Abstract: A torque control crescent oil pump, having low parasitic loss and rapid pressure transient response, and a method for controlling oil flow within the pump, are provided. In one embodiment, the crescent oil pump comprises a housing, toothed annular gears cooperatively rotating about preferably offset first and second axes, and a crescent body. The crescent body is adapted to move from a first position to a second position. In the first position, the crescent body is adapted to form a seal between the annular gears. In the second position, the crescent body is positioned so that it does not form a seal between the annular gears. In another embodiment, an actuating device moves the crescent body from the first position to the second position.

Abstract: The invention relates to a pump, in particular to oil pumps for internal combustion engines comprising a gear assembly or rotor assembly with one each of a pressure and suction region arranged in a pump housing, which may be sealed from each other by means of an axially displaceable piston valve which defines a supply chamber and a housing cover, closing the pump housing. The pressure region comprises a pressure channel connected to the waist of the control piston, whereby the control piston cooperates with a plunger on the end thereof facing the supply chamber, which is arranged at right angles to the control piston. The plunger is pre-tensioned against the control piston by means of a pressure spring, and the plunger and control piston are connected by means of a sliding surface, arranged at an angle to the control piston axis.

Abstract: A control device for a positive displacement pump includes a throttle device and a flow control valve. The flow control valve includes a flow control piston and is configured to regulate an unrequired excess flow of the pump at an increased speed. The throttle device is configured to produce a speed-related pressure differential in a bore section, the pressure differential being responsible for the displacement of the flow control valve and the throttle device. The throttle device is arranged in the pressure outlet (bore section) of the pump and includes a regulating pin connected to the flow control piston, having a control contour configured so that a modifiable through cross-section is created in association with a throttle bore. The control pin has a wider section in an axial displacement area of the throttle device, the area not being involved in control of the volume flow, whereby a minimum obturating section arises in the displacement area.

Abstract: An oil free screw compressor includes a low-pressure stage compressor body and a high-pressure stage compressor body. Power of a motor driven by an inverter is transmitted to the compressor bodies through gears. A low-pressure stage blow-off two-way valve is provided in a pipe branching off midway an air pipe connecting between the high-pressure stage compressor body and the low-pressure stage compressor body, and a high-pressure stage blow-off two-way valve is provided in a pipe branching off from a discharge air pipe provided on a discharge side of the high-pressure stage compressor body. During no-load operation, a controller gives a command to the inverter to make the rotational speed of the motor a set lower limit rotational speed, and also gives an open command to the low-pressure stage blow-off two-way valve.

Abstract: A compressor bearing assembly for use in a compressor comprises an anti-friction rotation bearing and a compressor component. The anti-friction rotation bearing, has a first and second side. The compressor component has a bearing press fitting hole. The bearing press fitting hole has a mouth and a bottom and is formed in the compressor component and is adapted to receive a first side of a rotation bearing. The bearing press fitting hole has a first inner diameter at its mouth and a second inner diameter in the vicinity of its bottom. The first inner diameter is less than the second inner diameter. The structure for the compressor bearing in this invention may strongly and uniformly fixes the rotation bearing. Further, this structure prevents the rotation bearing from slanting within the pressing hole and prevents undesirable adherence between the rotation bearing and the press fitting hole. As a result, the durability of the rotation bearing and the shaft are improved.

Abstract: A compressor with a capacity modulation system includes a compression chamber, a rotatable shaft within the compression chamber, and a roller mounted on the shaft in contact with a wall of the compression chamber. A suction channel is in fluid communication with the compression chamber for providing fluid at a suction pressure and a discharge channel is in fluid communication with the compression chamber for removing fluid at a discharge pressure. A re-expansion channel adjacent to the compression chamber has a first end forming a re-expansion port in the wall of the compression chamber. A re-expansion chamber is connected to the re-expansion channel. A valve disposed in the re-expansion channel is movable between a first position, in which the valve allows fluid communication between the compression chamber and the re-expansion chamber, and a second position, in which the valve prevents fluid communication between the compression chamber and re-expansion chamber.

