Abstract: A self-operated regulating valve has a spool (13) moving axially in an internal space of a cylindrical valve body (11). One pressure P1 acts on one end surface of the spool (13), and other pressure P2 acts on the other surface of the spool (13). A through-hole (13a) is provided in the spool (13). When a difference between the one pressure P1 and the other pressure P2 exceeds a set value, the through-hole (13a) and pipe lines (12) connected to the valve body (11) communicate to bring the self-operated regulating valve into an open state.

Abstract: The present invention is directed to a compact and modular gate valve comprising an elongated body which comprises first and second ends, a hole which extends longitudinally between the first and second ends, a first opening which communicates with the hole proximate the first end, a second opening which communicates with the hole proximate the second end, and a bore which extends transversely through the body and intersects the hole; a first seat which is mounted in a first intersection of the bore with the hole and a second seat which is mounted in a second intersection of the bore with the hole, the first and second seats each including a passageway that aligns with the bore; a valve stem which is slidably positioned in the hole and which includes first and second piston portions that are separated by a gate portion, the stem being movable between an open position in which a hole in the gate portion is aligned with the passageways and a closed position in which the hole is offset from the passageways; and

Abstract: A two-stage valve for controlling the flow of gas from a pressurized gas supply with an upper main body including a cavity; a lower main body with at least one flow exhaust passage forming a primary flow path through the two-stage valve; a pre-stressed diaphragm sandwiched between the upper and lower main bodies, and pressure control capability for controlling the pressure in the cavity. A secondary flow path exists from the pressurized gas supply through the lower main body, through the upper main body, and terminating in the cavity in the upper main body. A first valve is installed in the secondary flow path to open and close the flow of gas from the pressurized gas supply to the cavity. A second valve installed in an exhaust passage in the upper main body allows the pressure in the cavity to exhaust to the environment. When the second valve is closed, the pressure in the cavity in the upper main body can be increased to lower the pre-stressed diaphragm.

Abstract: A flow control valve is made from a one-piece housing which defines a substantially linear flow path. The housing comprises deformable portions coupled to a valve seat and a poppet to allow relative motion therebetween for opening and closing the valve. The deformable portion may comprise a thinned section of a side wall of the housing.

Abstract: A pressurized-fluid-operated actuator has two piston surfaces for providing increased output force. The actuator includes a hollow piston that is divided into two inner chambers by a stationary inner dividing wall that is rigidly connected with a cylinder end wall. The piston has an outer diameter that is smaller than the inner diameter of the cylinder, and the piston carries three axially spaced sealing rings that define two axially-spaced annular chambers between the piston and the cylinder. Each of the annular chambers is in fluid communication with a respective port provided in the cylinder wall. Introduction of pressurized fluid into one port causes the fluid pressure to act on a single piston surface to retract the piston and rod, and introduction of pressurized fluid into the other port causes the fluid pressure to act on two axially-spaced piston surfaces to provide an increased output force without increasing the diameter of the cylinder and piston and without increasing the pressure of the fluid.

Abstract: A high pressure fuel system includes tapped high pressure flows (22,24) with restrictors (44,46) to provide low pressure flows with which, via a valve (50) to enable either a low pressure flow to bias a main, high pressure fuel cut off valve (16) to close at a steady given rate, or a high pressure flow across a further valve (30), to close the valve (16) at a faster rate.

Abstract: A valve for controlling flow of cryogenic liquid propellant in a rocket engine comprises a double acting piston-cylinder unit having a first position in which the valve is closed and a second position in which the valve is open, a locking device being engageable with the double acting piston-cylinder unit to lock the unit in the closed position of the valve is closed while being free from the valve in its open position. The locking device has a control piston connected to a locking member to selectively lock and unlock the piston-cylinder unit against the force of a spring acting to lock the piston-cylinder unit, and a control chamber capable of receiving a pressure medium to move the piston and to unlock the piston-cylinder unit. A two-way control valve controls flow of the pressure to the control chamber and to valve closing and opening operation chambers of the piston-cylinder unit.

