Abstract: A compressor includes a low-pressure stage cylinder, a first high-pressure stage cylinder and a second high-pressure stage cylinder which are stacked, a partition is arranged between each two adjacent cylinders, the first and second high-pressure stage cylinders are both situated at a same side of the low-pressure stage cylinder or respectively situated at two sides of the low-pressure stage cylinder, the lower flange is situated below the low-pressure stage cylinder, the first high-pressure stage cylinder and the second high-pressure stage cylinder. A first sliding sheet is provided in the first high-pressure stage cylinder, a second sliding sheet is provided in the second high-pressure stage cylinder, and a third sliding sheet is provided in the low-pressure stage cylinder. The first and the second high-pressure stage cylinders are arranged in parallel, and the first and second high-pressure stage cylinders arranged in parallel are connected to the low-pressure stage cylinder in series.

Abstract: The scroll refrigeration compressor includes a sealed casing, stationary and moving volutes including spiral wraps engaged in one another and defining the variable-volume compression chambers, a delivery chamber defined by the plate of the stationary volute and the sealed casing, a heat shield disposed in the delivery chamber and dividing the delivery chamber into a first volume defined by the plate of the stationary volute and the heat shield and a second volume defined by the heat shield and the sealed casing, and at least one flow passage arranged to communicate the first and second volumes. The compressor further includes at least one bypass passage arranged to communicate the first volume with an intermediate compression chamber, and at least one bypass valve disposed in the first volume and movable between closing and opening positions for closing and opening the corresponding bypass passage.

Abstract: The scroll refrigeration compressor includes a stationary volute and a moving volute provided with spiral wraps defining variable-volume compression chambers, a separating member sealably mounted on a plate of the stationary volute so as to allow a relative movement between the separating member and the stationary volute, a delivery chamber at least partially defined by the separating member and the sealed casing. The compressor further includes a bypass passage arranged to communicate the delivery chamber with an intermediate compression chamber, and a anti-return device comprising a closing member movable between closing and opening positions for closing and opening the bypass passage, and an enclosure, positioned between the separating member and the plate of the stationary volute, including a first portion sealably mounted in a housing defined by the separating member and oriented substantially parallel to the longitudinal axis of the compressor.

Abstract: A system for providing pressurized hydraulic fluid in a transmission of a motor vehicle includes a pump for providing pressurized hydraulic fluid having an inlet port and an outlet port. A bypass valve includes an inlet port in communication with the outlet port of the pump, a first outlet port in communication with the inlet port of the pump, and a second outlet port. The inlet port of the bypass valve is in communication with the second outlet port of the bypass valve when the bypass valve is in a first position and the inlet port of the bypass valve is in communication with the first outlet port of the bypass valve when the bypass valve is in a second position. A control device and accumulator are operatively associated with the bypass valve.

Abstract: A system for pressurizing a working fluid including a cylinder having an outlet through which the working fluid is exhausted at a discharge pressure and a plunger translatably disposed within the cylinder, the plunger including a first piston coupled thereto. In addition, the system includes a second piston disposed opposite the first piston, the second piston driven to reciprocate and a variable-volume chamber disposed between the first piston and the second piston, the variable-volume chamber substantially filled with a volume of hydraulic fluid. Further, the system includes a hydraulic system configured to adjust the volume of hydraulic fluid within the variable-volume chamber, whereby the discharge pressure is maintained substantially at a first predetermined level. Still further, the system includes a transducer coupled to each of the first piston and the second piston, wherein the transducer is configured to measure a relative position of the first piston and the second piston.

Abstract: A compressor includes a housing, a first scroll member, a second scroll member and a modulation assembly. The first scroll member includes a first end plate having a discharge passage, a first spiral wrap, and a first aperture extending through the first end plate. The second scroll member includes a second end plate having a second spiral wrap extending therefrom and meshingly engaged with the first spiral wrap to form a series of pockets. The first aperture is in communication with a first of the pockets. The modulation assembly is in communication with the first aperture and is operable in a full capacity mode where the first aperture is isolated from a suction pressure region providing full capacity operation and in a reduced capacity mode where the first aperture is in communication with the suction pressure region providing approximately zero capacity operation.

Abstract: At least one choked flow passage communicates between one side of the movable member and the other side of the movable member and limits an amount of fuel, which passes from the one side of the movable member to the other side of the movable member, when the movable member is moved by an urging force of a relief spring toward a valve element. A larger amount of fuel, which is larger than the amount of fuel that is passable through the at least one choked flow passage, flows from a first return flow passage to a second return flow passage, when the movable member is moved toward the other side, which is opposite from the valve element, against the urging force of the relief spring.

