Abstract: An injection device for subcutaneous delivery of fluid which comprises a puncture cannula and an indwelling cannula. In a starting position, a distal end region of the puncture cannula runs coaxially inside the indwelling cannula. The device comprises displaceably mounted first and second runners. The first runner is connected to the puncture cannula and the second runner to the indwelling cannula. A control element is movable over a predefined control area. The control element is configured such that, in a first part of the control area, the control element effects an equidirectional displacement of the first and the second runners, and hence fitting of the indwelling cannula and, in a second part of the control area, effects blocking of the second runner, and hence holding of the indwelling cannula in a dwell position, and return of the first runner and withdrawal of the puncture cannula into an end position.

Abstract: An acoustic sensor, comprising: a side wall, closed by first and second end walls to form a substantially cylindrical cavity for containing a fluid, wherein a radius, a, of the cavity and an axial height, h, of the cavity satisfies the inequality a/h is greater than 1.

Abstract: A device (1) and the use thereof for dispensing fluid under aseptic conditions. The device (1) comprises conveying device (2) and container (3) with a variable inner volume. The conveying device comprises cylinder (4) with at least three openings (5, 6, 7) which are arranged along longitudinal central axis (11). Displaceable first and second pistons (9, 10) are arranged in the cylinder. The end faces (11, 12) of the pistons and inner wall (13) of the cylinder, delimit a variable fluid volume (14). The first opening is brought into fluidic communication with dispensing opening (15) and the second opening is brought into fluidic communication with the container. Each of the pistons comprise three seals (16, 16?, 16?) which are offset and sealingly close off the cylinder. Adjacent piston seals have inner spacing (di) which is equal to a shortest spacing (aA1) between two adjacent openings (5, 6 or 6, 7).

Abstract: The dosing apparatus comprises a conveying device (5), which is driven by at least one conveying drive (4), for conveying fluid from the interior (3) of a container (2). The fluid by means of the conveying device (5) is conveyable from the container to a dispensing opening (6). The conveying device (5) comprises a cylinder (7) having at least one intake opening (11) and at least one outlet opening (12) on an inner cylinder wall (8), and a first piston (9) and a second piston (10). The first piston (9) and the second piston (10) are mounted within the cylinder (7) so as to be displaceable in the longitudinal direction. Furthermore, the first piston (9) and the second piston (10) between the end sides thereof and together with a portion of the inner cylinder wall (8) delimit a variable fluid volume (17).

Abstract: The devices and systems are medical fluid treatment therapies. The device and systems are configured and capable of operating based on small volumes of fluids. The devices and systems include a pump configured for small volume of a fluid. The pump may include a first conduit configured for inflow of the fluid; a second conduit configured for outflow of the fluid; a fluid chamber configured to move the fluid through the pump; a diaphragm configured to force the fluid through the fluid chamber by indirectly exerting force on the fluid chamber; and a connector configured to removably attach the pump to a motor.

Abstract: A device for transfer of granular solid material between two chambers at different pressures. A piston type transfer pump device used in a horizontal position transfers granular material into the compression chamber by gravity and evacuates the material into the exhaust chamber at a higher pressure. Such a device may for example find an application for feeding a gasification reactor with biomass.

Abstract: A liquid discharge apparatus includes a head, a recovery tank, a supply tank connected to the recovery tank, and a pressure regulator. The pressure regulator includes a first cylinder connected to an upper portion of the recovery tank, a first piston movable in the first cylinder, a first valve configured to open and close a path between the recovery tank and the first cylinder, depending on a position of the first piston, a second cylinder connected to the first cylinder and an upper portion of the supply tank, a second piston movable in the second cylinder, a second valve configured to open and close a path between the supply tank and the second cylinder, depending on a position of the second piston, and a third valve configured to open and close a path between the second cylinder and an atmosphere, depending on a position of the second piston.

