Abstract: A vane cell machine is provided comprising a housing having a stator bore with an outer limitation formed by a circumferential wall and two axial end faces (5), a rotor mounted rotatably in said stator bore, a plurality of vanes moveable in radial direction relative to said rotor and sliding along said circumferential wall, and sealing means (12) at least at one of said end faces (5), said sealing means (12) acting on said rotor in axial direction. Such a vane cell machine should have a simple construction. To this end said end face (5) is formed at an end plate (11) of said housing wherein said end plate (11) comprises a recess in which said sealing means (12) are rotated.

Abstract: A limp home mode drive method and system for a hybrid vehicle are provided. The method includes prohibiting an operation of an overdrive brake that is included in a transmission for the hybrid vehicle and is driven by an electric oil pump when the hybrid vehicle is being driven and the electric oil pump is not operated. A speed of the hybrid vehicle is then limited based on a heat value of a rotation driver included in the transmission and a torque of a drive motor driving the transmission is limited based on a temperature of the drive motor. A mechanical oil pump included in the hybrid vehicle is operated to enable limp home driving of the hybrid vehicle.

Abstract: In an energy conversion method and a thermal power plant for converting heat into mechanical or electric energy using a working medium, a vapor state in the working medium is generated at a first pressure in a steam generator. The vaporized working medium is expanded to a lower second pressure in a steam expanding device. An energy obtained by the expansion process is discharged. The expansion of the steam state is carried out using a saturation line of the working medium. The working medium is thereby separated into a non-condensed portion and a condensed portion in a separating device. The non-condensed portion is then compressed into a compressed non-condensed portion in a compressor. The compressed non-condensed portion is cooled and condensed into a compressed condensed portion. The compressed condensed portion and the initially condensed portion are then heated, and both portions are returned to the steam generator together.

Abstract: The invention discloses an adaptor (10,50) for an air compressor (11,51). Adaptor (10,50) includes a manifold (14,52) having an inlet (20,74) adapted to be connected to the air exhaust of at least one air tool device (34) having an air motor connected, in use, to the air compressor (11, 51). An outlet (12,54) is adapted to be connected, in use, to the air intake of the air compressor (11,51), an air inlet (16,70) is open to ambient air and a valve mechanism (33,66) is adapted to, in use, close the air inlet (16,70) when a first predetermined pressure is reached by the air compressor (11,51).

Abstract: The present embodiments provide a control system and method that is able to automatically cycle one or more compressor valves, for example to prevent freeze up. For example, in one embodiment, a system includes a compressor having a compression device configured to increase a pressure of a gas, a valve configured to control flow of the gas from the compression device, and a controller configured to cycle the valve to reduce buildup of contaminants in the compressor.

Abstract: This disclosure relates to a centrifugal compressor. In a first example, the compressor includes a first impeller provided in a main refrigerant flow path, a second impeller provided in the main refrigerant flow path downstream of the first impeller, and a recirculation flow path. In the first example, the recirculation flow path is provided between a first location and a second location along the main refrigerant flow path. The first location is downstream of the second location, and the second location is downstream of the first impeller. In a second example, the compressor includes an impeller provided in a main refrigerant flow path, and a recirculation flow path provided between a first location and a second location along the main refrigerant flow path. In the second example, the recirculation flow path includes a recirculation volute. Further disclosed is a method for operating a centrifugal compressor.

Abstract: A high-pressure cleaning appliance with a high-pressure pump is provided. The pump has at least one pump chamber connected to a suction line and a pressure line. The pressure line is in flow connection with the suction line via a return flow line. A relief valve with a through-channel extending from a valve inlet to a first valve outlet is arranged in the return flow line. A valve element which in a closed position bears against a valve seat is held for movement in the through-channel. At least one outlet channel, which opens into a second valve outlet, branches off from the through-channel. The valve element is surrounded by a sealing ring which seals off an inlet area of the through-channel adjacent to the valve inlet from an outlet area of the through-channel adjacent to the first valve outlet.

Abstract: A hydraulic power steering system which includes a tank and a power steering pump which takes in a pressure medium from an intake area which is decoupled from the prevailing atmospheric pressure on the side of the tank wall and delivers it under pressure to the power steering system. A valve device builds up a pre-pressure in the intake area and prevents a negative pressure and a positive pressure from building up on the interior of the oil tank.

