Abstract: A combination valve including an electromagnetic shut-off valve and an integrated pipe-break protection includes an inflow and an outflow, between which a first flow path is defined, a sealing surface arranged in the first flow path, a movable sealing body including a main seat and a pilot seat, between which a pilot bore is defined as a second flow path, a closing spring, an armature with a sealing surface and a magnetic coil. The sealing body closes the first flow path in the closed position by abutting the main seat against the sealing surface and closes the second flow path by abutting the sealing surface against the pilot seat. The closing spring presses the sealing surface of the armature against the pilot seat of the sealing body and the main seat of the sealing body against the sealing surface. An opening spring presses the sealing body into the open position.

Abstract: A method of controlling a delivery pressure of an aircraft engine fuel system includes operating a rotodynamic fuel pump hydraulically connected to the fuel system to pump a fluid from an inlet of the rotodynamic pump and out of an outlet of the rotodynamic pump for delivery to the fuel system. The method further includes varying an angular relationship between the inlet and the outlet of the pump to control the delivery pressure. An aircraft engine fuel system and a rotodynamic pump are also described.

Abstract: Methods, apparatus, and articles of manufacture to validate position parameters of a valve are disclosed. An example apparatus includes a field device, the field device further including a sensor interface to receive an unprocessed valve position parameter from a sensor and a position comparator to determine a deviation between the unprocessed valve position parameter and an interpreted valve position parameter and a valve position validator apparatus, the valve position validator apparatus further including a parameter comparator to determine if the deviation exceeds a threshold and an alert generator to generate an alert when the parameter comparator determines the deviation exceeds the threshold.

Abstract: An example valve includes: a pilot seat member comprising: a channel that is fluidly coupled to a first port of the valve, a pilot seat, and one or more cross-holes fluidly coupled to a second port of the valve; a pilot check member configured to be subjected to a fluid force of fluid in the channel of the pilot seat member acting on the pilot check member in a proximal direction; a solenoid actuator sleeve comprising a chamber; a first setting spring disposed in the chamber and configured to bias the solenoid actuator sleeve in a distal direction; and a second setting spring configured to bias the pilot check member in the distal direction, such that the first setting spring and the second setting spring cooperate to apply a biasing force in the distal direction on the pilot check member toward the pilot seat against the fluid force.

Abstract: Provided is an electrically-driven flow rate control valve capable of controlling a flow rate of a fluid flowing between two inlet/outlet ports, restraining a high pressure of the fluid from being applied to a sub valve body connected to an electric motor. The flow rate control valve has a casing, a raising/lowering drive device, a supply-switching valve, a main valve body, a valve-closing spring. When the electric motor of the raising/lowering drive device moves the sub valve body upward, oil of a back pressure chamber is discharged from a discharge oil passage through a sub valve body communication port and a sub valve body oil passage to open the main valve body. When the main valve body is closed, a pressure of the back pressure chamber is inhibited from being directly applied to a lower end face of the sub valve body.

Abstract: The teachings of the present disclosure describe an injector having an injector housing, an actuator, and a nozzle needle, wherein the actuator is arranged in an actuator space of the injector housing. The injector may include a control piston bore in the injector housing, in which a control piston is arranged, a leakage pin bore between the actuator space and the control piston bore, and a leakage pin coupling the control piston to the actuator, the leakage pin arranged in the leakage pin bore. The control piston may be hydraulically connected to the nozzle needle in order to open or close an outlet opening of the injector housing. The injector may include a high pressure line configured to convey a fuel under pressure to the nozzle needle and a feedline in the injector housing connecting the leakage pin bore to the high pressure line.

Abstract: A process medium-controlled regulating valve for a liquid throughflow regulator, having a main valve, a pilot valve for controlling a main valve piston, a pilot valve piston which closes the pressure relief line in a closed position, a cleaning wire element which is stationary in the axial direction is guided with hole tolerance through the pilot line, and the pilot line can be moved along the cleaning wire element, which is guided therein, during a stroke adjustment of the main valve piston. The cleaning wire element has an actuating contour which, at least during the stroke adjustment, can be brought into sliding contact with a counter-contour formed on the main valve piston, with the build-up of a transverse force which acts on the cleaning wire element.