Abstract: A scroll compressor has a housing enclosing a compressor pump unit which includes an orbiting scroll member and a non-orbiting scroll member. Each of the orbiting and non-orbiting scroll members include a base and a generally spiral wrap extending from the base. The wraps interfit to define compression chambers, with a central-most discharge pressure chamber, and circumferentially spaced intermediate pressure chambers being defined. The base of the non-orbiting scroll includes ports associated with the intermediate pressure chambers. At least one port is associated with the discharge pressure chamber. Valves are associated with each of the ports. A discharge plenum is defined downstream of the ports and valves within the housing. A back pressure chamber is defined behind the base of one of the orbiting and non-orbiting scroll members, and taps a refrigerant from the discharge pressure chamber.

Abstract: An improved floating apparatus for scroll compressors is disclosed, which is a multi-function device integrating a temperature protection mechanism, a pressure protection mechanism and a backflow-proof mechanism and therefore substantially is a floating seal member with overheating protection, high pressure protection and backflow-proof capabilities. In detail, the present disclosure provides a floating apparatus for scroll compressors that not only can be manufactured easily, but also capable of distributing the acting force resulting from the gliding block for providing better sealing effect while preventing the scroll compressors from being damaged by high temperature and high pressure.

Abstract: A dual-pump fluid distribution system that includes a first pump having an inlet and an outlet, and configured to supply a first flow of fluid, and a second pump having an inlet and an outlet, and configured to supply a second flow of fluid. In an embodiment, a bypass flow valve with a four-way hydraulic bridge is configured to initiate the switch between single-pump mode and dual-pump mode based on fluid flow demand. The bypass flow valve is configured such that the position of the bypass flow valve member relative to the four-way hydraulic bridge operates a pump selector valve. In an embodiment, the pump selector valve has a valve member, a biasing element, and a pressure switching port, and is configured such that the position of the valve member determines whether the second flow of fluid is combined with the first flow of fluid.

Abstract: An oil supply system of an automatic transmission includes a first oil pump pumping up oil from the oil reservoir and supplying the oil to the low-pressure part, a low-pressure regulating valve connected to a low-pressure part channel connecting the first oil pump with the low-pressure part, and controlling the pressure of the oil discharged from the first oil pump at pressure required by the low-pressure part, a second oil pump receiving the oil of which the pressure is controlled through the low-pressure regulating valve and supplying the oil to the high-pressure part, and a high-pressure regulating valve connected to a high-pressure part channel connecting the second oil pump with the high-pressure part and controlling the pressure of the oil discharged from the second oil pump at pressure required by the high-pressure part.

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 compressor including a housing defining a suction pressure region and a discharge pressure region includes first and second scroll members forming compression pockets. A first chamber located on the first end plate of the first scroll member includes first and second passages and a first aperture extending therethrough and in communication with the first chamber. The first aperture provides communication between a compression pocket and the first chamber. A piston in the first chamber is axially displaceable to isolate the first passage from communication with the second passage when in first and second positions, prevent communication between the first aperture and the first passage when in the first position, and provide communication between the first aperture and the first passage when in the second position.

Abstract: A housing has a compression chamber and a first passage, through which the compression chamber communicates with an accumulation chamber. A discharge valve is provided in the first passage and configured to open to supply fuel from the compression chamber to the accumulation chamber in response to increase in pressure in the compression chamber. A second passage is configured to communicate the accumulation chamber with the compression chamber via the discharge valve. A valve element allows fuel flow from the accumulation chamber to the compression chamber. A biasing unit biases the valve element to seat the valve element on a valve seat of the second passage. The sidewall of the valve element and the inner wall defining the second passage therebetween define a throttle midway through the second passage for restricting fuel flow from the accumulation chamber to the compression chamber.

Abstract: In order to make a displacement type compressor be able to reliably start without increasing an outside diameter dimension of the compressor while using a self-start synchronous motor having high energy efficiency, the displacement type compressor according to the invention includes the self-start synchronous motor which starts as an induction-motor and performs synchronous operation by performing synchronization pull-in almost at a synchronous rotational frequency, a compression part having a compression chamber which compresses a working fluid, and a hermetic container which houses the self-start synchronous motor and the compression part. The displacement type compressor is provided with a start load reducing means which reduces a load of the compression part at startup and is placed at the compression part in the hermetic container.