Abstract: A high pressure fuel pump control system for an internal combustion engine includes a fuel injection valve provided in a fuel common rail and a high pressure fuel pump for feeding fuel by pressure to the fuel injection valve. The high pressure fuel pump includes a pressurized chamber, a plunger for pressurizing fuel in the pressurized chamber, a discharge valve provided in a discharge passage, an intake valve provided in an intake passage, and an actuator for operating the intake valve. The control system includes a means for calculating a drive signal for the actuator to make a discharge amount or pressure of the high pressure fuel pump variable. The means reduces pressure in the common rail by opening the discharge valve to return the fuel in the fuel common rail to the pressurized chamber when a requirement for reducing the pressure in the fuel common rail is made.

Abstract: The present disclosure provides a fluid pump having a pump motor, a pump drive shaft, and a vane pump assembly. The vane pump assembly includes a pump housing with a fluid inlet port in a distal portion of the housing and a fluid outlet port in a proximate portion. A first bearing member, having a plurality of inlet orifices in flow communication with the fluid inlet port, is disposed within the housing distal portion. A cam ring is adjacent the first bearing member. A rotor, which is mounted on the pump drive shaft, is disposed within an opening in the cam ring. This rotor includes a plurality of radial slots and vanes slidably received within the slots. A second bearing member, having a plurality of outlet orifices in flow communication with the fluid outlet port, is disposed within the housing proximate portion adjacent the cam ring. An end plate is also mounted within the distal portion of the pump housing.

Abstract: The present invention provides a valve assembly for relieving fluid pressure having a pump housing with a low pressure inlet chamber and a high pressure discharge chamber, a relief aperture positioned between the low pressure inlet chamber and the high pressure discharge chamber, a valve seat along the perimeter of the relief aperture, and a valve body located in the high pressure discharge chamber. The valve body has a first end capable of engaging the valve seat in a closed position and is also capable of axial travel opposite the fluid discharge at a predetermined pressure.

Abstract: A multi-cylinder dry-running piston compressor for generating compressed air. The piston compressor includes a crankcase having an interior and a crankshaft rotatably mounted in the crankcase. Also included are two connecting rods mounted in the crankshaft and configured to run counter to one another. Further included are two cylinders mounted in the crankcase and a piston arranged at an end of each of the connecting rods and configured to run in a respective one of the two cylinders.

Abstract: A compressor piston including a piston in a cylinder; a connecting rod connecting the piston to a crankshaft in a crankcase by a roller bearing; and an air inlet line and an air outlet line in a cylinder head. A tube connection between the air inlet line and the crankcase transports cooling air from the inlet line to the crankcase. The tube connection is exterior the cylinder. An inlet valve is connected to the tube connection which opens when the pressure in the crankcase is less than the pressure in the air inlet line; and an outlet valve is connected to the crankcase which opens when the pressure in the crankcase exceeds a predetermined value.

Abstract: A compressor arrangement includes a compressor housing, an intake region defined in the compressor housing, a control pressure connection in communication with the intake region, a control pressure chamber in communication with the control pressure connection, a control piston disposed in the compressor housing beneath the control pressure chamber, a guide element securing the control piston in the compressor housing, at least one sealing element disposed between the control piston and the guide element, and a feed pressure connection defined in the compressor housing to supply compressed air beneath the control piston. In a closed position, the control piston closes the feed pressure connection when in the closed position. In an opened position, the control piston opens the feed pressure connection when in the opened position, thereby permitting air to vent from the feed pressure connection via a venting connection.

Abstract: A fan unit for use in an air delivery system. The fan unit comprises a variable speed control for controlling the speed of the fan wheel in combination with a disk-type unloader assembly for controlling the air flow in response to fan speed changes. The unloader disk assembly includes an actuator that is responsive to changes in the air pressure on the disk and is biased in the closed position. At full speed, air flow through the housing presses the disk to the fully open position. As the fan speed slows and air flow declines, the actuator pulls the disk to an intermediate position, reducing the air flow through the fan. The disk unloader with its air pressure responsive actuator is also useful in fan units without a variable speed control. The fan unit may be used individually or as part of a fan array of like units.

