Abstract: A variable capacity type compressor has a swash plate, pistons reciprocating in the cylinder bores, a suction chamber, and a discharge chamber. A check valve arranged in the compressor. The check valve has a valve seat member having a flow passage and a valve seat, a case attached to the valve seat member, and a valve element arranged in the case for cooperation with the valve seat. The case has a communication hole formed therethrough to allow the gas to flow from the flow passage through the communication hole to the outside circuit. The case has a damper chamber formed therein on the back side of the valve element to damp vibration of the valve element.

Abstract: The invention relates to a hydraulic delivery device with a displacement unit which delivers a medium from a suction connection under output pressure to a pressure connection, connectable with a consumer, and under consumer pressure, and a regulating device for setting and/or limiting a volume flow delivered by the delivery device.

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 the case of a reciprocating pump for a high pressure cleaning appliance including a pump housing in which there is disposed at least one pumping chamber having an inlet valve, an outlet valve and a reciprocating piston that projects thereinto in sealed manner, said pump housing comprising a pump block and a pump head which abut closely together at a interface, wherein the pumping chambers and/or the connecting conduits penetrate the interface in sealed manner and, in the region of the interface, accommodate inserts that are insertable into the pumping chambers and/or the connecting conduits from the interface, said inserts being fixed between the pump block and the pump head when in their inserted position, it is proposed that the whole construction be simplified by making the inserts themselves and the region of the pumping chambers and the connecting conduits in which the inserts are accommodated out of a thermally softenable synthetic material, and by connecting the inserts to the wall of the pumping ch

Abstract: A self priming pump system that includes a motor coupled to a centrifugal pump for driving the centrifugal pump. A separator having a reservoir is provided for storing a limited amount of pumped fluid in advance of the centrifugal pump. A vacuum source provides a vacuum suction to the reservoir to draw pumped fluid into the reservoir to prime the pump. To increase the reliability of the vacuum pump system, a deflector and/or extension may be provided in the reservoir to help prevent pumped fluid from entering the vacuum pump input. Also, the configuration of a tank used to store liquid for the vacuum pump system may be configured to separate and collect sediments near a drain port, which then can be easily drained. For positive head pressures, one or more valves may be used to prevent pumped fluid from escaping the reservoir, if desired.

Abstract: In order to provide a diaphragm type fuel pump which is compact and assures a stable operation, a cavity is formed in a pump body at a position where the pump body is in contact with a fuel discharge chamber. The cavity is arranged between outer and inner parts of the pump body and perpendicularly extends to a diaphragm. The pump body has a return path communicating with a fuel intake chamber and the cavity via opposite ends thereof. A pressure regulating mechanism is housed in the cavity using a cap attached to the pump body, and is positioned inside an outer diameter of a pump chamber. This prevents the pressure regulating chamber from projecting out of the pump chamber contrary to a pressure regulating chamber of the related art, and makes the fuel pump compact. A valve seat is formed in the cap which is separate from the pump body. This facilitates machining of the valve seat.

Abstract: A scroll compressor is provided that has greater control over the compressed volume by having a plurality of sequentially spaced unloader valves and associated holes. By providing the plurality of valves, a control achieves greater variation over the final compressed volume. The present invention is most preferably utilized in the type of scroll compressor having a hybrid wrap geometry to provide an increased volume of refrigerant adjacent the suction area of the compressor.

Abstract: A scroll-type compressor for realizing the operating condition of complete 0% capacity without using an electromagnetic clutch. In order to minimize the power loss, a compliance crankshaft mechanism for allowing the orbiting radius of the movable scroll member to change steplessly to zero is interposed between a shaft and a scroll member. A guide hole having an inclined surface such as a two-step conical surface is formed at the end plate of the movable scroll member. A plunger adapted to engage by advancing toward and retracting from the guide hole is supported on a housing. When the plunger is advanced into the guide hole under the control of a control operation device including a control pressure chamber and a control valve, the movable scroll member moves radially, so that the amount of eccentricity and the orbiting radius thereof are reduced to achieve the 0% capacity.

Abstract: An inflatable shoe with a deflation valve designed to limit inadvertent operation of the valve and thereby limit inadvertent deflation of the shoe. The deflation valve has a shortened plunger, a collar to prevent tilt of the plunger, and a conformable ring on the valve face.

