Abstract: An autonomous flow control device with pilot amplification includes a primary valve responsive to changes in fluid composition, and a pilot valve responsive to and more sensitive to changes in fluid composition than the primary valve and configured to aid change in position of the primary valve in the event of a change in fluid composition.

Abstract: A control valve of hydraulic system for a working machine is provided, which includes a main body and a spool. The main body includes first, second, third, fourth and fifth ports, and first second, third, fourth and fifth inner fluid paths connected to the first, second, third, fourth and fifth ports, respectively. The spool is configured to move between a neutral position and a communicating position allowing fluid communication between the second inner fluid path and the fifth inner fluid path or between the first inner fluid path and the fifth inner fluid path. The spool includes a communicating hole configured to allow the fluid communication between the second port and the fourth port, or between the first port and the fourth port, when the spool is in a position between the communicating position and the neutral position.

Abstract: Passage forming blocks of a first pilot valve and a second pilot valve each include a supply passage, which opens in a first surface and a second surface and is connected to a valve chamber, a first output passage, which opens in the first surface and are connected to the valve chamber, and a second output passage, which opens in the first surface. Further, the passage forming blocks each include an output passage connecting recess. The output passage connecting recess is provided in a section of the second surface that overlaps with an opening region of the first output passage, which opens in the first surface, and is connected to the second output passage. The first output passage of the first pilot valve is connected to the second output passage of the second pilot valve via the output passage connecting recess of the second pilot valve.

Abstract: A system (100), including: a fluidic actuator (2) which can be acted upon by a pressurized fluid and has an actuator member (3), a pressurized fluid provision device (4) which is adapted to carry out a position control of the actuator member (3) and, within the position control, to apply the pressurized fluid to the fluidic actuator (2) in order to move the actuator (3) into a prescribed position, the pressurized fluid provision device (4) being adapted to carry out the position control taking into account at least one system parameter, which describes a physical property of the system and/or a requirement parameter which defines a requirement for the positioning of the actuator (3), wherein the pressurized fluid provision device (4) is further adapted to perform an assistance procedure and to determine and/or verify, within the assistance procedure, the system parameter and/or the requirement parameter on the basis of a movement of the actuator (3) and/or a consideration of physical limits.

Abstract: An improved servovalve for a seismic vibrator or vibration machine which includes a left additional passageway conducting a portion of sampled pressure from a left cylinder pressure chamber to only a portion of the right end drive surface of the spool, wherein the portion of the right end drive surface is less that of the entirety of the right end drive surface; and a right additional passageway conducting a portion of sampled pressure from a right cylinder pressure chamber to only a portion of the left end drive surface of the spool, wherein the portion of the left end drive surface is less that the entirety of the left end drive surface; thereby providing at least two additional passageways configured to provide linear proportional pressure feedback in spool movement control.

Abstract: An example valve includes: a first port fluidly coupled to a chamber of an actuator; a second port fluidly coupled to a reservoir; a third port configured to provide an output pilot fluid signal and receive an input pilot fluid signal; a fourth port fluidly coupled to a source of fluid; a main poppet configured to be subjected to a first fluid force of fluid received at the first port acting on the main poppet in a proximal direction to cause the main poppet to be seated at a main poppet seat to block fluid flow to and from the first port; a piston configured to move axially to contact the main poppet; and a spool that is axially movable between a first position and a second position to operate the valve in either a pilot-operated check valve mode of operation or a proportional flow control mode of operation.

Abstract: An example valve includes: a first port configured to be fluidly coupled to an actuator; a second port configured to be fluidly coupled to a reservoir; a third port configured to provide an output pilot fluid signal and receive an input pilot fluid signal; a fourth port configured to be fluidly coupled to a source of fluid; a pilot poppet configured to be subjected to a first fluid force of fluid received at the first port and configured to be subjected to a second fluid force of the input pilot fluid signal; a solenoid actuator sleeve that is axially movable between an unactuated state and an actuated state; and at least one setting spring configured to apply a biasing force on the pilot poppet.

