Abstract: A two-way valve comprises a body containing two cylinders, a pair of valve assemblies, each comprising a piston which slides in a respective cylinder, each piston having a spindle extending from one end, a metering valve member which slides on the spindle and normally engages a valve seat at an end of the relevant cylinder, a circlip or other abutment on the spindle which engages the valve member and moves it away from the seat upon movement of the piston in one direction by hydraulic pressure, and a restraining spring inhibiting that movement.

Abstract: A pair of opposed valve members defines a radial flow path therebetween which extends from the outer radial peripheries of each valve member to an axial bore formed in one of the valve members. The other valve member is mounted on a stem having an upper end which is urged upwardly by a spring disposed around the stem. A substantially cylindrical element is threadably engaged in the upper end of a valve body in which the valve members are received and the stem is urged thereagainst. In another embodiment, the stem is fixedly connected to the cylindrical element. Rotational movement of the cylindrical element axially moves the stem thereby controlling flow through the valve.

Abstract: A high pressure hydraulic flow control valve is formed with a spool which is capable of operating as a conventional spool to control the flow of fluid from an input port to an output port or to a return port. The spool also provides overload protection which will permit fluid to pass from the input port directly to the return port when an overload pressure condition exists in the fluid supply line. In alternative structure, the overload pressure release system may be incorporated into the valve which is used to control the return of fluid from the output port to the return passage. The high pressure hydraulic flow control valve is formed from a die-cast housing and has hardened seats mounted in access passages so as to bear against a seating shoulder. Preferably, a retaining sleeve is mounted in the access passage to bear against the hardened seat to retain it against the seating shoulder.

Abstract: Discrete volumes, or slugs, of liquid are accelerated to high velocities utilizing energy stored by compressing the liquid. Liquid is forced into a pressure vessel already filled with liquid to effect the compression. A slug of liquid is ejected from the pressure vessel into a cumulation nozzle by the energy stored in the compressed liquid when a valve is rapidly opened. The valve is unseated when an unseating force exceeds a closing bias. The valve is then opened rapidly by an opening force generated by the compressed liquid. By repetitively introducing highly pressurized liquid into the pressure vessel, the valve automatically cycles to generate a series of pulsed liquid jets. Rapid opening of the valve is aided by an extension on the valve member which sealingly slides inside the passage of the cumulation nozzle to block release of liquid until the valve member accelerates sufficiently that the required opening rate is achieved as the extension clears the nozzle passage.

Abstract: The regulating valve of a gear pump for an oil burner is urged to a closed position by a spring-loaded plunger. An adjusting screw is associated with the plunger and, when turned, causes the plunger to shift longitudinally so as to adjust the spring force applied to the valve. The screw is threadably received within a nut which is formed integrally with a sleeve. A pump inlet fitting extends through the sleeve to fasten the sleeve to the body of the pump. The inlet fitting and the sleeve coact to prevent rotation of the nut when the adjusting screw is turned.

Abstract: A high temperature safety relief system for a pressure vessel (10) including a pilot controlled main relief valve (16) and an associated non-flowing pilot valve (34) with high temperature metal or metal like seals for temperatures as high as around 1,000.degree. F. provided for both the main relief valve (16) and pilot valve (34). The main valve body (26) has a main body chamber (48) in fluid communication with the inlet flow passage (45) when the reciprocal piston valve member (88) is in seated closed position. The movement of the piston valve member (88) is cushioned during movement to open position and during movement to closed position. The non-flowing pilot valve (34) has an elongate internal housing (204) receiving the inlet line (36) along its longitudinal axis and the housing (204) is mounted for external rotational adjustment to control the blowdown pressure.

Abstract: A rotary compressor for use with refrigerating apparatuses such as freezing refrigerators, freezers, showcases for household or commercial use incorporates a mechanism in a compressor unit. When a space to be freezed is freezed in a on-off operation mode, the mechanism prevents a large amount of high temperature refrigerant gas in a closed casing of the compressor from being discharged to an evaporator during the suspension of the operation of the compressor.