Abstract: A compressor has a suction throttle valve, which includes a suction passage, a suction port, a valve body, an urging member, a valve chamber, a first communication hole, a closing valve and a valve seat. The closing valve closes the hole of the valve body by pressure difference between the valve chamber and the suction port. The valve seat limits movement of the closing valve toward the suction port. The hole of the valve body is closed when the closing valve is in contact with the valve body, and open when the closing valve is in contact with the valve seat. A communication passage is formed in the closing valve or the valve seat, which enables communication between the hole of the valve body and the suction port when the closing valve is in contact with the valve seat.

Abstract: Equipment for continuous regulation of the flow rate for a reciprocating compressor, provided with at least one compression chamber (1) in which is slidably inserted a piston means (101) movable with a reciprocating motion, at least one inlet valve (2) for the fluid to be compressed and at least one outlet valve (4) for the compressed fluid being provided in the said chamber, the said outlet valve (4) being connected to a storage reservoir (10) for the compressed fluid, and the said inlet valve (2) being provided with translation means (502, 512) which can act on the obturator (302) of the said valve (2), the said translation means (502, 512) being movable in a direction perpendicular to the plane of the said obturator (302), and interacting with actuator means (3, 103, 203) which are movable in the said direction with a reciprocating motion by means of suitable operating means (303, 403); the said operating means (303, 403) make it possible to control the velocity of displacement of the said actuator means (

Abstract: The present disclosure provides a fluid pump having a pump motor a pump drive shaft and a vane pump assembly. The vane pump assembly includes pump housing with a fluid inlet port in a distal portion of the housing and a fluid outlet port in a proximate portion. A first bearing member, having a plurality of inlet orifices in flow communication with the fluid inlet port, is disposed within the housing distal portion. A cam ring is adjacent the first bearing member. A rotor, which is on mounted the pump drive shaft, is disposed within an opening in the cam ring. This rotor includes a plurality of radial slots and vanes slidably received within the slots. A second bearing member, having a plurality of outlet orifices in flow communication with the fluid outlet port, is lo disposed within the housing proximate portion adjacent the cam ring. An end plate is also mounted within the distal portion of the pump housing.

Abstract: A hydraulic control system for controlling preferably at least two consumers, has a pump supplying the consumers with a pressure medium and having an adjustable pump capacity, an adjustable metering orifice assigned to each of the consumers, a power-beyond connection to which at least one power-beyond consumer is attachable, an inlet pressure scale connected downstream of the pump and provided in a pressure medium flow path between the pump and at least one of the two consumers, wherein the power-beyond connection branches off in the pressure medium flow path between the pump and the inlet pressure scale, a spring with a force acting upon the inlet pressure scale in a closing direction, an inlet having a pressure acting upon the inlet pressure scale in an opening direction, wherein the inlet pressure scale is configured so that it is actable upon in the closing direction selectively by either a highest load pressure or by a pressure that is greater than the highest load pressure.

Abstract: A control apparatus for controlling two oil pumps which are provided on a vehicle wherein the two oil pumps are selectively driven by respective different drive power sources such that one of the two oil pumps is operated while the other oil pump is held at rest, the control apparatus including an air removal control portion configured to temporarily operate the above-indicated other oil pump during an operation of the above-indicated one oil pump, to remove air staying at and around an oil inlet of the above-indicated other oil pump.

Abstract: Aiming at the problem of the difficulty in changing the displacement of vehicle scroll compressors, this invention opens a displacement changing control device for scroll compressors that is good for the quick start of the compressor, and can conveniently control the displacement and pressure of the compressor within the set range, and can be used with various kinds of scroll compressors. It includes the case (1). A piston barrel (3) that is used to install the piston control valve (2) that is set in the case (1). An air-intake channel (4) that connects with the piston barrel (3), high pressure feedback channel (7) and displacement adjustment channel (9) that are set on the piston barrel. The piston control valve (2) is located between the air-intake channel (4) and the high pressure feedback channel (7). A spring (10), which has one end that resists the piston control valve (2), is installed in the air-intake channel (4).