Abstract: An inflatable shoe with a deflation valve designed to limit inadvertent operation of the valve and thereby limit inadvertent deflation of the shoe. The deflation valve has a shortened plunger, a collar to prevent tilt of the plunger, and a conformable ring on the valve face. The plunger is provided with a groove sized and dimensioned to partially receive the inner surface of the ring.

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 control switch assembly for an air pump has a unidirectional valve mounted inside a port that is mounted together with a contact device on an actuation device. The actuation device has an extension slidably received in the actuation device and controllably connected to a knob. With the movement of the extension, a switch inside the contact device is able to selectively make an electrical connection and an actuating pin of the unidirectional valve is able to selectively open an airway inside the port. When the electrical connection of the switch is disconnected and the airway is opened by the movement of the actuating pin, the pressure above a diaphragm and inside the compressor is able to be released from the airway of the port so as to smooth the actuation of the compressor.

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: A scroll type compressor includes a fixed scroll member and an orbital scroll member disposed within a housing for defining a compression pocket compressing refrigerant gas, an open portion provided on the fixed scroll member at a position corresponding to an intermediate compression stage position of the compression pocket, and a mechanism for discharging refrigerant gas intermediately compressed in the compression pocket out of the compressor through the open portion. The refrigerant gas discharging mechanism includes a gas discharging path formed in the housing itself to communicate the open portion, without providing a particular member. The number of parts for forming a gas discharging route may be decreased, and the structure therefore may be simplified. The assembling ease of the compressor may be greatly improved. An excellent high-efficiency and low-load operation of the compressor may be achieved.

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 scroll compressor includes a fluid injection system. The fluid injection system includes a fluid passage which extends from a position outside of the shell of the compressor to the fluid pockets created by the wraps of the scroll members. The fluid passage extends through the orbiting scroll member. The fluid injection system can be used to inject gaseous or liquid refrigerant, lubricant or the fluid injection system can be used to vent the moving pocket to the suction area of the compressor for capacity modulation.

Abstract: The invention is based on a radial piston pump (1) with a pump body (2), in which pump body (2) are placed pistons (4), and cylinders (5) arrayed radial to a cam (14) and the pistons (4) upon an inward thrust suck in fluid by means of suction side intakes (17) and upon an outward thrust, the pistons (4) impel fluid through pressure openings (7) in the outer end walls (6) of the cylinder (5) into a plenum (10). It is proposed, that in the base of the cylinders (4) respectively a connection boring (32) is made to the cam (14), which connection boring (32) is controlled by a relief valve (18). Upon the exceeding of its opening pressure the relief valve (18) opens and pressure peaks in the cylinder (5) can be diminished by means of said connection boring. At the same time, a pressure buffer between the base of the piston (4) and the bearing shell (16) is formed.

Abstract: A high pressure fuel pump has a plunger that extends through a cylinder and is reciprocally located in a pressurizing chamber. The plunger is reciprocated by a lifter and changes the volume of the pressurizing chamber to pressurize fuel in the pressurizing chamber. A seal member seals the cylinder from the lifter to prevent fuel that leaks from the pressurizing chamber from being mixed with lubricant that lubricates the lifter. A support to which the seal member is attached is formed separately from the cylinder. The support is fixed to the cylinder with the plunger extending through the support.

Abstract: A reciprocating compressor that includes an auxiliary port 38 in series with a check valve 40 to move fluid at an intermediate pressure that is between the main suction and discharge pressures. Piston 31 normally covers the auxiliary port during a portion of its stroke. In one embodiment the check valve 40 is oriented so that fluid flows into the compressor. The piston 31 uncovers the auxiliary port 38 during the early part of the down stroke to allow fluid in through the port. As the piston 31 continues to move down it covers the auxiliary port, which drops pressure in chamber 37 to allow fluid to enter through a main suction valve 34. In other embodiments the orientation of the check valve is reversed and auxiliary port acts as an auxiliary discharge port. Multiple auxiliary ports may be used in a single cylinder to achieve multiple suction and/or discharge pressures.

Abstract: A fuel pump includes an O-ring seal to provide sealing contact with a diaphragm seal between a valve housing and associated valve cover interface despite some loss of clamping load between such mating parts. Also, a molded O-ring type ladder seal is used to maintain seal integrity between the valve housing and associated pump housing interface despite some loss of clamping load therebetween. Machined O-ring grooves are desirably provided in opposite sides of the valve housing to accommodate the O-ring against the diaphragm seal and the molded O-ring type ladder seal against the pump housing.