Abstract: An example valve includes a main stage and a pilot stage. The pilot stage includes a pilot poppet that is axially movable, a pilot piston, and a pilot spring applying a biasing force on the pilot poppet. The valve further includes a pilot seat member disposed between the main stage and the pilot stage and configured to form a pilot seat for the pilot poppet. When a pilot pressure fluid signal is received through a pilot port, the pilot pressure fluid signal applies a pressure on the pilot piston causing the pilot piston to move axially, thereby reducing the biasing force applied by the pilot spring on the pilot poppet.

Abstract: An extraction valve for overpressurized gas flowing from a compressed gas reservoir is disclosed. The extraction valve has a valve seat carrier, including a conical valve seat emerging centrally into an outflow chamber. An extraction piston, which is mobile in its axial direction at least indirectly via an electromagnetic coil, includes a valve body cooperating with the valve seat. An inflow chamber for the pressurized gas is designed totally or partially on the circumference of a central axis of the extraction piston and is connected in the axial direction of the extraction piston against a flow direction of the gas when the extraction piston is in the open position, between the valve seat and the valve body via an intermediate connection with an intermediate volume which includes a connection with the region in which the valve seat and the valve body co-operate.

Abstract: A stem assembly for a valve including a shaft having a longitudinal axis and a first end having a cross section less than a cross section of the shaft, and a protrusion near the first end extending away from the axis. In response to the first end and the protrusion being positionable inside a compartment of a valve plug having an opening in fluid communication with a fluid of a valve during operation of the valve, the first end and the protrusion being movable between a first position and a second position relative to the valve plug. In the first position, the first end blocking the opening for preventing fluid flow therethrough, and in the second position, the first end being movable away from the compartment opening for permitting fluid flow through the opening.

Abstract: A valve for controlling fluids, in particular hydraulic fluid, includes a first connector opening and a second connector opening, a preliminary stage with a first valve seat and a first displaceable closing body, and a main stage with a second valve seat and a second displaceable closing body. The first valve seat is assigned to a through opening of the second closing body. A filtering gap is formed in a flow path from the first connector opening to the preliminary stage by way of a constriction of the flow path.

Abstract: A solenoid valve includes a main poppet configured to control a flow rate of working fluid flowing in a valve passage according to a pilot pressure, an auxiliary poppet configured to adjust the pilot pressure according to the electromagnetic force, and a first seat portion and a second seat portion provided in the valve passage. The main poppet includes a poppet valve seated on the first seat portion and a spool valve slidable in the second seat portion. The spool valve includes an outer peripheral surface slidable relative to the second seat portion and through holes open on the outer surface and configured such that areas thereof exposed from the second seat portion change in accordance with a movement of the spool valve.

Abstract: A pilot valve element includes a metallic pilot valve body formed integrally with a plunger, a flexible sealing member, fitted on a tip of the pilot valve body, which touches and leaves a pilot valve seat, and a stopper for restricting the displacement of the pilot valve element relative to a driven member in a manner such that the sealing member is stopped in a direction of axis line after the sealing member has seated on a pilot valve seat. The stopper is configured such that the pressure-receiving diameter of the sealing member, which receives a pressure difference between an upstream side and a downstream side of the pilot valve, remains unchanged from when the sealing member comes in contact with the pilot valve seat until when the sealing member is stopped by the stopper with the result that the sealing member has completely seated on the pilot valve seat.

Abstract: A fuel injector, particularly for injecting fuel into a combustion chamber, is provided as including a housing having at least one spray orifice, an armature assembly that is movable linearly in the housing, along a longitudinal axis, a magnetic coil acting magnetically on the armature assembly, a valve element that is movable linearly with respect to the armature assembly and with respect to the housing, for opening and closing the spray orifice, and a pin for limiting the movement of the valve element with respect to the armature assembly.

