A pump housing (4) for an eccentric screw pump, comprising a housing casing (5) extending along a housing longitudinal axis (L), a first end-face opening (6), to which a shaft seal (7) for a connection shaft (8) can be connected, and a second end-face opening (10), to which a stator (I) can be connected, and comprising a tubular inlet nozzle (11), oriented transversely to the housing longitudinal axis (L), for feeding a medium that is to be conveyed, which inlet nozzle is connected to the housing casing (5) tangentially, offset in relation to the housing longitudinal axis (L). The geometry of the inlet nozzle (11) is designed in such a way that, as the medium flows into the housing interior through the inlet nozzle (II), a flow (S) is generated which has a radial direction component (RI) directed away outwardly from the housing longitudinal axis (L) and/or an axial direction component (R2) directed towards the first end-face opening (6).

A uniaxial eccentric screw pump includes: a rotor 1 including a shaft body of a male screw type; a stator 2 having a through hole 2a of a female screw type through which the rotor 1 is inserted; a casing 3 connected to one end side of the stator 2; an end stud 4 connected, to the other end side of the stator 2; and a position adjusting member 5 that adjusts a relative position of the stator 2 with respect to the rotor 1 in an axial direction.

What is concerned is an eccentric screw pump having at least one stator (1), a rotor (2) rotating in the stator, a drive (3) for the rotor, a pump housing (4) which is connected to the stator (1) and has at least one inlet opening (6) for the medium to be conveyed, a connection housing (14) arranged between the pump housing (4) and drive (3), a connection shaft (9) which is connected to the drive (3) and is arranged at least in certain regions in the connection housing (14), and a coupling rod (10) which is arranged in the pump housing (4) and is connected to the connection shaft (9) via a drive-side joint (11) and to the rotor (2) via a rotor-side joint (12). The drive-side housing connection piece (16) can be demounted in such a way that the drive-side joint (11) can be exposed for maintenance or demounting.

An all-metal conical combined screw pump suitable for petroleum field includes: a stator, a rotor (2), a sleeve (3) and a sucker rod (4), wherein the internal threaded curved surface and the external threaded curved surface are both tapered The spiral structure and the taper are the same, and the end of the inner threaded surface and the outer threaded surface with the larger radial size is adjacent to the sucker rod; the all-metal conical combined screw pump further comprises an elastic telescopic component, wherein the elastic telescopic component comprises a movable part, a fixed part and a elastic part, the movable part is fixedly connected to the rotor, the fixed part is fixedly connected to the sucker rod, the movable part and the fixed part are slidly fitted in the up and down directions and can be To transmit torque to the sucker rod and the rotor, one end of the elastic member abuts against the movable part or the rotor, and the other end abuts against the fixed part or the sucker rod, the elastic member can Elastic contraction or elastic expansion along the sliding direction of the movable part.

A progressive cavity pump for transporting a liquid containing solids comprises a helical rotor, a stator having an inlet and an outlet, within which the helical rotor is rotatably disposed about a longitudinal axis of the stator, and comprising a helical inner wall corresponding to the helical rotor. The helical rotor comprises a shape tapering down toward the outlet or inlet, and the helical rotor and stator are disposed relative to each other and implemented such that at least one chamber is formed for transporting the liquid, and the chamber is cut off by a constriction. The progressive cavity pump includes an adjusting device for adjusting a relative axial position of the helical rotor and stator, wherein the adjusting device is implemented for expanding the constriction between the helical rotor and stator.

Rotary positive displacement machines with trochoidal geometry that comprise a helical rotor that undergoes planetary motion within a helical stator are described. The rotor can have a hypotrochoidal cross-section, with the corresponding stator cavity profile being the outer envelope of the rotor as it undergoes planetary motion, or the stator cavity can have an epitrochoidal cross-section with the corresponding rotor profile being the inner envelope of the trochoid as it undergoes planetary motion. In some multi-stage embodiments, the rotor-stator geometry remains substantially constant along the axis of the rotary machine. In other multi-stage embodiments, the rotor-stator geometry varies along the axis of the rotary machine.

An apparatus and method for pressure testing a tubing string of a fluid production well, the tubing string being provided with a progressing cavity pump at a downhole end, which apparatus and method can be used to help determine whether the tubing string has failed or the pump has failed. The apparatus comprises a plug member connected to the rod string assembly that includes the pump rotor, such that the rod string assembly can be lowered to seat the plug member in a seat member within the tubing string above the pump, thus sealing off and isolating the pump from the rest of the tubing string, allowing pressure testing of the tubing string above the pump.

A universal joint (U-joint) assembly transmits torque from a drive component to a driven component across an articulating joint. The U-joint assembly includes male and female U-joint members, a central ball joint, and a retaining device configured to secure the assembly in an assembled configuration. The female U-joint member includes a cavity extending into a receptacle end thereof. The cavity terminates in a circular receptacle and includes a plurality of rectangular channels extending radially outward from the cavity at equal intervals, each channel defined by three planar drive surfaces. The male U-joint member has a drive end with a plurality of corresponding rectangular extensions protruding from an outer periphery of the drive end, each extension including a plurality of axial angular surfaces. When assembled, each of the angular surfaces of the drive end opposes a corresponding one of the drive surfaces of the cavity. Other embodiments are also disclosed.

This disclosure relates to pumps and, more particularly, to progressive cavity pumps.

A hydraulic pump may include: a screw including: an internal tubular cavity, and an internal port in fluid communication with the internal tubular cavity; a nut surrounding a longitudinal portion of the screw; and a cylindrical tube fitting within the internal tubular cavity of the screw, the cylindrical tube having a hollow channel that is in fluid communication with the internal tubular cavity of the screw.