Abstract: A high pressure pump and delivery system mating to LNG storage and suited for natural gas powered trucks and buses, but also suitable for other cryogenic liquid fuels. The reciprocating pump is comprised of a liquid pumping portion and a vapor compressing portion, operating in concert so that it is possible to locate the pump above a source of saturated LNG and to reliably supply high pressure LNG. The delivery system provides a method of utilizing both the pumped LNG and the compressed NG in a Diesel type fuel injection system, and also to scavenge NG vapor from the LNG storage container so as to extend it's storage life. While especially useful for trucks and buses, the present invention is not limited thereto, as it is also useful for locomotives, automobiles and other vehicles designed to operate through combustion of natural gas, as well as stationary applications.

Abstract: A dual-direction inflator has a tube and a cover mounted on the tube. A rod extends through the cover and is inserted in the tube. A piston is received in the tube and mounted on an end of the rod. The piston has an air-in chamber and an air-out chamber defined therein. A handle is mounted at the other end of the rod. The handle has an inlet and an outlet formed at a middle portion thereof. An inner tube is received in the rod and communicated with the inlet and with the air-in chamber. By a space defined between the inner tube and the rod, the air-out chamber is communicated with the outlet.

Abstract: A hydraulic actuator that is capable of substantial actuation but does not require a conventional pump, uses only deflectable membranes and passive valves, or, at most, a minimum of active valves, and, under certain circumstances, may be free to move when the actuator is de-energized, is provided. The actuator utilizes the deflectable membranes to move fluid throughout the actuator. The movement of the fluid actuates a shaft or other suitable device, as required.

Abstract: The invention relates to an arrangement in a pump block. The pump block includes a plurality of pump valves each connected to a piston in a piston pump. The pump block also includes an inlet pipe which is common to all of the pump valves. The inlet pipe has a connection to each pump valve. One connection between the inlet pipe and the pump block is fixed and includes a flange fixedly screwed in the pump block, the remaining connections are movable in the longitudinal direction of the inlet pipe. The movable connections each include a flange with over-dimensioned boltholes in which a spacer is placed.

Abstract: Since many valves are used, pressure loss is large, resulting in low reliability of a pump. Even when the period of increasing and decreasing the volume of a pump chamber is long, and a piezoelectric element is used as an actuator that drives a diaphragm, a driving operation cannot be performed at a high frequency, or a proper flow rate cannot be realized under a high load pressure. In accordance with the invention, the combined inertance value of an entrance passage used to make working fluid flow into a pump chamber is smaller than the combined inertance value of an exit passage used to make the working fluid flow out from the pump chamber. A fluid resistance member is provided at the entrance passage in which fluid resistance when the working fluid flows into the pump chamber is smaller than fluid resistance when the working fluid flows out of the pump chamber.

Abstract: The present invention relates to a thick matter pump comprising at least two pump units alternating in the pump and suction mode, a delivery line, a suction line and a switching valve for switching between the pump units, one pump unit being connected in the pump mode by the switching valve to the delivery line, and one pump unit being connected to the suction line in the suction mode. The filling level of the pump unit in the suction mode is to be improved. To this end a pressure boosting device which acts independently of the pump units is provided in the area of the suction line for actively effecting a precompression of thick matter. The invention also relates to a suction/pumping method which is carried out by said thick matter pump.

Abstract: A diaphragm pump includes a pump housing having an inlet and an outlet for the fluid. The pump housing (2) includes a partition wall (4) which delimits two chambers (3) on a respective side of the partition wall. The two chambers are each closed by a respective diaphragm (9) connected to an electric coil (12) for causing the diaphragm to oscillate in coaction with a magnetic unit (14-16), therewith pumping the fluid.

Abstract: A power generating assembly structured to have dual functionality by combining an interactive operation of both an engine assembly and a compressor assembly in an at least partially segregated or isolated relation to one another within a common housing. The engine assembly may be connected to anyone of a plurality of different power take-offs in order that the power generated thereby is capable of doing work. Concurrently the compressor assembly is operative to pressurize a fluid flow passing there through and more specifically to increase the pressure of a refrigerant vapor which, after compression is transfer to a condenser or other utilitarian device for operation of a space conditioning or like facility.