Abstract: A dual directional relief valve including a chamber within which is mounted a piston or valve member. The valve member is biased into a closed position covering and closing the open ends of two conduits. In the preferred embodiment, the conduits are respectively connected to opposite sides of a pump and the open ends of the conduits are concentrically positioned relative to each other. In operation and should dangerously high pressure develop on either side of the pump, the valve member will be opened and the high pressure relieved to pass harmlessly from one conduit to the other through the chamber. The valve member preferably has two surface portions of equal area covering the open ends of the conduits wherein the relief valve can be set to open when a predetermined pressure is exceeded in either conduit.

Abstract: A relieving valve for a fluid or liquid storage tank to permit release of pressure from inside the tank as necessary. A piston is movable within the valve to open the same to atmosphere as pressure builds up slowly therewithin. Upon occurrence of a sudden or rapid pressure rise in the tank, such as when the fluid therein surges against the valve, a snubber assembly in the valve is moved by said pressure rise to a partially closed position to impede the rate at which pressure can build within the valve and thus increase the time before which the valve opens to atmosphere.

Abstract: Discrete volumes, or slugs, of liquid are accelerated to high velocities utilizing energy stored by compressing the liquid. Liquid is forced into a pressure vessel already filled with liquid to effect the compression. A slug of liquid is ejected from the pressure vessel into a cumulation nozzle by the energy stored in the compressed liquid when a valve is rapidly opened. The valve is unseated when an unseating force exceeds a closing bias. The valve is then opened rapidly by an opening force generated by the compressed liquid. By repetitively introducing highly pressurized liquid into the pressure vessel, the valve automatically cycles to generate a series of pulsed liquid jets. Rapid opening of the valve is aided by an extension on the valve member which sealingly slides inside the passage of the cumulation nozzle to block release of liquid until the valve member accelerates sufficiently that the required opening rate is achieved as the extension clears the nozzle passage.

Abstract: A valve having dual seats and dual poppets operating in series to function as either a conventional check valve, or may be operated by an independent piston which may be styled to either combine or eliminate the check valve feature. One seat poppet combination employes a metal-to-metal seal. The other seat poppet combination utilizes a resilient o-ring seal vented so that when the seal is raised from the bottom of its groove, the upstream and downstream sides of the soft seat poppet can communicate. Alternative embodiments provide a family of zero leakage valves for different purposes, e.g. a check valve, pilot operated check valve, and an in line or balanced relief valve with or without the check valve feature by employing generally the same elements with modifications.

Abstract: A pressure regulator-reducer in a first embodiment comprises two pistons (6, 7) provided with elastically deformable rings (9, 10) mounted in a bore (5) and held by a spring (12) bearing against a bulkhead packing (13) surrounding an outlet orifice (16). The double piston defines three chambers (19, 20, 21) respectively in communication with the product under pressure, the atmospheric pressure and the outlet. Facing the ring of the piston (6) on the outlet side there is provided a narrow longitudinal slot (24). A second pressure regulator-reducer is also disclosed that uses a slide mounted in a bore. The side has a piston and a spaced shoulder. The shoulder and piston controls flow along the bore to a dispensing orifice. A spring, mounted in the bore, controls the movement of the side in response to fluid flow.

Abstract: A reciprocating piston fluid powered motor having fluid inlet and outlet, wherein reciprocation is controlled by a reciprocable valve spool communicating with said fluid inlet and outlet and cooperating with a valve slide shiftable on said valve spool to control reciprocation of said valve spool. A needle valve assembly controls the exhaust rate proportionally to the operative speed of the motor.

Abstract: In an expansion engine used in cryogenic refrigeration, a stepped inlet valve 10 and a stepped exhaust valve 11 are fluid activated to control high pressure gas such as helium into and out of the engine. Clearance seals in the stepped valve are achieved by sizing a small diameter of a stepped piston to a small bore and by sizing a sleeve 16 to a larger diameter of the stepped piston. The sleeve 16 fits loosely within a large bore, and is fixed into position by placing a wire of soft metal 9 between the sleeve and the wall of the cylinder.