Abstract: A centrifugal pump includes a casing having an impeller chamber, an inlet, an outlet, and a bearing chamber. A shaft disposed within the casing has an impeller end and a motor end. The impeller is coupled to the impeller end of the shaft and is disposed within the impeller chamber. A bearing is disposed within the bearing portion. The bearing has an inboard end with an inboard-bearing surface and an outboard end with an outboard-bearing surface. The bearing and the shaft have a bearing clearance therebetween. A disc is coupled to the shaft on the impeller end which is spaced apart from the inboard-bearing surface. A seal ring is disposed between the disc and the inboard-bearing surface. The shaft, the seal ring, the disc, and the inboard-bearing surface define a thrust chamber therebetween. The thrust chamber is in fluid communication with the impeller chamber through the bearing clearance so that an axial thrust in an inboard direction is generated by the thrust chamber.

Abstract: A pump head for a fluid pump driven by a motor includes an inlet for receiving fluid at a first pressure and an outlet for outputting fluid at a second pressure greater than the first pressure. A relief valve cavity formed in the pump head housing includes a first portion in fluid communication with the inlet and a second portion in fluid communication with the outlet. A relief valve is disposed in the relief valve cavity with no portion of the relief positioned to block or otherwise impede the normal flow of fluid through the inlet or outlet.

Abstract: A centrifugal pump with facilitated self-priming, which comprises a casing with a suction inlet and a discharge outlet and with an internal series of diffusers and impellers, which form a cylindrical assembly that forms, together with the casing, an annular interspace which is connected to the inside of the series of diffusers and impellers on the discharge side through corresponding openings and on the inlet side through a hole arranged perimetrically in the intake region; the hole is controlled, on the side of the interspace, by a normally-open flexible metallic laminar valve. A wall of the pump struck by the fluid exiting from the interspace through the controlled hole is shaped so as to have a double symmetrical channel for imparting to the fluid a double vortex before passing through the first impeller.

Abstract: A compressor has a high-pressure relief valve and a low-pressure relief valve. The high-pressure relief valve in use for a discharge region opens when the pressure of gas in the discharge region is more than a first predetermined pressure. The high-pressure relief valve is provided with a first shim. The low-pressure relief valve in use for a suction region opens when the pressure of gas in the suction region is more than a second predetermined pressure which is lower than the first predetermined pressure. The low-pressure relief valve is provided with a second shim. The high-pressure relief valve and the low-pressure relief valve have similar structure to each other.

Abstract: An apparatus for preventing vacuum compression of a scroll compressor comprising: a suction tube and a discharge tube each combined to one side of a closed container filled with oil to an adequate height; a fixing scroll having a wrap and a coolant inlet and an outlet; a high and low pressure separating plate installed at the upper side of the fixing scroll, dividing the inside of the closed container into a high pressure chamber and a low pressure chamber, the high and low pressure separating plate having a gas discharge hole at its central portion; an orbiting scroll having a plurality of compressive chambers for compressing a sucked coolant by being rotably engaged with the wrap of the fixing scroll at the lower side of the fixing scroll, and having a wrap for rendering each compressive chamber to have different pressure to be successively moved as being turned; and a high vacuum preventing unit installed at the inner side of the body of the fixing scroll.

Abstract: A hydraulic system for a reciprocating piston pump that includes an accumulator for producing a steady-pressure supply of compressible material to a distribution nozzle. The hydraulic system includes an adjustable means for constricting the flow of hydraulic fluid from the accumulator to the hydraulic system. The means for constricting the flow of hydraulic fluid allows the operator to compensate for the type of material being pumped, the vertical distance the material is being pumped, as well as the overall distance the material is being pumped in order to reduce or eliminate line surge. The means for restricting the flow from the accumulator preferably includes a needle valve that allows the operator to select the flow characteristic from the accumulator.

Abstract: A centrifugal pump (10) with facilitated self-priming, which comprises a casing (11) with a suction inlet (12) and a discharge outlet and with an internal series (14) of diffusers and impellers, which form a cylindrical assembly that forms, together with the casing (11), an annular interspace which is connected to the inside of the series (14) of diffusers and impellers on the discharge side through corresponding openings (13a) and on the inlet side through a hole (18) arranged perimetrically in the intake region; the hole (18) is controlled, on the side of the interspace (16), by a normally-open flexible metallic laminar valve (19). A wall (20) of the pump struck by the fluid exiting from the interspace (16) through the controlled hole (18) is shaped so as to have a double symmetrical channel (21) for imparting to the fluid a double vortex before passing through the first impeller.