Abstract: A pump assembly for an aquarium includes a water circulation pump having a first casing and an aeration pump having a second casing, wherein the aeration pump is operated by the magnetic field of a rotating magnetic shaft that is rotatably mounted in the water circulation pump. The first casing and the second casing are connected to each other. A lever in the aeration pump is reciprocated continually to draw air into the pump and discharge air into the aquarium due to the magnetic field of the rotating magnetic shaft so that the coil is unnecessary in the aeration pump. Consequently, the pump assembly can be marketed for a lower price and save energy when used.

Abstract: A reciprocating compressor is provided with a plurality of gas compression means having a cylinder and a piston, the piston of each gas compression means is cooperated with the compressor by converting a rotating motion of a crankshaft provided on an electric drive source to a reciprocating motion by a scotch yoke mechanism, wherein an increase of the volume of discharged gas can be achieved without designing a gas compression means to be wide or without increasing the number thereof, a pulsation of discharged gas can be decreased by an attachment of an expansion muffler on the cylinder head so as to decrease a vibration and noise of the compressor, an attachment of the fly wheel to the crankshaft and an adjustment of the shaft with the crankshaft can be improved easily, further compressed gas flows are joined and discharged in concentration, thereby the pulsation of discharged gas can be restrained.

Abstract: A reciprocating compressor is provided with a plurality of gas compression means having a cylinder and a piston, the piston of each gas compression means is cooperated with the compressor by converting a rotating motion of a crankshaft provided on an electric drive source to a reciprocating motion by a scotch yoke mechanism, wherein an increase of the volume of discharged gas can be achieved without designing a gas compression means to be wide or without increasing the number thereof, a pulsation of discharged gas can be decreased by an attachment of an expansion muffler on the cylinder head so as to decrease a vibration and noise of the compressor, an attachment of the fly wheel to the crankshaft and an adjustment of the shaft with the crankshaft can be improved easily, further compressed gas flows are joined and discharged in concentration, thereby the pulsation of discharged gas can be restrained.

Abstract: A pump comprises a first substrate having a fluid inlet port for receiving a fluid, a fluid outlet port for discharging the fluid, a first pumping section for pumping the fluid from the fluid inlet port to the fluid outlet port, a first inlet valve section disposed between the fluid inlet port and the first pumping section, and a first outlet valve section disposed between the fluid outlet port and the first pumping section. A second substrate has a second pumping section, a second inlet valve section, and a second outlet valve section. An intermediate substrate is disposed between the first and second substrates to form a first fluid feeding path and a second fluid feeding path for feeding the fluid pumped by the first and second pumping sections. The first fluid feeding path extends from the first inlet valve section to the first outlet valve section through the first pumping section.

Abstract: Disclosed is a piston pump having a pump housing with a cylinder head comprised of a first plate and a second plate. The plates which rest against each other and are screwed to the pump housing, have a first conduit which carries low-pressure fuel and leads to a first check valve disposed between the two plates. The check valve communicates with a cylinder chamber of the radial piston pump. A second conduit carrying high-pressure fuel leads from this cylinder chamber to a second check valve, which is disposed between the first plate and the pump housing. Seals that are appropriate to the load, in fact low-pressure seals, are provided in the region of the cylinder head that is subjected to low pressure and high-pressure seals are provided in the region of the cylinder head that is subjected to high pressure.

Abstract: A compressor has a first housing, a second housing, a valve plate, a suction valve, a discharge valve and a sealing coat. The first housing includes a compression chamber. The second housing includes a suction chamber and a discharge chamber. The valve plate is interposed between the first housing and the second housing. The suction valve is disposed between the first housing and the valve plate. The discharge valve is disposed between the second housing and the valve plate. The valve plate forms a suction port intercommunicating the suction chamber and the compression chamber, and a discharge port intercommunicating the discharge chamber and the compression chamber. The sealing coat made of soft metal is provided between the suction valve and the valve plate, and/or between the discharge valve and the valve plate.