Abstract: A magneto-caloric effect type heat pump apparatus includes a magneto-caloric element which generates heat when an external magnetic field is applied to and which absorbs heat when the external magnetic field is removed from; a magnetic field switcher which switches the applying and the removal of the external magnetic field from each other; a pump pumping a heat transport medium between a low-temperature end and a high-temperature end of the magneto-caloric element; and an auxiliary heat source device which supplies heat of a heating element to the magneto-caloric element.

Abstract: An air compressor mountable to a sidewall of an annular tire cavity, wherein the compressor comprises an air inlet for receiving air to be pumped into the tire cavity and an air outlet for releasing air into the tire cavity. Further, the compressor comprises a double membrane assembly having a first membrane and a second membrane arranged in parallel to the first membrane. A pressure compensation chamber is provided between the first membrane and the second membrane, the pressure compensation chamber being in fluid communication with the tire cavity. Further, an air compression chamber is arranged on a side of the second membrane opposite to the pressure compensation chamber, wherein the compression chamber is in fluid communication with the air inlet and the air outlet. Moreover, a tire comprises the aforementioned compressor.

Abstract: A fluid dispenser head, such as a pusher, includes an inlet duct, and a dispenser orifice in dispensing communication with the inlet duct. The dispenser head further includes diversion means for selectively interrupting dispensing communication between the inlet duct and the dispenser orifice, and for establishing filling communication with a filling duct formed by the dispenser head and exiting outside the dispenser head.

Abstract: A compressor including a pair of opposed pistons disposed in a housing and defining a compression chamber. An electromagnetic actuator reciprocatedly drives the pistons within the housing in cooperation with force accumulator. The force accumulators bank the force during a first reciprocation, decelerating the pistons, and apply the force in a subsequent reciprocation, thereby accelerating the pistons.

Abstract: A pump cartridge which has a polymer shell with moveable cores inserted from each end. The polymer shell contains perpendicular passages along the top for connection of fluid supply and prime chambers. Statically mounted elastomers adjacent to perpendicular passages provide sealing around movable cores. Fluid moves by translation within the pump cartridge by filling the cavity volume between the oblate ends of the moveable cores with a liquid and matching the rotation angle and translation position of advancing left moveable core with retreating right moveable core, maintaining equivalent volume. Both moveable cores can be directed toward one another or one moveable core can remain stationary while the other advances to extrude fluid. Pump cartridge rotation changes the angle of the fluid exit passage.

Abstract: A method and a lubricant dosing pump for accurately dosing the small lubricant quantities. It is provided that at least two pistons are moved from an initial position relative to one another, thereby enlarging a dosing volume situated between them, and that thereby lubricant is conveyed through an inlet into the closing volume. Subsequently, the inlet is sealed and the two pistons situated opposite to each other in the stroke direction are moved together with the dosing volume until in a discharge position the dosing volume is connected with a discharge opening spaced apart from the inlet in the stroke direction. Then, the pistons are moved relative to each other, thereby reducing the dosing volume, and convey a predetermined dosing quantity of the lubricant through the discharge opening. Finally, the pistons are moved back into their initial positions.

Abstract: A magnetic reciprocating pump includes a tube having ends defining intake and discharge ports, first and second magnetic plungers axially aligned within the tube of corresponding cross section for reciprocation therewithin, and a plurality of longitudinally spaced coils circumscribing the tube for driving the plungers axially when electrically energized. A gap is defined between the plungers so that the first plunger is slidable between one tube end and the second plunger and the second plunger is slidable between the other tube end and the first plunger. The first plunger closes one port when moved thereagainst and has a peripheral flow path permitting flow when moved away. The second plunger closes the other port when moved thereagainst and has an outer peripheral flow path and a communicating inner axial flow path permitting flow when moved away. The plungers when moved together close the second plunger axial flow path.

