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 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.

The present disclosure relates to hydraulic machinery engineering, more specifically to stators of rotary vane-type pumps intended for pumping-over viscous, plastic masses and other fluids and multiphase mixtures lacking unctuous properties, but rich in mechanical impurities and/or having high viscosity, particularly such as stratum fluids of oil deposits, and may be applied in food-processing, chemical, petrochemical and other branches of industry.

Liquid ring pumps are used to pump a variety of fluid types. The present invention provides a two stage liquid ring pump through which an exhaust gas comprising compounds to be destroyed is passed. The exhaust gas passes through the first stage to a gas abatement device, following which it is passed back to the second stage of the liquid ring pump for removal of the compounds formed in said abatement device. The stages of the liquid ring pump may be adjustable.

A hermetic compressor is provided that may include a cylinder having an inner circumferential surface which forms a compression chamber formed in an elliptical shape; a roller provided to be eccentric from the inner circumferential surface of the cylinder, and configured to change a volume of the compression chamber by being rotated; and at least one vane formed to be withdrawn towards the inner circumferential surface of the cylinder when the roller is rotated, and configured to divide the compression chamber into a plurality of spaces. When it is assumed that on the basis of a contact point where the inner circumferential surface of the cylinder and an outer circumferential surface of the roller are closest to each other, and a first center line passing through a center of the cylinder, an ellipse positioned at a first side of the first center line and forming the inner circumferential surface of the cylinder is defined as a first ellipse, a center point of the first ellipse is defined as a first center point, an ellipse positioned at a second side of the first center line and forming the inner circumferential surface of the cylinder is defined as a second ellipse, a center point of the second ellipse is defined as a second center point, under these assumptions, the first center point and the second center point are spaced apart from the center of the cylinder.

A double-working-medium expander used for a two-stage organic Rankine cycle, comprising a cylinder body, a rotor disposed inside the cylinder body and provided with a plurality of slip sheets in a radial direction of the cylinder body, and a rotary shaft fixedly connected to the center of the rotor, wherein, the cylinder body is of an annular structure formed by two semi-oval structures which are in butt joint with unequal semi-major axes and equal semi-minor axes; the outer peripheral surface of the rotor can be rotationally tangent to the inner peripheral surface of the cylinder body at the butt joint position of the two semi-oval structures of the cylinder body; a low-temperature cycle volume for expanding the low-temperature working medium with a large flow and a small expansion ratio and a high-temperature cycle volume for expanding the high-temperature working medium with a small flow and a large expansion ratio are formed among two sides of the rotor and the cylinder body, respectively; and, a first fluid inlet and a first fluid outlet, which are arranged on the wall of the cylinder body, are communicated with the low-temperature cycle volume, and a second fluid inlet and a second fluid outlet, which are arranged on the wall of the cylinder body, are both communicated with the high-temperature cycle volume. In the present invention, two working mediums in the two-stage organic Rankine cycle can do expansion work in an expansion mechanism.

An engine housing has the shape of a regular dodecagonal, and includes a piston of the same shape that moves with a circular pivot movement about the axis of a main shaft. The piston is guided in parallel by three crankshafts synchronously rotating about this center of rotation. Through this pivot movement, the piston in six combustion chambers each consecutively brings about the four cycles of a spark ignition or diesel engine. The three crankshafts are in permanent engagement through gears which are attached in a fixed manner with a sun wheel, which is seated on a main shaft in a fixed manner, driving it.

A pneumatic motor includes a stator having a stator inner wall including a dwell region and a rotor eccentrically disposed within the stator. The rotor is configured to rotate about the axis of rotation and includes a plurality of vanes disposed around the rotor. Each vane of the plurality of vanes is configured to slide within a respective slot formed in the outer surface of the rotor between a fully retracted position and a fully extended position as the rotor rotates about the axis of rotation to maintain contact with the stator inner wall. The stator inner wall has a radius relative to the axis of rotation that is substantially constant within the dwell region so that vanes of the plurality of vanes are in the fully extended position within the dwell region.

An eccentric screw pump comprising an outer part (2) and an inner part (3) therein, one of the parts (2, 3) being driven rotatably and the other part (2, 3) being able to move eccentrically relative to the other part (3, 2). The screwthreads (5a, 5b) of the outer part (2) extend angularly over less than an entire helix along the axial length (L) of the part, so that during operation pumping chambers that are open to both ends are created, through which sudden pressure relief takes place.

A rotary device for use with a fluid includes a housing, a rotor, a ring, and at least one vane. The housing includes a tubular surface defining, in part, a tubular volume. The housing is segregated into at least a pumping zone positioned between first and second working zones. The first working zone is configured to receive a fluid and the second working zone is configured to output the fluid. The rotor is mounted for rotation about a rotation axis. The rotor includes a body mounted within the tubular volume. The body includes a plurality of slots. The ring is at least indirectly coupled to the housing by way of a bearing. The at least one vane is associated with one slot of the plurality of slots. The at least one vane is connected at least indirectly to the ring and configured to rotate within the tubular volume.

A vane pump used as a fluid pressure source includes: a rotor that is rotationally driven; a plurality of vanes that are inserted into the rotor in a freely slidable manner; a cam ring at which tip-end portions of the vanes slides as the rotor rotates; a pump chamber that is defined between the adjacent vanes; a suction port that guides working fluid to the pump chamber; a discharge port through which the working fluid discharged from the pump chamber is guided; a groove-like notch that extends from an opening edge of the discharge port in an opposite direction from rotation direction of the rotor, and the notch has a gradient-changing portion at which a rate of change of opening area is decreased in the rotation direction of the rotor.