Abstract: A solenoid valve, the magnet armature of which is designed to be movable relative to a first valve-closing element, for which purpose the first valve-closing element is accommodated telescopically in a coupling element attached to the magnet armature, wherein the coupling element is guided along the inner wall of a guide sleeve inserted in the valve housing in order to align the magnet armature precisely with the first valve-closing element in the direction of a second valve-closing element which is likewise accommodated in the guide sleeve.

Abstract: A selector with at least two settings, useful for controlling flow of fluid in a hydraulic control valve. In at least one of the settings of the selector, control of fluid flow is fully automatic, being controlled by the valve actuator, and in at least one of the settings of the selector, control of fluid flow is fully manual, being entirely independent of the valve actuator.

Abstract: A working fluid flow rate flowing from a second port (13) to a first port (12) is controlled using a solenoid (S). A pilot pin (60) of a pilot valve (V3) driven by the solenoid (S) regulates an auxiliary pilot pressure. An opening of an auxiliary valve (V2) is varied according to the auxiliary pilot pressure, whereby the auxiliary valve (V2) causes working oil to flow out to the first port (12) from the second port (13) and varies a main pilot pressure according to the working oil flow rate. An opening of a main valve (V1) is varied according to the main pilot pressure, whereby the main valve (V1) causes the working oil to flow out to the first port (12) from the second port (13). Precise flow control at a low flow rate and responsive flow control at a high flow rate are thereby realized.

Abstract: A piloted proportional throttle valve has a valve piston (29) displaceably guided in the longitudinal direction in a valve housing (13) having a fluid inlet (2) and outlet (1). The front side of the valve piston (27) can be pressurized against a main valve seat (25) by fluid pressure acting on its back side. A pilot valve device has an actuating member (7) displaceable in the longitudinal direction by an electrically actuatable magnet system (4), and works with a pilot valve seat (37) in a bore (17) of the valve piston (29) connecting its back side to the fluid outlet (1) on the front side of the piston. The fluid pressure on the back side of the piston (29) is reduced for an opening motion when the pilot valve seat (33) is released. A flow baffle device (39) is disposed between the back side of the piston and the fluid inlet (2) of the housing (13) to build up the fluid pressure pressurizing the piston (29) against its closed position by introducing pilot fluid.

Abstract: A solenoid-operated control valve has a primary piston and a secondary piston located within a sleeve, and a solenoid coil disposed about the sleeve to effect movement of the primary piston. The primary and secondary pistons are independently movable along the sleeve. The secondary piston defines a pilot orifice connected with a center passage. The primary piston has a seal pin that extends into the pilot orifice of the secondary piston to block and unblock the center passage with movement of the primary piston in relation to the secondary piston. A spiral cut scarf ring disposed about the secondary piston is in contact with both the secondary piston and the sleeve to allow controlled leakage of a fluid through the valve via space between the secondary piston and the sleeve. The leaked fluid is permitted to collect in a cavity between the primary and secondary pistons.

Abstract: In a fluid-working machine having a high-pressure line and a working chamber, a valve arrangement is arranged to control fluid flow from the high-pressure line to the working chamber. The valve arrangement comprises a main valve having a valve element arranged to provide sealing contact with a valve seat, and an auxiliary valve comprising an electromagnetically-movable valve member for equalising pressure on either side of the main valve by placing the working chamber in direct fluid communication with the high-pressure line. The electromagnetically-movable valve member may comprise a spool valve member or a poppet valve member.

Abstract: A valve assembly comprising an inlet port, an outlet port, and a diaphragm configured to selectively allow communication between the inlet port and the outlet port, the diaphragm including a first side adjacent the ports and a second side opposed to the ports. The valve preferably includes at least one bleed path between the first side and the second side of the diaphragm with a one way flow device configured to allow flow from the first side to the second side of the diaphragm and prevent flow from the second side to the first side of the diaphragm. The valve may include a first bleed path from the inlet port to the second side of the diaphragm and a second bleed path from the outlet port to the second side of the diaphragm. Either bleed path, or both, may comprise a check valve mounted in the diaphragm.

