A fluid end assembly comprising a plurality of fluid end sections positioned in a side-by-side relationship. Each fluid end section comprises a housing having a bore formed therein for housing a reciprocating plunger. Fluid is prevented from leaking around the plunger by a packing seal assembly. The packing seal assembly comprises one and only one packing seal.

A fluid cylinder for a fluid end section of a reciprocating pump is described. The fluid cylinder includes a body defining a pressure chamber in fluid communication with a plunger bore, the plunger bore comprising a packing segment configured to hold a packing stack, and a tubular sleeve in interference-fit within the plunger bore. The sleeve has an internal passage configured to accommodate a plunger operatively reciprocating within the plunger bore during operation of the reciprocating pump, and a stepped shoulder disposed at an interface between a first segment of the sleeve and a second segment of the sleeve, where a diameter of the first segment being greater than a diameter of the second segment of the sleeve. An annular seal is disposed at the stepped shoulder f the sleeve between the sleeve and the plunger bore. A packing flange is secured within the plunger bore abutting an end portion of the first segment of the sleeve.

A fluid cylinder for a fluid end section of a reciprocating pump is described. The fluid cylinder includes a body defining a pressure chamber in fluid communication with a plunger bore, the plunger bore comprising a packing segment configured to hold a packing stack, and a tubular sleeve in interference-fit within the plunger bore. The sleeve has an internal passage configured to accommodate a plunger operatively reciprocating within the plunger bore during operation of the reciprocating pump, and a stepped shoulder disposed at an interface between a first segment of the sleeve and a second segment of the sleeve, where a diameter of the first segment being greater than a diameter of the second segment of the sleeve. An annular seal is disposed at the stepped shoulder f the sleeve between the sleeve and the plunger bore. A packing flange is secured within the plunger bore abutting an end portion of the first segment of the sleeve.

An internal oil filter is installed at least partially inside a crankcase and/or an oil sump of a compressor. The internal oil filter can receive oil from an oil pressure regulator and filter the oil via filter media. The received oil radially penetrates through the filter media and flow directly into the oil sump from an outside surface of the filter media. This can eliminate the need of fluid lines connecting an outlet of an oil filter to the oil sump and any sealing mechanism therebetween.

An internal oil filter is installed at least partially inside a crankcase and/or an oil sump of a compressor. The internal oil filter can receive oil from an oil pressure regulator and filter the oil via filter media. The received oil radially penetrates through the filter media and flow directly into the oil sump from an outside surface of the filter media. This can eliminate the need of fluid lines connecting an outlet of an oil filter to the oil sump and any sealing mechanism therebetween.

A pump comprises a housing (141) having a cavity (142) with an inlet valve (143), an apparatus (144) for raising fluid pressure in the cavity (142) and a discharge valve (145), the discharge valve (145) comprises a valve head (160) movable between an open and closed position and a valve seat (167), wherein the pump further comprises a booster piston (182) arranged in a booster cylinder (183), the booster piston (182) has a first face (191) exposed to a low pressure zone (189) and a second face (194) exposed to fluid pressure in the cavity (142), and at least one of the booster piston (182) and the booster cylinder (183) is movable relative to the other to add an opening force to the discharge valve. The pump is preferably a mud pump for circulating drilling mud through a drill string in a wellbore or a cement pump which may be of the type for pumping cement into a wellbore. Also disclosed is a method for facilitating opening a valve comprising a valve head (160) and a valve seat (167), the valve head (160) is movable a predetermined distance from a closed position on the valve seat (167) to a fully open position distant on the valve seat, and the method comprises the step of adding a force to the valve head (160) along a small portion of the predetermined distance.

The present invention relates to a pump unit applied to a high-pressure cleaning machine, including: a water inlet chamber, a water outlet chamber, and a central chamber connected to the water inlet chamber and the water outlet chamber. The pump unit further includes a plunger disposed in the central chamber and an eccentric mechanism connected to the plunger. The eccentric mechanism drives the plunger to perform reciprocating motion in the central chamber.

The present invention relates to a pump unit applied to a high-pressure cleaning machine, including: a water inlet chamber, a water outlet chamber, and a central chamber connected to the water inlet chamber and the water outlet chamber. The pump unit further includes a plunger disposed in the central chamber and an eccentric mechanism connected to the plunger. The eccentric mechanism drives the plunger to perform reciprocating motion in the central chamber.

A pump body of a high-pressure pump includes a pressure chamber formed in a deep portion of a cylinder. The pump body closes the pressure chamber on a side opposite to a plunger. The plunger reciprocates within the cylinder to vary a volume of the pressure chamber. The large-diameter portion provided at an end of the plunger on a side protruding to the pressure chamber has an outside diameter larger than an inside diameter of the cylinder and smaller than an inside diameter of the pressure chamber. In this case, the large-diameter portion is engaged with a step portion between the cylinder and the pressure chamber in a state before attachment of the high-pressure pump to an internal combustion engine. Accordingly, separation of the plunger from the cylinder is avoidable.

Various assemblies that can be used in a mud pump with a plunger-style piston to reduce seal failures, to offer control in variability of the circumference of the piston to thereby control fluid pressure, and to provide visibility into seal condition during operation. In one embodiment, a sleeve that can vary the overall effective circumference of the piston enables fluid pressure control. In some embodiments, seal failure within a pump can be monitored via a drain port that would receive drilling fluid leaking past a seal during operation of the pump. A discharge valve can be provided between an inlet and an outlet of the mud pump to reduce the load on pump components during start-up. Additional systems, devices, and methods are also disclosed.