Abstract: An image forming apparatus includes cap members for capping ejection outlets of an ejection portions for ejecting liquid to a recording material; pump means including suction inlets in fluid communication within the cap members; discharging outlets for discharging the liquid; cylinder means including a plurality of cylinders having the suction inlets and the discharging outlets, respectively; a seal member for dividing inner space in the cylinder means into the cylinders; and a plurality of pistons reciprocable in the spaces in contact with the inner surfaces of the cylinders to produce pressure change in the inner spaces; wherein in each of the cylinders, the suction inlet is disposed more away from seal member than the discharging outlet.

Abstract: A head cover assembly for a two cylinder compressor is described. The head cover assembly is mounted over the compressor cylinders and includes a one piece valve plate with a pair of removable heads. The valve plate includes two substantially identical cylinder covers disposed over a pair of plate sections, thereby enclosing a volume above each plate section with a head installed. Each cylinder cover includes a divider wall which divides the enclosed volume of the cover into an intake volume and an exhaust volume. A pair of passageways provides communication between the cylinder covers connecting the exhaust volumes and the intake volumes.

Abstract: An air pump comprises an outer tube, a distribution guide tube, and a spring. The outer tube is provided in the interior with a large cylinder and a small cylinder. The distribution guide tube is disposed at the lower end of the outer tube and is provided with two air chambers, one of which is in communication with the large cylinder and is provided with a pressure leaking slide block, two leakproof rings, and an annular groove located between the two leakproof rings for forming a duct. The spring is disposed in the air chamber for providing the pressure leaking slide block with a recovery spring force. Another air chamber of the distribution guide tube is in communication with the large cylinder and the small cylinder for discharging air to inflate an inflatable object.

Abstract: The linear pump (10,110) includes a housing (12, 112) and either two (20,22) or one (120) flexible bladders each within a pump housing and interconnected to respective end caps (30, 32, 130, 132, 134, 136). Upon movement of a movable end cap relative to a stationary end cap, the volume in each bladder may be variably controlled to pump blood or another selected fluid. Linear movement of the end caps may be controlled by an attractive or repulsive force between end caps. The pump (110) with a permeable bladder (120) may be used to pump wastewater.

Abstract: A portable apparatus for ventilation support to persons with respiratory distress is provided with a compressed air pump. The pump may be connected to the mouth or the nose via a tube for generation of pressure pulses with an individually adaptable air volume. The pump comprises a rigid container having two symmetrical halves and with a flexible membrane which is located as a laterally reciprocating diaphragm between the two container halves. These are provided with check valves permitting ambient air to be fed into the pump and from the pump into the tube while the membrane wall is moved, for generation of a pressure pulse. The pump is provided with a flexible pull device for reciprocating operation of the membrane in the container. The pull device extends via pulley wheels to a driving device located substantially in the same plane as the container and beside it.

Abstract: An air pump has a positioning seat provided to have two mouths each with an inner thread formed on an inner face thereof and an outer thread formed on an outer face thereof and a nozzle formed to adjust to an inlet of a tire; and two pump barrels each corresponding to one of the mouths to pump the air out from the nozzle. The two mouths of the positioning seat enables the user to operate the air pump in opposite directions simultaneously.

Abstract: A two-cylinder air compressor has a motor with a through drive shaft. Identical housings are provided at each end of a cylindrical spacer sleeve that surrounds the motor. The housings include cylinder housing extensions each of which mounts a cylinder sleeve, a valve plate, and a head. The heads are part of a one-piece cylinder head member. Wobble pistons are mounted on each end of the motor shaft and operate in the cylinder sleeves. The cylinder sleeves rest on a floor in the housing which has integrally formed passages for cooling air to circulate around the cylinder sleeves. The one-piece cylinder head member includes integral tubes connecting the heads. The integral tubes span the distance between the beads and are spaced from the outside of the spacer. The housings may be joined by through bolts or without bolts by press fitting the bearings in the housing, press fitting the housings to the spacer sleeve, and press fitting the motor shaft into the bearings.