Abstract: An engine prelubrication pump includes a pump housing with a pump cavity in which a first and second gear are positioned for pumping fluid. The first gear is operably and sealably connected to a motor for rotation and the second gear is rotatably mounted to a second shaft for geared rotation with the first gear. Fluid inlet and outlet ports are located in communication with the pump cavity and adapted respectively for connection with a source of fluid and a discharge means and an internal vent is positioned in between the armature shaft of bore and the pump housing along the inlet port. Alternatively, a valve is positioned between the inlet and outlet ports to selectively permit fluid pumped between the inlet and outlet ports to pass through when the outlet port is flow restricted.

Abstract: In a compresor at least one bypass valve is arranged in a low-pressure zone inside a casing of the compressor. The bypass valve defines a chamber connected by a first duct to at least one compression pocket situated in the peripheral zone of the compression stage and by a second duct to low-pressure zone, the two ducts opening near one another so that they can be shut off by a shutter which can move in the chamber, being guided by the walls that delimit this chamber, a third duct intended for conveying a shutter-control fluid opening into the lower wall of the chamber of the valve. The shutter is opened by gravity when no control fluid is applied.

Abstract: A scroll type machine incorporates a unique system for monitoring the status of a valve which is used to control the capacity of the compressor. The valve functions to open and close a fluid passage between two areas of the compressor for capacity modulation. By monitoring the temperature of the fluid after the valve, it can be determined whether or not the valve is functioning. If the temperature fluctuates, the valve is functioning. If the temperature is constant, the valve is not operating properly. Another embodiment monitors the pressure within the fluid line controlled by the valve.

Abstract: A variable displacement pump has a cam ring, a rotor, a plurality of vanes, a pressure plate and a rear body. The cam ring is accommodated within a pump body. The rotor rotates within the cam ring. The plurality of vanes are inserted retractably into slits formed at regular intervals circumferentially in the rotor. The pressure plate and the rear body carry the cam ring and the rotor. A circular groove communicating to a back pressure inlet bore on a bottom portion of the slits is formed in a suction area on a face of the rear body on a side of the rotor. The groove is communicated via a communication passage to a passage between a power steering gear and a tank T to introduce a working oil after used in the power steering gear.

Abstract: An improved scroll compressor has condition responsive lubricant volume flow. The lubricant is preferably delivered to a tap positioned adjacent the suction chamber such that lubricant is delivered into the scroll compressor in a quantity which is desirable for normal operation of the scroll compressor. A valve is associated with the tap, and restricts the flow of lubricant through the tap to a first more restrictive non-actuated position. If operational conditions within the scroll compressor indicate that a greater lubricant flow would be desirable, the valve moves to an actuated position at which it is less restrictive to the flow of lubricant.

Abstract: A hydraulic pump has a pair of inlets each with a pair of outlets. The inlets and outlets are arranged to balance the forces on the motor. The flow from the outlets of each pair may be combined to maximize flow or separated to reduce power consumption by recirculating the flow from the outlet to the inlet.

Abstract: A Lysholm compressor is provided with a rotor 5 in which a spiral tooth groove 5a is formed in order to form a tooth groove space 7, the rotor 5 taking-in and compressing a fluid in the tooth groove space 7, a discharge port 9 which discharges fluid which is compressed by the rotor 5, a bypass path 11 which communicates the discharge port 9 and the tooth groove space 7, and an outlet portion 13 of the bypass path which faces the discharge port 9. The outlet portion 13 has a pipe shape which projects out into the discharge port 9. An outer peripheral portion of an end portion of the pipe-shaped bypass path outlet portion is tapered so as to become narrow toward a distal end.

Abstract: In a variable displacement pump, a relief valve is constituted by a pilot drive type relief valve obtained by adding a pilot valve to a main valve, a fluid pressure in a downstream side of a metering orifice provided in a pump discharge side passage is applied to the pilot valve, and the main valve is capable of opening and closing a downstream side passage of the metering orifice with respect to a drain passage.