Abstract: An example valve includes: a first port configured to be fluidly coupled to an actuator; a second port configured to be fluidly coupled to a reservoir; a third port configured to provide an output pilot fluid signal and receive an input pilot fluid signal; a fourth port configured to be fluidly coupled to a source of fluid; a pilot poppet configured to be subjected to a first fluid force of fluid received at the first port; a pilot piston interfacing with the pilot poppet and configured to be subjected to a second fluid force of the input pilot fluid signal; a solenoid actuator sleeve that is axially movable between an unactuated state and an actuated state; and at least one setting spring configured to apply a biasing force on the pilot piston and the pilot poppet.

Abstract: An apparatus for pumping a fluid from a fluid inlet to a fluid outlet is disclosed. The apparatus comprises: a spool axially movable within a cavity, wherein a first chamber is located at a first axial end of the cavity and a second chamber is located at a second axial end of the cavity, wherein the volume of the first chamber and the second chamber varies depending upon the axial position of the spool within the cavity; a valve movable between a first position and a second position, wherein in the first position the valve is configured to convey fluid from the fluid inlet to the first chamber and from the second chamber to the fluid outlet, and in the second position the valve is configured to convey fluid from the fluid inlet to the second chamber and from the first chamber to the fluid outlet.

Abstract: A flow control valve apparatus includes: a housing including two pump ports, two tank ports, a first supply/discharge port, a second supply/discharge port, and a spool hole; a first spool configured to switch a connection status among one of the pump ports, one of the tank ports, and the first supply/discharge port depending on a position of the first spool; a first actuator configured to move the first spool to each of a first supply position and a first discharge position; a second spool configured to switch a connection status among the other pump port, the other tank port, and the second supply/discharge port depending on a position of the second spool; and a second actuator configured to move the second spool to each of a second supply position and a second discharge position. The first spool and second spool are inserted in the spool hole so as to reciprocate.

Abstract: A hydraulic system for a working machine includes a hydraulic actuator having a first fluid chamber and a second fluid chamber, an accumulator, an outputting fluid tube to output an operation fluid, and a switching valve to be switched between a first position and a second position. The first position allows the first fluid chamber and the second fluid chamber to be communicated with the outputting fluid tube and thereby allowing a floating operation. The second position allows the first fluid chamber and the accumulator to be communicated with each other, allows the second fluid chamber and the outputting fluid tube to be communicated with each other, and thereby allows an anti-vibration operation.

Abstract: A servo valve comprising first and second nozzles and first and second piezoelectric actuators arranged to control fluid flow through the first and second nozzles respectively. A first fluid flow path is defined between the first nozzle and the first piezoelectric actuator and a second fluid flow path is defined between the second nozzle and the second piezoelectric actuator. The first and second piezoelectric actuators are arranged such that applying a voltage to the first and second piezoelectric actuators causes a change in dimension thereof, which acts to open or restrict said first and second fluid flow paths respectively.

Abstract: An example valve includes: a main piston 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 main piston 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: An example valve includes: (i) a pilot seat member comprising a first channel and a second channel, a pilot seat, and a pilot sleeve portion comprising a pilot chamber and a cross-hole; (ii) a pilot check member disposed in the pilot chamber and subjected to a biasing force of a setting spring, wherein the pilot check member is configured to be subjected to fluid force of fluid in the second channel; and (iii) a solenoid actuator sleeve slidably accommodated about the pilot sleeve portion, wherein the solenoid actuator sleeve comprises a cross-hole and an annular groove, wherein the cross-hole of the solenoid actuator sleeve is fluidly coupled to a second port of the valve, and the annular groove is configured to selectively fluidly couple the first channel to the second channel based on a position of the solenoid actuator sleeve.

Abstract: A servovalve includes a fluid transfer valve assembly comprising a supply port and a control port; a moveable valve spool arranged to regulate flow of fluid from the supply port to the control port in response to a control signal; and a drive assembly configured to axially move the valve spool relative to the fluid transfer assembly in response to the control signal to regulate the fluid flow. The drive assembly comprises a steerable jet pipe moveable by an amount determined by the control signal to cause corresponding movement of the valve spool and the jet pipe terminates at one end in a nozzle and at the other end being in fluid flow engagement with a fluid supply pipe. Movement of the valve spool is caused by fluid flowing from the nozzle to engage with the valve spool.