Abstract: A pressure sensing piston connected to a valve of a leak detector senses leakage of gasoline from underground piping and restricts the flow of gasoline through the piping whenever any leakage exceeds a certain, predetermined rate of flow. The piston is shiftably received in a piston chamber and carries an inner cylindrical wall that is sealingly engageable with a mating cylindrical seal of structure connected to the piston chamber whenever the valve of the detector is in a leak sensing position to enhance movement of the valve in accordance with relatively small changes in the volume of fluid within the region.

Abstract: This invention adds a fuel pressure sensitive piston at a location adjacent to the automatic shut off mechanism of a fuel dispensing nozzle. A lever responsive to the reciprocal movements of the piston biases against the diaphragm of the shut off mechanism raising it and disengaging its associated latch mechanism for release of the dispenser handle and closure of the nozzle poppet valve when there is no fuel being delivered from the pump. When there is fuel pressure from the pump at the inlet of the nozzle, the piston is forced in an opposite direction releasing its contact through a lever with said diaphragm and allowing the automatic shut off mechanism to routinely function.

Abstract: A pressure relief valve is disclosed. The pressure relief valve comprises a valve housing including fluid passageways, a poppet valve disposed within the housing, a piston disposed within the housing, and spring means disposed intermediate the piston and the poppet valve for biasly urging apart the piston and the poppet valve. The poppet valve has a valve seat which, together with a portion of the housing, defines a variable valve area. The piston has a piston area, relatively greater than the variable valve area, for modulating flow through, and pressure drop across, the poppet valve. The pressure relief valve preferably includes an orifice disposed within the housing for selectively controlling flow of hydraulic fluid through the housing passageways to the piston. The housing preferably includes an elongated cage within which the poppet valve is longitudinally slidable.

Abstract: A control stop for a flushing system including a metering flush valve connected to supply liquid to a toilet fixture. The control stop is in series flow relation between a source of pressurized liquid and the metering flush valve and serves the several functions of controlling flow to the metering flush valve for reducing noise and maintaining desired flushing action, preventing reverse flow and trapping pressure at the metering flush valve in the event of loss of inlet pressure, and shutting off the flow path for installation, service or replacement of the metering flush valve. The control stop includes a regulator having a valving portion engageable with a valve seat communicating with the outlet of the control stop and acts as a low pressure cut-off rather than a check valve. A spring biases the regulator toward the valve seat and the regulator is normally held open by liquid pressure.

Abstract: A pressure regulating valve for controlling pressure in high pressure hydraulic circuits includes a closure member with an integral control piston and a conical seating surface cooperable with a complementary surface on a seat member. The valve closure member is biased in the closed position by an actuating mechanism including a pressure gas piston and cylinder arrangement utilizing a flexible diaphragm for sealing the actuator pressure chamber. The effective cross-sectional area of the control piston is large enough to minimize the differences in cross-sectional areas on the closure member exposed to pressure fluid between the valve closed and valve open positions whereby a minimum variation between the valve opening pressure and the control pressure is experienced.

Abstract: A sealing valve either blocks or releases the gas held under pressure in a gas cylinder, for example. When the sealing valve is opened, the flow path is opened and a pressure impact travels to the equipment connected downstream of the valve and can cause damage thereto. The attenuator valve of the invention is disposed in the pressure-gas conduit between the pressure-gas source and the sealing valve and prevents this kind of an impact from occurring. Since the attenuator valve of the invention is controlled exclusively by pressure, it can be mounted at any location in the pressure-gas conduit. The attenuator valve of the invention includes a housing and a valve body mounted in the housing which shuts off the pressure-gas conduit with the aid of a closure cone which is held in sealing contact to a conical valve recess by means of a spring. The pressurized gas in the cylinder is present above the valve body via an alternate path.