Abstract: The invention relates to a valve arrangement with a pressure limiting valve and a flow regulator valve, which comprises a flow regulator piston, having at least one first hydraulic resistor, distinguished in that the flow regulator valve's (5) flow regulator piston (15) has a split pressure return surface and in that the first part (ring surface (45)) of the pressure return surface is capable of working at a pressure p1 and a second part (annulus surface (31)) of the pressure return surface is capable of working at a pressure p2.

Abstract: This present application discloses an improved valve configuration such that an indicator port is incorporated directly within the valve allowing a sensing device to be mounted directly to the valve or within the valve body, this application being directed to both suction and discharge valves which sense at least one condition within a compressor comprising a cylinder, a piston, at least one discharge valve, and at least one suction valve, the valve further including a valve guard, a valve seat, a hollow area adapted and configured for housing a sensing device and a sensing device disposed within the hollow area.

Abstract: A pump comprises a housing having a fluid inlet and a fluid outlet. A piston is mounted for reciprocating motion in first and second directions within the housing. The housing has first and second cavities on first and second sides of the piston, respectively. The first and second cavities are fluidly coupled to the fluid inlet and fluid outlet, so that fluid is pumped to the fluid outlet when the piston moves in either of the first and second directions. A bleed valve is coupled between the first and second cavities. The bleed valve has first and second closed states and an open state. The bleed valve changes from the first closed state through the open state to the second closed state when the piston moves in the first direction. The bleed valve changes from the second closed state through the open state to the first closed state when the piston moves in the second direction.

Abstract: A back pressure structure of a scroll compressor having a fixed scroll forming a plurality of compressive chambers together with an orbiting scroll in its casing; including: a suction pressure space having a predetermined volume formed at one side of the fixed scroll; a suction hole formed for guiding a part of an intermediate gas filled in an intermediate pressure space filled in the rear side of the orbiting scroll to the suction pressure space by passing through the fixed scroll; a vent hole formed at the other side of the suction pressure space for guiding the intermediate pressure gas flown into the suction pressure space through the suction hole to the outermost compressive chamber which has a relatively low pressure; and a back pressure control valve elastically supported by an elastic member in the suction pressure space to open and close the suction hole, and receiving almost the same pressure no matter that it is opened or closed, according to which an intermediate pressure space between a main fram

Abstract: An oil pump apparatus, including a pump mechanism portion for discharging operating fluid, a valve-receiving bore formed in a housing, a flow control valve arranged in the valve-receiving bore connected to a bypass hole, and a bypass passage. The bypass passage is connected to the bypass hole, having a space radially extending from an edge of the bypass hole in a fluid stream direction of the excess operating fluid spouting from an opening area of the bypass hole. When fluid stream of the excess operating fluid reaches the inner surface of the bypass passage, the pressure of the excess operating fluid has been weaken sufficiently because fluid stream of the excess operating fluid is diffused by the long span of the bypass passage extended from the edged of the bypass hole. Therefore, the inner surface of the bypass passage is protected from cavitation damages and erosion.

Abstract: A hydraulic fluid pump (10), including a housing (12), a pumping apparatus (14), an inlet (16), a pressure chamber (17), an outlet (18), a bypass valve (20) and a diffuser (24). Wherein cavitation is reduced by using the diffuser (24) to supercharge fluid from the outlet (18) to increase the static pressure of the fluid entering the pumping apparatus (14). And wherein the inlet (16) and the diffuser (24) are designed to minimize the complexity, cost and packaging considerations of the hydraulic fluid pump (10).

Abstract: A pump, electromagnetically operable valves and at least one low-pressure accumulator are arranged in a valve block. The valve actuators are disposed in front of a base of the valve block opposite to an electric motor which drives the pump. The housing of the low-pressure accumulator is formed of an add-on piece which is deepdrawn from sheet metal in a bowl-type configuration. The edge of the add-on piece is attached in the mouth of a blind-end bore in the valve block. The add-on piece projects beyond the and has roughly the same height as the actuators of the valves. The actuators and the add-on pieces are covered by a housing cap on the valve block which protects them against environmental influences. The arrangement is extremely compact and permits achieving a relatively small and, thus, light-weight valve block.

