentrically surrounds the jet orifice. A jet control valve is provided for allowing selective variation of the diameter of the solid stream emitted from the jet orifice. A fog control valve is provided for selectively varying the intensity of the discharge from the fog spray opening. The jet control valve and the fog control valve are operable independently of and simultaneously with one another, so that either a variable diameter solid stream or a variable fog cone, or both, can be produced at once. Various remote control arrangements are available for actuating the jet and fog control valves.

Abstract: An autoclosing flow-control valve assembly has a housing forming an inlet chamber normally filled with a fluid under pressure, an outlet chamber, and a main valve seat between the chambers. A piston defining in the housing a control chamber carries a valve element sealingly engageable with the seat. A piston spring braced between the piston and the housing urges the piston and element into the closed position. The piston is formed with a small bleed passage extending between the control chamber and the outlet chamber. A control passage extending between the inlet chamber and the control chamber has a pilot valve that when open pressurizes the control chamber and pushes the piston and element into the open position and when closed blocks flow through the control passage. An actuating member is actuatable to open the pilot valve and an actuating spring braced between the member and the housing urges the member out of contact with the pilot valve.

Abstract: The disclosure is directed to a valve arrangement for controlling a linear or rotary hydraulic motor. The valve is connected to a pump which acts as a pressure medium source by the valve means and to a tank. The tank connection may be either direct or indirect. The arrangement of the present invention includes at least one seat valve located in a main flow connection between the pump and a port of the motor. Each of the seat valves would adjust the flow in the main flow connection to the motor via a pilot flow adjustable by a pilot valve. The pilot flow originates from the main flow through the seat valve.

Abstract: An automatic choke has two piston-cylinder assemblies mounted within a housing having an inlet and an outlet. The piston-cylinder assemblies are connected in a closed hydraulic loop configuration. One piston-cylinder assembly is responsive to pressures at the inlet and the other piston-cylinder assembly controls valve at the outlet.

Abstract: A metering valve for controlling fluid flow is provided which includes a piston assembly disposed between a fluid inlet and a fluid outlet and mounted for relative movement within a tubular unit between a first open mode, a second open mode connecting the fluid inlet and outlet and a close mode. The assembly is biased to assume the close mode and assumes the first open mode when a predetermined first external form is applied to a valve actuating element forming a component of the metering valve. The assembly assumes the second open mode when the first external force is enhanced by a predetermined second external force applied to the valve actuating element. When the external forces are released, the piston assembly automatically returns to the close mode upon successively moving through first and second segments of travel relative to the tubular unit. The rate of travel during the first segment is substantially less than the rate of travel during the second segment.

Abstract: A pressure control system in which a pressure in a back pressure chamber of a flow control valve is controlled according to a throttle opening of a pilot valve to locate stationary the valve body of the flow control valve at a position corresponding to the throttle opening of the pilot valve. In the system, a fixed throttle is provided in an oil passage extended to the back pressure chamber of the flow control valve, thereby applying a dampering action to the valve body.

Abstract: A pressure control system in which a pressure in a back pressure chamber of a flow control valve is controlled according to a throttle opening of a pilot valve to locate stationary the valve body of the flow control valve at a position corresponding to the throttle opening of the pilot valve. In the system, a fixed throttle is provided in an oil passage extended to the back pressure chamber of the flow control valve, thereby applying a dampering action to the valve body.

Abstract: Flow amplifying poppet valves are useful in hydraulic circuits requiring low leakage when the circuit is in a load holding condition. Pressure compensation of the known flow amplifying poppet valves has not been totally successful and thus, the output flow varies somewhat with changing pressure drops across the poppet valve. The subject pressure compensated flow amplifying poppet valve utilizes a pressure compensating valve and a compensating orifice disposed in a compensating flow path disposed in parallel with a valve device for controllably regulating fluid flow through a flow regulating passage. Fluid flow through the compensating flow path is restricted by the orifice to a flow rate substantially equal to the amount of fluid that can flow through a flow control slot in a valve element at a closed position of the valve element.

Abstract: An hydraulic valve of the flow-controlled type and including a valve housing provided with an inlet and an outlet and a valve body which is intended to coact with a valve seat in a manner to open and interrupt the connection between the inlet and outlet in dependence on a continuously controllable pilot flow in a pilot-flow channel extending from a pilot-flow chamber located on the side of the valve body remote from the valve seat to the outlet in the flow direction after the valve body. The pilot-flow chamber, in turn, communicates with the inlet via a variable constriction. For the purpose of simplifying this type of valve and rendering the valve more compact, the valve body is arranged in a recess which extends to the valve seat and which is formed concentrically with the valve seat. The recess is formed in a seat-part which incorporates one or more slots which are open towards the recess and which discharge into the pilot-flow chamber.