Abstract: The emergency shutoff device is provided with a casing (21) in which inflow ports (22) through which control oil flows into a space (A1) provided therein and a plurality of outflow ports (23) through which the control oil flows outside of the space (A1) are formed; and a switching unit (24) configured to slide along an inner circumferential surface of the casing (21) in which the space (A1) is formed, to change its position relative to the plurality of outflow ports (23), and thus to switch a circulation state of the control oil in the space (A1). The switching unit (24) switches the circulation state between the first circulation state in which the control oil is circulated from a first inflow port (221) to a first outflow port (231) and the third circulation state in which an open and closed state of a test outflow port (236) is switched while the control oil is being circulated from the first inflow port (221) to the first outflow port (231).

Abstract: A six-way directional valve (100) is provided, including: a valve body (1), defining a valve cavity (4) therein, and provided with a first connecting pipe to a sixth connecting pipe (11-16); a valve spool (2), movably disposed in the valve cavity (4), two valve chambers (3) being defined between two moving ends of the valve spool (2) and an inner circumferential wall of the valve cavity (4), so that the valve spool (2) being allowed to be driven to move by a pressure difference between the two valve chambers (3), a first chamber (21) and a second chamber (22) being defined between the valve spool (2) and a same side wall of the valve cavity (4), a third chamber (23) being defined between the valve spool (2) and the inner circumferential wall of the valve cavity (4); and a pilot valve assembly (5).

Abstract: The present invention provides a vacuum processing apparatus that includes gas supply means having a hard interlock of a pair of gas valves. The present invention provides a vacuum processing apparatus including: a gas supply unit that supplies gas, for performing vacuum processing using normally closed type air-driven valves, to a processing chamber where the vacuum processing is performed, the gas supply unit having an interlock function in which, when a first valve of a pair of the air-driven valves is opened, a second valve of the pair is closed, the gas supply unit including an air circuit that controls air for driving the air-driven valves, the air circuit being configured using an electromagnetic valve having a solenoid coil corresponding to each of the pair of the air-driven valves.

Abstract: A valve includes a modulating chamber for sending and receiving fluid through a first chamber port, a supply chamber, and a damping chamber for sending and receiving a second fluid through a damping chamber port. The valve also includes a passageway between the damping chamber and the supply chamber, and a piston assembly movable within the valve, wherein the piston assembly is configured to open and close a flow control device. The piston assembly includes a rod, a modulating piston attached to the rod movable within the modulating chamber, a supply piston attached to the rod movable within the supply chamber, and a damping piston attached to the rod movable within the passageway and the supply chamber. The piston assembly also includes a damping piston bypass that provides a restricted flow passage between the supply chamber and the damping chamber when the damping piston is located in the passageway.

Abstract: Disclosed is an actuator for axial displacement of an object, including an actuator piston disc displaceable in a cylinder volume, an inlet channel, a first inlet valve body arranged in the inlet channel, a second inlet valve body operatively connected to the actuator piston disc and arranged in the inlet channel, an outlet channel and an outlet valve body arranged therein. The actuator includes an electrically controlled pilot valve communicating a first control pressure to the first inlet valve body via a first control pressure channel and communicating a second control pressure to the outlet valve body via a second control pressure channel. The pilot valve places itself in either a resting state or an active state.

Abstract: A method of setting a vehicle in motion over a driving surface and/or maintaining motion of said vehicle over the driving surface implemented by a control system, said method comprising initiating motion control, initiating motion control comprising: commanding by the control system application of brake torque and drive torque to one or more wheels such that the vehicle is held stationary; subsequently initiating motion from rest while brake torque continues to be applied to the one or more wheels. The strategy may also be implemented to maintain vehicle progress on low friction surfaces. The vehicle driver may be commanded to vary a control input, such as accelerator pedal position, in order to facilitate the maintaining of progress.