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 fluid-actuated valve control actuator, comprising a body in which two mutually opposite pistons are accommodated, each piston being provided with a rack and being adapted to engage a shaft for actuating a stem of a valve, wherein an end of the actuation shaft that lies opposite to an end adapted to engage the stem of valve is octagonal for engagement with an indicator for indicating the opening/closure of the valve.

Abstract: A fast-acting valve includes a valve body and a spool slidably mounted within the valve body between first and second limit positions. Both the spool and the valve body have a flow passage which come into alignment with the valve spool at a position intermediate the first and second limit positions and spaced therefrom by a given distance. That given distance allows the spool member to accelerate in travel from the first and second limit positions to the valve open position so that the opening of the valve (and closing) occurs quite quickly. Reciprocating movement of the valve spool relative to the valve body can be provided by springs mounted in opposing ends of the valve body bore in cooperation with solenoids mounted on opposing sides of the valve body. The fast-acting valve may be modified into the form of poppet valve or a cartridge valve.

Abstract: A proportional control valve has inlet and outlet solenoids controlling the pressurization and evacuation of a chamber between two pistons in a control valve of the rack and pinion opposed-piston type. The control valve can be maintained in fully open, fully closed, or intermediate positions by selectively energizing and de-energizing the solenoids. The solenoids can be of the normally open or normally closed solenoid poppet types depending on whether the control valve is to open, close or maintain its current state in the event of a power failure.

Abstract: A gas motor actuator is provided for opening or closing an actuated valve, such as a pipeline valve, using power gas, which is a gas under pressure. The gas motor actuator includes a gas turbine motor, a high-volume shuttle valve coupled to the gas turbine motor, and a pair of control-limit valve assemblies for delivering power gas to the shuttle valve. One control-limit valve assembly is for opening the actuated valve, and the other is for closing the actuated valve. The gas motor actuator can receive a signal to open or close the actuated valve, which allows pilot gas to open a control valve portion of one of the control-limit valve assemblies, allowing power gas to pass through the control portion to the shuttle valve. The power gas passes through the high-volume shuttle valve, through the gas turbine motor, and back to the shuttle valve for discharge as an exhaust. The power gas rotates a shaft in the gas turbine motor, which, through gears, opens or closes the actuated valve.

Abstract: An actuator valve for an air driven reciprocating device including a housing with a cylinder having a sliding valve piston located therein. The valve piston includes circumferential grooves near the ends of the piston to receive floating piston rings. The piston rings exhibit a positive clearance with the cylinder which allows axial airflow thereby. The housing provides an inlet extending into one side of the cylinder and passageways diametrically opposed extending from the cylinder. Controlled passageways at the ends of the cylinder alternately vent. Between venting, the cylinder accumulates pressure at both ends of the piston. With venting, the pressurized air at the unvented end of the piston shifts the piston toward the vented end. Bleed passageways extend from adjacent the inlet to the ends of the piston to assist shifting once the piston proceeds over center.

Abstract: A probe structure for inserting into and operating upon an object within a pipeline, especially a high pressure pipeline carrying liquid or gas, is characterized by two coaxial cylinders that can be either pneumatically or hydraulically actuated. A primary cylinder is adapted to be mounted onto a pipeline tee and/or valve, and includes a movable primary piston to which is fixedly attached a primary lower hollow shaft that moves with the primary piston and preferably a primary upper hollow shaft that also moves with the primary piston. The primary lower hollow shaft is adapted to selectively extend into the pipeline while the primary upper hollow shaft extends above the primary cylinder and is fixed to a secondary cylinder, such that the secondary cylinder moves with the primary piston. The secondary piston includes a secondary piston that moves independently of the first and second cylinders.

Abstract: A rotary valve actuator with movable actuator linkage maintained in a constant "pull-pull" tension, includes a sliding canister, rotatable lever, and a return spring substantially aligned in-line with each other. The linear motion of the canister in response to an expanding and contracting pressurized bladder is converted through chain linkage into rotary lever motion. The return spring is connected through respective chain linkage to the lever so the pulling tension of the spring/lever linkage rotates the lever and maintains tension on both chain linkages. Adjustable travel stops are provided. In an alternate embodiment the return spring chain linkage is configured at right angles to the linear movement of the canister. A double acting rotary valve actuator with pressurized bladders on opposite sides of a rotatable lever. One bladder is oval shaped.