Abstract: A combination gladhand and dirt protection plug includes a gladhand body with a chamber within the body. There are a pair of air ports in communication with the chamber, with one of the ports functioning as an air inlet. A seal is positioned in one of the air ports and there is a dirt protection plug movable in the chamber toward and away from the seal to open and close said one port. A spring is positioned within the body to bias the plug toward a port closing position. The plug has a surface in communication with the air inlet, with air pressure at the inlet, applied to the plug surface, causing the plug to automatically move against the spring and away from the seal to an open position.

Abstract: The present invention is a pressure compensated directional control valve. The present invention allows the flow rate to a given hydraulic implement to be constant regardless of the load imposed upon the hydraulic implement or the hydraulic pressure supplied by the hydraulic pump. Pressure compensation is achieved by a piston mounted within a sleeve valve insert wherein the piston moves to create a variable orifice to control the amount of hydraulic fluid supplied to the hydraulic implement. The desired flow rate is maintained regardless of changes in the supply pressure and the implement load pressure. The present invention eliminates the need for two separate valves for directional flow control and pressure compensation, without increasing the casing size of the flow control auxiliary valve.

Abstract: A valve device, especially for die casting machines. The device comprises a control drive and a control member which is arranged between the control drive and the valve cone, and which converts the rotary movement of the control drive into an axial stroke movement. The object of the invention is to provide a quick acting valve device with which the adjustable limited opening of the valve cone can, with the aid of small manual or motor forces, be effected with structurally simple means in a space saving device housing in the direct drive. For this purpose, the control member which serves to adjust the opening limitation of the valve cone is a threaded sleeve which engages in a thread of the valve housing. Every time the working surfaces of the valve cone are acted upon by pressure, different hydraulic pressures are exerted upon the oppositely located end faces of the threaded sleeve for releasing the sides of the threads of the sleeve from the sides of the threads of the housing.

Abstract: An apparatus for metering fluids at high pressures of about 20,000 to 60,000 psi is disclosed. The apparatus includes first and second plates which are positioned adjacent each other to form a valve chamber. The plates are made of materials which have substantially equal elastic properties. One plate has a planar surface area, and the other a recessed surface area defined by periphery and central lips. When the two plates are positioned in adjacent contacting relationship, a valve chamber is formed between the planar surface area and the recessed surface area. Fluid is introduced into the chamber and exits therefrom when a deformation occurs at positions where they no longer form a valve seat. This permits the metering of fluids at high pressures and at slow variable rates. Fluid then exits from the chamber until an applied external force becomes large enough to bring the valve seats back into contact.

Abstract: A sprinkler system for plants and schrubs growing on the side of a hill has non-drain valves connected at discharge heads that are positioned at elevations below the main control valve for the system. The non-drain valves are opened by pressure of water exerted when the main control valve is opened. After the main control valve is closed and water pressure in the pipe system that feeds the discharge heads falls to a selected value, the non-drain valves automatically close, thereby preventing drainage from the discharge heads of water retained in the pipe system between the relatively low discharge heads and the relatively high control valve.

Abstract: A pressure protection system including a valve for isolating an auxiliary fluid circuit from a main fluid circuit when a leak occurs in the auxiliary fluid circuit. A valve is connected between a governor controlled compressor and the main fluid circuit and a pressure protection valve is connected between the compressor and an auxiliary fluid circuit. If a leak develops in the auxiliary fluid circuit, the pressure protection valve closes which permits most of the output from the compressor to be used to recharge the main fluid circuit. The pressure protection valve includes a supply passage and a delivery passage disposed substantially perpendicular to the supply passage. A plunger member is movable within the delivery passage for closing the supply passage when there is insufficient fluid pressure in the auxiliary fluid circuit.

Abstract: A valve comprises a hollow body having an inlet and an outlet, a seat ring in the outlet provides a face adapted to engage a gate, a closure mounted for movement relative to the seat ring and including a carrier having a passage therethrough in which are slidably disposed a lipped gate disc adapted to engage the seat face and block the outlet when the valve is in closed position, a pressure spring pressing the gate disc against the seat face when the valve is in closed position, and a ball transferring the reaction of the spring to the body.