Abstract: The present invention relates to a roots vacuum pump which is capable of implementing a good outer appearance and an improved layout design of a pump by forming a certain path through which a remaining compression gas is returned to a suction port side of a roots pump in a housing of a roots pump in the case that a gas compressed by a roots pump is not fully exhausted by a latter part pump and remains in an exhaust pot side of the roots pump and is capable of concurrently operating a roots pump and a latter part pump. The roots vacuum pump apparatus in which a root pump and a latter part pump are connected, includes bypass paths formed in at least one inner surface among the inner surfaces of the front cover and the rear cover for communicating the suction pot and exhaust port of the cylinder, and an one-way valve installed in an inlet of the bypass path contacting with the exhaust port for opening the bypass path when a pressure of the exhaust port exceeds a certain level.

Abstract: A scroll compressor of simple structure and low production cost which can be protected when abnormal pressure state or abnormal temperature state of the compressor comprises: a sealed casing including a first chamber for forming a low pressure and a second chamber for forming a high pressure which are divided by a separating panel; a driving unit built in the casing for generating a driving force; a compressed unit connected to the driving unit via a rotating shaft for compressing and discharging fluid when the driving unit is operated; and a protecting device mounted on one side of the separating panel for bypassing the fluid of high pressure or of high temperature in the second chamber to the first chamber when a pressure difference or temperature difference between the first and second chambers is larger than a set value.

Abstract: A compressor C has a construction comprising a cylinder block 1 in which cylinder bores 1a are formed, a front housing 2 and a rear housing 4 which are arranged at the front and at the rear, respectively, of the cylinder block 1. Pistons 20 which are accommodated in each cylinder bore 1a so as to be able to reciprocate, are connected to the cam plate 12, which connects to a drive shaft 6 so as to be able to integrally rotate, so as to operate, and the pistons 20 compress refrigerant gas according to the rotation of the drive shaft 6. A suction muffler 40, a discharge muffler 41 and a control valve 31 are provided between the cylinder bores 1a in the cylinder block 1. Further, a unit 60 which comprises a discharge check valve and an oil separator is disposed in the suction muffler 40.

Abstract: The invention relates to a vane-cell pump comprising a pump rotor (20), provided with a radially displaceable rotor blade (22). Said pump rotor is mounted in a pump stator (12) which can be pivoted inside a pump bearing house (10) around a stationary pivotal axis (34) in a radial position with regard to said pump rotor. A control device (30) is associated with the pump stator (12) for automatic pressure adjustment. Said control device has an actuating member protruding on the outside, therefrom, perpendicular to the pivotal axis thereof. The actuating member forms a pivoting piston (38) in a guide element (10) of the pumpbearing housing (10) which is directly impinged upon by a pumping medium. The pivotable piston can pivot in a direction against the action of a pressure spring (50).

Abstract: A multi-stage internal gear fuel pump for a vehicle includes a housing having an inlet and an outlet and a motor disposed in the housing. The multi-stage internal gear fuel pump also includes a shaft extending axially and disposed in the housing for rotation by the motor. The multi-stage internal gear fuel pump further includes a plurality of pumping modules disposed axially along the shaft and each having an internal gear and an external gear cooperating with each other for rotation by the motor to pump fuel from the inlet to the outlet.

Abstract: An integrated, i.e unitary, rotary hydraulic vane pump assembly reduces cost and simplifies manufacturing thereof. The integrated assembly includes an electric motor, a rotary vane pump, a pump housing and an end bell. The end bell has an inlet fitting or passageway which communicates with the inlet of the rotary vane pump. The pump housing receives the vane pump and is received within the end bell. The electric motor is secured to the face of the pump housing opposite the end bell. The pump housing includes outlet passageways and a centrally disposed axial opening for receiving an output shaft of the electric motor. The rotary vane pump includes end sections and a center, cam ring section which receives a vane rotor assembly coupled to the output shaft.

Abstract: A scroll compressor includes a plurality of components which are force-fit together. The components include the separator plate, a pressure relief valve mounted in the separator plate, and a discharge tube. By force-fitting these components, the necessity of welding operations in the interior of the scroll member is eliminated. This will reduce the occurrence of weld splatter, which is undesirable. Further, the assembly of the scroll compressor is simplified by this invention.