Abstract: A valve driving apparatus for actuating a shutoff valve or a dump valve provided in a pipeline for conveying a gaseous or liquid substance. The valve driving apparatus is constructed by disposing a gas/oil type booster and a hydraulic pump between a gas pipe which is branched from a primary side of the gas pipeline and a cylinder of an actuator and connecting them with a pipe thereby driving the actuator to close the shutoff valve or open the dump valve with the hydraulic pressure raised by the booster with the primary side pressure of the gas pipeline as the power source and meanwhile resetting the booster with a hydraulic pump disposed between the booster and the actuator thereby enabling the gas in the booster to return to the gas pipeline via the gas pipe.

Abstract: A selector valve system has been invented for selectively operating a motor for selectively actuating a main line valve on a pipeline, gas flowing through the pipeline, the system having, in one aspect, a body, a first poppet valve mounted on a first channel through the body, a second poppet valve mounted in a second channel through the body, a first limit valve for controlling flow of a portion of the gas to the first poppet valve so that upon such gas flowing to the first poppet valve the first poppet valve is actuated to permit gas flow to the motor to open the main line valve, and a second limit valve for controlling flow of a portion of the gas to the second poppet valve so that upon such gas flowing to the second poppet valve the second poppet valve is actuated to permit gas flow to the motor to close the main line valve. In one aspect the poppet valves are O-ring-saving cartridge valves.

Abstract: A multiple step valve opening control system, particularly for an EGR control valve unit, having a plurality of valve lifts. The system comprises a valve member for opening a fluid passage in multiple steps, a first piston slidably housed in a housing, a second cylinder substantially coaxial with the first piston, a second piston fitted in the second cylinder and coupled to the valve member, and a first piston stroke regulating member which is moved selectively to a first position for regulating an allowable displacement of the first piston to a first predetermined extent (l.sub.1) or to a second position for regulating the allowable displacement of the first piston to the first predetermined first extent (l.sub.1) plus a third predetermined extent (l.sub.3). By changing the position of the first piston displacement regulating member, the valve member is opened by various valve lifts.

Abstract: A pressurized fluid-operated, three-position shift actuator piston assembly (12) and associated control system (10) are provided. The system requires only a single controlled source of pressurized fluid (A) to provide movement to and retention in a selected one of three axially displaced positions (D, N, OD).

Abstract: A safety relief valve (10) having a main valve member (22) in a normally closed seated position has a diaphragm actuator (24) with a dome chamber (34) adjacent the outer side of the diaphragm (26). A pilot valve (28) is in fluid communication with the dome chamber (34) through a dome line (35) for controlling the opening and closing of the main valve member (22). An underdome chamber (40) on the inner side of the diaphragm (26) has an underdome line 44 extending to an underdome control valve (42) for controlling fluid communication to underdome chamber (40) from the inlet (18). An inlet line (48) extends from the inlet (18) to the underdome control valve (42). When the set pressure of the pilot valve (28) is reached, inlet fluid pressure on the inner side of the diaphragm (26) increases while dome pressure in the dome chamber (34) decreases.

Abstract: A pneumatic assist valve receives constant air pressure from supply air to provide the pneumatic assist to shift the pilot, eliminating false signals acting on the trip rod and the design also assures the pilot has completely shifted before diaphragm reversal occurs.

Abstract: The invention relates to safety device for a cylinder valve automatic switching unit, wherein said valve is automatically closed when some abnormality such as down of an air pressure takes place. A first air-operated selector valve 8 is installed which causes air flowing out of a reservoir tank 10 to flow into a second supply line 3 when air pressure is reduced, whereby a cylinder valve automatic switching unit 1 in the opening situation is caused to make a closing motion for closing a cylinder valve in the opened situation. And, a second air-operated selector valve 9 is further installed which discharges air flowing out of a first supply line 2 to the atmosphere when the air pressure is reduced.

