A high-pressure pump has a metering valve and a valve stopper. The stopper has a regulation portion which an end surface of the valve is brought into contact with. An outer diameter of the regulation portion is equal to an outer diameter of the outer peripheral surface of the valve. A cylindrical sleeve is disposed around the regulation portion. When the end surface of the valve is in contact with the regulation portion, the sleeve covers a tapered surface of the valve.

Plunger pump includes cylinder having inside cylinder chamber; plunger disposed in cylinder to be relatively movable forward and backward to cylinder chamber so outer plunger's circumferential face is in slide contact with cylinder's inner circumferential face, and having cut face on distal end's outer periphery; and suction and discharge ports provided to cylinder to communicate with cylinder chamber, plunger pump transferring fluid by reciprocating plunger in axial direction while rotating plunger relative to cylinder chamber to let suction and discharges ports alternately communicate with cylinder chamber, wherein cylinder includes cylinder main body and spacer section being disposed in cylinder main body's inner portion of proximal end side, and sliding against plunger's portion closer to proximal end side than portion of plunger advancing and retracting into cylinder chamber, and plunger pump further includes seal section provided on cylinder's proximal end side for sealing cylinder main body, plunger and spacer section.

A pump having two pistons which are driven by a cam belonging to an external rotor and which are inserted into two cylinder blocks mounted parallel to each other in such a way as to form two opposite, parallel, eccentric pump chambers The pump chambers have at least one inlet port through which liquid is drawn into the pump chambers during the fill stroke of the pistons, and then expelled from the pump chambers during the discharge stroke of the pistons to at least one outlet port, the outflow rate of which is constant and even.

A reciprocating compressor-expander according to the present invention comprises a cylinder, a piston, a crankshaft connected to the piston, a first valve for a low pressure compressible fluid, a second valve for a high pressure compressible fluid, and a valve drive mechanism for driving the first valve and the second respectively such that, during a compression process, the low-pressure compressible fluid is sucked into the cylinder from the first valve in synchronization with the rotation of the crankshaft and the high-pressure compressible fluid compressed in the cylinder is discharged from the second valve, and that, during an expansion process, the high-pressure compressive fluid is introduced from the second valve into the cylinder, and the low-pressure compressible fluid expanded in the cylinder is discharged from the first valve.

A plunger pump includes: a motor; a bracket attached to the motor; a holding member fixed to the bracket; a plunger extending in a axial direction; a pump head holding the plunger such that the plunger is capable of rotating and reciprocating in the axial direction; and a joint mechanism for converting rotation of the motor into rotation and reciprocation of the plunger, wherein the holding member includes first and second plate members each formed into a flat plate shape, and the first and second plate members are parallel to each other so as to sandwich the pump head.

A self-energizing valve includes a valve body defining an inner chamber having an inlet and an outlet. A valve head within the inner chamber is moveable between a first position and a second position. A valve seal in fluid communication with the inlet has a sealing surface with a sealing member between the valve head and the valve seal. The sealing member is movable between a closed position where the sealing member engages with the sealing surface and an open position where the sealing member disengages from the sealing surface to allow flow through the inlet into the inner chamber. A cam is coupled to the valve head. Rotation of the cam causes movement of the valve head between the first position and the second position to move the valve head to the first position to hold the sealing member in the closed position.

A dual active valve positive displacement pump comprising: A housing holding the pump's components. A piston with an internal cavity divided into two fluidly-isolated volumes by a freely-moving diaphragm, one of the two volumes being fluidly connected with a volume between piston and housing which contains driver pressure from a pressure source. The piston is reciprocally movable inside the housing under positive or negative driver pressure. An active inlet valve operable by driver pressure actuates when the driver pressure is more than the maximum pressure at the pump inlet port. An active outlet valve operable by driver pressure actuates when the driver pressure is less than the minimum pressure at the pump outlet port. The diaphragm separates pumped fluid from operational fluid used to move the diaphragm inside the piston cavity and transmits pressure at the inlet port when the inlet valve is open, and at the outlet port when the outlet valve is open.

A multi-channel positive displacement piston pump apparatus includes a motor and a plurality of positive displacement piston pumps driven by the motor. The plurality of pumps are aligned in a stacking direction, and each pump has an intake port and an outlet port, wherein the intake ports and the outlet ports of all pumps face in the same direction generally perpendicular to the stacking direction. In a method for retrofitting a positive displacement piston pump for use in a multi-channel pumping apparatus, an outlet port of a pump housing of the pump and a flush outlet port of the pump housing are plugged and an alternative fluid path is formed within the pump housing. The outlet port is disposed in line with an inlet port of the pump housing but on an opposite side of the pump housing. The flush outlet port is disposed in line with a flush inlet port of the pump housing but on an opposite side of the pump housing. In this way, the alternative fluid path is formed between the inlet port and the flush inlet port.

A pump having two pistons which are driven by a cam belonging to an external rotor and which are inserted into two cylinder blocks mounted parallel to each other in such a way as to form two opposite, parallel, eccentric pump chambers The pump chambers have at least one inlet port through which liquid is drawn into the pump chambers during the fill stroke of the pistons, and then expelled from the pump chambers during the discharge stroke of the pistons to at least one outlet port, the outflow rate of which is constant and even.

A valve closure for a piston compressor valve including: a valve seat having a plurality of passage openings, a shaft having an axis of rotation (D), and a rotatable closing element connected to the shaft for opening and closing the passage openings, the valve seat having a flat end face, to which the passage openings lead and a center (Z): the passage openings extending radially to the center (Z); and the closing element having a center point (M) and a plurality of closing arms extending radially to the center point (M). The shaft can be rotated about the axis of rotation and can be slid in the extension direction of the axis of rotation extending perpendicularly to the end face and through the center (Z); each closing arm having a sealing surface substantially complementary to the passage openings in accordance with the rotation of the closing element.