Abstract: A fuel system for a turbine engine is provided. The fuel system includes a positive displacement pump driven by an electric motor. The pump is rotated in a first direction to deliver fuel to the turbine engine, and a second direction for evacuating fuel from the turbine engine. A shut-off check valve is open in a first direction in response to a first differential pressure created by the pump in the first direction. The shut-off check valve is biased to a closed position when the pump is rotating in the second direction. An ecology check valve is biased to a closed position in the first direction and open in the second direction in response to a second differential pressure created by the pump. The check valves open and close automatically in response to the pressures generated by the positive displacement pump in each of the first and second rotational directions. In this manner, simple, reliable valves are utilized to regulate the flow of fuel in the fuel system.

Abstract: A housing has a compression chamber and a first passage, through which the compression chamber communicates with an accumulation chamber. A discharge valve is provided in the first passage and configured to open to supply fuel from the compression chamber to the accumulation chamber in response to increase in pressure in the compression chamber. A second passage is configured to communicate the accumulation chamber with the compression chamber via the discharge valve. A valve element allows fuel flow from the accumulation chamber to the compression chamber. A biasing unit biases the valve element to seat the valve element on a valve seat of the second passage. The sidewall of the valve element and the inner wall defining the second passage therebetween define a throttle midway through the second passage for restricting fuel flow from the accumulation chamber to the compression chamber.

Abstract: A flow sensing dual pump switching system and method are provided that control the supply of fuel from a dual pump fuel system to a fuel metering unit. The system senses bypass pressure from the fuel metering unit to control the differential pressurization of the second pump. As the bypass is reduced, the pressure of the second pump is increased so that it may be added to that of the first pump to supply the increased fuel consumption needs of an engine. As the fuel consumption needs decrease, the flow from the second pump added to the first pump is reduced and the differential pressure of the second pump is similarly reduced. If the bypass pressure remains high, the switching system disconnects the output of the second pump from that of the first in favor of bypassing the flow to its input to reduce its differential pressure and conserve energy.

Abstract: A fuel system for a turbine engine is provided. The fuel system includes a positive displacement pump driven by an electric motor. The pump is rotated in a first direction to deliver fuel to the turbine engine, and a second direction for evacuating fuel from the turbine engine. A shut-off check valve is open in a first direction in response to a first differential pressure created by the pump in the first direction. The shut-off check valve is biased to a closed position when the pump is rotating in the second direction. An ecology check valve is biased to a closed position in the first direction and open in the second direction in response to a second differential pressure created by the pump. The check valves open and close automatically in response to the pressures generated by the positive displacement pump in each of the first and second rotational directions. In this manner, simple, reliable valves are utilized to regulate the flow of fuel in the fuel system.

Abstract: A compressor may include a housing and first and second scroll members supported within the housing, each having an end plate with a spiral wrap extending therefrom and meshingly engaged with the other to form a series of compression pockets operating at an intermediate fluid pressure between a suction pressure and a discharge pressure. A first passage in communication with one of the compression pockets extends from a first side of the first end plate to a second side of the first end plate generally opposite the first side. A modulation plate overlies the second side of the first scroll member for radial displacement between first and second positions. The modulation plate isolates the first passage from communication with a suction pressure region of the compressor when in the first position and provides communication between the first passage and the suction pressure region when in the second position.

Abstract: A compressor may include a shell assembly defining suction and discharge pressure regions, first and second scroll members disposed within the shell assembly, and a capacity modulation assembly. The first scroll member may include a first end plate defining a discharge passage, a biasing passage, a modulation port, a first spiral wrap extending from a first side of the first end plate, and an annular hub extending from a second side of the first end plate. The second scroll member may include a second spiral wrap meshingly engaged with the first spiral wrap forming a suction pocket in communication with the suction pressure region, intermediate compression pockets, and a discharge pocket in communication with the discharge passage. A first intermediate compression pocket may be in communication with the biasing passage and a second intermediate compression pocket may be in communication with the modulation port.

Abstract: A compressor includes a housing, a first scroll member supported within the housing and having a first end plate with a discharge passage, and a second scroll member supported within the housing and having a second end plate with a second spiral wrap extending therefrom and meshingly engaged with the first spiral wrap to form a series of pockets. A first aperture extends through the first end plate and is in communication with a first product of the series of pockets. A modulation assembly axially biases the first scroll member into engagement with the second scroll member when the first aperture is in communication with a suction pressure region of the compressor.