Abstract: An electric oscillating drive with at least one oscillating system (1), which is driven in an oscillating manner by an actuator, especially a piezo actuator (2) or an oscillating armature magnet generating periodic force pulses with a small motion amplitude with adapted natural frequency in a preset plane (31). At least one oscillating arm (30?) performing oscillating motions has a resonant mass (55?) and with a balance arm (60?), which is in mechanical driving connection with a working member (7) of a working device, especially of a pump (3), which working member is to be driven in an oscillating manner. The oscillating arm (30, 30?) is fastened to two levers of unequal length, namely a control arm (32?) and a driving lever (33?). At least one of these two levers, especially the control arm (32?), is flexurally elastic at least in some sections.

Abstract: A hydraulic piston machine includes a plurality of pistons (12, 14) which are driven by a drive/output shaft (40), guided in an axially displaceable manner in a piston barrel (4) of a housing (2), and, in each case, bound one working chamber (44) into which the pressure medium may be fed via a suction valve (46), and from which the pressure medium may be discharged via a pressure valve (48). The housing (2) includes at least one further housing part (6) which is connected to the piston barrel (4) on the front side. The suction valves (46) and pressure valves (48) are situated in the region of a parting plane (50) between the housing parts (4, 6), in housing receptacles (52, 54), approximately axially parallel to the longitudinal axis of the piston machine.

Abstract: A HFCWO system includes an air pulse generator having a blower inlet in communication with a blower and an air port in communication with an inflatable garment. The air pulse generator includes a housing and an air pulse assembly coupled to the housing. The air pulse assembly has at least one diaphragm, at least one driver operable to move the at least one diaphragm and at least one spring arranged to bias the at least one diaphragm away from a portion of the housing.

Abstract: A hydraulic station in a hydraulic system of a wind turbine includes a tank for storing working fluid, first and second pumps fluidly connected to the tank, first and second flow paths extending from the respective first and second pumps to a hydraulic circuit, and first and second relief valves in fluid communication with the respective first and second flow paths. The first pump and first relief valve are controlled based on maintaining pressure of the working fluid in the hydraulic circuit between a first minimum limit and first maximum limit. If the pressure falls below the first minimum limit, the second pump and second relief valve are controlled in addition to the first pump and first relief valve, with the control then based on a second maximum limit and second minimum limit.

Abstract: A pump having a substantially cylindrical shape and defining a cavity formed by a side wall closed at both ends by end walls wherein the cavity contains a fluid is disclosed. The pump further comprises an actuator operatively associated with at least one of the end walls to cause an oscillatory motion of the driven end wall to generate displacement oscillations of the driven end wall within the cavity. The pump further comprises an isolator operatively associated with a peripheral portion of the driven end wall to reduce dampening of the displacement oscillations. The pump further comprises a valve for controlling the flow of fluid through the valve. The valve has first and second plates with offsetting apertures and a sidewall disposed between the plates around the perimeter of the plates to form a cavity in fluid communication with the apertures.

Abstract: A pump having a substantially cylindrical shape and defining a cavity formed by a side wall closed at both ends by end walls wherein the cavity contains a fluid is disclosed. The pump further comprises an actuator operatively associated with at least one of the end walls to cause an oscillatory motion of the driven end wall to generate displacement oscillations of the driven end wall within the cavity. The pump further comprises an isolator operatively associated with a peripheral portion of the driven end wall to reduce dampening of the displacement oscillations.

Abstract: The invention relates to a hydraulic piston engine comprising a plurality of pistons which are driven by a drive/output shaft, are axially movably guided in a piston drum of a housing, and each define a working region into which a pressurised means can be supplied via a suction valve, and from which the pressurised means can be discharged via a delivery valve. The housing comprises at least one other housing part connected to the piston drum on the front side. According to the invention, the delivery valves and the suction valves are arranged approximately parallel to the longitudinal axis of the piston engine in the region of a separating plane between the housing parts, in the housing receiving areas.

