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 fixed scroll for a scroll compressor includes a plurality of pillar portions extending axially from a first face of the fixed scroll to an opposing second face thereof. Each of the plurality of the pillar portions is spaced radially outwardly of a spiral structure at least partially defining a compression chamber of the scroll compressor. The fixed scroll further includes an annular array of spaced flow openings into the compression chamber of the scroll compressor with each of the flow openings formed between adjacent ones of the pillar portions.

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.

The present invention refers to a progressive cavity pump developed for tintometric dosing machines. The proposal set out in the present invention is to make precision dosages through pumping by just one stator and rotor stage. The PCP proposal enhances the traditional constructive arrangement for tintometric application. The object makes precision dosages through pumping by just one stator and rotor stage, reducing the length of the pump, facilitating the manufacture of its components and requiring less robustness of the transmission components and of the drive motor. Therefore, the present invention has a simplified transmission system, uses special geometry for fastening the stator, optimizes the bearing of the drive shaft and its sealing element, reduces the dimensions of the components and uses a low torque motor.

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.

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.

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 cam ring is capable of moving while rolling on a cam support surface. The cam ring is provided such that within a range in which the cam ring can move on the cam support surface, an eccentricity amount increasing-side angle is always greater than an eccentricity amount decreasing-side angle. On a plane perpendicular to the rotation axis of a driving shaft, the eccentricity amount increasing-side angle is an angle, in a direction opposite to a rotation direction of the driving shaft, from a first reference line, which connects a tangent point between the cam ring and the cam support surface to a rolling center of the cam ring, to a starting end of a first discharge port. The eccentricity amount decreasing-side angle is an angle, in the rotation direction of the drive shaft, from the first reference line to a terminal end of the first discharge port.

Rotary positive displacement machines can include a rotor having a teardrop-shaped profile that undergoes planetary motion relative to a stator having an elliptical or near-elliptical profile. In some embodiments, these rotary positive displacement machines can be used for a variety of applications including as positive displacement pumps. In some embodiments the rotor and stator are helical. In some embodiments the rotor comprises a dynamic seal. Aspects of the machine geometry can be selected to provide operational and/or durability benefits.

A static scroll and a scroll compressor are provided. The static scroll has a scroll body, a partition, and a protrusion of a closed annular shape. The scroll body has a working fluid inlet and a working fluid outlet, and defines a working fluid flow groove having an open end. The partition is disposed in the working fluid flow groove to divide the working fluid flow groove into a working fluid entry cavity and a working fluid compression cavity. The working fluid entry cavity connects the working fluid inlet with the working fluid compression cavity, and the working fluid outlet is in communication with the working fluid compression cavity. The protrusion is disposed on the scroll body and surrounds the open end of the working fluid flow groove.