Abstract: A relief valve which maintains generally constant pressure in a fluid system for a wide range of flow rates through the system. When the valve opens as the pressure in the system exceeds a predetermined value, the flow about the valve plug is allowed to impinge on itself adjacent to the bottom surface of the plug to create a stagnation pressure on the plug which maintains generally constant liquid pressure within the valve for different plug settings even though the spring force on the plug increases as the flow increases and the plug is lifted further from its seat.

Abstract: A back pressure control choke operates to automatically control and maintain a desired back pressure on the fluid passing through the choke. The choke housing has an inlet channel which intersects with an axial bore, part of which bore constitutes the discharge channel. An annular choke seat concentrically arranged in the discharge channel of the axial bore is adapted to receive an annular choke element. The choke element is affixed to a shuttle which is mounted on a fixed mandrel extending into the axial bore of the choke housing. The shuttle is dynamically sealed against the housing and mandrel such that a closed chamber is created in that portion of the axial bore opposite the discharge channel. The shuttle element is constructed to be fluid balanced such that it will move to achieve an equilibrium of pressure on its forward and rear surfaces.

Abstract: A fuel injection nozzle unit includes a differential valve member biased by a spring to a closed position and opened to allow fuel flow through an outlet by fuel under pressure from an inlet. The spring is housed within a spring chamber and fuel leaking into this chamber is vented to the inlet when delivery of fuel has ceased. A relief valve is provided which has a valve element having a surface exposed to the pressure in the chamber and an opposing surface exposed to the pressure exterior of the nozzle unit. The valve element is biased to a closed position by a spring and it controls flow along a path from the chamber to the inlet. The flow path also incorporates a non-return valve. The valve element is set to lift from its seating at a pressure which is greater than the residual pressure in the inlet plus the pressure required to open the non-return valve.

Abstract: A gas-inlet attachment includes an air-tightly sealed pressure differentiator in the mouthpiece of a gas charger, wherein the pressure differentiator includes a valve-opener slidably and air-tightly connectable to the check valve in the cock with a pressure differentiating space interposed therebetween, thereby enabling the check valve to be biased in its opening direction under the differentiated pressure provided by the pressure differentiator.

Abstract: This invention is an improved injection molding nozzle whereby the shut-off plunger is operated by a fluid and the opening of the nozzle is accomplished by the flow of plasticized material through the nozzle. A control rod internal to the nozzle controls the movement of the plunger shut-off member and is adjustable so that the amount of plasticized resin flowing through the nozzle can be accurately controlled.

Abstract: A multi-level pressure regulating valve for a hydraulic control circuit. It includes a three-level or four-level pressure regulating valve utilizing an intermediate chamber which is fed with fluid through two parallel ducts, each having its own throttling device.

Abstract: In oil well remedial operations, a powerful generally acidic solution is pumped down a pipestring and out into the well annulus at the level of casing perforations wherein the solution will pass through the perforations and clean them out to facilitate oil flow into the annulus for subsequent recovery. When increasing the depth of the pipe string as by adding further pipe sections at the surface of the well, it is desirable to retain the solution within the pipe string and towards this end, there is provided an internal fluid control valve normally closed to retain fluid but responsive to an increase in the fluid pressure above a given value to open and permit the treating fluid to pass into the annulus and treat the casing perforations. Basically the internal valve comprises a valve seat and ball, the ball being positioned on the upstream side of the valve so that should any seals fail in the valve structure, the valve will failsafe to a closed position.

Abstract: The dewaxing valve comprises a ball and valve seat where the ball is on the upstream side of the flow of hot dewaxing fluid through a production pipe string to the well annulus. The design of the dewaxing valve is such that it can be readily attached to a production tube in the production tubing string by simply boring a hole in the side of the production tube and welding a supporting T-collar for the valve to the periphery of the side opening.