Abstract: A compressor may include a housing, orbiting and non-orbiting scroll members, a first porting, and a second porting. The first and second porting may each extend through the end plate of the non-orbiting scroll member and may each have an angular extent of at least twenty degrees. An ending point of the first porting may be rotationally spaced from a starting point of the first porting by the angular extent in a rotational direction of a drive shaft of the compressor. An ending point of the second porting may be rotationally spaced from a starting point of the second porting by the angular extent in a rotational direction opposite the rotational direction of the drive shaft. The ending point of the second porting may be rotationally spaced from the starting point of the first porting by less than one hundred and eighty degrees in the rotational direction of the drive shaft.

Abstract: A compressor may include a housing, first and second scroll members, and a compressor output adjustment assembly. The first scroll member may define a first chamber having first and second passages in communication therewith, a second chamber having third and fourth passages in communication therewith, and first and second apertures. The first and third passages may be in communication with a first pressure source and the second and fourth passages may be selectively in communication with a second pressure source. The compressor output adjustment assembly may include a first piston located in the first chamber and displaceable between first and second positions and a second piston located in the second chamber and displaceable between first and second positions. The first piston may isolate the first aperture from the first passage and the second piston may isolate the second aperture from the third passage when in their respective second positions.

Abstract: A flow prioritizing system includes a regulating valve and a flow prioritizing valve. The regulating valve receives a first portion of the fluid supplied from a fuel supply pump, and is responsive to a control pressure to selectively allow or prohibit flow to secondary loads. The flow prioritizing control valve is responsive to fluid pressure representative of delivery pump discharge pressure to control the control pressure to which the regulating valve is responsive.

Abstract: A system and method provide dual level pressurization control of a fuel supply system based on whether fuel is being supplied to one or more secondary fuel loads. Fuel pump discharge backpressure is maintained above either a first minimum pressure value or a lower second minimum pressure value by determining whether fuel is being supplied to one or more secondary fuel loads. The fuel pump discharge pressure is maintained above the first minimum pressure value if it is determined that fuel is being supplied to the one or more secondary loads. The fuel pump discharge backpressure is maintained above the lower second minimum pressure value if it is determined that fuel is not being supplied to the one or more secondary loads.

Abstract: An apparatus for preventing vacuum of a scroll compressor is provided. The apparatus includes a fixed scroll having a bypass hole, through which a suction chamber of a casing is connected to a discharge chamber of the casing; a valve block having an inner channel, through which the bypass hole of the fixed scroll is connected to the discharge chamber of the casing, and fixedly installed at the fixed scroll; and a valve member disposed between the bypass hole of the fixed scroll and the inner channel of the valve block. Since the apparatus is assembled at an outer periphery of the fixed scroll, a processing error of the fixed scroll is prevented, thereby reducing production costs. Also, since foreign materials generated when a refrigerant channel is processed do not remain in a valve hole, the valve member is prevented from being mal-operated, productivity is enhanced, and fabrication costs reduced.

Abstract: A fluid metering device for monitoring flow of fluid is provided. The fluid metering device comprises: an electric motor; and a housing having a manifold section, a motor adapter plate and a pressure retaining container, said pressure retaining container encompassing a pressurized chamber having a hydraulic pump placed in the pressurized chamber; and the manifold section including an air bleed valve and a pressure biased relief valve for maintaining pressure within the housing.

Abstract: A fuel system for a turbine engine is provided. The fuel system includes a positive displacement pump driven by an electric motor. The pump is rotated in a first direction to deliver fuel to the turbine engine, and a second direction for evacuating fuel from the turbine engine. A shut-off check valve is open in a first direction in response to a first differential pressure created by the pump in the first direction. The shut-off check valve is biased to a closed position when the pump is rotating in the second direction. An ecology check valve is biased to a closed position in the first direction and open in the second direction in response to a second differential pressure created by the pump. The check valves open and close automatically in response to the pressures generated by the positive displacement pump in each of the first and second rotational directions. In this manner, simple, reliable valves are utilized to regulate the flow of fuel in the fuel system.