Abstract: An apparatus has a pilot-operated spool valve connecting first and second work passages selectively to a supply conduit and a tank conduit. A first check valve normally allows fluid flow only in one direction from the first work passage to a first workport and when pilot-operated allows bidirectional fluid flow. A second check valve normally allows fluid flow only from the second work passage to a second workport and when pilot-operated allows bidirectional fluid flow. A first pilot valve selectively applies pressure to one end of the spool and to pilot operate the first check valve. A second pilot valve selectively applies pressure to another end of the spool and to pilot operate the second check valve. When fluid drains from a workport to the tank conduit, the associated check valve operates to maintain a predefined pressure in the first or second work passage through which that fluid flows.

Abstract: A solenoid fluid control valve is disclosed for controlling a variable displacement pump. The solenoid fluid control valve comprises a fixed solenoid component, a movable armature component, a fixed nozzle body, a movable spool within the fixed nozzle body, and a valve member. The valve member regulates fluid pressure in a first and second feedback chamber. Fluid in the second feedback chamber establishes a second feedback pressure that acts on the movable spool with a motive feedback force in a first axial direction. The movable spool moves in the first axial direction in response to the motive feedback force.

Abstract: A pilot stage for a jet type servo-valve, the pilot stage including an ejector for ejecting a jet of fluid and that is movable facing a deflector suitable for generating a pressure difference that can be used for moving a spool of the servo-valve. The ejector extends radially projecting from a column to which the ejector is secured and is in fluid-flow communication with a central bore of the column through which the ejector is fed with fluid, the column having a first end that is embedded in the servo-valve and through which the fluid is introduced into the column, and the column has a second end that is subjected to drive from a torque motor for selectively twisting the column in one direction or the other about a rest position.

Abstract: A hydraulic pilot control arrangement for a spool valve is provided, wherein the spool of the spool valve is biased towards a central position. The arrangement includes a first and a second pilot hydraulic line connected to opposite sides of the spool of the spool valve and a pilot pressure regulating arrangement is provided for selectively establishing or removing a pilot pressure in each of the first and second lines. The arrangement includes a damping device including a chamber divided into a first and a second pressure compartment by a sliding piston, the first and second pressure compartments being connected respectively to the first and second pilot hydraulic lines, and the piston is biased towards a rest position in the chamber.

Abstract: The present invention relates to a two-stage electrohydraulic servo valve with a first stage, which operates as pilot stage and includes a movable nozzle tube, and a second stage which operates as power stage, wherein the nozzle tube of the pilot stage is guided by means of a torsion element and the oil supply of the movable nozzle tube is integrated in the torsion element.

Abstract: A pilot valve configured to provide a control pressure within a dynamic fluid system, the pilot valve comprising: (a) a valve body having a supply port, a return port, and a control pressure port, the pressure control port in fluid communication with a subsequent valving component; (b) an axial bore formed in the valve body and in fluid communication with each of the supply, return, and control pressure ports; (c) a valve spool slidably supported within the axial bore of the valve body, the valve spool configured to control fluid flow through the supply, return, and control pressure ports, and to vary the rate of change of area of at least one of the supply and return pressure ports upon being displaced, thereby providing a variable resistance to fluid flowing therethrough and reducing the quiescent power of the pilot valve; and (d) means for displacing, in a selective manner, the valve spool within the axial bore about the supply, return, and control pressure ports to apportion fluid therethrough to provide

Abstract: This disclosure describes embodiments of a system and device to prevent damage that can occur during an over-speed condition in a turbo-machine. The embodiment includes a fluid circuit with a header, which couples to the turbo-machine, and a hydraulic circuit through which fluid can evacuate the header to a drain. The hydraulic circuit includes a trip header manifold with a pilot element in flow connection with a drain valve element that has an actuator to regulate the flow of fluid from the header. In one example, the pilot element uses solenoid valves to change the pressure of a fluid in the drain valve element and, in particular, maintains the actuator in a first position to prevent fluid to evacuate during normal operating conditions at the turbo-machine. When the over-speed condition occurs the actuator moves to a second position to place the header in flow connection with the drain.

Abstract: An actuator system (14) comprising a valve assembly (40) having an inner spool (50), an outer spool (60), and a sleeve (70). An assembly (80) directly drives the inner spool (50) to move it relative to the outer spool (60), and thereby hydromechanically causes the outer spool (60) to move relative to the sleeve (70). A control assembly (90) provides current input to the drive assembly (80), which converts current input into mechanical motion. The control assembly (90) senses the position of the inner spool (50) and regulates current in accordance with the sensed position.