Abstract: A compressor with a capacity modulation system includes a compression chamber, a rotatable shaft within the compression chamber, and a roller mounted on the shaft in contact with a wall of the compression chamber. A suction channel is in fluid communication with the compression chamber for providing fluid at a suction pressure and a discharge channel is in fluid communication with the compression chamber for removing fluid at a discharge pressure. A re-expansion channel adjacent to the compression chamber has a first end forming a re-expansion port in the wall of the compression chamber. A re-expansion chamber is connected to the re-expansion channel. A valve disposed in the re-expansion channel is movable between a first position, in which the valve allows fluid communication between the compression chamber and the re-expansion chamber, and a second position, in which the valve prevents fluid communication between the compression chamber and the re-expansion chamber.

Abstract: A housing for a screw compressor, includes a single-piece casting defining a motor housing section and a rotor housing section and has an inlet for compressor medium, an outlet end and a bridge member disposed between the motor housing section and the rotor housing section and defining an inlet side bearing housing; a discharge housing mounted to the outlet end and defining an outlet and a discharge side bearing housing; and at least one rotor disposed in the rotor housing section and rotatably mounted between the inlet side bearing housing and the discharge side bearing housing.

Abstract: A variable pressure oil pump assembly for use with a vehicle having a controller includes a pump body having an inlet, an outlet, a valve chamber, a first passage disposed between the inlet and the valve chamber, and a second passage disposed between the outlet and the valve chamber. The assembly further includes a pressure relief valve subassembly having a movable plunger that is disposed at least partially in the valve chamber for controlling flow of oil through the valve chamber so as to control outlet oil pressure at the outlet. A plunger adjustment mechanism is associated with the valve subassembly and adapted to communicate with the controller. The plunger adjustment mechanism is operable to control movement of the plunger based on control signals provided by the controller.

Abstract: A relief valve assembly, comprises: a relief valve; a valve housing including a valve path along which the relief valve can slide; a relief inflow portion formed on one end of the valve housing; and relief discharge portions formed at an intermediate location of the valve path of the valve housing and provided with small aperture portions axed large aperture portions formed in communication with one another. A side wherein the relief discharge portions are provided with the small aperture portions is the side near the relief inflow portion.

Abstract: This invention offers advantages and alternatives over the prior art by providing a dual port hydraulic fixed displacement pump which exhibits improved efficiency by limiting the volume of discharged fluid which is subjected to the line pressure of a hydraulic system through mechanical valve control. According to the present invention, a pair of discharge ports are provided, namely a first discharge port and a second discharge port. Under all operating conditions, e.g., low and high pump speed operating conditions, the fluid flowing within the first discharge port and primary discharge passageway is exposed to the working pressure of the primary line, which represents a high pressure line. The second discharge port fluidly communicates with a secondary discharge passageway which is in selective fluid communication with a low pressure line connected to a low pressure area of the pump (e.g.

Abstract: A first bypass valve (27) that sets discharge capacity to 60% is provided in a first scroll 21 of an asymmetrical spiral-type scroll compressor. Also, a second bypass valve (40) that makes suction side and discharge side communicated with each other so that set load of the compressor becomes 50% is provided outside a scroll of the first scroll (21). In this way, by closing the first and second bypass valves (27, 40), effective load of the compressor is set to 100%. Also, by opening the first bypass valve (27) and concurrently closing the second bypass valve (40), the effective load of the compressor is set to 60%. Further, by opening both the first and second bypass valves (27, 40), the effective load of the compressor is set to 30%.

Abstract: A variable displacement pump (28) having a combination inlet port (71) and an outlet (76) formed integrally on the rear body (32). By integrating the combination inlet port (71) and outlet (76) on the rear body (32), this invention simplifies the manufacture of the pump (28) as compared with known variable displacement pumps.

Abstract: A rotary machine includes a rotor and a disk-shaped valve that contra-rotate within a cylindrical housing while in non-slipping contact with each other. The rotor includes one or more pistons. In one embodiment of the rotary machine, the valve includes a recess that is shaped epitrochoidally to accommodate the pistons as the pistons pass the valve. Each piston includes a seal that is in sliding contact with the surface of a lining of the recess as the piston passes the valve and that is otherwise in sliding contact with the surface of an inner lining of the housing. The linings and the seal are coated with a polishing composition, so that the seal and the lining are continuously polished as the machine operates. In another embodiment of the rotary machine, the rotor and the valve are shaped to be in constant mutual rolling contact.