Abstract: Provided is a connecting structure for a vacuum pump, which can block propagation of electrical noise, generated by a main body of the vacuum pump. Between both ends of a connection piping for connecting the vacuum pump to a vacuum chamber of an apparatus to be connected with and evacuated by the vacuum pump, there is interposedly provided an electrical insulating portion formed of an insulating material so as to provide electrical insulation therebetween. The electrical insulation portion may be provided to a connection piping member such as a damper (or a valve depending on the connection arrangement) for absorbing mechanical vibrations.

Abstract: A method and system for determining pump cavitation is disclosed. In accordance with the principle of the invention, changes in dynamic fluid pressure within a pump are monitored and compared to a determined cavitation alarm pressure. The determined cavitation pressure is determined as a known percentage of a known non-cavitation pressure. Fluid cavitation is determined when the change in dynamic fluid pressure falls below the determined cavitation alarm pressure. In a further aspect of the invention, a remaining mechanical seal operational life can be determined by maintaining a total time of fluid cavitation and reducing the expected life by the known operational time of the pump and the time the pump is in cavitation.

Abstract: This invention discloses a method for limiting a critical variable (such as, discharge pressure or suction pressure or pressure ratio) of either a compressor station or an individual compressor when these machines are subjected to large, fast disturbances. Each configuration, whether a station or an individual compressor, is equipped with two PID controllers: (1) a main controller for compressor critical variables and (2) a limiting controller that participates in modulating recycle valves. At the onset of sudden, large changes of mass flow at a compressor's or station's discharge, the effectiveness of the two controllers (acting independently) may be insufficient to prevent discharge pressure from reaching the shutdown set point which, in turn, disrupts the process supported by the compressors, and the longevity of the drivers is diminished. For these reasons, this disclosure relates specifically to a technique that combines the functions of the main and limiting controllers.

Abstract: For controlling a displacement depending on a pressure differential between a crank chamber (9) and a suction chamber (4), a compressor is provided with a bleed passage (46) establishing communication between the crank chamber and the suction chamber and with a bleed control mechanism which fully closes the bleed passage while the compressor is stopped. The bleed control mechanism may be a suction valve (15) which controls the opening of suction holes of a valve plate (2) synchronously with a compressing operation of the compressor.

Abstract: A cylinder injection high-pressure fuel pump permits reduction in size and cost thereof and it is also capable of securely absorbing high-frequency pulsations. The cylinder injection high-pressure fuel pump (200) has: a casing (1) in which an inlet passage (2) for taking fuel in and a discharge passage (35) for discharging the fuel are formed; a cylinder (30) formed in the casing (1); a fuel pressurizing chamber (32) formed in a part of the cylinder (30); and a plunger (31) disposed in the cylinder (30) such that it may reciprocate therein. As the plunger (31) reciprocates, the fuel is taken into the fuel pressurizing chamber (32) through the inlet passage (2) and pressurized therein, then the pressurized fuel is discharged through the discharge passage (35) and forcibly fed into a fuel injector of a cylinder injection type engine.

Abstract: A cylinder injection high-pressure fuel pump prevents the pulsations of fuel generated by a high-pressure fuel pump from spreading to a low-pressure pipe connected to a low pressure end. The cylinder injection high-pressure fuel pump has: a casing (1) in which an inlet passage (2) for taking fuel in and a discharge passage (35) for draining the fuel are formed; a cylinder (30) formed in the casing (1); a fuel pressurizing chamber (32) formed in a part of the cylinder (30); and a plunger (31) disposed in the cylinder (30) such that is may reciprocate therein. As the plunger (31) reciprocates, the fuel is taken into the fuel pressurizing chamber (32) through the inlet passage (2)and pressurized therein, then the pressurized fuel is discharged through the discharge passage (35) and forcibly fed into a fuel injector of a cylinder injection type engine. The inlet passage (2) is equipped with a check valve (70).

Abstract: A variable capacity vane compressor includes side members secured to opposite end faces of a cylinder block, respectively, and a rotary plate mounted in one of the side members, for adjusting compression starting timing of the compressor to thereby increase or decrease capacity or delivery quantity of the compressor.