Abstract: A hydraulic control system for controlling a variable fluid volume flow to a consumer (6, 60, 94, 126, 146, 162), for example a flow of cooling oil to a wet-operating clutch, with a hydraulically pilot-controlled control valve connected to a fluid supply. The first control valve (2, 56, 90, 122, 142) is designed such that, in the absence of any pilot control pressure (pVST), the valve delivers a specified initial volume flow (Q1) and, as the variable pilot control pressure (pVST) increases, the valve delivers a continuously increasing volume flow (QK). At least one second, independent, also hydraulically pilot-controlled valve (170) is designed such that this valve is activated in a specified range (55, 88, 120, 132, 140, 152) of the variable pilot control pressure (pVST).

Abstract: A print head includes a fluid cavity and nozzle in fluid communication with the fluid cavity. A stopper is positioned adjacent the nozzle and adapted to control flow of fluid through the nozzle. An arm supports the stopper and is configured to pivotally move the stopper with respect to the nozzle. An electromagnet is positioned adjacent the arm and configured to move the arm toward the electromagnet to open the nozzle.

Abstract: A valve assembly includes a valve body having a valve bore. A valve member is slidably disposed within the valve bore between first and second stop positions. First and second valve elements of the valve member have first and second sealing surfaces equally angled with respect to a valve member longitudinal axis. Each of the first and second sealing surfaces is oriented parallel with conical shaped first and second seat surfaces. Both first and second seat surfaces are equally angled with respect to the longitudinal axis and have an adjustable spacing such that the first sealing surface contacts the first seat surface and the second sealing surface contacts the second seat surface simultaneously in the first stop position.

Abstract: The invention relates to a pressure-regulator servo-valve comprising a body having a utilization port, a pressure feed port, and a return port, a distributor spool movably mounted in the body to put the utilization port into communication either with the feed port or with the return port, the spool co-operating with the body to define at least one pilot chamber connected to a nozzle that is arranged to open out into a cavity connected to the return port, a vane extending in the cavity facing the nozzle and being mounted to be moved in controlled manner. According to the invention, the pilot chamber is connected to the utilization port.

Abstract: A hydraulic servo drive device for driving a slide mechanism of a variable geometry turbocharger includes a servo piston connected to a driveshaft of the slide mechanism and a pilot spool that is accommodated in a center hole of the servo piton and slides by pilot pressure. A first hydraulic chamber and a second hydraulic chamber to and from which pressure oil flows are provided in a housing. The servo piston separately includes a pressure port for introducing pressure oil from an outside, a first piston port for intercommunicating the center hole and the first hydraulic chamber, a second piston port for intercommunicating the center hole and the second hydraulic chamber, and a return port for exiting pressure oil.

Abstract: The actuator (50) comprises a slide (52) carrying at least two stages (54, 56) and being capable of sliding in a cylinder and two control chambers (62, 64) connected to respective use holes (U1, U2) of an electrically controlled servo-valve hydraulic distributor (20). The control chambers (62, 64) are each situated on one side of a respective stage and an intermediate chamber connected to high or low pressure is situated between the other sides of the stages. In the event of electrical control failure, the distributor (20) slide is taken to a safety position in which the control chambers (62, 64) of the actuator (50) are at the same low or high pressure opposed to that applying in the intermediate chamber (66) so that each stage of the actuator slide is then subjected to high pressure on one side and to low pressure on the other side.

Abstract: A spool for a servovalve. The spool includes a first end land and a second end land. The spool includes an intermediate land having a first side and a second side opposite the first side. The intermediate land is positioned between the first end land and the second end land in a spaced-apart, axially aligned relationship such that a first annular space is defined between the first end land and the first side of the intermediate land and a second annular space is defined between the second end land and the second side of the intermediate land. The intermediate land further includes at least one fluid passageway formed in and extending through the intermediate land from the first side to the second side to establish fluid communication between the first annular space and the second annular space to provide a fluid pressure feedback between the first and second annular spaces.