Abstract: The invention relates to a valve arrangement with a pressure limiting valve and a flow regulator valve, which comprises a flow regulator piston, having at least one first hydraulic resistor, distinguished in that the flow regulator valve's (5) flow regulator piston (15) has a split pressure return surface and in that the first part (ring surface (45)) of the pressure return surface is capable of working at a pressure p1 and a second part (annulus surface (31)) of the pressure return surface is capable of working at a pressure p2.

Abstract: The rated system pressure in a pressure control system is adjusted through a pressure relief valve (2). In addition to the pressure relief valve (2), the system includes a check valve (4), a pressure sensor (3), a position switch (10), a first pressure adjustment member (13) for the relief valve, a second pressure adjustment member (12) for the check valve (4), an actuator (16), and a microcontroller (15) with a memory (6) and a display (7). Faults caused by pressure adjustment interactions are prevented by permitting an adjustment of the pressure relief valve only if the check valve is fully open and a pump provides pressure. For this purpose the actuator (16) of the check valve in its normal position prevents an adjustment of the pressure relief valve. Opening the check valve by the actuator permits adjusting the pressure relief valve (2) and the switch (10) operated through the actuator sends a signal to the microcontroller to drive the pump.

Abstract: Apparatus for injecting a reagent into a stream of pressurized rinse fluid delivered to a vacuum toilet. The apparatus is pressure-operated in response to the flow of pressurized rinse fluid, thereby eliminating the need for electric outlets or controls. The apparatus includes an orifice located in a main conduit upstream of a reagent discharge outlet. The orifice reduces the pressure of the rinse fluid thereby to unload a check valve which controls injection of the reagent into the rinse fluid stream. In addition, the volume of a pump chamber for holding reagent is reduced to ensure that the pump maintains its prime. Furthermore, the piping leading into the pump chamber has a relatively uniform inside surface and a tapered insert is used to reduced the cross-sectional area of the reagent extreme, thereby directing air bubbles through the pump chamber.

Abstract: An oil pump apparatus which includes an oil pump for being driven by a driving source and for being connected to a plurality of components to which an oil is supplied from the oil pump and a control valve preventing the oil which is unnecessary to the components from flowing into the components, wherein at least one of the components is an actuator operated by an oil pressure generated by the oil pump and wherein the control valve permits the oil of which the quantity is smaller than that of the oil which is consumed by the actuator to flow into the components when the actuator is not operated and the control valve permits the oil of which the quantity is larger than that of the oil which is consumed by the actuator to flow into the components when the actuator is operated.

Abstract: A compressor of scroll type or the like, in which, in order to change the discharge capacity automatically in accordance with the rpm (rotational speed) of a shaft (4) by simple means, the centrifugal force exerted on a movable scroll (9) orbiting with the rotation of the shaft (4) is used as a vibratory force to forcibly vibrate a spool (23) constituting a valve body supported on an elastic member (25), thereby opening and closing bypass holes (22) for establishing communication between a working chamber (V) and a suction chamber (15).

Abstract: A control for a refrigeration system serviced by a special pulse width modulated compressor coupled to a condenser and evaporator. The system can be of the distributed type wherein the condenser and compressor may be coupled to service a group of adjacent refrigeration cases, wherein each case would have its own evaporator. A controller is coupled to a load sensor for producing a variable duty cycle control signal in which the duty cycle is a function of demand for cooling. Moreover, fuzzy logic techniques may be utilized in order to provide self adaptive tuning control for the system.

Abstract: A refrigerant circuit includes a compressor and an expansion valve. The expansion valve is connected to a discharge muffler of the compressor by a high pressure conduit. The expansion valve is also connected to a suction passage of the compressor by a low pressure conduit. The high pressure conduit includes a condenser and the low pressure conduit includes an evaporator. A check valve is located between the discharge muffler and the high pressure conduit to selectively connect and disconnect the high pressure conduit with the discharge muffler. A relief valve is attached to the discharge muffler upstream of the check valve. If the pressure in the compressor is abnormally high when the check valve closes, the relief valve releases the abnormally high pressure from the discharge muffler. Therefore, if the check valve fails to function, the relief valve prevents the pressure in the compressor from being abnormally high.

