In one aspect, the present invention provides a plunger for use in a pumping system. The plunger can include a cylindrical plunger body that is adapted to be coupled to a drive rod. The plunger body can define an aperture configured to receive pumped fluids. The aperture can define an inner diameter of the plunger body. The plunger body can include a leading end having a tapered portion configured to direct solids into the aperture. The tapered portion can be tapered from the inner diameter toward an outer diameter of the plunger body to form a tip aligned with the outer diameter. The tapered portion can include two or more different degrees of taper along a length of the tapered portion. The plunger body can further include a rear end coupleable to a traveling valve.

A pump assembly for generating pressure in a brake circuit of a controllable power brake system of a motor vehicle. The pump assembly has, as a pressure generator, a piston-cylinder unit in which a piston is actuated with the aid of a piston drive. The piston drive converts a rotational movement, with which a nut of this piston drive is driven, into a translatory movement of a spindle, which is in turn connected to the piston in a rotationally fixed manner. The piston is a steel component in which a plastic deformation at a piston head forms a device for connecting the spindle to the piston in a rotationally fixed manner.

A pump assembly for generating pressure in a brake circuit of a controllable power brake system of a motor vehicle. The pump assembly has, as a pressure generator, a piston-cylinder unit in which a piston is actuated with the aid of a piston drive. The piston drive converts a rotational movement, with which a nut of this piston drive is driven, into a translatory movement of a spindle, which is in turn connected to the piston in a rotationally fixed manner. The piston is a steel component in which a plastic deformation at a piston head forms a device for connecting the spindle to the piston in a rotationally fixed manner.

A piston rod assembly for a reciprocating compressor. The piston rod assembly may include a piston rod having a longitudinal axis and forming a piston rod neck and a piston rod shoulder. The piston rod may include a first end integral or coupled with a piston head and a second end axially opposing the first end and configured to couple with a crosshead including a flange. An inner surface of the flange may have a Brinell hardness. The piston rod assembly may also include a cylindrical sleeve disposed circumferentially about the piston rod neck. The cylindrical sleeve may have a lower Brinell hardness than the Brinell hardness of the inner surface of the flange.

A piston rod assembly for a reciprocating compressor. The piston rod assembly may include a piston rod having a longitudinal axis and forming a piston rod neck and a piston rod shoulder. The piston rod may include a first end integral or coupled with a piston head and a second end axially opposing the first end and configured to couple with a crosshead including a flange. An inner surface of the flange may have a Brinell hardness. The piston rod assembly may also include a cylindrical sleeve disposed circumferentially about the piston rod neck. The cylindrical sleeve may have a lower Brinell hardness than the Brinell hardness of the inner surface of the flange.

The present disclosure relates to a piston-cylinder unit with a cylinder jacket and a piston rod longitudinally shiftably guided in the cylinder jacket as well as an evaluation unit which determines the position of the piston rod with respect to the cylinder jacket by the intrinsic electrical properties of an interconnection of cylinder jacket, piston rod and piston, wherein the piston rod is short-circuited against the cylinder or the cylinder head in a manner suitable for high frequencies via one or more contact elements in the region of the exit opening of the piston rod out of the cylinder head.

The present disclosure relates to a piston-cylinder unit with a cylinder jacket and a piston rod longitudinally shiftably guided in the cylinder jacket as well as an evaluation unit which determines the position of the piston rod with respect to the cylinder jacket by the intrinsic electrical properties of an interconnection of cylinder jacket, piston rod and piston, wherein the piston rod is short-circuited against the cylinder or the cylinder head in a manner suitable for high frequencies via one or more contact elements in the region of the exit opening of the piston rod out of the cylinder head.

In one aspect, the present invention provides a surface unit for a pumping system. The surface unit may include a conduit that is reciprocatable to pump produced fluid from downwell to the surface unit and a flow line in fluid communication with the conduit such that the produced fluid may be collected from the conduit. The surface unit may also include a pump barrel that separates the conduit from a well tubing and a diluent line in fluid communication with a space between the pump barrel and the well tubing. The diluent line may be sealed from the conduit and the flow line such that a diluent or lubricant may be delivered to the space between the pump barrel and the well tubing via the diluent line without contaminating the produced fluid.

A system, in certain embodiments, includes a composite crosshead. The composite crosshead comprises a crosshead body made of a first composite material, wherein the first composite material comprises a first reinforcing material distributed in a first matrix material, wherein the composite crosshead is configured to move in a reciprocating motion in a machine.

A piston unit of a working cylinder has first and second coupling partners. The first coupling partner is a piston. The second coupling partner a piston rod. The piston rod is inserted axially into the piston. Each of the coupling partners has an annular groove. The groove of the piston rod is an external groove. The groove of the piston is an internal groove. The grooves of the coupling partners lie opposite one another. The unit has a coupling strand which engages in the grooves of the coupling partners and is placed into engagement by insertion into an annular groove gap defined by the grooves. The engagement of the coupling strand in the grooves produces a form-locking connection between the partners. The piston rod is oversized in relation to the piston and provides an additional frictional connection.