Abstract: A swash plate type hydraulic pump or motor comprises first and second swash plates which move reciprocally while opposing first and second pistons, so as to expand and contract a volume chamber according to rotation of a cylinder block. Drive pistons push on the swash plates from behind, causing the first and second swash plates to tilt, respectively. A tilt angle control valve controls the tilt angles of the swash plates by selectively increasing drive pressures that are guided to the drive pistons. A port plate is provided in a sliding portion between the first swash plate and the first piston. The port plate rotates integrally with the cylinder block and guides high and low pressure side hydraulic fluid, which flows through the supply and discharge ports provided in a sliding surface of the first swash plate, to the volume chamber via an inner portion of each first piston.

Abstract: A device for the metered delivery of a viscous liquid has a pump body with a drill hole accommodating two pistons which connects a first chamber serving as an intake chamber and a second chamber serving as a discharge chamber. Two swivel arms driven by two cam discs are foreseen as the drive mechanism for the back and forth movement of the two pistons. For the metered delivery of an adhesive which contains flakes of silver the drill hole is designed such that it serves for guiding the pistons as well as for sealing the pump path.

Abstract: There is disclosed an improved pump (5, 5?) particularly suitable for use in a method of “artificial lift” in an oil/gas well. Known pumps used in artificial lift methods suffer from a number of problems/disadvantages—e.g. low efficiency (hydraulic efficiency). The disclosed embodiments of the invention provide a pump (5, 5?) which provides a positive displacement of a predetermined volume of well production fluid for each operative cycle of the pump-in contra-distinction known to pumps which provide axial flow of well production fluid. The inventive pump (5, 5?) provides a chamber (10, 10?) having a volume (V, V?), an inlet (15) to the chamber (10, 10?), an outlet (20) from the chamber (10, 10?), and means for varying the volume (V, V?) of the chamber (10, 10?). The means for varying the volume (V, V?) of the chamber (10, 10?) is controlled by relative rotation of first and second bodies (30, 35, 30?, 35?).

Abstract: A transmissionless variable output pumping unit comprising a multiple crankshaft pump driven by a prime mover. The apparatus includes an adjustment mechanism for adjusting a phase angle between first and second crankshafts. Plungers in the pump are disposed in cylinders forming part of a pumping chamber. When the phase angle is at a minimum, the plungers operate together for maximum discharge from the pump. When the phase angle is at a maximum, the plungers operate substantially opposite one another for zero discharge. The phase angle may be infinitely adjusted between the minimum and maximum.

Abstract: A syringe for accurately metering small volumes of fluid samples and with dual resolution capabilities is provided. The syringe permits the aspiration of a tiny sample and also the dilution of a tiny sample with a much larger volume of reagent with the same syringe. The syringe also allows the aspiration of a minute fluid sample and the touchless transfer of the fluid sample from the tip of the syringe. The present invention allows the aspiration resolution to differ from the dispensing resolution. The dual resolution capability also permits the present invention to be substituted for a conventional syringe in existing conventional syringe drive system. The syringe may include a housing, a piston within the housing, and a plunger extending from the housing. A chamber is formed in the housing between the plunger and a sealing means and between the piston and the inner surface of the housing.

Abstract: An oil supplying apparatus for an opposed type reciprocating compressor comprises oil kickers which are mounted on spring supporting plates coupled to armatures of respective reciprocating motors, or oil valves which are mounted on oil paths formed on a cylinder and coonnecting with a suction path, and thereby, oil in a casing can be supplied to a slant portion between the cylinder and pistons regardless of the installation type of the compressor. In addition, lack of oil in the compressor and friction caused by the lack of oil can be prevented in advance, and a reliability of the compressor can be improved.

Abstract: A device for the metered delivery of a viscous liquid has a pump body with a drill hole accommodating two pistons which connects a first chamber serving as an intake chamber and a second chamber serving as a discharge chamber. Two swivel arms driven by two cam discs are foreseen as the drive mechanism for the back and forth movement of the two pistons. For the metered delivery of an adhesive which contains flakes of silver the drill hole is designed such that it serves for guiding the pistons as well as for sealing the pump path.