Abstract: A compressed gas dispensing station having a high pressure gas compressor with a cyclic control system for selective recirculation of cooled, ultra high pressure gas through the compression chamber after the end of the compression stroke for scavenging hot compressed gas from the compression chamber and providing a residual, partially-expanded replacement gas for the expansion stroke which is mixed with the incoming, new charge of gas for a cryogenic gas at the start of compression and a relatively low temperature gas at the end of compression for a single stage compressor.

Abstract: A scroll compressor includes a capacity modulation system. The capacity modulation system has a piston that is connected to the non-orbiting scroll that disengages the non-orbiting scroll from the orbiting scroll when a pressure chamber is placed in communication with the suction chamber of the compressor. The non-orbiting scroll member moves into engagement with the orbiting scroll when the chamber is placed in communication with the discharge chamber. The engagement between the two scrolls is broken when the pressure chamber is placed in communication with fluid from the suction chamber. A solenoid valve controls the communication between the pressure chamber and the suction chamber. By operating the valve in a pulsed width modulated mode, the capacity of the compressor can be infinitely varied between zero and one hundred percent.

Abstract: A scroll compressor has a valve normally closed during forward operation of the scroll compressor. Upon reverse rotation, force imbalances allow the valve to open and communicate a chamber downstream of a check valve to a chamber upstream of the check valve. By communicating these two chambers, the detrimental effects of reverse rotation are reduced or eliminated. Two valve embodiments are disclosed. One embodiment also relieves unduly high discharge pressures. In a third embodiment, a pressure relief valve is provided to prevent desirably high pressure ratios or pressure differentials.

Abstract: In a scroll compressor provided with a fixed scroll member (4) and a movable scroll member (3) which define a plurality of compression spaces (6) therebetween in cooperation with each other, a hole (32) is formed to the fixed scroll member to be communicable with adjacent ones of the compression spaces. The adjacent compression spaces are different from each other in pressure when the scroll compressor is driven. A piston valve (33) is disposed in the hole and controls communication between the adjacent compression space through the hole. The compression spaces are movable with volumes reduced by movement of the movable scroll member.

Abstract: A water pump includes a housing having a water inlet, a water outlet, an exit and a mouth. A circulating water passage couples the exit to the mouth of the housing. A pump may pump water from the exit to the mouth of the housing via the circulating water passage. The housing includes two ducts communicating with each other and communicating with the mouth, and the water inlet and the water outlet respectively. Two plugs are slidably disposed in the ducts for switching water to circulate through the exit and the circulating water passage when the water outlet is closed.

Abstract: A method and system for determination of a pressure of the pressurized fluid with the use of a diaphragm pump responsible for accumulating the pressurized fluid in the vessel. The pump has a pump cavity and a diaphragm with a piezoelectric element which is actuated by an application of a voltage to displace the diaphragm for pumping a fluid into the vessel. The method comprises the steps of:(a) deactivating the diaphragm by removal of the voltage to the piezoelectric element so as to stop pumping the fluid and accumulating the pressurized fluid into the vessel;(b) introducing the pressurized fluid only from the vessel back into the pump cavity so as to cause a displacement of the diaphragm by the pressurized fluid;(c) deriving an electrical signal indicative of the displacement of the diaphragm; and(d) translating the electrical signal into a corresponding pressure value indicative of the pressure of the pressurized fluid in the vessel.

Abstract: A variable discharge-amount compressor includes a compression unit for compressing refrigerant, and a discharge-amount varying unit for varying a discharge amount of refrigerant discharged from the compression unit. The discharge-amount varying unit has a first control room communicating with inlet and outlet of the compression unit, a second control room communicating with the inlet, and a third control room communicating with the second control room through a orifice. The first control room communicates with the inlet through a control passage opened and closed by a control valve. Further, a bypass passage communicating with the inlet is opened when the control passage is opened. Therefore, when an engine for driving the compressor is rotated to be accelerated, a pressure difference is generated between a pressure inside the second control room and a pressure inside the third control room, thereby opening the control passage and the bypass passage.