Abstract: A hydraulic control device of an automatic transmission is provided wherein three-stage valve bodies are superposed on and fixed to each other with partition plates interposed therebetween, and a pressure regulator valve is mounted in a middle-stage valve body out of the three valve bodies. An inlet oil path that extends from an oil strainer to an inlet port of an oil pump is formed in a lower portion of the valve body. A drain port of the pressure regulator valve communicates with the inlet oil path leading to the inlet port, through a drain hole formed through the partition plate between the middle-stage and lower-stage valve bodies, and a drain hole formed through the low-stage valve body. In this arrangement, the oil drained from the pressure regulator valve is led to the inlet port without passing through the oil strainer, assuring an increased degree of freedom in selecting the position of the pressure regulator valve.

Abstract: An electromagnetic pump having an electromagnet carried by the housing external to the fluid chambers, and an armature moveable in the housing having a pole magnetically attracted by the electromagnet and a piston to force fluid out of the chambers and through the pump outlet. A path provides controlled bypass for bubbles in the fluid around the armature piston between the fluid pumping chamber and the fluid receiving chamber only during the return stroke of the armature. Fluid inertia is reduced by an outlet orifice in the path of fluid flow from the pump outlet and by a bypass orifice for fluid flow in the bypass path, the orifices being provided either individually or in combination depending upon the fluid flow characteristics of the system including the pump. An accumulator in the fluid flow path between the pump outlet and a catheter leading away from the pump alleviates inertial and viscous effects arising from the catheter.

Abstract: A control mechanism for a fluid displacement apparatus is disclosed. The control mechanism controls fluid communication between an intemediate pressure chamber and a suction chamber of the fluid displacement apparatus, which has a communication channel extending between the intermediate pressure chamber and the suction chamber. The mechanism includes a first valve element having a cylinder and a piston slidably disposed within the cylinder between positions corresponding to maximum and reduced displacement of the compressor. This movement defines a maximum amplitude of the compressor. The cylinder has a bottom wall seperating the cylinder chamber from the suction chamber. A hole is formed in a wall between the cylinder chamber and the intermediate pressure chamber. A distance between the bottom wall and the hole is designed to be greater than the maximum amplitude to prevent the piston from striking the bottom wall.

Abstract: Normally closed valve structure is located in a fluid path between the suction and discharge sides of a compressor. The valve structure opens upon a small pressure differential when the higher pressure is in the normal suction side which is indicative of reverse operation. Additionally, relief valve structure opens when the discharge pressure becomes excessive.

Abstract: An electromagnetic pump comprising a housing having fluid receiving and pumping chambers in communication with an inlet and outlet, respectively, an electromagnet carried by the housing external to the fluid chambers thereof, and an armature movable in the housing having a pole portion magnetically attracted by the electromagnet and a piston portion to force fluid out of the chambers and through the pump outlet. A path provides controlled bypass for bubbles in the fluid around the armature piston portion between the fluid pumping chamber and the fluid receiving chamber only during the return stroke of the armature.Fluid inertia is reduced by an outlet orifice in the path of fluid flow from the pump outlet and by a bypass orifice for fluid flow in the bypass path, the orifices being provided either individually or in combination depending upon the fluid flow characteristics of the system including the pump.

Abstract: A pump with a priming circuit containing a valve having a seating with an orifice and an obturator mounted so as to be able to be applied onto the seating in front of the orifice, where the obturator is a resilient blade embedded on one side to the seating. The flexibility of the blade increases from the embedded side to the other. An L-shaped member protrudes from an outer curvilinear wall of a priming element fixed onto the pump. The L-shaped member allows for the seating to be slide into a groove space. The obturator has two holes so that the obturator can be embedded onto the seat by mating with two projections from the seating surface.

Abstract: A pressure relief assembly for use with a paint pump having a chamber with a pressure relief port located immediately adjacent an inlet port of the pump. The pressure relief assembly includes a mounting member, inlet washer, rupture pad and outlet washer. The mounting member is threaded on its exterior surface and includes an inlet end, an outlet end, and a relief passage extending between the inlet and outlet ends. A rupture recess in the inlet end is sized to receive the inlet washer, rupture pad and outlet washer, with the rupture pad positioned between the washers. The inner diameter surface of the outlet washer is convex. The pressure relief assembly is screwed into the pump with the inlet end adjacent to the pressure relief port. The rupture pad forms a seal between the pump chamber and atmosphere that ruptures to vent the chamber when the pressure within the chamber exceeds a predetermined rupture pressure.

