In a piston pump, for example, a piston sub assembly includes a columnar plunger that lies along an axial direction, a cap that is fixed with the plunger to cover an adjacent region between a first end surface at one end in the axial direction of the plunger and the first end surface at a first outer circumferential surface of the plunger, and provided with an intake passage extending from an inlet on an outer side of the first outer circumferential surface to an outlet on an outer side of the first end surface outside the plunger, and a first valve seat of a first intake check valve located at the outlet, and a seal member that is a member different from the cap and that prevents leakage of hydraulic fluid from the first chamber through a gap between the first cylinder and the piston sub assembly.

A valve assembly for a fracturing pump includes a valve seat having a bore, the valve seat having an upper region forming at least a portion of a strike face. The valve assembly also includes a groove and a valve seat insert positioned within the bore. The valve seat insert includes a body portion extending at least a portion of a bore length. The valve seat insert also includes an insert bore extending through the body portion. The valve seat insert further includes an upper insert region, at least a portion of the upper insert region positioned within the groove. The valve assembly also includes a valve member positioned to reciprocate within the bore, the valve member moving between an open position and a closed position.

A proportional spool valve (1) for adjusting a displaced volume of a displacement pump, in particular of an oil pump in a motor vehicle, the proportional spool valve (1) includes a valve housing (2) and a valve spool (3) which is mounted in the valve housing (2) and displaceable along a displacement axis (V) and which can be displaced against the spring force of a valve spring (6) axially supported on a spring holder (7) which is fixed relative to the valve housing (2) by energizing an electrical coil assembly (10), characterized in that wherein both the preferably single-piece spring holder (7) and the valve housing (2) are made of plastic and that the spring holder (7) is welded to the valve housing (2), an integral welded connection (9) being formed.

A digital positioner for a valve includes a valve controller configured to obtain a set point value for a valve travel of a valve, and generate a pulse-width modulated current signal based on the set point value. The digital positioner also includes a current-to-pressure converter configured to receive the pulse-width modulated current signal from the valve controller, convert the pulse-width modulated current signal to a pulse-width modulated pressure signal, and provide the pulse-width modulated pressure signal to a pneumatic actuator in the valve to adjust a position of the valve.

A digital positioner for a valve includes a valve controller configured to obtain a set point value for a valve travel of a valve, and generate a pulse-width modulated current signal based on the set point value. The digital positioner also includes a current-to-pressure converter configured to receive the pulse-width modulated current signal from the valve controller, convert the pulse-width modulated current signal to a pulse-width modulated pressure signal, and provide the pulse-width modulated pressure signal to a pneumatic actuator in the valve to adjust a position of the valve.

A high pressure reciprocating pump (10) for high fluid pressures having a valve cartridge (57) positioned within a manifold block (15) of the pump (10). The valve cartridge (57) has a fixed body (58) with a plurality of equally spaced suction opening (69) extending therethrough. A central bore (70) of the valve cartridge body (58) has a valve assembly (72) mounted therein. Valve assembly (72) include a discharge valve member (74) and a two-piece suction valve member (280) mounted for sliding movement about the outer surface of discharge valve member (74). A spring (84) biased between spring retainer (87) and the two-piece suction valve member (280) continuously urges the valve members (74, 280) toward closed position. On the suction stroke, the two piece suction valve member (280) is opened and fluid through suction openings (69) enters the pump chamber (37). On the discharge stroke, high pressure fluid is discharged through the central bore (77) and lateral slots (79) of open discharge valve member (74) past seat (78). The two-piece suction valve 280 includes a spring seat 282 and a hard sealing member 284.

An automatic double-acting valve includes: a valve body, a central duct, passing through the valve body and is equipped with a first opening made in a first end of the valve body and a second opening made in an opposite second end, a peripheral duct made in the valve body, eccentric to the central duct and equipped with a first opening, in a side surface between the first end and the second end, and a second opening in the second end of the valve body, a first blocking body movable at least between a closed position, in which it obstructs the first opening of the central duct, and an open position, a first elastic element configured to generate a force adapted to keep the first blocking body closed, a second blocking body movable at least between a closed position, in which it obstructs the second opening, and an open position.

A diapharagm pump for a bioprocess system comprises a pump head (1; 101; 201; 301) comprising: a common inlet (3); a common outlet (5); a plurality of pump cavities (7) each including at least one cooperating pair of one-way valves, the at least one pair of one-way valves including an inlet valve (9) and an outlet valve (11), wherein the respective inlet valves (9) are in fluid communication with the common inlet (3) and the respective outlet valves (11) are in fluid communication with the common outlet (5) and wherein a centre of the outlet valve (11) for each pump cavity is positionable above a centre of the inlet valve (9) for the same pump cavity when the diaphragm pump is oriented for use to inhibit trapped gas; and a plurality of moveable diaphragms (13) each respectively provided in a respective of said pump cavities (7) for varying a volume of the pump cavities. The system further comprises a pump drive (31) which is configured to transfer a motion to the diaphragms (13) of the pump head (1; 101; 201) for accomplishing a fluid displacement from the common inlet (3) to the common outlet (5) of the pump head (1; 101; 201; 301) as a result of said varying of the volume of the pump cavities (7).

A valve assembly for a fracturing pump includes a valve seat having a bore extending therethrough, the valve seat including a strike face at a top region opposite a bottom region, at least a portion of the strike face formed by an insert positioned within a groove formed in the valve body. The valve assembly also includes a bore liner arranged within the bore, at least a portion of an axial length of the bore liner covering at least a portion of the ceramic to form a barrier between the insert and the bore. The valve assembly further includes a valve member positioned to reciprocate within the bore, the valve member moving between an open position and a closed position, wherein at least a portion of the valve member engages at least a portion of the strike face in the closed position.

A digital positioner for a valve includes a valve controller configured to obtain a set point value for a valve travel of a valve, and generate a pulse-width modulated current signal based on the set point value. The digital positioner also includes a current-to-pressure converter configured to receive the pulse-width modulated current signal from the valve controller, convert the pulse-width modulated current signal to a pulse-width modulated pressure signal, and provide the pulse-width modulated pressure signal to a pneumatic actuator in the valve to adjust a position of the valve.