Abstract: A pressure-responsive valve unit is received in the cavity of a valve assembly housing, the inner end of the cavity being connected with a fluid container. The valve unit includes a main body having a chamber containing a check valve body that is movable toward and away from engagement with a valve seat on the main body, the valve seat facing the check valve body and the inlet end of the cavity, and the main body having passage means communicating fluid from the container to the front end portion of the check valve body. The check valve body is biased into engagement with the valve seat by a spring, the force of which is adjustable with a plug threaded into the inner end of the main body chamber. An outlet bore extends from the outer end of the main body to the valve seat, and the check valve body is engageable by a push rod inserted through said outlet bore.

Abstract: A relief and make-up valve assembly is connected to first and second fluid pressure passages in a fluid pressure device. The valve assembly includes a housing of a hollow cylindrical form which communicates with the passages, a valve axially movable in the housing, a piston partitioning the interior of the housing into a low pressure chamber and a back pressure chamber, and a plunger biased by the piston against the valve to move the valve to an opened position away from a valve seat. The valve assembly controls the level of pressure in the first pressure passage by unseating the valve to relieve a preselected pressure from the first pressure passage or alternately to build up a pressure therein.

Abstract: A control valve is provided between a direction-changeover valve and an actuator in a fluid-pressure operating system. This control valve includes a body having an inlet and an outlet; a fluid passage interconnecting the inlet and the outlet; a valve body and a valve seat which are cooperative with each other to define a clearance therebetween and positioned within the fluid passage; a spring for resiliently urging the valve body toward a constrictive position to where a diminished clearance is defined between the valve body and the valve seat; and pressure responsive means for displacing the valve body in an opposite direction against the force applied by the spring thereby enlarging the clearance and bringing the valve body to its fully open position. An adjusting rod enabling adjustment of the first position of the valve body is provided, and a pilot piston operates under a pilot fluid pressure applied through a pilot port for forcing the valve body to its fully open position.

Abstract: A fluid control valve, principally for controlling the flow of fuel to a compression ignition engine, comprises a valve body and a valve member slidable within the body, the valve member co-operating with a seating on the valve body to control the flow of fluid through the valve. A spring urges the valve member into engagement with the seating and in use, the pressure of the fluid entering the valve is arranged to act on the valve member in opposition to the spring so as to lift the valve member off the seating. The valve member and the seating are formed from electrically conductive material and are electrically insulated from each other except when the valve member is engaged with the seating. An electrical terminal extends to the exterior of the valve body and enables the electrical resistance between the valve member and the seating to be measured. The measured electrical resistance provides an indication of movement of the valve member towards and away from the seating.

Abstract: A pressure regulating valve for use in a high-pressure fluid flow line, comprises a cylindrical needle-housing structure that is slidable within a bore in a valve body. An external spring urges the needle-housing structure toward a valve seat at a selectable pressure. Contact between the needle-housing structure and the valve seat is prevented by an annular protrusion in the bore. Conduit means through the valve body, connectable to the flow line, permits passage of the flow-line fluid into the needle-housing structure. A cylindrical needle is disposed coaxially within the needle-housing structure, and is urged toward the valve seat by a spring located in the needle-housing structure. When the pressure of the flow-line fluid entering the needle-housing structure exceeds the selected pressure urging the needle-housing structure toward the valve seat, the needle-housing structure assumes a position at which the needle remains spaced apart from the valve seat.

Abstract: A fluid pressure shock absorbing valve is mounted between an oxygen supply tank and a fluid pressure regulator in a supply system such as that for welding torches. The valve includes a housing slidably supporting a valve member having a head biased to seat in the direction of flow from the tank to the regulator to normally close the valve. The valve member has a central flow passageway extending thereinto from the downstream end, and a restricted passageway extends through the head and opens into the flow passageway to bleed fluid through the head when the latter engages the seat. Radially extending passageways open into the flow passageway downstream from the seat. When the supply tank is opened, flow through the restricted passageway allows for gradual pressurization of the regulator and an eventual build-up of pressure to displace the valve member from the seat to allow full flow past the seat and into the flow passageway through the radial passages.