Abstract: An apparatus for regulating the fluid throughput of a rotary screw compressor from a full capacity operating condition to a desired predetermined capacity operating condition includes a turn valve or spiral valve which is disposed in fluid communication with a low pressure fluid. A stepping motor positions the turn valve in a predetermined orientation. A position sensing means is operably connected to the turn valve. The position sensing means detects the angular orientation of the turn valve. A pressure sensing means detects a compressor service pressure. An electronic control means directs the stepping motor in a predetermined orientation. The electronic control means is independently operable to regulate the fluid throughput of the rotary screw compressor from a full capacity operating condition to a predetermined capacity operating condition in response to the first pressure sensing means.

Abstract: A variable displacement compressor includes a housing having therein a space, a rotor eccentrically disposed in the space of the housing so as to define a compression chamber and an intake chamber in the housing, a bypass passage formed in the housing for establishing fluid communication between the compression chamber and the intake chamber and being in the form of a slot, and a device for opening and closing the bypass passage which is movable depending on a pressure in the intake chamber in a direction perpendicular to the bypass passage.

Abstract: In cryogenic applications a compression device circulates a fluid, such as helium, in a closed cooling circuit. The compression device includes at least one compressor, preferably a helical compressor, with a bypass valve connected in parallel thereto, which serves to decompress the compressed fluid. The suction pressure is measured with a pressure measuring device and is supplied to a control device, which controls the position of a powered valve spool of the compressor and also the position of the bypass valve. In order to achieve a high control performance with small bypass losses for load cases which are hard to predetermine, the positions of bypass valve and power valve spool are adjusted so that a fluid flow flows as a control reserve through the bypass valve and is on the order of a fraction of the total fluid flow.

Abstract: In a positive displacement hydraulic pump (68), a system for preventing cavitation includes a regulator valve, a valve spool (74) formed with control lands (76,78) moveable within a bore (72) communicating with control pressure taken at an inlet port (100) and control pressure at a reservoir inlet port (62). The spool opens and closes a connection between the inlet port (96) and outlet port (90) in accordance with changes in differential pressure between the reservoir (atmospheric pressure) and pressure in the inlet port (100). When the differential pressure is low, the valve closes the connection; when the differential pressure is large, the valve opens the connection.

Abstract: A fluid pressure relief assembly for a system operating under an elevated pressure includes a support structure having means defining a bore therethrough of desired cross-sectional configuration, the support structure being provided with a shoulder extending transversely into the bore and presenting a peripheral abutment surface which divides the bore into a first zone an a second zone. The assembly further includes a bidirectional relief means having a central frangible section, and means mounting the relief means across the bore of the support structure in normal flow blocking relationship thereto. A peripheral portion of the central frangible section is disposed to engage the shoulder for support thereby. The central portion of the frangible section within the innermost margin of the shoulder is constructed to undergo rupture only when the pressue in the first zone exceeds the pressure in the second zone by a preselected first magnitude.

Abstract: A fluid pump unit has a flow control valve which returns a portion of a working fluid discharged from a pump assembly when rotation speed of a rotor increases to become greater than a predetermined value. The flow control valve includes an essentially cylindrical spool chamber defined in a pump case, and a valve spool movably housed within the spool chamber. The spool chamber has a pair of through openings on the side wall thereof which through openings are selectively open and closed by movement of the spool valve. The pump case is formed with a pair of drain passages which are respectively communicated with the through openings of the spool chamber independently of each other. When rotation speed of a rotor of the pump assembly becomes greater than a predetermined value, the spool valve opens the through openings to return a part of the discharged working fluid to an inlet passage through which working fluid is introduced from a fluid source into the pump assembly.

Abstract: A pressure relief valve for positive pressure pump systems in which fluid is displaced from the inlet to the outlet of the pump. The pressure relief valve includes a bypass tubing member interconnecting the outlet and a lower pressure area such as the inlet. Pressure limiting means normally occlude the bypass tubing to restrict flow when the outlet pressure of the pump is below a predetermined level and responds to pressure above a predetermined level to shunt fluid from the outlet to the inlet. In the preferred embodiment, the pressure limiting means consists of bar-like members which engage the exterior of the tubing and are biased to compress the bypass tubing to a flow restricting position by elastic bands extending around the bar-like members.

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).