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.

A blower may include a blower housing that may include a plurality of rotor chambers and a plurality of rotors. The plurality of rotors may be substantially identical and each may include a twist angle and a helix angle. The rotors and the blower housing may be configured to create internal fluid compression when the rotors are rotating at a first rotational speed and not to create internal fluid compression when the rotors are rotating at a second rotational speed. The rotors and the blower housing may be configured to create the internal fluid compression without backflow slots in the blower housing. The twist angle may include the angular displacement of lobes of the plurality of rotors between axial ends of the plurality of rotors. The helix angle may be a function of the twist angle and a pitch diameter of the plurality of rotors.

A method for delivering a gas/liquid mixture fluid via a screw spindle pump that has a housing forming at least one fluid inlet and one fluid outlet and in which a drive spindle and a running spindle, coupled in terms of rotation, are accommodated. The spindles, in each rotation position of the drive spindle, delimit together with the housing multiple pump chambers. The drive spindle is rotated by a drive in a drive direction, whereby a respective one of the pump chambers that is initially open toward the respective fluid inlet is closed off. The resulting closed-off pump chamber is moved axially toward the fluid outlet and, there, upon attainment of an opening rotation angle, is opened toward the fluid outlet. The drive spindle is driven so that, for a given pump geometry of the screw spindle pump, the pressure in the respective pump chamber prior to and/or upon attainment of the opening rotation angle is increased in relation to the suction pressure of the screw spindle pump, which prevails in the region of the respective fluid inlet, by at most 20% or by at most 10% of a difference in pressure between the suction pressure and the pressure in the region of the fluid outlet.

Lobe pumps have rings which can be located at least partially in at least one of cover plates and rotors, if not both to provide at least thrust bearings to space the rotors from the cover plates. Some rotors may have voids in ears to make the rotor lighter in weight with the voids potentially capped, symmetrically disposed, arcuately shaped and/or have other desirable features. Some rotors may have ears extending beyond cutouts which may extend beyond hubs, if not beyond hub extensions as well which may receive cover spigots thereabout. Some rings may act as radial bearings as well when located in the cover spigots.

In a screw compressor, a lobe profile of cross-sections perpendicular to the axial direction in a female rotor that rotates about a second rotation center changes in the axial direction. One lobe of the lobe profile of the female rotor includes: a first contour line defining a leading flank on a rotation direction side of the female rotor with a lobe bottom as a boundary point; a second contour line defining a trailing flank on an opposite side of the rotation direction; and a third contour line defining a lobe tip having both endpoints at which the female has the maximum radius. In the lobe profile of the female rotor, when a first angle, a second angle, and a third angle are respectively defined as an angle formed by two line segments linking a second rotation center as a vertex and both ends of the first contour line, an angle formed by two line segments linking the second rotation center and both ends of the second contour line, and an angle formed by two line segments linking the second rotation center and both ends of the third contour line, the third angle is greater on the delivery side in the axial direction, and the first angle is smaller on the delivery side in the axial direction.

Provided is a fluid machine configured such that liquid supplied to a working chamber from the outside of the fluid machine is dispersed extensively in the working chamber. This fluid machine is constituted of a screw rotor and a casing for accommodating the screw rotor and is provided with a liquid supply section for supplying liquid into a working chamber from the outside. The liquid supply section is configured so that liquid is dispersed in the longitudinal direction of the tooth groove of the screw rotor rather than in the width direction thereof.

A first rotor configured to rotate adjacent to a second rotor is disclosed. The second rotor includes a circular main body with a first axis of rotation and a vane extending radially from the main body. The first rotor includes a first curved surface that corresponds to a curve swept at a constant radius about a second axis of rotation, a second curved surface that corresponds to a curve swept by a leading edge of the vane when the second rotor is simultaneously rotated about the first axis of rotation and the second axis of rotation, a third curved surface that corresponds to a curve swept by a trailing edge of the vane when the second rotor is simultaneously rotated about the first axis of rotation and the second axis of rotation, and a vane-receiving groove disposed between the second curved surface and the third curved surface.

A supercharger rotor comprising a plurality of lobes around a center axis, each lobe of the plurality of lobes comprising a rotor profile. The rotor profile comprises a tip, a convex addendum comprised of at least two interpolated and stitched spline curves, an undercut region, and a root base.

Provided is a rotor structure of a screw compressor and an inverter screw compressor with the same. The rotor structure includes: a female rotor including a female rotor body, wherein the female rotor body is includes a plurality of female teeth, and a tooth profile is formed between tooth crests of two adjacent female teeth of the female rotor body, and the tooth profile is formed by sequentially connecting an arc segment a.sub.1b, an envelope bc, an arc segment cd, an arc segment de, an arc segment ea.sub.2, an arc segment a.sub.2a.sub.3 from front to rear along a counterclockwise direction, wherein centers of the arc segment cd and the arc segment de are respectively located on both sides of the tooth profile. The tooth profile reduces rotation speed of the rotor structure. The inverter screw compressor reduces the leakage of the compressor and improves the compression energy efficiency and application of the compressor.

In an internally rotating gear pump, a pinion having external teeth and a gear having internal teeth are housed in a casing. The pinion and the gear rotate while the internal teeth and the external teeth are meshed with each other. The pinion is a driving gear that is coupled to a rotating shaft receiving a rotating force from an external motor, such that the pinion and the rotating shaft are rotationally driven in an integrated manner when the rotating shaft is driven. The gear is a driven gear, and is rotatably supported on a gear pin provided to the casing via a gear bush serving as a slide bearing.