Abstract: A scroll-type refrigeration compressor is disclosed which incorporates an efficient, reliable, low cost modulation system employing a single actuator to effect switching between full and reduced capacity operation. The modulation system of the present invention includes an annular valving ring rotationally supported on the non-orbiting scroll or main bearing housing which operates to ensure simultaneous opening and closing of one or more unloading passages thus avoiding the possibility of even transient pressure imbalances between opposed compression pockets during operation of the compressor or in one of the alternative embodiments, providing a controlled imbalance to provide a noise reducing torsional loading on the Oldham coupling. Further, the modulation system of the present invention provides for reduced capacity at both start up and shut down thus enabling the use of more efficient lower starting torque motors and reducing the potential for noise generating reverse rotation on shut down.

Abstract: An improved capacity modulation system for scroll-type compressors is disclosed in which a valve body of a solenoid valve assembly is secured to the inner wall of the hermetic shell and the actuating coil is mounted on the outer surface thereof. The actuating coil includes a plunger/valve member which cooperates with passages provided in the valve body to selectively actuate the capacity modulation arrangement utilizing compressed fluid. The construction offers the advantage that all fluid pressure lines are located within the hermetic shell and thus protected from potential damage, the solenoid coil may be easily changed/replaced to accommodate different available operating voltages and/or malfunction thereof and the system can be easily tested prior to final welding of the outer shell.

Abstract: A scroll-type compressor having a capacity modulation system of the delayed suction type is disclosed which incorporates a valving ring rotatably supported on one of the scroll members. Seals are provided acting between the valving ring and scroll member which serve to effect a fluid tight sealing relationship therebetween when the compressor is operating in a full capacity mode thus reducing the need for maintaining tight tolerances during manufacture of the valving ring.

Abstract: A hydraulic oil tank connects to a valve head (10) which is provided with an oil return switch (2) accomodated in an oil return hole (14). An adjusting valve (3) is accomodated in an adjusting hole (13) of the valve head. An oil chamber hole (15) accomodates a check valve (4). A pivot rod hole (11) accomodates a pivot rod (5) and a pump hole (12) accomodates a pump (6). The check valve is in fluid communication with a conduit (8) which, for example, connects to a tube of a hydraulic jack. The valve head allows hydraulic fluid to be imparted to a jack at a controlled, desired pressure and allows advantageous return of fluid to the oil tank.

Abstract: The invention relates to a piston pump for a slip-controlled hydraulic vehicle brake system. The piston pump has a piston which is driven to execute a stroke motion, and two check valves as an inlet valve and outlet valve for controlling the fluid flow through the piston pump. The outlet valve has a valve closing spring that effects a fast closure of the outlet valve. To enable completely evacuating a positive displacement chamber of the piston pump, the invention includes connecting an evacuation valve, embodied as a springless check valve with a small diameter and with a lightweight valve closing body, hydraulically parallel to the outlet valve.

Abstract: A gerotor pump includes a pressure relief return flow guide system, composed of two distinct structures, a pressure relief port, and a flow guide. The pressure relief port separates the pressure relief flow and inlet flow, preventing them from mixing and causing turbulence in the inlet cavities. The flow guide is located at the end of the pressure relief port and the inlet to make the two flows smoothly merge in the inlet cavities.

Abstract: A compressed air installation having a normal operating mode and an idling mode includes a feed valve, a feed line which is connected to and receives air through the feed valve, at least one compressor having at least one compression chamber, and at least one inlet valve which is connected to the feed line and supplies air to the compression chamber. The feed valve and the inlet valve are switchable between open positions and one-way positions wherein air can pass through the valve in one direction only. In normal operating mode, the feed valve is in its open position and the inlet valve is in its one-way position, thereby allowing air to enter and exit the installation through the feed valve and the feed line, and to pass from the feed line through the inlet valve into the compression chamber.

Abstract: A helical-screw rotary compressor having a twin rotor configuration or a multi-rotor (i.e., at least three) configuration with defined compressor induction and discharge ends has at least one unloader piston disposed at said compressor discharge end.

Abstract: A bicycle tire pump includes a cylinder having two passages defined therethrough which are separated by a board, two openings respectively defined in a top of the cylinder and communicating with the two passages into which two pistons are respectively and movably received. A head is mounted to the top of the cylinder and has two ways defined therein which respectively communicate with the two passages in the cylinder and an outlet of the head. A bolt extends through one of the two passages and is threadedly connected to the head. The bolt has a longitudinal passage defined therethrough which communicates with one of the two ways.