Abstract: A series of valves with tapered-conical seats including valves such as safety relief or self-regulating in-line check valves which operate without springs but by the use of self-holding tapers which firmly stay in place when seated, the angle of the taper varying between 0.5.degree. to 45.degree., depending on the kind of material chosen and the valve type, TEFLON requiring a smaller angle for the same pressure holding capacity as conventional materials or other plastics, offering also valve design variations which include novel relief valves with springs and with self-relieving tapers, as well as shutoff valves with self-holding and self-relieving tapers operated by solenoids directly, and piloted valves, the valve series with conical seats, and improved sealing characteristics reduces dribble range while reference load is self-holding taper or a spring, and allows for reusable valves to replace safety rapture discs in some applications.

Abstract: A solenoid valve mechanism includes a cooperating poppet and valve seat and a first bias spring for urging the poppet into sealing engagement with the valve seat. A solenoid armature carries the poppet and includes means for selectively urging the poppet against the spring bias. A solenoid coil cooperates with the solenoid armature and the armature is provided with a fluid seal and a second bias spring for urging the armature into position at which the fluid sealing means forms a fluid seal around the valve member. The fluid seal includes a path for bleeding fluid across the valve seat.

Abstract: A power transmission providing cushioned shock-absorption power flow from a rive member to a driven member. The transmission includes a gear pump wherein both the gear and gear housing are free to rotate; the transmission also includes a recirculation flow path from the pump outlet to the pump inlet, said flow path comprising a metering valve that responds to pump outlet chamber pressure for progressively throttling the flow as the outlet chamber pressure rises. As the recirculation flow is throttled the pump gear and pump housing gradually lock together and thereafter rotate at approximately the same speed.

Abstract: In a fluid-flow pulsator, a housing has a chamber with an inlet and an outlet. Within the housing is a piston assembly having first and second pistons with the first having a working area less than that of the second. A valve associated with the assembly closes the outlet on movement of the assembly. The assembly is resiliently urged in a direction effecting closure of the outlet with the first and second pistons effectively being disposed in the chamber on opposite sides of the inlet. The introduced fluid pressure, the urging strength and the piston areas are correlated so as to produce pulses of fluid from the outlet in response to a supply of fluid to the inlet.

Abstract: A shut-off cut-off nozzle for a plastic injection machine is constructed to ensure even heating and thereby avoid seizure of moving parts and to provide efficient and reliable mechanism.

Abstract: In a modulator assembly for a vehicle anti-skid braking system comprising a housing having a chamber of which the effective volume is variable by an expander piston to modulate the pressure supplied to a wheel brake in accordance with skid conditions, the chamber comprises first and second compartments, and a valve assembly is located in the housing to control communication between the compartments. The valve assembly is closed when the expander piston is in an advanced position in which the effective volume of the chamber is substantially at a minimum so that a first area of the piston is exposed only to pressure in one of the compartments, and the valve assembly is open when the expander piston is retracted away from the advanced position so that a second area of the piston which is greater than the first is exposed to pressure in both compartments.

Abstract: A lock-out valve for pneumatic systems which provides the operator with mechanical means to exhaust the system and lock it out with a padlock or similar device and, when unlocked, provides a valve to control automatically the gradual reset of working cylinders and the filling of the system with operating pressure to a safe percentage of line pressure before full line flow is established.

Abstract: A valve body contains a coaxially slidably valve element with a seal member at the upstream end and a pair of differential area pistons at the other end. Fluid passage means direct fluid from the upstream end to a zone between the pistons to cause the pistons to seat the seal member. An orifice in the downstream, larger area piston bleeds fluid to an accumulator of preselected volume. Once the pressure forces on the large piston balance, the pressure force on the small piston unseat the seal member.

Abstract: A combination lock and relief valve in which a single valve poppet provides both functions. The combination valve is so arranged that the opening pressure of the poppet as a relief valve is independent of system pressure and remains constant regardless of system pressure variations. Moreover, when the poppet opens as a relief valve while the system pressure is on, the differential pressure across the poppet is relatively small whereby to minimize or eliminate erosion of the valve seat as occurs more readily when relief valve poppets are opened with high pressure differentials thereacross.