Abstract: A two-cylinder air compressor has a motor with a through drive shaft. Identical housings are provided at each end of a cylindrical spacer sleeve that surrounds the motor. The housings include cylinder housing extensions each of which mounts a cylinder sleeve, a valve plate and a head. The heads are part of a one-piece cylinder head member. Wobble pistons are mounted on each end of the motor shaft and operate in the cylinder sleeves. The cylinder sleeves rest on a floor in the housing which has integrally formed passages for cooling air to circulate around the cylinder sleeves. The one-piece cylinder head member includes integral tubes connecting the heads. The integral tubes span the distance between the heads and are spaced from the outside of the spacer. The housings may be joined by through bolts or without bolts by press fitting the bearings in the housing, press fitting the housings to the spacer sleeve, and press fitting the motor shaft into the bearings.

Abstract: A lubricating system has a housing formed with an intake passage, a drive shaft extending longitudinally in the housing and carrying a plurality of longitudinally spaced worm gears, and respective pumps juxtaposed with the worm gears in the housing. Each pump has a cylinder fixed in the housing, centered on a respective transverse axis, and forming an intake port connected to the passage and an output port. A cavity-forming piston is rotatable about and reciprocal along the respective transverse axis and a worm wheel on the piston meshes with the respective worm gear. An axially projecting cam ramp on the worm wheel is axially engageable with an abutment on the housing. This abutment can be moved axially and for fixing it in any of a multiplicity of positions for varying axial deflection of the piston. A spring bearing against the piston urges the ramp toward the abutment.

Abstract: A manual air pump includes a cylinder having a first chamber and a head provided to the second end of the cylinder. The head includes an outlet passage communicated with the first chamber for supplying air to an object to be inflated. A first piston rod has a first end with a first piston slidably received in the first chamber. The first piston separates the first chamber into a first chamber section adjacent to the head and a second chamber section distal to the head. The first piston rod defines a second chamber therein. A second piston rod has a first end with a second piston slidably received in the second chamber. The second piston separates the second chamber into a third chamber section adjacent to the first piston and a fourth chamber section distal to the first piston. A handle is secured to the second end of the second piston rod to move therewith.

Abstract: A pump includes a first cylinder with a first valve member connected to a first end of the first cylinder and a first handle disengagably connected to a second end of the first cylinder. A first piston is movably received in the first cylinder and a second cylinder fixedly connected between the first handle and the first piston. A second piston is movably received in the second cylinder and a rod is connected to the second piston. The rod extends through the first handle and connected to second handle which is disengagably connected to the first handle. The movement of the first piston is used to pump tires and the movement of the second piston is used to pump a cylinder of air suspension device.

Abstract: A metering pump includes a motor compartment with a drive compartment defining a drive chamber. The drive chamber has an inlet and an outlet for a main liquid. A drive piston is moveably arranged in reciprocating translational motion in the drive chamber. A controller for controlling the movement of the drive piston under the action of the main liquid. A metering compartment defines a metering chamber. The metering chamber has an inlet and an outlet for an auxiliary liquid. The outlet for the metering chamber is separated from the outlet of the driving chamber. A metering piston is arranged in the metering chamber. The metering piston is driven by the drive piston. A frustoconical sealing member is arranged with its small base facing the drive compartment. An extension of the metering piston has a diameter smaller than a body of the metering piston. The extension and the frustoconical sealing member form a suction valve. A suction-delivery portion is arranged on the metering piston.

Abstract: A cylinder is divided into two chambers by a wall to receive a pair of pistons. This reduces the stroke length and correspondingly reduces the linear speed of the piston. This leads to a reduced PV factor associated with degradation and wear of the piston rings. Moreover, the multi-cylinder arrangement provides the same performance in an oil-free compressor assembly without appreciably expanding dimensional constraints relative to known systems.