Abstract: The present invention relates to a variable capacity helical screw compressor for compressing a gaseous medium, usually air. The compressor includes at least one lift valve (1) which connects with a first compression chamber in the compressor.

Abstract: A fluid pump includes a pump housing with a pump cavity in which a first and second gear are positioned for pumping fluid. The first gear is operably connected to a motor for rotation and the second gear is rotatably mounted to a shaft for geared rotation with the first gear. Fluid inlet and outlet ports are located in communication with the pump cavity and adapted respectively for connection with a source of fluid and a discharge means. A bypass valve is positioned between the inlet and outlet ports to selectively permit fluid pumped between the inlet and outlet ports to pass through it when the outlet port is flow restricted. The bypass valve is normally closed to fluid pumped by said first and second gears to flow from said inlet port to said outlet port, but is opened to permit flow to cavitate when not desired to pump.

Abstract: A scroll type machine incorporates a unique system for monitoring the status of a valve which is used to control the capacity of the compressor. The valve functions to open and close a fluid passage between two areas of the compressor for capacity modulation. By monitoring the temperature of the fluid after the valve, it can be determined whether or not the valve is functioning. If the temperature fluctuates, the valve is functioning. If the temperature is constant, the valve is not operating properly. Another embodiment monitors the pressure within the fluid line controlled by the valve.

Abstract: An integrated, i.e. unitary, rotary hydraulic vane pump assembly reduces cost and simplifies manufacturing thereof. The integrated assembly includes an electric motor, a rotary vane pump, a pump housing and an end bell. The end bell has an inlet fitting or passageway which communicates with the inlet of the rotary vane pump. The pump housing receives the vane pump and is received within the end bell. The electric motor is secured to the face of the pump housing opposite the end bell. The pump housing includes outlet passageways and a centrally disposed axial opening for receiving an output shaft of the electric motor. The rotary vane pump includes end sections and a center, cam ring section which receives a vane rotor assembly coupled to the output shaft.

Abstract: To provide a gas compressor in which saving of power as well as improved compression performance and durability are attained by enabling reduction of vane back pressure without degrading the projectability of the vanes upon starting operation of the compressor. Scoop grooves and a high pressure supply hole are arranged so as to be spaced apart from each other, and the interval therebetween is set to an interval sufficient to ensure that a vane groove is communicated with neither the scoop grooves nor the high pressure supply hole while the vane groove moves apart from the scoop grooves toward the high pressure supply hole. Further, if there has occurred a reversed pressure relationship between a suction chamber (low-pressure chamber) and a discharge chamber (high-pressure chamber), a pressure control valve is actuated upon starting operation of the compressor to interconnect the scoop groove with the suction chamber side.

Abstract: A device for supplying liquids, in particular, fuel, has a first geared supply pump (30) with a pair of meshed gear wheels (41, 43) in a pump chamber, of which one is rotatably driven by means of a drive shaft (38). In the pump chamber (40), an inlet opens on a suction side (48) and an outlet (86) opens on a pressure side (49). In the direction of rotational axes (42, 45) of the gear wheels (41, 43) of the first supply pump (30), a second geared supply pump (60) is provided, which has a meshed pair of gear wheels (64, 68) in a pump chamber (62). One of the gear wheels (64) of the second supply pump (60) is rotatably and lockingly connectable to the drive shaft (38) by means of a coupling arrangement (66). The coupling arrangement (66) is controlled by the existing pressure on the pressure side (49) of the first geared supply pump (30).

Abstract: A capacity-controlled scroll compressor for reducing a start shock and improving machinability of a fixed end plate, wherein a high pressure Ph to be guided to a control valve (70) for controlling a control pressure Pm for operating a shuttle valve (60) is introduced from a high pressure passage (72) opening at a discharge port (1c) to reduce a start shock. A bypass hole (52a) and the high pressure passage (72) are constituted by a straight through-hole extending through a cylinder (61) from the outer peripheral portion of a fixed end plate (1a) and consequently, machinability of the fixed end plate (1a) can be improved.