Abstract: A hydraulic actuator for an isolator, comprising a casing (1) having a flange (1a) to be mounted to the isolator to be driven, a lever arm assembly (2) connected at each end thereof to a respective one of a pair of identical double acting cylindrical rams (3), the other ends of the rams being respectively connected to opposite ends of the casing remote from the flange, wherein the identical rams are arranged to operate in opposite directions, the radial load exerted by one ram being equal in magnitude but opposite in direction to the radial load exerted by the other ram.

Abstract: An electrically-operated control valve includes a rotor rotatably mounted to a first position connecting a fluid inlet port to a fluid outlet port, or a second position disconnecting the fluid inlet port from the fluid outlet port; a battery-operated electrical rotary motor for rotating the rotor; and limit switches for deenergizing the electrical motor when the rotor arrives in either the first or second positions. The electrical motor is coupled to the rotor by a speed-reducing, torque-increasing transmission such that very little electrical power is required to operate the motor, thereby enabling the control valve to be used as a remotely-controlled pilot valve for controlling a water irrigation system.

Abstract: A valve assembly comprising a tubular member (2) having an axial bore (4) which is selectively opened and closed by a gate valve. The gate valve includes a sliding gate (5), a first actuating stem (9,27) engagable with one side of the gate and a second actuating stem on the opposite side of the gate and also engagable with the gate. The actuating stems can move the gate between open and closed positions, and an intermediate position in which the gate can be run into and withdrawn from a support with the tubular member.

Abstract: A fuel valve comprising main fuel valve connected to a burner staging valve such that fuel flow from the main fuel valve is divided between pilot and main domes in a dual annular combustor. The burner staging valve includes a movable spool located within a fixed sleeve such that the spool may be moved both laterally and rotated within predetermined limits. The movable spool and sleeve include pilot, main and inlet windows arranged such that the inlet windows receive fuel from the main fuel valve and the pilot and main windows split the fuel flow between the pilot and main domes of the combustor.

Abstract: The present invention refers to a control valve provided with a valve closure member (5) for closing and opening a valve opening. The valve closure member (5) has attached thereto a piston (11), which is arranged such that it is movable within a housing (13), said piston (11) being adapted to be acted upon by the force of a spring (spring 27) in one direction and by a fluid pressure in the opposite direction. A property characterizing the present invention is that the length of the path of movement of the piston (11) can be adjusted with the aid of a positioning means (29, 73). In accordance with a preferred embodiment, the positioning means (29) consists of a rod (31), which is adapted to be axially moved in the direction of movement of the piston (11).

Abstract: A recording disc filing device for storing optical recording discs such as compact discs. The filing device includes a recording disc filing sheet having a plurality of recording disc storing sections for receiving recording discs, respectively. The recording disc storing sections are arranged in a predetermined pattern. The filing device further includes a leaflet filing sheet having leaflet storing sections for receiving leaflets carrying information on recorded contents in the recording discs stored in the recording disc storing sections. The leaflet storing sections correspond in number to the recording disc storing sections. The recording disc filing sheet and the leaflet filing sheet are arranged so that the leaflet storing sections in the leaflet filing sheet are located at positions corresponding to the recording disc storing sections in the recording disc filing sheet.

Abstract: A variable valve assembly, engine valve control system, and method of operation wherein the valve is hydraulically controlled and includes a valve piston subjected to fluid pressure acting on surfaces at both ends of the valve piston. The cavity at one end of the valve piston is connected to a source of high pressure fluid while the cavity at the other end is connected to a source of high pressure fluid and a source of low pressure fluid, and disconnected from each through action of controlling means such as solenoid valves. The valve assembly includes a damper to limit the velocity of the valve during a portion of the travel of the piston, particularly as the valve head lands on the valve seat.

Abstract: A waste removal flushing system for storing and selectively outputting water for flushing animal waste from a waste collection surface of a hog house or other animal pen. The flushing system includes a tank with a plurality of water output openings. A flushing valve is slidably mounted at each water output orifice on a valve guide rod that extends from a bottom surface through the water output opening, and into the tank. The valves are slidably positionable on the guide rods between a closed position where water in the tank is prevented from passing through the water output openings and an open position where water in the tank passes through the water output openings. Each valve is sized to extend beyond the outer periphery of the output opening and is sized to seat with a seating surface surrounding the output opening such that a water-tight seal is formed when the valve is in the closed position. The valve is positioned between the open and closed positions by a dual-acting, pneumatic cylinder.