Abstract: A device consisting of two piston pumps for supplying two separate liquid systems, particularly a fuel injection system and an oil system in an internal combustion engine.

Abstract: A positive-displacement pump includes multiple pumping elements, each pumping element having a pressure vessel with a first and a second chamber and a separating member disposed between the first and second chambers. The first chambers and the second chambers are hydraulically connected to receive and discharge fluid, wherein the separating members move within the pressure vessels in response to pressure differential between the first and second chambers. A valve assembly having suction and discharge valves communicates with the first chambers. The suction and discharge valves are operable to permit fluid to alternately flow into and out of the first chambers. A hydraulic drive alternately supplies hydraulic fluid to and withdraws hydraulic fluid from the second chambers such that the fluid discharged from the first chambers is free of pulsation.

Abstract: A piezoelectrically actuated fluid pump including a pump housing, a pump chamber, inlet and outlet ports for communicating the pump chamber with the exterior of the pump housing, valves for opening and closing the ports, a pre-stressed piezoelectric diaphragm member which is self-actuated, a piston member, and a power source is provided. The diaphragm member includes a prestressed piezoelectric element which is durable, inexpensive and lightweight as compared with diaphragm members of prior diaphragm pumps of comparable discharge capacity, and is actuated via electrical signals from an outside power source. The diaphragm member drives the piston member. No exterior mechanisms are necessary for driving the diaphragm member.

Abstract: A pneumatic cylinder for actuating fume extraction valves in fume and heat extraction plants has a piston (2) that may be actuated from both sides with at least one working surface and that can be made to slide by pressurised air in a cylinder (1) with at least one working chamber (4), as well as an energy accumulator with regulating means. The regulating means can be controlled by control means to open or keep open the fume extraction valves. In order to obtain a compact pneumatic cylinder for a fume and heat extraction plant which is easy to install, a storage chamber in which air or pressurised air is stored as compressible pressure medium is provided as energy accumulator. The storage chamber is in communication with a compression surface (7) of the piston (2), at its side opposite to the working surface (7), so that pressure medium may flow between the storage chamber and the compression surface (7).

Abstract: A two-cylinder air compressor has a motor with a through drive shaft. Identical housings are provided at each end of a cylindrical spacer sleeve that surrounds the motor. The housings include cylinder housing extensions each of which mounts a cylinder sleeve, a valve plate, and a head. The heads are part of a one-piece cylinder head member. Wobble pistons are mounted on each end of the motor shaft and operate in the cylinder sleeves. The cylinder sleeves rest on a floor in the housing which has integrally formed passages for cooling air to circulate around the cylinder sleeves. The one-piece cylinder head member includes integral tubes connecting the heads. The integral tubes span the distance between the heads and are spaced from the outside of the spacer. The housings may be joined by through bolts or without bolts by press fitting the bearings in the housing, press fitting the housings to the spacer sleeve, and press fitting the motor shaft into the bearings.

Abstract: Pump to supply fluid to at least two circuits in a control system for a production well. Each of the circuits is maintained at different pressures. The pump provides fluid to a plurality of poppets that are opened or closed depending on the positions of a cam surface which controls the position of the poppet. A pressure relief valve is used to prohibit fluid from entering a circuit unless the pressure exceeds the pressure of the fluid in the control circuit. The cam surfaces are controlled by a knob rotatable by an operator. By rotating the knob, the poppets can be opened or closed so as to provide fluid sequentially to each of the circuits and pressurize each circuit individually.

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.

Abstract: The present invention relates to a pump, more particularly a radial piston pump, including at least two pump pistons (10) with an associated working chamber (13) each, wherein the working chambers (13) are connected to suction lines (4) by way of suction valve devices (8) and to a joint pressure line (5) by way of pressure valve devices (9), wherein at least one of the suction valve devices (8) opens during the pressure stroke in dependence on the pressure in one of the associated lines (4, 5), and wherein at least one of the suction valve devices (8) opens during the pressure stroke in dependence on the pressure in the pressure line (5).