Abstract: In a compressor, a yoke constituting a linear drive section together with a driver coil, through which magnetic fluxes from a permanent magnet pass, is integrated with a cylinder and a container. A piston inserted into the cylinder is supported by springs, and the other end thereof faces an operating-gas-compressing space. The linear drive section is arranged parallel to the piston in a diametrical direction thereof. This construction reduces the longitudinal dimension of a piston portion. Further, a plurality of parts is combined together in a main body block, thereby reducing the number of parts required and improving the assembly accuracy.

Abstract: An electromagnetic compressor capable of reciprocating a piston to suck in and compress a gas by the force of an electromagnet and the resilient force of a return spring and a manufacturing method therefor are provided. The compressor includes a cylinder assembly including a front cylinder portion, a rear cylinder portion, and a center hole capable of storing the piston for reciprocation and having a working chamber defined by means of the piston, and an electromagnet located between the front cylinder portion and the rear cylinder portion and capable of actuating the piston. The cylinder assembly and the electromagnet have an integral structure molded from a resin in a manner such that the internal passage is hermetically sealed with respect to the electromagnet and the electrically conductive member.

Abstract: An oil supplying apparatus for an opposed type reciprocating compressor comprises oil kickers which are mounted on spring supporting plates coupled to armatures of respective reciprocating motors, or oil valves which are mounted on oil paths formed on a cylinder and communicated with a suction path, and thereby, oil in a casing can be supplied to a slant portion between the cylinder and pistons regardless of the installation type of the compressor. In addition, lack of oil in the compressor and dried friction caused by the lack of oil can be prevented in advance, and a reliability of the compressor can be improved.

Abstract: A double side action type reciprocating compressor is provided. The double side action type reciprocating compressor includes suction valve assemblies and discharge valve assemblies loaded in a suction passage and a discharge passage to thus control suction of fluid and respectively combined with each other so that movement direction of fluid flowing inside the suction valve assemblies and the discharge valve assemblies is vertical to the movement direction of the reciprocating motor. Accordingly, it is possible to remove the suction passage and the suction valve directly formed or loaded in the piston. Therefore, it is possible to easily process the pistons. Because the diameter and the length of the pistons can be reduced, it is possible to miniaturize the compressor.

Abstract: A device for the metered delivery of a viscous liquid has a pump body with a drill hole accommodating two pistons which connects a first chamber serving as an intake chamber and a second chamber serving as a discharge chamber. Two swivel arms driven by two cam discs are foreseen as the drive mechanism for the back and forth movement of the two pistons.

Abstract: A linear compressor, comprises a retaining member, a fixed member supported by said retaining member and formed with a hermetically sealed compression chamber to receive a working fluid therein, a pair of pistons axially movably received in said compression chamber to assume respective compression positions, a pair of piston rods each having an outer peripheral portion and slidably movably supported by said fixed member, said piston rods respectively connected to said pistons to have said pistons axially move in said compression chamber, a plurality of magnet units mounted on each of said outer peripheral portions of said piston rods, each of said magnet units having a plurality of magnet segments each made of a permanent magnet and circumferentially arranged with neighboring two magnet segments different in magnetic pole, a plurality of electromagnet units supported by said retaining member to be axially spaced apart from each other in predetermined relationship with said magnet units, respectively, and resi

Abstract: In a compressor, a yoke constituting a linear drive section together with a driver coil, through which magnetic fluxes from a permanent magnet pass, is integrated with a cylinder and a container. A piston inserted into the cylinder is supported by springs, and the other end thereof faces an operating-gas-compressing space. The linear drive section is arranged parallel to the piston in a diametrical direction thereof. This construction reduces the longitudinal dimension of a piston portion. Further, a plurality of parts is combined together in a main body block, thereby reducing the number of parts required and improving the assembly accuracy.