Abstract: A housing has a pilot bore with an electrically controlled pilot valve therein, an intermediate bore with an intermediate valve therein, and an engine bore with a main valve therein, each valve being reciprocable between first and second stable positions. When said pilot valve is switched to its first stable position, high pressure hydraulic fluid drives said intermediate valve to its first stable position and releases said engine valve from its second stable position, whereupon a double acting spring drives the engine valve toward its first stable position. High pressure hydraulic fluid completes this movement then holds the main valve in its first stable position against the force of the double acting spring. Switching the pilot valve to its second stable position effects movement of the other valves back to their second stable positions.

Abstract: A valve for controlling fluid flow is provided, which permits fluid flow through the valve upon a first exposure to incident light, and prevents fluid flow through the valve upon a second exposure to incident light. The valve includes inlet and outlet passageways that are adapted to divert a portion of the fluid away from a central passageway to shift a plunger between a first position and a second position. In the first position, the plunger permits fluid flow through the valve, and in the second position, the plunger prevents fluid flow through the valve.

Abstract: A self-cleaning valve for discharge of a pressurized dissolved air flotation aqueous treatment liquid from a high pressure reservoir to a low pressure body of liquid to be treated is provided. The valve includes a discharge head body adapted to be attached to a conduit supplied with pressurized treatment liquid which is provided with a central opening for discharge of a treatment liquid. The opening is controllable by means of a reciprocable cap positioned to reciprocate from a position whereon it restricts flow of liquid through the opening to a position wherein flow in unrestricted. The cap is attached to a reciprocable piston rod attached at its opposite end to a piston that is movable within an enclosed cylinder. The cylinder is provided with a port or opening on each side of said piston into which a source of pressurized air connectable to cause movement of the piston and thus opening and closing of the valve by selectively directing the flow of said pressurized air to either side of the piston.

Abstract: A fast-actuating on-off valve and pressure regulator particularly well-suited for use with high-pressure incompressible fluids. An actuator, manually-operated or powered, provides a linear push-pull force to a valve stem assembly mounted inside a valve cavity having a fluid inlet and one or more fluid outlets. The valve stem assembly includes a valve stem that has a shoulder at one end. The valve stem assembly includes a stem collar having a capped end with a central hole to engage the valve stem, a cylindrical cavity to house the stem shoulder, and a threaded portion engageable with a valve poppet or a poppet extension. Each valve poppet has a threaded end engageable with the stem collar and a sealing end to engage with a fluid outlet centrally positioned within a valve seat or a valve poppet.

Abstract: There is provided a closed loop system for measuring an amount of liquid under pressure in a container. The system comprises a container holding a liquid under pressure, a novel differential valve with check valves which are connected to the container and to a differential gauge, and a means for activating the valve.

Abstract: A hydraulic lock cylinder in which a cross bore is provided in an end structure of the cylinder housing which intersects the hydraulic fluid inlet passage to the central bore of the cylinder; a control piston is reciprocally mounted in the control bore; and pressurized fluid is admitted to the opposite ends of the control bore to shuttle the control piston within the control bore between a closed position in which the inlet passage is blocked and an open position in which the passage is open. The control piston includes a flat surface and a control port opening in the flat surface and an annular fitting screws into the inlet passage housing and includes a seal on its lower end for sealing coaction with the flat surface on the control piston to seal the inlet passsage.

Abstract: A stand-alone electropneumatic closed loop servo system, with a separate gas supply to an air actuated cylinder, provides pressure, position, or fluid flow control of a variable conductivity valve in a device by automatically varying the conductance of the device. The air cylinder defines a control chamber and a smaller volume response chamber separated by a piston operatively connected to the variable conductivity valve. The gas supply includes a constant pressure line, with a pressure regulator valve and a check valve, into the control chamber and a variable pressure line, with a variable pressure solenoid valve, into the response chamber. A feedback signal from the device to a controller is compared to a desired pressure set point. The controller signals the solenoid to vary its output pressure thereby causing the piston to move accordingly to actuate the variable conductance valve.