Abstract: The invention provides a pulsation free pump which includes a plurality of hydraulic diaphragm pumps, a plurality of plungers corresponding to the hydraulic diaphragm pumps, each of the plungers performing a reciprocal movement which provides a pumping cycle operation of corresponding one of the plurality of hydraulic diaphragm pumps and an adjustable exhaust differential pressure regulating valve. Each of the pumping cycles includes a discharge process and a subsequent suction process. A controller is provided for controlling reciprocal movements of the plungers in association with each other at a predetermined difference in phase of the pumping cycle.

Abstract: A liquid transfer pump includes a housing having an inner space, a cross head disposed in the inner space of the housing and attached to a driving mechanism to reciprocate inside the housing, a plunger attached to and held by a plunger holder of the cross head, and a pump head situated near the cross head. The pump head includes a pump chamber with an inlet path and an outlet path, and the plunger is disposed in the pump chamber to be reciprocated therein together with the cross head. A resilient O-ring is disposed in the plunger holder, and a plunger seal is disposed in the pump head, wherein one side of the plunger is engaged with and held by the resilient O-ring and the other side of the plunger is engaged with and held by the plunger seal. Accordingly, the plunger can be flexibly supported by the O-ring and the plunger seal. The plunger seal can be used for a long time without leakage.

Abstract: The invention is based on a reciprocating piston pump having two radial pistons disposed symmetrically to one another, which are drivable to a reciprocating motion by an eccentric disposed between them and are held in contact with the eccentric by a hoop spring that engages the pistons. For ease of installation, the invention proposes embodying the hoop spring as a bent wire part, with two open, hooklike eyelets on their ends, which ends are inserted into annular grooves of the pistons and enter into a snap connection with them in order to hold the pistons tightly against the eccentric.

Abstract: A hydraulic pump includes a pump housing block, a rotary drive shaft and plural pumping assemblies extending radially from the rotary drive shaft. Each pumping assembly includes a reciprocating piston, a cylinder lining, and a piston return spring mounted between the piston and the lining. The cylinder linings are inserted into the pump block from the outside and a detachable latching device secures the linings to the block. The cylinder lining, the piston and the piston return spring can be easily removed and replaced after the latching device, for instance a locking ring, has been removed.

Abstract: A multistage compressor has a yoke with a cross slider and roller bearings pressed against the sides of the cross slider by spring forces to enable the cross slider to slide smoothly within the yoke. The spring forces are generated by springs disposed between the yoke and a liner plate that urges the roller bearings against the cross slider. By this construction, the yoke and cross slider are not damaged during operation of the compressor even if the dimensions of the members change due to thermal expansion.

Abstract: A pump system has first and second pumps. Each pump has a housing, which housing has an inboard end and an outboard end. The pumps are arranged so that the inboard ends are adjacent to each other. The inboard ends each have a crankshaft, while the outboard ends each have an output manifold. Each crankshaft is connected to a plunger by way of a connecting rod and a crosshead. The crosshead reciprocates inside of a cylinder. The crosshead has an axis that is coplanar with a rotational axis of the crankshaft. The connecting rod is connected to the crosshead by way of a wrist pin. The wrist pin is offset from the cylinder axis in order to allow the respective pump to be compact in length. The first and second pumps are on a trailer. In the first pump, the wrist pin is offset on one side of the respective cylinder axis, while in the second pump, the wrist pin is offset on the opposite side of the respective cylinder axis.

Abstract: A method and apparatus to convert the torque of a drive shaft into reciprocating energy to drive and pull a piston utilizing a nodal rotator attached to the drive shaft, or alternatively to convert reciprocating energy into torque, said rotator having compression and repositioning means associated with cam followers which drive and pull opposed pistons and cylinders in air compressors, internal combustion engines, and other technology.