Abstract: A hydraulic actuating device for a sliding stem control valve assembly is mounted between a control valve and an actuator housing. The hydraulic actuating device is connected to one of a control valve stem, an actuator stem, and a stem connector and the hydraulic actuating device moves either the control valve stem, the actuator stem, or the stem connector in response to varying hydraulic pressure within the hydraulic actuating device. The hydraulic actuating device may be used to override an actuator of the sliding stem valve during emergency operations, or to provide a backup actuator in the case of a primary actuator malfunction.

Abstract: A poppet valve assembly includes a body having a first axial end portion and a second axial end portion. The first axial end portion includes a tapered surface adapted for sealing engagement with a valve seat. The second axial end portion defines a metering orifice. The body defines a passage that includes an opening in the first axial end portion and is in fluid communication with the metering orifice. The passage includes a check valve seat. A check valve is disposed in the passage. The check valve is adapted to sealingly engage the check valve seat.

Abstract: A switch device for water conduit valve comprises a valve body having a water inflow passage bifurcated to form more than one water outflow passage, a first water inlet and a second water inlet disposed between the water inflow passage and the water outflow passage, a magnetic valve switch device connected to the first water inlet and a manual control switch device connected to the second water inlet to provide a user to freely select controlling water flow that is introduced into the water outflow passage from the first water inlet or the second water inlet through any switch device.

Abstract: An electronically actuatable valve assembly having a primary face seating valve, including a primary valve member, and a secondary valve, including a secondary valve member. The secondary valve opens before the primary valve to equilibrate pressure across the primary valve member and thereby facilitate opening of the primary valve member. The secondary valve is coupled to an armature which moves from a first position to a second position, in use, attracted by an electromagnet. The coupling between the armature and the secondary valve is configured to enable the armature to begin to move from the first position without movement of the secondary valve.

Abstract: An electronically actuatable valve assembly including a valve member comprising a ferromagnetic member, and a magnetic circuit adapted to direct magnetic flux through the ferromagnetic member when the valve member is spaced apart from its valve seat, to hold the primary valve open.

Abstract: An automate fluid flow control system includes a relief valve for being sealedly disposed within a fluid chamber in an immovable manner to seal a flow of fluid flowing from a fluid inlet to a fluid outlet, and an actuator. The relief valve has a fluid passage for controlling a flow rate of the fluid passing from the fluid chamber to the fluid outlet, and a valve stopper sealedly closing the fluid passage for controlling the fluid flowing from the fluid chamber to the fluid outlet, wherein the valve stopper is driven to move between a closed position that the valve stopper is sealedly retained to close the fluid passage for blocking said fluid passing to the fluid outlet, and an opened position that the valve stopper is moved to unseal the fluid passage for allowing the fluid passing to the fluid outlet through the fluid passage.

Abstract: The invention relates to a valve comprising a valve housing having a valve inlet and outlet, a valve seat arranged in the direction of flow of the fluid between the valve inlet and outlet, a closure means which is movably arranged in the valve housing, and has a first side and a second side, wherein the closure means closes off the valve seat tightly when the valve is in the closed state, a balancing opening for producing a pressure compensation between the first side and the second side of the closure means, and at least one control actuator, wherein the control actuator closes off the balancing opening of the closure means in a closed position and frees the balancing opening of the closure means in an open position so that the closure means frees the valve seat as a result of a pressure compensation via the balancing opening.

Abstract: The apparatus and method of the invention provides for a rinse valve for controlling the flow of rinse fluid to a vacuum waste receptacle. The rinse valve comprises a primary rinse fluid flow path and a poppet assembly intersecting the primary rinse fluid flow path. The rinse valve also comprises a solenoid-driven fluid control device having a solenoid armature movable between an inactive state in which the armature engages the poppet assembly to block flow of the rinse fluid through a poppet channel and an active state in which the solenoid armature is disengaged from the poppet assembly to allow flow of the rinse fluid through the poppet channel to raise the poppet assembly, permitting the flow of the rinse fluid through the primary rinse fluid flow path and out of the valve, the armature being located at all times out of the primary flow path of the rinse fluid.