Abstract: A linear compressor, comprises a retaining member, a fixed member supported by said retaining member and formed with a hermetically sealed compression chamber to receive a working fluid therein, a pair of pistons axially movably received in said compression chamber to assume respective compression positions, a pair of piston rods each having an outer peripheral portion and slidably movably supported by said fixed member, said piston rods respectively connected to said pistons to have said pistons axially move in said compression chamber, a plurality of magnet units mounted on each of said outer peripheral portions of said piston rods, each of said magnet units having a plurality of magnet segments each made of a permanent magnet and circumferentially arranged with neighboring two magnet segments different in magnetic pole, a plurality of electromagnet units supported by said retaining member to be axially spaced apart from each other in predetermined relationship with said magnet units, respectively, and resi

Abstract: A compressor integrated pulse tube refrigerator of an oil free type is disclosed. The refrigerator includes a driving unit including a sealed casing having a cylinder disposed at an upper center portion of the same and a working gas filled therein, a linear motor installed in the interior of the sealed casing for generating a driving force, a driving shaft which is engaged to a rotor of the linear motor and linearly reciprocates, a piston connected with the driving shaft and inserted in the cylinder and reciprocating together with the driving shaft for thereby pumping a working gas, and a plurality of elastic guide support members provided in the interior of the sealed casing; and a refrigerating unit, for thereby implementing a stable reciprocating movement between a cylinder and a piston in a state that an outer surface of the piston does not contact with an inner surface of the cylinder.

Abstract: A linear compressor having improved heat-radiating performance incorporates first and second cylinders disposed coaxially, a first piston reciprocatably disposed inside the first cylinder, a second piston reciprocatably disposed inside the second cylinder, a compression chamber formed by the front face of the first piston and the front face of the second piston and a connecting wall connecting the first and second cylinders, and multiple working gas passages having openings formed in the connecting wall and connecting the compression chamber to the outside via these openings. The working gas passages are formed on a plane perpendicular to the axial direction of the first and second cylinder. Heat-radiating means are provided around the working gas passages. The first cylinder and the second cylinder are made of aluminum (or an aluminum alloy).

Abstract: A peristaltic piezoelectrically actuated fluid pump including two or more pairs of piezoelectric deformable members that are self-actuated, a flexible hose member, a pump chamber, inlet and outlet ports for communicating the pump chamber with the exterior of the flexible hose member, valves for opening and closing the ports, and a power supply is provided. The diaphragm members may include 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. Each pair of piezoelectric diaphragm members is actuated out of phase with the other(s) so as to allow fluid to be pumped through the flexible hose member peristaltically.

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: An improved displacement pump is provided with flow path means preventing hysteresis-causing bubbles from accumulating in piston clearances.

Abstract: A pump for performing suction and discharge of a liquid, including: a cylinder supported at at least a first support point and a second support point; a piston slidably disposed in the cylinder and forming a pump chamber having a volume changeable by sliding movement of the piston; a drive shaft, the piston and the drive shaft moving in association with each other; a cam in contact with the drive shaft so that rotation of the cam drives the drive shaft to move, the piston sliding within the cylinder in association with movement of the drive shaft to perform suction and discharge of a liquid; and a cam rotational shaft rotatably supporting the cam and disposed at the first support point.

Abstract: An apparatus for delivering fluid to a site at a controlled rate and pressure, which comprises a housing enveloping three interconnected chambers comprising a first end chamber, a connecting chamber and a second end chamber, an inlet port and an outlet port each located in a side wall of the connecting chamber, each of the inlet port and the outlet port being associated with a valve for opening and closing the respective port; a first piston positioned within the first end chamber and a second piston positioned within the second end chamber, each of said pistons having a head with an inwardly facing surface having a periphery which fits snugly within the corresponding end chamber to form a fluid-tight seal with the at least one side wall of the end chamber, wherein at least a portion of a side wall of the connecting chamber intrudes inwardly to provide a stop for the head of each piston; and a closure to close the open end of each end chamber.