Abstract: The present invention is directed to a method of reducing cooling capacity in a rotary vane compressor in such a way that the power requirement to drive the rotor is reduced to the same extent (or close to) as capacity is reduced. An economizer port operating in economizing and unloading cycles is located in the compression region at a point after the compression chamber has been closed for the compression and at a point where sufficient both unloading (reducing) and economizing (increasing) capacities are provided. A valve is associated with the economizer port, the valve body being formed from a part of the stator body. A seat of the valve in the closed position is shaped to be contiguous with the wall portion of the stator. In an opened position the valve provides conmumnication between the compression chamber and an external portion of the economizer port.

Abstract: In a scroll compressor which is capable of simplifying a structure of a valve, decreasing a size of a whole compressor and lowering a noise occurred in the valve by having simultaneously a function for preventing a backward flow of a fluid and a function for preventing a compressor from being in a vacuum state simultaneously with one valve, a scroll compressor in accordance with the present invention includes a casing having a hermetically sealed certain space divided into a first chamber at which a fluid is sucked and a second chamber at which a compressed fluid is discharged, a driving unit housed inside the casing and generating a driving force, a compressing unit including a fixed scroll and an orbiting scroll connected to the driving unit by a rotational shaft in order to compress and discharge the fluid when the driving unit is operated and a valve assembly rotatively installed to the upper surface of the fixed scroll, opening/closing a discharge hole at which the compressed fluid is discharged and open

Abstract: A cam ring 10 is slidably supported within a pump body 2, and a rotor 20 is rotatably disposed inside the cam ring. The cam ring is eccentric to a rotation shaft 22 of the rotor. The rotor carries a plurality of vanes 18 that can be advanced or retreated, in which a pump chamber 24 is formed in a space between the cam ring and the rotor. The cam ring is formed with the first and second fluid pressure chambers 14 and 16 on both sides thereof, and biased in a direction where the displacement of the pump chamber is at maximum by a spring 26. A control valve 28 is provided in which a differential pressure across a metering orifice is applied on both ends of a spool 32 and a spring 36 is disposed on the side of an end face where a downstream fluid pressure is applied. The fluid pressures of the fluid pressure chambers 14 and 16 are controlled by means of the control valve, whereby the cam ring is swung.

Abstract: A highly-viscous-fluid applying apparatus including a fluid supply device operable to supply a highly viscous fluid, a delivery nozzle from which the highly viscous fluid is delivered, a pump disposed between the fluid supply device and the delivery nozzle and operable to feed the highly viscous fluid received from the fluid supply device, to the delivery nozzle, and a pump control device operable to control the pump, for controlling an amount of delivery of the highly viscous fluid to be delivered from the delivery nozzle.

Abstract: A first bypass valve (27) that sets discharge capacity to 60% is provided in a first scroll 21 of an asymmetrical spiral-type scroll compressor. Also, a second bypass valve (40) that makes suction side and discharge side communicated with each other so that set load of the compressor becomes 50% is provided outside a scroll of the first scroll (21). In this way, by closing the first and second bypass valves (27, 40), effective load of the compressor is set to 100%. Also, by opening the first bypass valve (27) and concurrently closing the second bypass valve (40), the effective load of the compressor is set to 60%. Further, by opening both the first and second bypass valves (27, 40), the effective load of the compressor is set to 30%. That is, 50% or lower partial load operation with high reliability is performed by setting volume ratio Vr during minimum capacity operation to a value of “1” or more. As a result of this, 50% or lower partial load operation can be changed over in multiple stages.

Abstract: A dual gerotor pump is used for an automatic transmission. A dual gerotor pump which is driven by a central drive mechanism has a first chamber which continuously provides transmission fluid to the automatic transmission. The pump also has a second pumping chamber which selectively directs fluid to the automatic transmission when necessary. A valve mechanism is provided to divert fluid from the second pumping chamber back to the second pumping chamber so that it can recirculate thereby decreasing fluid pressure to the automatic transmission when it is not required.