Abstract: An adjustable damping valve device, for a vibration damper, includes a first valve and emergency operation valve, both of which are actuated by a shared solenoid. The emergency operation valve carries out a relative movement relative to the first valve when passing from the emergency operation position into normal operation. A magnetic flux guiding element is arranged in the magnetic flux between the first valve and the emergency operation valve and determines the magnetic flux for the emergency operation valve and for the first valve.

Abstract: An automate fluid flow control system includes a valve member for being sealedly disposed within a fluid chamber to seal a flow of fluid flowing from a fluid inlet to a fluid outlet, a relief valve having a fluid passage extended along the valve member for communicating the fluid chamber with the fluid outlet and including a valve stopper sitting on a top opening of the fluid passage to sealedly close the fluid passage, and a powering assembly including an actuator to move the relief valve between a closed position that the valve stopper is sealedly retained to close the fluid passage and an opened position that the actuator drives the valve stopper to unseal the fluid passage for releasing a pressure within the fluid chamber to allow the fluid passing to the fluid outlet.

Abstract: An electromagnetic valve includes a valve body, a valve element, a movable iron core, a guide tube, a coil, a yoke, and a fixed iron core. The valve body includes a fluid flow path. The valve element is movable and seated on a valve seat provided in the fluid flow path of the valve body. The movable iron core moves the valve element with respect to the valve seat. The guide tube is cylindrical and movably supports the movable iron core. The coil is mounted on an outer periphery of the guide tube. The yoke covers an outside of the coil and forms a magnetic circuit. The fixed iron core is provided facing the movable iron core and attracts the movable iron core by energization of the coil. The valve body is coupled to the guide tube on one opening end side of the guide tube, and the fixed iron core is provided on an other end side of the guide tube with a clearance spaced from an inside of the guide tube.

Abstract: The invention relates to a relief valve comprising a first valve body for opening and closing a fluid passageway between a first valve connection and a second valve connection, a second valve body which is disposed on the first valve body and is used for opening and closing a valve passageway located between the first valve connection and a valve interior, a one throttle duct between the valve interior and a face of the first valve body, a spring for opening the second valve body, and an actuator for closing the second valve body. This relief valve further comprising a movable member that can be moved further in the same direction once the second valve body has been closed, thus allowing the first valve body to be opened by having the second valve body engage a valve seat located on the first valve body, and a stop element connected to the second valve body and/or the movable member engages the first valve body via the spring to close the first valve body.

Abstract: A valve for an anti-lock brake system is capable of reducing the cost of production through structural improvement of a valve housing. The valve includes a valve core, an armature located below the valve core and having a ball, a cylindrical sleeve coupled to the valve core and armature and guiding the armature to move backward and forward, a first elastic member installed between the valve core and the armature, a valve housing coupled to the sleeve and having a longitudinal hollow space, a seat plunger movably installed in the hollow space and having a first orifice, a second elastic member installed between the seat plunger and the valve housing, a seat having an outlet and a second orifice that communicates with the first orifice, and a seat housing coupled to the valve housing and the seat, supporting the valve housing and the seat spaced apart from each other, and having an inlet between the valve housing and the seat.

Abstract: A directional or flow control valve has an inlet connection, an outlet connection, and a slide that controls a fluid connection between the inlet connection and the outlet connection and is configured to control the fluid connection in at least two adjustable opening cross-sections that are spaced axially apart from each other and allow a partial flow to pass through.

Abstract: An automate fluid flow control system includes a valve member for being sealedly disposed within a fluid chamber to seal a flow of fluid flowing from a fluid inlet to a fluid outlet, a relief valve having a fluid passage extended along the valve member for communicating the fluid chamber with the fluid outlet and including a valve stopper sitting on a top opening of the fluid passage to sealedly close the fluid passage, and a powering assembly including an actuator to move the relief valve between a closed position that the valve stopper is sealedly retained to close the fluid passage and an opened position that the actuator drives the valve stopper to unseal the fluid passage for releasing a pressure within the water chamber to allow the fluid passing to the fluid outlet.

