Rotary positive displacement machines based on trochoidal geometry that includes a helical rotor that undergoes planetary motion relative to a helical stator are described. The rotor can have a hypotrochoidal-based cross-sectional shape, with the corresponding stator cavity cross-sectional shape being the outer envelope of the rotor cross-sectional shape as it undergoes planetary motion, or the stator cavity can have an epitrochoidal-based cross-sectional shape with the corresponding rotor cross-sectional shape being the inner envelope of the stator cross-sectional shape as it undergoes planetary motion. Such machines can be configured so that the stator axis is spaced from the rotor axis, the rotor is configured to spin about its axis and the stator is configured to spin about its axis, and/or the rotor and the stator are held at a fixed eccentricity so that the rotor undergoes planetary motion relative to the stator, but does not orbit.

Tapered stator designs are engineered in a positive displacement motor (PDM) power section to relieve stator stress concentrations at the lower (downhole) end of the power section in the presence of rotor tilt. A contoured stress relief (i.e. a taper) is provided in the stator to compensate for rotor tilt, where the taper is preferably more aggressive at the lower end of the stator near the bit.

A full-metal anti-high temperature cycloid downhole motor comprises an outer tube, a stator, a rotor, a partition plate, a flow distribution disc, and a flow guide mechanism. The inside of the stator is provided with N grooves, the inner side walls of the N grooves form an annular inner contour surface; the rotor is formed with N−1 rotating heads provided along the axial direction of the outer tube, and each rotating head is provided with an embedding slot, one side of the embedding slot is provided with a notch, a rotor copper rod that can be in rolling engagement with the inner contour surface through the notch is provided in the embedding slot, and there is a changing gap between the outer wall of the rotor copper rod and the inner wall of the embedding slot.

One example of a gerotor pump includes an inner rotor comprising multiple teeth, the inner rotor configured to rotate about a first longitudinal gerotor pump axis. The gerotor pump also includes a hollow outer rotor including an outer surface and an inner surface having substantially identical contours, the inner surface configured to engage with the multiple teeth and to rotate about a second longitudinal gerotor pump axis. The pump includes a pump housing within which the inner rotor and the outer rotor are disposed, wherein the outer surface of the outer rotor defines gaps between the pump housing and the outer rotor.

A fuel pump unit includes a suction filter and a fuel pump. The fuel pump includes: a rotatable shaft placed along a rotational axis; a rotor portion that rotates in response to rotation of the rotatable shaft; a suction hole portion, through which the fuel is suctioned into an inside of a rotor receiving chamber; and an outer peripheral wall that surrounds the suction hole portion. The suction filter includes: a filter element that filters the fuel and conducts the filtered fuel into an inside space; and a columnar hole portion having an inner peripheral wall, while the outer peripheral wall and the inner peripheral wall are fitted with each other, so that the columnar hole portion communicates between the inside space and the suction hole portion. The columnar hole portion is placed such that the rotational axis extends on an inner side of the inner peripheral wall.

A stator for a helical gear device includes a first section having first helically convoluted chamber with a set of radially inwardly extending lobes and a second section adjacent to the first section. The second section includes a stack of cutter disks. Each cutter disk includes a front surface, a rear surface, an interior surface defining a central opening extending from the front surface to the rear surface, a forward cutting edge, and a rearward cutting edge. The interior surface forms a same number of lobes for the central opening as the set of radially inwardly extending lobes in the first section. Each cutter disk is aligned along a common centerline, and each cutter disk is rotated slightly relative to each other to form a second helically convoluted chamber with a same pitch as the first helically convoluted chamber. The second helically convoluted chamber exposes, to materials passing through, portions of the forward cutting edge or the rearward cutting edge of each cutter disk.

A pump includes a housing having a first end and a second end and extending along a longitudinal axis and a discharge casing having a first end coupleable to the second end of the housing. The discharge casing extends along the longitudinal axis coaxial to the housing. A dismounting device includes a first dismount casing and a second dismount casing disposed between the discharge casing and the second end of the housing. The dismounting device extends along the longitudinal axis coaxial to the housing and the discharge casing.

Embodiments of the present invention disclose a method, a computer program product, and a system for removing gas locking in a pump. The method includes setting the pump into a gas interference condition based on a variable speed drive driving a pump at a first frequency and a choke valve set at a first restriction value and adjusting the variable speed drive to a second frequency and the choke valve to a second restriction value such that the adjustment produces a backpressure that lets free gas get dissolved in a fluid phase and keeps fluids drawn by the pump at a single-phase flow based on pressure-volume-temperature characteristics of the fluids.

Tapered stator designs are engineered in a positive displacement motor (PDM) power section to relieve stator stress concentrations at the lower (downhole) end of the power section in the presence of rotor tilt. A contoured stress relief (i.e. a taper) is provided in the stator to compensate for rotor tilt, where the taper is preferably more aggressive at the lower end of the stator near the bit.

A downhole pumping apparatus comprising a positive displacement rotary gear pump (RGP), driven by a rotating rod string or a submersible electric motor.