Abstract: A reciprocating pump including a piston is disclosed. In some embodiments, the piston includes an annular hub, a flexible sealing element coupled to an outer surface of the hub, and a sleeve seated on the outer surface of the hub adjacent the sealing element. The sleeve is axially moveable relative to the hub to compress the sealing element. The sealing element includes a lip, which is displaced radially outward when the sleeve compresses the sealing element.

Abstract: A pump cylinder liner apparatus includes a replaceable sleeve captured between two cylinder hull portions that are releasably coupled to allow access to the sleeve for replacement. An elastomeric material or tube may be disposed between the sleeve and the two coupled hull portions for radial compressive pre-loading of the sleeve upon assembly and during operation.

Abstract: A pump including a pressure compensated piston is disclosed. In some embodiments, the pump includes a piston with an annular body and an annular sealing element disposed radially outward of the annular body. The annular body has a radially-facing outer surface adjacent an inner surface of the sealing element and an axially-facing surface with an inlet port. A flowpath extends between the inlet port and the radially-facing outer surface of the annular body.

Abstract: A valve cover assembly for a pump. In an embodiment, the valve cover assembly comprises a first cylindrical member having a central axis and a first throughbore. In addition, the valve cover assembly comprises a second cylindrical member coaxially disposed within the first throughbore and rotatable relative to the first cylindrical member about the central axis between a first position and a second position. In the first position, the second cylindrical member is axially translatable relative to the first cylindrical member. In the second position, the second cylindrical member is axially fixed relative to the first cylindrical member.

Abstract: A connector assembly comprising a housing and a tensile member disposed within the housing. The tensile member comprises first and second end portions. Each end portion sealingly engages the housing to form a hydraulic chamber therebetween. A first connector pivotally coupled to the first end portion. The axial position of the first connector relative to the housing is controlled by pressure within the hydraulic chamber.

Abstract: A pump including a pressure compensated piston is disclosed. In some embodiments, the pump includes a piston with an annular body and an annular sealing element disposed radially outward of the annular body. The annular body has a radially-facing outer surface adjacent an inner surface of the sealing element and an axially-facing surface with an inlet port. A flowpath extends between the inlet port and the radially-facing outer surface of the annular body.

Abstract: A seal assembly, for sealing between a stationary conduit and a rotating conduit, comprises an upper gland assembly, a washpipe, and a lower gland assembly. The upper gland assembly is operable to engage the stationary conduit. A washpipe partially disposed within the upper gland assembly. An upper seal member is disposed within the upper gland assembly around a periphery of the washpipe. An upper packing ring is engaged with the upper gland assembly so as to compress the upper seal member into sealing engagement with the washpipe. A lower gland assembly is disposed about the washpipe and operable to engage the rotating conduit. A lower seal member is disposed within the lower gland assembly and is compressed into sealing engagement with the washpipe by a lower packing ring that is engaged with the lower gland assembly. The engagement of the packing rings with their respective gland assemblies is independent of the engagement of the gland assemblies and the conduits.

Abstract: A pump cylinder liner apparatus includes a replaceable sleeve captured between two cylinder hull portions that are releasably coupled to allow access to the sleeve for replacement. An elastomeric material or tube may be disposed between the sleeve and the two coupled hull portions for radial compressive pre-loading of the sleeve upon assembly and during operation.

Abstract: A reciprocating pump including a piston is disclosed. In some embodiments, the piston includes an annular hub, a flexible sealing element coupled to an outer surface of the hub, and a sleeve seated on the outer surface of the hub adjacent the sealing element. The sleeve is axially moveable relative to the hub to compress the sealing element. The sealing element includes a lip, which is displaced radially outward when the sleeve compresses the sealing element.

Abstract: A valve cover assembly for a pump. In an embodiment, the valve cover assembly comprises a first cylindrical member having a central axis and a first throughbore. In addition, the valve cover assembly comprises a second cylindrical member coaxially disposed within the first throughbore and rotatable relative to the first cylindrical member about the central axis between a first position and a second position. In the first position, the second cylindrical member is axially translatable relative to the first cylindrical member. In the second position, the second cylindrical member is axially fixed relative to the first cylindrical member.

Abstract: Apparatus and method for applying radial compressive stress pre-loading to a cylinder liner. A cylinder housing is attached to a pump, and a cylinder liner is disposed within the cylinder housing. A fluid inlet in fluid communication with the annular space between the cylinder housing and cylinder liner is disposed on the cylinder housing. The annular space is filled with pressurizing fluid through the fluid inlet, which creates radial compressive stress pre-loading on the cylinder liner.

Abstract: Apparatus and methods for constructing a valve comprising a sealing member and a hollow ball operable to sealingly engage the sealing member. A guide housing disposed about said hollow ball and does not constrain rotation of said hollow ball. A spring is disposed between the hollow ball and the guide housing so as to bias the hollow ball into sealing engagement with the sealing member. The hollow ball is constructed from two unequal sized portions and may comprise a hollow, spherical body having an aperture and a plug sized so as to closely fit within the aperture.

Abstract: A seal assembly, for sealing between a stationary conduit and a rotating conduit, comprises an upper gland assembly, a washpipe, and a lower gland assembly. The upper gland assembly is operable to engage the stationary conduit. A washpipe partially disposed within the upper gland assembly. An upper seal member is disposed within the upper gland assembly around a periphery of the washpipe. An upper packing ring is engaged with the upper gland assembly so as to compress the upper seal member into sealing engagement with the washpipe. A lower gland assembly is disposed about the washpipe and operable to engage the rotating conduit. A lower seal member is disposed within the lower gland assembly and is compressed into sealing engagement with the washpipe by a lower packing ring that is engaged with the lower gland assembly. The engagement of the packing rings with their respective gland assemblies is independent of the engagement of the gland assemblies and the conduits.

Abstract: Methods and apparatus for securing a cylinder liner to a pump module. A tension body is disposed about the cylinder liner and attached to the pump module. A locking body engages the cylinder liner and is threaded to the tension body. A hydraulic load cell is removably attached to the tension body and includes a hydraulic ram arranged to impart a compressive load to the cylinder liner and a tension load in the tension body. The locking body can be adjusted axially to contact the cylinder liner and maintain the applied loads, which act as a pre-load to keep the cylinder liner in contact with the pump module.

Abstract: A preamplifier that includes an input configured to receive a preamplifier control signal and a fault detection circuit configured to monitor the preamplifier control signal received at the input is provided. The fault detection circuit is further configured to identify a fault condition triggered by an improper temperature control signal provided by the preamplifier.

Abstract: An economical power take-off unit with a direct mount hydraulic pump that attaches directly and rigidly to the differential housing of an automobile or truck. When installed, the unit shares the differential gear lubricant and is an integral component of the vehicle power train. The unit can be remotely operated from the cab of the vehicle while the vehicle is in motion or stationary. A one way roller clutch is used to protect the hydraulic pump and equipment when the vehicle is operated in reverse gear.