Abstract: A pilot-operated, diaphragm-controlled float valve assembly has a primary valve and a pilot valve operated by a float arm, a cavity for the main valve is formed between a split segment casing and is divided by a valve disc centrally mounted upon a flexible diaphragm into a lower, larger, pressure-differential chamber and an upper, smaller, pressure-differential chamber, both chambers being fluidly connected by a variable restricting orifice formed by a gap between an axial bore in the valve disc and a fixed guide rod for the disc. The top of the guide rod acts as a seat for a pilot valve; a lateral bore extends through the top of the guide rod and another through the base of the valve, enabling water to flow into both pressure differential chambers when the main valve outlet is held normally closed against its seat by bias of the diaphragm to prevent backflow under low pressure conditions.

Abstract: A metering valve is provided having a piston assembly mounted for movement between open and close modes. The piston assembly is biased to assume a close mode. The piston assembly assumes an open mode only when a predetermined external force is applied to a valve actuating element forming a component of the metering valve. When the external force is removed, the piston assembly automatically returns to the close mode. The rate of movement of the piston assembly during a first segment of travel from the open mode to the close mode is substantially slower than the rate of movement during a second segment of the travel.

Abstract: A flow control valve assembly, for preventing the pressure oil confined in an inlet port of a valve housing from pulsating and for additionally performing a safety valve function without employing a separate safety valve, has a valve housing which is easy in machining thereof and neat in construction. In the valve housing of the flow control valve assembly is formed a valve-receiving bore (21) in which a poppet (32) and a second spool valve (51), serving as a safety valve, are axially aligned with each other in series. In the valve housing (20), a hydraulic operating oil flows to a communication port (39) of the poppet (32) through an inlet port (23) formed in the valve housing (20), and then further flows to a back-pressure chamber portions (38a, 38b) of the poppet (32) through a variable orifice (44). The pressure oil, having been received in the back-pressure chamber portion (38b), flows out of the portion (38b) to an outer peripheral portion of the second spool valve ( 51).

Abstract: Pressure medium valve having a valve piston located in a valve housing for control of a main pressure medium flow through the valve by the aid of a pilot flow through a variable pilot flow restriction disposed in the valve piston, the pilot flow being derived from the main pressure medium flow and being controllable by means of a control pilot valve. To achieve temperature independent control without area increase in the pilot flow chambers, an additional restriction between the valve piston and the cylindrical wall surrounding the valve piston of the valve housing is incorporated. The additional restriction has the form of a peripheral clearance of a substantially greater axial length than height.

Abstract: A metering valve is provided having a piston assembly mounted for movement between open and close modes. The piston assembly is biased to assume a close mode. The piston assembly assumes an open mode only when a predetermined external force is applied to a valve actuating element forming a component of the metering valve. When the external force is removed, the piston assembly automatically returns to the close mode. The rate of movement of the piston assembly during a first segment of travel from the open mode to the close mode is substantially slower than the rate of movement during a second segment of the travel.

Abstract: A fluid pressure control device is described effective to actuate an external device when the differential-pressure between a high-pressure fluid source and a lower pressure fluid source rises to a predetermined magnitude. The control device comprises a housing having a partition wall therein dividing its interior into two compartments communicating with each other through an opening in the partition wall. A differential-pressure sensing member is disposed in one of the compartments and is movable therein in response to the sensed differential-pressure. A stem is fixed to the differential-pressure sensing member so as to be moved therewith and carries a valve member at one end for moving it with respect to the valve opening to control the flow of the fluid therethrough and thereby to actuate the external device.

Abstract: The disclosure is directed to a valve arrangement for controlling a linear or rotary hydraulic motor. The valve is connected to a pump which acts as a pressure medium source by the valve means and to a tank. The tank connection may be either direct or indirect. The arrangement of the present invention includes at least one seat valve located in a main flow connection between the pump and a port of the motor. Each of the seat valves would adjust the flow in the main flow connection to the motor via a pilot flow adjustable by a pilot valve. The pilot flow originates from the main flow through the seat valve.