Abstract: An automate fluid flow control system includes a valve member for being sealedly disposed within a fluid chamber to seal a flow of fluid flowing from a fluid inlet to a fluid outlet, a relief valve having a fluid passage extended along the valve member for communicating the fluid chamber with the fluid outlet and including a valve stopper sitting on a top opening of the fluid passage to sealedly close the fluid passage, and a powering assembly including an actuator to move the relief valve between a closed position that the valve stopper is sealedly retained to close the fluid passage and an opened position that the actuator drives the valve stopper to unseal the fluid passage for releasing a pressure within the water chamber to allow the fluid passing to the fluid outlet.

Abstract: A solenoid valve has a main body defining a gas inlet passage, a gas outlet passage, and a cavity; a core tube forming a closure for said cavity so as to prevent an escape of gas; a cylindrical main piston slidably movable in said cavity of said main body, said main piston forming a front chamber and a back chamber in said main body, said main piston having a gas conduit for passing the gas from said gas inlet passage to said front chamber and an axial hole for passing the gas from said back chamber into said gas outlet passage with a bleed orifice at one end of said axial hole; said main piston being spring biased to a closed position; a spring biased pilot piston; and electrical coil means associated with said core tube to provide a magnetic field for movements of said pilot piston and said main piston, so that when said coil means is deenergized said pilot piston closes said outlet passage and causes a pressure equalization allowing said return spring to push said main piston to close the valve, while when

Abstract: The invention relates to a device for controlling the switching movement of a valve according to the preamble of claim 1. It is the object of the present invention to design a control device in this regard such that it can be largely prefabricated and can be very easily converted to different operating voltages or data protocols, that the stock inventory of these control devices can be reduced and that economical quantities can be achieved more easily than before.

Abstract: A pilot-operated valve has a main poppet controlling fluid flow between inlet and outlet ports in response to pressure in a control chamber. Fluid flow through a pilot passage, linking the control chamber and the outlet port, moves an exhaust spool between first and second positions to control fluid flow through passages in the main poppet. The first position blocks flow between the control chamber and the outlet port and provides a path between the control chamber and the inlet port. In the second position, flow between the control chamber and the outlet port is enabled, and a second path, that is more restricted than the first path, is provided between the control chamber and the inlet port. When the valve closes, flow through the first path allows movement of the main poppet at a faster rate than during opening when flow occurs through the more restricted second path.

Abstract: An apparatus (such as a valve assembly or other actuator) includes a pressure plate having a first hole and a second hole. The apparatus also includes a plunger configured to selectively cover the second hole of the pressure plate. The apparatus further includes a coil configured to move the plunger away from the pressure plate to uncover the second hole of the pressure plate in order to allow a material to flow through the apparatus. The coil is also configured to move the plunger towards the pressure plate to cover the second hole of the pressure plate in order to block the material from flowing through the apparatus. Pressure may equalize on a first side and a second side of the pressure plate after the plunger covers the second hole of the pressure plate.

Abstract: The invention relates to a hydraulic slide valve for controlling flow-rate or pressure comprising at least one movable valve moving from a closed position by contacting a seat and an open position remote therefrom, the displacement of said valve being controlled by a piezoelectric washer.

Abstract: An integrated three-way poppet valve is disclosed with an intermediate pilot port and an integral load holding check valve. The valve incorporates a reverse flow check poppet for load hold capability, which enables a lower cost solution compared to a combination of valves of similar functionality. A control method is also disclosed using an integrated three-way poppet valve to control the flow of hydraulic oil to a cylinder, hydraulic motor, or other hydraulic device in proportion to the amount of a current applied to a solenoid coil. Depending on the current applied, the valve blocks all flow or else permits flow from one inlet port to two outlet ports proportional to the current applied.