Abstract: A switch valve structure of a fluid machine (10) having a pump mode to operate as a compressor and a motor mode to operate as an expander is disclosed. In pump mode, a communication path (106) between a working chamber (V) and a high-pressure chamber (104) is closed, while in motor mode, the communication path (106) is opened by a valve unit (107d). The valve unit (107d) is includes a spool portion (117) sliding in the direction substantially perpendicular to the surface to which the communication path (106) opens and a valve portion (127) arranged at the forward end of the spool portion (127) and sliding with the spool portion (117) thereby to open/close the communication path (106). A swivel mechanism (137) is interposed between the spool portion (117) and the valve portion (127) to tilt the sliding axis of the valve portion (127) at an arbitrary angle with respect to the sliding axis of the spool portion (117).

Abstract: In order to make a displacement type compressor be able to reliably start without increasing an outside diameter dimension of the compressor while using a self-start synchronous motor having high energy efficiency, the displacement type compressor according to the invention includes the self-start synchronous motor which starts as an induction-motor and performs synchronous operation by performing synchronization pull-in almost at a synchronous rotational frequency, a compression part having a compression chamber which compresses a working fluid, and a hermetic container which houses the self-start synchronous motor and the compression part. The displacement type compressor is provided with a start load reducing means which reduces a load of the compression part at startup and is-placed at the compression part in the hermetic container.

Abstract: Bypass valve assembly that selectively establishes a bypass path for a fluid delivery system and having a body member with a fluid inlet and a bypass fluid outlet, a slidable piston assembly and a slidable cage assembly. Spring members bias the piston assembly and the cage assembly to a closed position to prevent fluid flow from the fluid inlet to the bypass fluid outlet when the delivery pressure is between an upper first threshold pressure value and a lower second threshold pressure value. When the delivery system pressure exceeds the first threshold pressure value, the piston assembly is moved to a first open position that permits fluid flow to the bypass fluid outlet; and when the delivery system pressure is less than the second threshold pressure value, the piston assembly is moved to a second open position to permit fluid flow to the bypass fluid outlet.

Abstract: A screw vacuum pump which allows reduced power, lower inside gas temperature, and reduced discharging time. The pump has a pair of screw rotors rotatively engaged with each other in a pump casing to discharge a gas along a longitudinal direction of the pump. Each rotor has three types of helical teeth serially located in a longitudinal direction of the rotor and different from each other in theoretical displacement volume. A bypass conduit communicating with a delivery side of the pump is connected via a first check valve to a first intermediate space defined between the first helical teeth and the second helical teeth and via a second check valve to a second intermediate space defined between the second helical teeth and the third helical teeth. The gas is compressed at the third stage to half the first stage volume before a discharge port opens.

Abstract: A scroll compressor having a vacuum preventing structure includes: a casing forming a receiving space therein; a fixed scroll fixed to a main frame installed in the casing, and including a back pressure passage at an outer side surface thereof, a discharge pressure hole formed at one side of the back pressure passage such that the back pressure passage and a discharge pressure space of the casing can communicate with each other, a middle pressure hole formed at another side of the back pressure passage such that the back pressure passage and a compression space of the casing can communicate with each other, and a suction pressure hole formed at still another side of the back pressure passage such that the back pressure passage and a suction pressure space can communicate with each other; an orbiting scroll positioned between the fixed scroll and the main frame and forming a compression space by being coupled with the fixed scroll; a piston slidably installed in the back pressure passage, for opening or closin

Abstract: A two-stage pressure relief valve for use with hydraulic systems is disclosed. The two-stage pressure relief valve has a first stage that relieves increases in hydraulic system pressure over the normal operating pressure and up to a selected threshold pressure level, and a second stage that brings the hydraulic system pressure down to a selected reduced operating pressure that is below the normal operating pressure in response to increases in the operating pressure over the threshold pressure level.

Abstract: A self-modulating scroll compressor includes a pair of valves. A first valve moves to a low capacity position when the pressure differential is below a predetermined amount. A second valve moves to a low capacity position when the suction pressure is above a predetermined amount. Low capacity operation will only occur when both valves are open. The present invention thus provides a scroll compressor design with the ability to self-modulate and control the conditions under which low capacity operation occurs based upon two criteria.

Abstract: A fuel metering unit for controlling a variable displacement pump including a main metering valve in fluid communication with the pump for metering an output of the pump, a pressure regulator in fluid communication with the metering valve to create a spill return and a control valve in fluid communication with the pressure regulator and the pump for regulating the spill return flow so the spill return flow is maintained substantially constant at a low level to minimize the heat generated by recirculation by setting a displacement of the pump.

Abstract: Variable displacement pump pumps oil to one or the other ports of an oil operated vehicle wheel motor to drive a lawn mower.