Abstract: A pump unit includes a suction pump and a driving mechanism for driving the suction pump. The suction pump has a pump body provided with a suction port and a discharge port which are axially spaced, and a first piston and a second piston slidably fitted in the pump body to form a suction chamber therebetween.

Abstract: The present invention provides a pump for inducing a displacement of a fluid from a first medium to a second medium, including a conduit coupled to the first and second media, a transducing material piston defining a pump chamber in the conduit and being transversely displaceable for increasing a volume of the chamber to extract the fluid from the first medium to the chamber and for decreasing the chamber volume to force the fluid from the chamber to the second medium, a first transducing material valve mounted in the conduit between the piston and the first medium and being transversely displaceable from a closed position to an open position to admit the fluid to the chamber, and control means for changing a first field applied to the piston to displace the piston for changing the chamber volume and for changing a second field applied to the first valve to change the position of the first valve.

Abstract: A measured amount of a first fluid is metered into a measured amount of a second fluid by a method where a fluid is confined within a first chamber and a plunger of predetermined volume is mechanically moved into the chamber to displace a first measured amount of fluid after which a second plunger is mechanically moved into a defined volume of the chamber to displace a second volume of fluid therefrom different from the first volume whereupon the first and second volumes can be mixed in predetermined proportions.

Abstract: A first cylinder bore (7) for accommodating a first piston (8), a plunger bore (20) for accommodating a plunger (21), and a second cylinder bore (57) for accommodating a second piston (58) are provided in this order from above. The plunger (21) is fixed to the first piston (8). A cushion chamber (61), provided below the second piston (58), and an outlet (25b) of a second check valve (25) for gas discharge are connected to each other via a communicating passage (62). The second piston (58) is prevented from moving upward in excess of a set extent by a stopper (64) provided in the peripheral wall of the second cylinder bore (57).

Abstract: The present invention pertains to a pump, in which two pistons moving in the same direction in a common cylinder bore are provided to generate the suction intake and pressure, discharge effects as well as for control. Both pistons are held by fastening members to perform a lifting movement, and one of the pistons is a control piston for performing a constant lifting movement, while the other piston is a pump piston for performing a variable lifting movement. The difference in the lifts, multiplied by the cross section of the cylinder bore, determines the delivery volume of the pump. A braking force to the oscillating piston eliminated and the velocity of discharge of the medium to be delivered is increased by providing a member 8, whose longitudinal extension between fastening members of the two pump pistons is variable during one pump cycle so as to generate the difference between the heights of lift of the two pistons that are rigidly connected to said fastening members.

Abstract: A multi-mode, differential fluid displacement pump provides for at least two different measured doses. The pump has a chamber in which are mounted a first diameter piston and a second diameter piston defining first and second volumes for reciprocation in the chamber. Means are provided for reciprocating the pistons as desired to obtain predetermined volume changes corresponding to movement of either or both of the first and second pistons. A system of operation and a mixing chamber useful in connection with dosages from the pump are interconnected with the pump.

Abstract: A pump assembly (1) for an atomizing piston pump comprising a piston (16) slidably located in a cylinder (4), a variable volume fluid storage chamber (5) in communication with the cylinder on one side of the piston, means (18) for varying the volume of the chamber, resilient means (17) urging the varying means into a position corresponding to the minimum volume of the chamber, a fluid flow passageway (30, 31) through the piston, a resilient valve member (25) normally closing the passageway and deforming means (23) for deforming the valve member so as to open the passageway only after the piston has moved relative to the cylinder by a predetermined amount greater than zero. The pump assembly has application to dispensing metered doses of medicinal products and ensures that the dispensed dose is independent of finger pressure applied to the actuator.