Abstract: A flow loading unloader valve wherein the operating force for moving the valve from the unloaded condition to the loaded condition is supplied by the flow through the valve itself. The valve, which may be interposed between a fluid supply and a high pressure load, comprises a valve body, having an inlet, a working outlet, a bypass outlet, and a valve operator, which may include a spool, that controls the direction of flow through the body. Movement of the valve operator to change the valve from the unloaded condition to the loaded condition is accomplished by applying the differential pressure created by the flow of fluid from the inlet to the bypass outlet to the piston ends. As the pressure increases as a result of increased flow resistance through the valve, the valve operator moves from an unloaded to a loaded position, terminating flow to the bypass port and resulting in high pressure flow to the working outlet.

Abstract: A self-cleaning valve for discharge of a pressurized dissolved air flotation aqueous treatment liquid from a high pressure reservoir to a low pressure body of liquid to be treated is provided. The valve includes a discharge head body adapted to be attached to a conduit supplied with pressurized treatment liquid which is provided with a central opening for discharge of a treatment liquid. The opening is controllable by means of a reciprocable cap positioned to reciprocate from a position whereon it restricts flow of liquid through the opening to a position wherein flow in unrestricted. The cap is attached to a reciprocable piston rod attached at its opposite end to a piston that is movable within an enclosed cylinder. The cylinder is provided with a port or opening on each side of said piston into which a source of pressurized air connectable to cause movement of the piston and thus opening and closing of the valve by selectively directing the flow of said pressurized air to either side of the piston.

Abstract: A fuel control valve construction having a flexible diaphragm defining two chambers that are disposed on opposite sides of the diaphragm that carries a main valve member that is urged in a direction to close a main valve seat by a spring, and a control unit interconnected to an inlet and an outlet and to the chambers and being adapted to interconnect the inlet to one of the two chambers and the outlet to the other of the two chambers to move the diaphragm to a first position that causes the main valve member to close the main valve seat whereby inlet pressure in the one chamber will generate an additional seating force on the main valve member to ensure a tight closure of the main valve seat and adapted to interconnect the inlet to the other of the two chambers and the outlet to the one of the two chambers to move the diaphragm to a second position that causes the main valve member to open the main valve seat.

Abstract: A fluid control valve 10 and an actuator 17 for a closure member 18 therefor are disclosed and claimed. The actuator 17 comprises a shaft 20 mounted to be stationary in valve body 11. A hollow member 19 is mounted on shaft 20 to reciprocate relative to the longitudinal axis of the shaft. A stationary partition mounted on shaft 20 divides member 19 into first and second fluid tight, variable volume chambers 26 and 27. By varying the pressures of fluids in chambers 26 and 27 the member 19 is caused to move between first and second positions on the shaft thereby to move the closure member 19 between open and closed positions.

Abstract: A valve arrangement for intermittent application of a liquid adhesive, in particular a thermoplastic high-polymer material, to a substrate comprises a valve body with a bore therein terminating in an outlet nozzle, a conduit for supplying the adhesive to the bore, a valve needle reciprocable in the bore for opening and closing the outlet nozzle and a step or differential piston connected to the valve needle. The lower surface of the differential piston faces the outlet nozzle and is smaller; it is subjected to a permanently applied gas pressure which brings the valve needle into the opened position. A controllable, usually constant gas pressure applicable via a solenoid valve acts on the upper larger surface of the differential piston; and upon subjection of the differential piston to the gas pressure, the gas pressure overcomes the force generated by the continuously applied, permanent gas pressure and brings the valve needle into the closed position.

Abstract: For controlling the internal volume of a rotary compressor (5), adjustable valve bodies (3) are used on the outlet side. External control means, often of an extremely complicated nature, have previously been used to control the internal volume in the rotary compressor. By allowing the different pressure levels of the rotary compressor (5) to directly influence a control section (1), the position of the valve body (3) can be controlled by an operating section (2). In the control section (1) an intermediate pressure (9) from the compressor is balanced against a pressure from the high-pressure side (19) of the compressor by a plunger (6) having different diameters. The position of the plunger (6) then determines the control of the internal volume by the position of the valve body (3) connected to the operating section (2).