Abstract: A solenoid valve for a brake system, which has a simplified configuration and can be easily manufactured with reduced manufacturing costs.

Abstract: A proportional pressure control valve includes a valve housing (38) with at least three fluid connections (1, 2, 3). The valve can be connected to a hydraulic drive system with a pre-determinable consumer pressure. The valve can perform reliable valve switching functions even for low-viscous fluid media, and can reduce its susceptibility to disturbance variables. A valve piston (56) actively connected to a pilot seat (5) by an energy accumulator (62) can be controlled by a control device (40). The consumer pressure on a fluid connection (1) acts on the valve piston (56) such that, according to the consumer pressure and the actuating force of the control device (40), a fluid can flow between the two other fluid connections (2 and 3) in both directions inside the valve housing (38).

Abstract: A valve includes a housing having an inlet (3), an outlet (1) and a movable sealing member (2) which allows the inlet (3) and the outlet (1) to be connected in fluid communication with each other, the sealing member (2) having associated therewith effective areas (4b) to which pressure can be applied, and sealing areas (4), and the sealing member (2) further having associated therewith a sealing seat (4a) for sealing the inlet (3) from the outlet (1). In order to provide a valve by which pressure can be relieved in a very short time, the sealing member (2) has associated therewith a conduit (2a) by which the inlet (3) and the outlet (1) can be connected in fluid communication with each other when the sealing member (2) rests on the sealing seat (4a).

Abstract: The invention provides a servo valve which is operable in vacuum systems and can be switched between an open and a closed state even by use of low forces. For that purpose, the valve has a closure member (4) moving between the open and a closed position under influence of a difference between a control pressure of a control chamber (13) and the pressures of the intake (2) and outlet (3), respectively. The control chamber is in constant fluid communication with the intake, and in adjustable fluid communication with the outlet to influence the control pressure mainly by the intake pressure and the outlet pressure depending on the adjustable fluid communication. The invention further provides a vacuum system with such a servo valve.

Abstract: A valve, in particular, a proportional seat valve or gate valve, includes a valve housing (10) and at least three fluid connections (1, 2, 3) extending through the valve housing. A main piston (18) extends in the valve housing (10). A pilot piston (24) for executing a pilot control (26) may be controlled by a current-carrying magnetic device (28). During an open pilot control (26), fluid from one (2) of the connectors (1, 2), controlled by the main piston (18), reaches the connector (3), controlled by the pilot piston (24), by a cross-sectional narrowing (38) in the main piston (19). The pilot control (26) and, as a result of the corresponding pressure drop, the main piston (18) achieves a control position, controlling both fluid connections (1, 2) with regard to fluid amount.

Abstract: In a fluid-working machine having a high-pressure line and a working chamber, a valve arrangement is arranged to control fluid flow from the high-pressure line to the working chamber. The valve arrangement comprises a main valve having a valve element arranged to provide sealing contact with a valve seat, and an auxiliary valve comprising an electromagnetically-movable valve member for equalising pressure on either side of the main valve by placing the working chamber in direct fluid communication with the high-pressure line. The electromagnetically-movable valve member may comprise a spool valve member or a poppet valve member.

Abstract: A solenoid valve has a main body defining a gas inlet passage, a gas outlet passage, and a cavity; a core tube forming a closure for said the cavity so as to prevent an escape of gas; a cylindrical main piston slidably movable in said the cavity of said the main body, said the main piston forming a front chamber and a back chamber in said the main body, said the main piston having a gas conduit for passing the gas from said the gas inlet passage to said the front chamber and an axial hole for passing the gas from said the back chamber into said the gas outlet passage with a bleed orifice at one end of said the axial hole; said the main piston being spring biased to a closed position; a spring biased pilot piston; and an electrical coil means associated with said the core tube to provide a magnetic field for movements of said the pilot piston and said the main piston, so that when said the coil means is deenergized said the pilot piston closes said the outlet passage and causes a pressure equalization allowing