Abstract: The invention relates to a pneumatic unit for activating a plurality of discharge valves of a turbomachine, the pneumatic unit having activation outlets corresponding to the number of discharge valves forming said plurality of discharge valves, and a single control input receiving a single control signal from an electronic control unit, the control signal serving to act on a control winding of a manifold means having outlets that form said activation outlets.

Abstract: A solenoid actuated valve assembly includes a valve body having a slidable main valve member and a pilot valve body mechanically connected to the valve body including a slidable pilot valve member. A first solenoid operated valve connected to the pilot valve body when energized directs pressurized fluid to move the pilot valve member between pilot valve open and closed positions. A second solenoid operated valve connected to the valve body when simultaneously energized with the first valve directs the fluid to move the main valve member between valve closed and open positions. A third solenoid operated valve connected to the pilot valve body when energized and when both the first and second solenoid operated valves are de-energized directs the fluid to move the pilot valve to the pilot valve open position and the main valve member to the valve closed position.

Abstract: A valve for controlling fluid flow in a fluid system is disclosed. The valve includes a housing, a servo spool, and a piston. The servo spool defines a spiral groove and a spiral land. The piston defines an orifice configured to provide flow communication to a supply of pressurized fluid and an orifice configured to provide flow communication to a portion of the fluid system exterior to the valve. The valve further includes a main spool operably coupled to the piston. The main spool is configured to control flow of fluid in the fluid system. The spiral groove and spiral land are configured such that angular displacement of the servo spool results in a force imbalance on the piston, thereby moving the piston and the main spool in one of a first direction and a second direction.

Abstract: A torque motor (10) includes a support (20), a jet tube passage (42) in the support having a first end opening (43) and a second end opening (45), a jet tube (30) extending into the jet tube passage (42) through the first end opening (43) for directing a flow of fluid into a chamber (40) in fluid communication with the jet tube passage second end opening (45), and a flexible, convoluted, seal (46) hermetically connected to the jet tube passage (42) and the jet tube (30) for sealing the jet tube passage first end (43) while permitting at least a portion of the jet tube (30) to move relative to the jet tube passage (42).

Abstract: A hydraulically actuated pneumatic regulator is configured to receive hydraulic fluid from a hydraulic source and pressurized air from a pressurized air source to control air pressure downstream of the pneumatic regulator. The hydraulically actuated pneumatic regulator includes a valve element, an actuator, and pneumatic-to-hydraulic servo. The actuator is adapted to receive one or more pneumatic control signals supplied by the pneumatic-to-hydraulic servo, and is operable, in response to the pneumatic control signals, to control the air pressure downstream of the pneumatic regulator.

Abstract: A hydraulic actuator is configured to provide redundant boost control to an aircraft within approximately the same space required by a single hydraulic cylinder. The hydraulic actuator includes a housing and a piston assembly disposed within the housing. The piston assembly includes a ram, a first piston secured to the ram, and second and third pistons disposed on the ram such that the second and third pistons are translatable relative to the longitudinal axis of the ram. The pistons form two hydraulically separate actuator cylinders within the space required by a single cylinder which results in a reduction in the weight and size of the hydraulic actuator.

Abstract: An electro-hydraulic servovalve (EHSV) (10) that includes a nozzle (16), a motor (12) operably connected to the nozzle (16) for controlling the position of the nozzle (16) based on current provided to the motor (12), a spool (18) having first and second ends (22,26) slidably mounted in a sleeve (34) having first and second ends (31,33) and a first land (21) near the first end (22), a first passage (40) extending from near the nozzle (16) to the first end (31) of the sleeve (34), a second passage (42) extending from near the nozzle (16) to the second end (33) of the sleeve (34), the spool (18) shifting to a first fail-safe position when the current is below a first predetermined level and latching in a second fail-safe position different than the first fail-safe position when the current exceeds a second predetermined level greater than the first predetermined level.