Abstract: Disclosed is a vacuum preventing device of a scroll compressor comprising: a discharge cover installed at a body of a fixed scroll for dividing inside of a case into a discharge region and a suction region; a vacuum cylinder installed in the discharge cover thus to be connected to a compression chamber formed between the fixed scroll and an orbiting scroll and having a pressure space therein so that the discharge region can be connected to the suction region; a piston movably installed in the pressure space for selectively connecting the discharge region with the suction region by a pressure difference between the compression chamber and the suction region; and an elastic member installed in the pressure space for providing an elastic force to the piston.

Abstract: A self-modulating scroll compressor includes a pair of valves. A first valve moves to a low capacity position when the pressure differential is below a predetermined amount. A second valve moves to a low capacity position when the suction pressure is above a predetermined amount. Low capacity operation will only occur when both valves are open. The present invention thus provides a scroll compressor design with the ability to self-modulate and control the conditions under which low capacity operation occurs based upon two criteria.

Abstract: An air compressor includes a machine base, a transmission device, a cylinder, a valve, an automatic pressure-releasing valve and a manual pressure-releasing valve. When a pressure gauge indicates that air pressure is excessive, surplus pressure can be released either by the automatic pressure-releasing valve or by the manual pressure-releasing valve, able to protect the components in the air compressor from damaged and ensure safety of a tire receiving compressed air from the air compressor.

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: A multistage compressor assembly containing at least two guided rotor compressor stages, each of which contains an eccentric mounted on a shaft located within a housing, a rotor mounted on the eccentric shaft which contains at least three intersecting faces, a partial bore located at the intersection of adjacent faces, and at least three rollers rotatably mounted within the partial bores of the rotor.

Abstract: A safety device limits the pressure in an axial-piston compressor with variable piston displacement. The compressor has as wobble plate or swash plate whose tilt angle can be variably controlled by the pressure differential between the high pressure in the discharge pressure zone and the pressure in the piston-drive chamber. The safety device consists of a valve arranged in a connector channel between the discharge pressure zone and the pressure zone of the piston-drive chamber. When the discharge pressure exceeds a given pressure limit, the safety device responds by allowing an increased flow of pressure medium from the discharge pressure zone to the piston-drive chamber. The influx of pressure medium into the piston-drive chamber causes a reduction of the tilt angle of the swash plate or wobble plate.

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 fluid pump having a motor operably coupled to a pump assembly, the motor and pump assembly acting cooperatively to pressurize a fluid includes a pressure switch being in communication with the fluid under pressure and being in communication with the motor for sensing the fluid pressure and controlling the operation of the motor to maintain a selected fluid pressure. A method of controlling fluid pressure in a fluid pump, the fluid pressure being generated by activating a pump motor to operate a pump assembly.

Abstract: An integrated instrument assembly for compressors, having a pressure switch and a pressure reducer connected to each other by a pneumatic circuit, is connectable to a compressor having a compressed-air tank communicating with the pneumatic circuit; the pressure switch and pressure reducer being supported on a supporting member having the pneumatic circuit.

Abstract: A valve combination for vibration pumps performs multiple functions of self-priming, compensation of negative pressure and protection against over pressure. A body (12) contains a non-return valve (18). A valve (26) releases air and compensates for negative pressure. A safety valve (48) vents accidental over pressure originating, for example, from a boiler source. The valve (26) in order to achieve negative pressure compensation, comprises a plug provided with grooves or incisions (40a-c) for favoring the external flow of air subject to negative pressure.

Abstract: A variable capacity swash plate type compressor 10 incorporates a pressure relief valve 43 in fluid communication with a suction chamber 20 and a crank chamber 40. The pressure relief valve 43 prevents over pressurization in the crank chamber 40 to minimize friction and forces acting on the components of the compressor 10.

Abstract: An oil pump for an internal combustion engine includes a pump body with a first gear chamber and a second gear chamber, and a cover mounting to the pump body. The pump also has a check valve and a pressure relief valve in fluid communication with the gear chambers. The oil pump has a supply set of intermeshing involute spur gears in the first gear chamber with nine involute teeth. A return set of intermeshing involute spur gears with the same gear profile as the supply gears is housed in the second gear chamber. Both sets of gears are driven by a common drive shaft so that the pump may be retrofitted to existing engines. The profile of the gears provides for improved pump volume without increasing angular velocity or gear diameter over gears of the prior art. The return gears are deeper than the supply gears to provide an improved supply to return flow ratio.