Abstract: A hydraulic motor vehicle brake installation, the braking pressure modulation of which occurs over adjustable wing cell pumps, as space-saving solution it is proposed to have all the required wing cell pumps driven over a common shaft by a turning-rate stabilized electric motor. An individual control of each individual wing cell pump occurs through the drive of a lift ring each by one proportional magnet per wing cell pump.

Abstract: An IV pump actuates a disposable cassette having two parallel fluid paths that include first and second pumping chambers. The disposable cassette (12) has a housing(14) that includes a back portion (152) in which is defined a fluid path (60) between an inlet port (16) and an outlet port (18). An elastomeric membrane (150) is sealed between the back portion and a front portion (52). The elastomeric membrane is exposed through the front portion at a first pumping chamber (82), a second pumping chamber (84), inlet valves (70, 76), and outlet valves (86, 92). The inlet valves operate in a fully open mode, a fully closed mode, and a cracking mode. The cracking mode of the inlet valve occurs as the elastomeric membrane is initially forced further into the pumping chamber. If the pressure of the fluid in the pumping chamber exceeds a predetermined cracking pressure, the inlet valve is forced open so that the fluid flows from the pumping chamber back toward the inlet port.

Abstract: A multistage vacuum pump is achieved by utilizing a single piston and cylinder assembly having opposite end portions with substantially equal diameters and an enlarged diameter central portion. One end of the cylinder is closed by a valve and a first stage pumping chamber is defined between the valve and the piston. The enlarged diameter portion of the piston has an axial extent less than the axial extent of the enlarged diameter portion of the cylinder to define second and third stage pumping chambers on opposite sides of the enlarged diameter portion of the piston. The three pumping chambers are interconnected by passage means to an inlet and outlet to provide a sequential reduction in pressure. A single drive unit may be connected to a plurality of pumping units for reciprocating the piston in each pumping unit.

Abstract: A two-stage positive displacement pump (1) is used in particular to operate in conjunction with a turbomolecular pump (2) that can be placed ahead of it in series. The two-stage positive displacement pump (1) is configured as a hybrid pump (3) that has on the medium-entry side a reciprocating pump (5) with a comparatively large displacement area (6), whereby its piston-cylinder space (7) is sealed off with respect to the crank area (8) by means of a sealing membrane (9). Also as a part of this two-stage positive displacement pump (1) which forms the hybrid pump (3), there is placed in series behind the reciprocating pump (5) a diaphragm pump (10), whose displacement area (11) is noticeably smaller compared to that of the reciprocating pump (5).

Abstract: A reciprocating piston pump having a housing, pistons disposed opposite one another in the housing, an eccentric between the pistons, annular grooves that fit around the piston necks machined into piston ends oriented toward the eccentric, and a U-shaped hoop spring curved radially outside the eccentric in the circumferential direction thereof. The hoop spring includes forklike hoop spring ends which engage the annular grooves and press the piston ends toward the eccentric. In the circumferential direction of the substantially U-shaped hoop spring, a continuation is formed on the hoop spring and together with a stop disk aligned transversely to the eccentric shaft, forms a device that limits the pivotability of the hoop spring about the piston necks. The reciprocating piston pump is usable for instance in hydraulic motor vehicle brake systems and in other hydraulic equipment.

Abstract: A cylinder pump having a controllable piston/drive detachment is disclosed that can engage or disengage a piston rod using a solenoid. Most any type of drive can be used. The cylinder pump could have one or more cylinders. Each cylinder and piston rod has quick connect and disconnect mountings. The cylinder pump could be a syringe pump or drive.

Abstract: A diaphragm pump with a driving motor has arranged in a case (5) at lease one drive (3) for transferring the pump movement to a pump diaphragm (4a). The case (5) of the diaphragm pump is essentially formed by at least one extrusion (6) configured to accommodate the drive(s) (3) and the driving motor (2). The extrusion (6) carries the driving motor (2), the drive(s) (3) and the pump head(s) (4). The extrusion (6) enables the pump case (5) to be specially dimensionally stable, to be manufactured at reasonable price, and has substantially smooth external surfaces. It is therefore easy to clean.

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.