Abstract: A hydraulically operating actuating device for a lift valve, in particular in an internal combustion engine, has a piston which is connected to the valve stem. The piston is positioned in a cylinder and separates two stroke spaces which are connectable, in each case via inlet and outlet openings which can be occluded by the piston, to a pump for the working fluid or a reservoir. In order to reduce the energy requirement of the actuating device, the two inlet openings, which in a central actuation range of the piston are open, are connected to one another directly by a line, and two springs which act in opposite directions and, in equilibrium, hold the piston in a central position relative to two end positions engage on the piston or valve stem.

Abstract: The length of time a bather can use a shower is controlled by a pair of timers and a solenoid operated valve. A first timer controls the length of time water flows through the shower by energizing and de-energizing solenoids. Another timer prevents the solenoids from being energized for a predetermined time period after the first timer has turned the water off. This prevents the shower from being turned on again until the time period has elasped.

Abstract: The double disk gate has a moving gate which includes two closure disks which define a space into which pressurized medium can be delivered. The closure disks are mounted to be moveable within the gate valve when the gate is in a closed position so as to be brought into sealing contact with the seating surfaces of the inlet and outlet ports of the valve. The pressure medium may be obtained from the medium passing through the valve.

Abstract: A dual-circuit brake system in which diagonally opposite wheels of an automotive vehicle are in communication with each brake circuit and, in the event of a traction slip control, the non-actuated wheel is hydraulically separated from the brake conduit. The valve is hydraulically driven, with the pressure difference between the pressure in the master brake cylinder (1) and the pressure in the pressure conduits (24, 25) being used as the switching pressure. By that measure, the valve is less susceptible to trouble and provides lower production costs.

Abstract: A rotary shear seal hydraulic valve which can be used in three- and four-way embodiments is formed by a housing and a body together defining therebetween a generally cylindrical stepped cavity in which a rotor is rotatably positioned. The housing contains at least two shear seal valve assemblies positioned to be aligned with ports in the rotor to establish communication between the shear seal means. The body contains at least one piston member including a rack portion engaging a profiled pinion portion of the rotor to effect the rotational drive of the rotor. The pistons can be driven in both directions by fluid means or in one direction by spring return means. The pistons can also be actuated by solenoid means and the positioning of the rotor can be strained by a lever providing a manual override. By selectively plugging the various ports, the four-way valve can be utilized in a three-way configuration, thereby providing a great degree of flexibility.

Abstract: A fluid-powered actuator having a body with first and second end walls, with a bulkhead positioned therebetween, which is adjustably rotatable to angularly position the bulkhead relative to the body for fluid-powered operation to establish the end limits of rotation of an output shaft. The actuator has first and second piston heads disposed in the body on opposite sides of the bulkhead to define four fluid-tight chambers. In the preferred embodiment, the bulkhead is selectively clamped between two sidewall portions. A sleeve extends between and fixedly connects the piston heads together. A plurality of guide rods are fixedly attached to and extend between the piston heads and through apertures in the bulkhead in one embodiment, and between the first piston head and the bulkhead and through apertures in the first piston head in another embodiment to transmit torque to the body and through the bulkhead.

Abstract: A valve comprises a connection plate attached to the housing, such plate having a sealing surface facing into such housing, a flat spool arranged to be able to be reciprocated in a direction parallel to such sealing surface so as to sealingly wipe said surface and to connect together and separate from each other ports opening into said surface, said ports being at the ends of ducts extending through said plate, and means for operating said spool by reciprocating same, said operating means taking the form of wall means defining operating spaces at the ends of the spool, means for passing an operating fluid into said spaces for changing the volume thereof so that when the volume of one space is increased the volume of the other is decreased, said wall means being at least in part secured to said housing, said operating means further defining two operating surfaces at the two ends of said spool, said operating surfaces and said wall means part secured to said housing being connected together by at least one flex