An improved screw pump such as, for example, a twin screw pump is disclosed. In one embodiment, the screw pump includes a casing, first and second intermeshing rotors, and a liner positioned between the first and second rotors and the casing. In use, the liner is arranged and configured to bend and/or pivot in unison with the first and second rotors under the axial hydraulic pressure experienced by the screw pump during use. In one embodiment, the liner may be arranged and configured to include an asymmetric axial stiffness to facilitate bending of the liner. In another embodiment, the liner may be arranged and configured in multiple segments, the segments being arranged and configured to pivot to approximate the bending of the rotor shafts.

A rotary pump includes: a pump rotor having a flat rotor side surface facing in an axial direction; a housing body having an opening in the axial direction and a flat flange surface formed around the opening, the housing body rotatably housing the pump rotor in the opening such that the rotor side surface is flush with the flange surface; and a cover member having a flat mating surface that is fixed while being pressed against the flange surface by fastening of a bolt, and a flat sliding/guiding surface that slides and guides the rotor side surface. The cover member is formed of a crosslinked fluororesin and a metal body. The metal body is provided with the mating surface, and a recess obtained by recessing an area corresponding to the sliding/guiding surface, in the axial direction with respect to the mating surface.

An eccentric screw pump with a rotor (2) and with a rotationally fixed stator (6; 6′) surrounding the rotor (2). The rotationally fixed stator includes at least one elastomeric portion, wherein a pressure chamber (16) is arranged on this elastomeric portion of the stator (6; 6′) at a side facing away from the rotor (2). The pressure chamber (16) is connected to a pressure region of the eccentric screw pump such that the at least one elastomeric portion of the stator (6; 6′) is subjected to a pressure produced by the eccentric screw pump.

Provided is a rotary pump including: a pump rotor having a flat first rotor side surface facing one side in an axial direction, and a flat second rotor side surface facing the other side in the axial direction; and a housing configured to rotatably house the pump rotor. The housing includes: a ring member having a hollow tubular shape and openings at both ends in the axial direction; a first side member detachably mounted to one end in the axial direction of the ring member to slide and guide the first rotor side surface by using a first crosslinked fluororesin flat surface formed of a crosslinked fluororesin; and a second side member detachably mounted to the other end in the axial direction of the ring member to slide and guide the second rotor side surface by using a second crosslinked fluororesin flat surface formed of the crosslinked fluororesin.

A progressing cavity device operates as a motor to impart torque to a bit. A stator of the device defines an internal profile having uphole stages with a first dimension being less than a second dimension of downhole stage. A rotor has an external profile with a constant outer dimension along its length. Disposed in the stator, the rotor defines cavities with the stator and is rotatable with pumped fluid progressing in the cavities from the uphole to downhole to transfer torque to the drive toward the downhole end. Although the rotor is subjected at the downhole end to a reactive torque from the bit, the interference fit of the rotor's constant dimension with the stator's downhole stages is less than with the uphole stages, which can mitigate issues with heat buildup in the downhole stages. The device can also operates as a progressing cavity pump.

The invention relates to a dual-spindle helical spindle pump with a single-entry design, comprising a pump housing (11) which has a pump portion (12), a bearing portion (13) and a gear portion (14) with a gear chamber, wherein the bearing portion (13) and the pump portion (12) are designed separately from one another, comprising a feed housing part (50) as a component of the pump portion (12) in which two feed screws (17, 18) are provided, said feed screws having flanks (46) and being arranged on shafts (15, 16) in a feed space (51), wherein the shafts (15, 16) are mounted in the bearing portion (13) (external bearing system) and extend into the gear portion (14), and wherein the feed housing part (50) has at least one feed portion (52) with an inner wall (58) which faces the outer face (59) of the feed screws (17, 18). The invention provides that at least one separating element (60), which is in contact with at least one portion of the outer face (59) of the feed screws (17, 18), is between the inner wall (58) of the feed portion (52) and the outer face (59) of the feed screws (17, 18), at least in the region (57) of the feed screws (17, 18), and in that the separating element (60) is floatingly mounted in the feed housing part (50) relative to the inner wall (58) of the feed portion (52).

A cylindrical rotor inside of the cylindrical stator, wherein the cylindrical rotor has a screw thread with an opposite direction relating to the stator screw thread, wherein the rotor has a curvilinear external surface shape and a stator having an internal semicircular surface shape wherein rotor external surface shape and the stator has an internal surface shape having rounded shapes without rectangular edges to obtain high speed performance with reduced vortices, wherein a gap between the internal surface of the stator and the external surface of the rotor is 0.1-0.2 millimeters and an unloading thrust bearing attached to the rotor shaft positioned between intake thrust bearing and the intake end of the rotor and a cavity in the unloading thrust bearing configured to receive production fluid from the discharge end of the rotor.

A mud motor stator or a pump comprising of a tubular outer portion; a number of lobes extending radially inwardly from the tubular outer portion, at least one of which comprises a skeletal structure and method for producing a mud motor stator or a pump comprising of placing material and bonding the material together in a pattern dictated by the design shape of the stator or pump.

A compressor is provided and may include a shell, a hub, an insert, and at least one collar. The hub may be disposed within the shell and define an axis of rotation. The hub may include an axially extending aperture. The insert may be disposed within the aperture. The at least one collar may be disposed about the hub.

A mud motor and a drill string having the mud motor. The mud motor includes a stator and a rotor. A lining between the stator and the rotor includes fibers forming a fiber pattern. The lining is a coating of at least one of a lobed inner surface of the stator and a lobed outer surface of the rotor.