Abstract: In a variable displacement pump for a power steering device of a vehicle, the adapter ring is arranged to be easily engaged with the engagement hole at the pump casing, to improve ease of assembly. The relationship of the adapter ring with the engagement hole reduces vibration and noise.

Abstract: A screw vacuum pump (1) has rotors (5), bearings (7, 8), a casing (4), a suction side (15), and a delivery side (24). Each of the rotors includes at least two rotor sections, a suction side rotor section (17) and a delivery side rotor section (18). The two rotor sections are separately constructed and joined together in a positive, form-fitting or friction locking manner. The suction side rotor section is preferably larger in diameter and constructed with looser tolerances as compared to the delivery side rotor section. The suction side rotor is preferably of an inexpensive material such as aluminum while the discharge side rotor is preferably constructed of a higher performance material such as stainless steel. The rotor sections are supported on a rotor shaft (6) into which cooling fluid is injected through a cooling pipe (33). Cooling fluid from the shaft is also circulated through the bearings and passages in the casing eventually reaching a sump (37) in preparation for recirculation.

Abstract: A capacity-controlled scroll compressor having a simple, compact and high-reliability control mechanism, including two pairs of bypass holes (50a, 50b, 51a and 51b) each communicating with each of a pair of fluid pockets in the same compression process, a bypass hole (52a) communicating with one fluid pocket formed from the pair of fluid pockets aligned as the compression process further proceeds, and a shuttle valve (60) for sequentially opening and closing the bypass holes by reciprocating motion, and fitted into a cylinder (61) disposed inside a fixed end plate (1a). The shuttle valve (60) has a stepped cylindrical structure having different outer diameters so as to improve the strength and rigidity of the shuttle valve itself. The smooth operation of the shuttle valve (60) can be ensured even at high temperatures and high pressures.

Abstract: A tube pump in which the rotor is axially supported by permanent magnets at each end, so arranged as to apply attractive force across the gap between the rotor and a stator such that permanent magnets provide the sole radial support for the rotor. The axially effective permanent magnets are provided in conjunction with an electromagnetic stabilizer restoring the axial position of the rotor upon a shaft toward one or the other of the opposite ends thereof.

Abstract: A scroll compressor assembly includes a first linear drive for driving a first scroll along a first linear axis and a second linear drive for driving the first or second scroll along a second linear axis which is non-parallel to the first linear axis. Relative orbital movement between the first and second scrolls is obtained by controlling the frequency of oscillations of the first linear motor along a first linear axis and the second linear motor along the second linear axis. Further, capacity control is achieved by varying the movement of the first and second linear motors.

Abstract: A motor-driven compressor is formed integrally with a compressor device for compressing refrigerant and a motor for driving the compressor device. The motor-driven compressor includes a drive circuit and a plurality of cooling fins. The drive circuit controls the operation of the motor. The drive circuit is provided on an outer surface of a wall of a refrigerant suction route. The plurality of cooling fins are formed on an inner surface of the wall of the refrigerant suction route. In such motor-driven compressors, the drive circuit may be sufficiently cooled without using cooling devices. As a result, providing cooling devices with the drive circuit in motor-driven compressors is no longer necessary.

Abstract: A vane pump, having an inlet for receiving fuel and an outlet from which fuel is supplied, comprising a generally cylindrical member, a driven rotor arranged within the cylindrical member and a closure member. The cylindrical member and the closure member co-operate to define a recirculation passage interconnecting the outlet and the inlet, the output pressure of fuel discharged from the pump being regulated by a resiliently biased valve means controlling the flow of fuel through said recirculation passage.

Abstract: A medical gear pump is used for suction and irrigation, in particular for endoscopy or the laboratory, and it has two meshing gears as conveying elements, one of which is joined to a drive mechanism. The gears are received in non-journal-mounted fashion in openings, and are each equipped with a helical tooth set. It is proposed to configure the helical tooth set such that, when viewed along a surface line of said gears, at least two tooth tip/root contact points of said meshing gears are present, and a contour of tooth spaces of the one gear is matched to the teeth of the other gear in such a way that when a tooth has completely penetrated into the tooth space, its tooth tip almost completely fills up the tooth space radially inside the pitch circle.