Abstract: A valve accommodating hole (11), and each of a supply port (20), discharge ports (21 and 22), and output ports (23 and 24) connected to the valve accommodating hole are formed in a valve casing (15), and a valve shaft (12) is attached to the valve accommodating hole (11) so as to be reciprocable in the axial direction. Circular rubber elastic valve elements (51 and 52) are attached to the valve shaft (12) and used for switching between a communication state where either one of the elastic valve elements is spaced away from an inner peripheral sealing surface of the valve accommodating hole (11) such that the supply port (20) and the respective output port (23 or 24) communicate with each other and a shut-off state where either one of the elastic valve elements comes in contact with the inner peripheral sealing surface such that the communication is shut off.

Abstract: A torque motor (10) includes a support (20), a jet tube passage (42) in the support having a first end opening (43) and a second end opening (45), a jet tube (30) extending into the jet tube passage (42) through the first end opening (43) for directing a flow of fluid into a chamber (40) in fluid communication with the jet tube passage second end opening (45), and a flexible, convoluted, seal (46) hermetically connected to the jet tube passage (42) and the jet tube (30) for sealing the jet tube passage first end (43) while permitting at least a portion of the jet tube (30) to move relative to the jet tube passage (42).

Abstract: A jet reflector servovalve includes a flexure tube and reflector that opposes a fluid nozzle and fluid receivers of the servovalve. During operation, the nozzle directs a pressurized fluid jet toward the reflector. The pressurized fluid travels within a second stage of the servovalve, toward the reflector. The reflector directs or reflects the fluid back toward the fluid receivers to adjust a position of a spool of the servovalve. The configuration of the reflector, the nozzle, and the receivers allows transmission of the pressurized fluid within the second stage of the servovalve and minimizes the necessity for multiple o-rings between the second stage of the servovalve and a torque motor of the servovalve, thereby reducing manufacturing costs of the servovalve.

Abstract: A servovalve has a sleeve having both a first metering aperture and a second metering aperture in fluid communication with a single port cavity defined by the servovalve. A spool oriented within the sleeve has a first land and a second land and defines a channel oriented between the first land and the second land. When the spool orients in a null position within the sleeve, the first land overlaps the first metering aperture and the second land overlaps the second metering aperture. As a low viscosity fluid within the servovalve assembly leaks across the first land and enters the channel, the overlap of the first and second lands with the first and second metering apertures minimizes flow of the fluid from the channel into the port cavity associated with the metering apertures. The configuration of the sleeve assembly, therefore, maintains a relatively large pressure gain within the servovalve assembly.

Abstract: A pilot control valve for controlling a reciprocating pump has a valve member shiftable within a valve body between a first or “downstroke” position and a second or “upstroke” position. In its first and second positions, the valve member positions slide valves to allow communication of control fluid to move the piston to a second and first position, respectively. When the piston reaches its second position a poppet disposed in a rod attached to the piston allows control fluid acting on the valve member to depressurize. Pressurized control fluid then acts on the valve member to move to its second position. When the piston returns to its first position, the poppet allows pressurized control fluid acting on the upper surface of the piston to act on the valve member to move the valve member back to its first position and repeat the process.

Abstract: The servovalve comprises an electric motor and a distributor valve integrating a hydraulic slide under the control of said electric motor and further comprising two load channels pierced in a central rod on which blocks are mounted for co-operating with communication orifices of the distributor valve and co-operating with one another and with the ends of the hydraulic slide to define annular chambers including two load chambers connected to the receiver member to be controlled. The two load channels put each of the load chambers into communication respectively with an immediately adjacent annular chamber so as to ensure that the same pressure exists on both sides of the blocks separating said two chambers.

Abstract: A proportional hydraulic valve has a primary control spool with a force feedback actuator attached to one end, wherein the control spool meters flow of fluid to a work port. The force feedback actuator includes a piston coupled to the control spool and defining a first control chamber and a second control chamber on opposite sides of the piston. The surface of the piston has a depression with a first tapered section and a second tapered section. The force feedback actuator includes first electrohydraulic valve with a valve element that meters pressurized fluid selectively to the first and second control chambers to move the piston in opposite directions and produce motion of the control spool. A solenoid exerts a first force that on the valve element. A pilot pin engages the piston and the valve element, whereby, movement of the pilot pin on the first and second tapered sections of the piston applies a second force to the valve element.