A stator-rotor system of an eccentric screw pump including a rotor with a rotor screw and a stator with an internal thread. The stator includes a support element and an elastomer part. The support element surrounds the elastomer part in sections around the whole circumference. The stator-rotor system includes a mechanism for adjusting the stator, having two adjustment elements arranged on the stator-rotor system, which are distance-variable relative to one another. In a first working position the two adjustment elements have a first distance from one another and in a second working position, a second distance. The cross-section and the length of the elastomer part of the stator in the second working position are changed compared to the cross-section and the length of the elastomer part in the first working position.

The dynamic fatigue and hysteresis performances of fiber reinforced rubber compounds are compared using different plasticizers. Fiber reinforced rubber compounds including a non-linear functionalized fatty acid ester, preferably a trimellitate, and more preferably Tris (2-Ethylhexyl) Trimellitate (TOTM) are shown to demonstrate greatly improved dynamic fatigue and hysteretic performance as compared to reference fiber reinforced rubber compounds including conventional reference plasticizers such as Di-isodecyl phthalate (DIDP).

Rotary positive displacement machines based on 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 embodiments, the geometry is offset in a manner that provides structural and/or operational advantages in the rotary machine.

Sealing in rotary positive displacement machines based on trochoidal geometry that comprise a helical rotor that undergoes planetary motion within a helical stator is described. Seals can be mounted on the rotor, the stator, or both. 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 embodiments, the geometry is offset in a manner that provides advantages with respect to sealing in the rotary machine. In multi-stage embodiments, the rotor-stator geometry remains substantially constant or varies along the axis of the rotary machine.

Rotor and/or stator designs and methods thereof to improve progressive cavity motor or pump durability. In one or more implementations, the rotor may have a variable outer diameter or variable stiffness along an axial length thereof. The stator may similarly have a variable inner diameter or variable stiffness, which may compliment or diverge from the variable outer diameter or variable stiffness of the rotor.

Rotary positive displacement machines based on trochoidal geometry and including a helical rotor that undergoes planetary motion relative to a helical stator can be designed and configured so that the axial load or rotor pressure force is positive, negative, or neutral. In some embodiments, a change in axial load, caused by a change in differential pressure across the machine, can be used to trigger a change in a mechanical configuration of the machine.

Provided is a scroll compressor. The scroll compressor may be provided with at least one refrigerant accommodating groove recessed to a preset depth in at least one from a side surface of a fixed wrap constituting a compression chamber and a side surface of an orbiting wrap. Thus, a volume of the compression chamber in a discharge area may be increased in correspondence with a volume of the at least one refrigerant accommodating groove, and a space into which liquid refrigerant, etc. may escape may be ensured to resolve excessive compression in the compression chamber. Then, a stress exerted on the fixed wrap is reduced, and a damage to the fixed wrap due to pressure in the compression chamber may be suppressed.

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.

A scroll compressor includes a casing; a drive motor; a rotary shaft; a fixed scroll including a fixed wrap; and an orbiting scroll eccentrically coupled to rotary shaft and including an orbiting wrap configured to engage with the fixed wrap. At least one of the fixed wrap or the orbiting wrap defines an offset section that is defined between the fixed wrap and the orbiting wrap and that is greater than an orbital radius corresponding to a distance between the fixed wrap and the orbiting wrap in a state in which a center of the fixed scroll is aligned to a center of the orbiting scroll. The offset section is disposed at a contact portion between the fixed wrap and the orbiting wrap. The contact portion has a maximum length based on a rotation angle of the rotary shaft being within a pre-set range with respect to a reference point.

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.