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.

A high-pressure fuel pump includes a drive shaft, and a vane pump and a plunger pump which are driven by the drive shaft. The vane pump is configured to supply pre-pressurized fuel to the plunger pump. The drive shaft includes a cam configured to drive a piston rod of the plunger pump such that the plunger pump alternately executes a fuel suction stroke and a fuel discharge stroke. The drive shaft further includes a shaft portion for driving a rotor of the vane pump. The vane pump is configured such that for each fuel suction stroke of the plunger pump the vane pump provides a fuel supply cycle that is advanced by a phase angle relative to the fuel suction stroke.

A compressor includes a drive shaft having a main shaft and an eccentric portion, and a compression mechanism having a fitted tubular portion into which a fitted shaft portion of the drive shaft is fitted. The fitted shaft portion and the fitted tubular portion slide relative to each other with an oil film interposed between. The fitted tubular portion has first and second sliding surfaces formed as portions of an inner peripheral surface of the fitted tubular portion in the circumferential direction. The second sliding surface has a smaller axial width than the first sliding surface. A sliding portion between the fitted shaft portion and the fitted tubular portion has a gap adjacent to the second sliding surface into which a lubricating oil flows, and an oil retainer to keep the lubricating oil in the gap from flowing out toward an end surface of the fitted tubular portion.

The present disclosure describes a rotary pulsation generator having a simple structure capable of transferring fluid while implementing low noise and low vibration and having high flow of fluid and high pressure suction and discharge functions. According to the present disclosure, fluid is transferred by adjusting a width and interval of pulsation while reducing vibration caused by eccentric rotation of a 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.

A dual-section gear pump that enhances compactness of the design includes two pump sections separated by a divider. Each pump section includes a pump cavity and a gear set configured to convey fluid from an intake side to a discharge side of the respective pump cavities. The divider includes a fluid flow passage that enables the two pump sections to share common intake flow via the flow passage provided across the divider. The divider also is configured to enable each gear set in each pump section to provide independent pressurization of the fluid in each pump section, which is discharged from each pump cavity via separate outlets. The gear pump is configured to provide suitable sealing between each pump section and support of the respective gear sets in each pump section while enhancing compactness of the design.

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.

A scroll compressor includes a motor portion fixed in an inner space of a casing, a compression portion fixed to the inner space of the casing at one side of the motor portion in an axial direction, a rotation shaft to transmit a driving force from the motor portion to the compression portion, and a flow path guide provided in a discharge space between the motor portion and the compression portion and provided with a guide outlet communicating with the discharge space and opened in a direction toward the rotation shaft. Therefore, most of refrigerant discharged to the discharge space through the flow path guide is moved toward an air gap to enhance an oil separation effect, and thus a normal operation point of the air conditioner can be accelerated.

A progressing cavity device includes a stator including a first end, a second end, and an inner surface formed from a metallic material that extends between the first end and the second end, and a rotor rotatably disposed in the stator, the stator including a first end, a second end, and an outer surface formed from a metallic material that extends between the first end and the second end, wherein the outer surface of the rotor contacts the inner surface of the stator, wherein the inner surface of the stator includes a conical taper extending between the first end and the second end, wherein the outer surface of the rotor includes a conical taper extending between the first end and the second end.

A rotary compressor is provided that may include a cylinder having an inner circumferential surface with an annular shape to form a compression space; a roller having a plurality of vane slots disposed at predetermined intervals along an outer circumferential surface thereof, and rotatably inserted into the compression space of the cylinder; and a plurality of vanes slidably inserted into the respective vane slots to rotate together with the roller and by which the compression space is divided into a plurality of compression chambers. At least one of the vane slots is unequally spaced in a circumferential direction. Accordingly, periodicity of noise may be reduced to thereby increase the effect of noise reduction of the compressor.