A rotor for use in a fluid machine includes a rotor shaft, a first portion supported by the rotor shaft and having a plurality of first lobes, and a second portion supported by the rotor shaft having a plurality of second lobes. The plurality of first lobes at an inwardly facing end of the first portion is arranged at a stagger angle relative to the plurality of second lobes at an inwardly facing end of the second portion. The stagger angle is greater than zero.

A system includes a compressor configured to compress a vapor, or a vapor and liquid mixture, and a first rotor of the compressor disposed on a first shaft, where the first rotor includes a first plurality of pockets in a first body portion to form a first semi-hollow internal volume or a plurality of flanks and/or a first plurality of flutes on a first external surface of the first rotor, where the plurality of flanks or the first plurality of flutes comprises a first pitch to form first variable leads.

The invention relates to a screw compressor comprising a compressor housing (11) having two rotor screws (1, 2) mounted axially parallel therein, which mesh with each other in a compression space (18), can be driven by a drive and are synchronized with each other in their rotational movement, wherein the rotor screws (1, 2) each have a single-part or multi-part base body (24) with two end faces (5a, 5b, 5c, 5d) and a profiled surface (12a, 12b) extending therebetween, and shaft ends (30) projecting beyond the end faces (5a, 5b, 5c, 5d), wherein at least the profiled surface (12a, 12b) is formed in multiple layers, comprising a first, inner layer (3) and a second, outer layer (4), wherein the first, inner layer (3) and the second, outer layer (4) both comprise or are formed from a thermoplastic synthetic material, wherein particles (25) or pores (32) supporting a running-in process are embedded in the second, outer layer (4) and the thermoplastic synthetic material defines a matrix for receiving the particles (25) or for forming the pores (32).

In a screw compressor, a lobe of a lobe profile of a female rotor includes: a first contour line defining a leading flank; a second contour line defining a trailing flank; and a third contour line defining a lobe tip having both endpoints at which the female has the maximum radius. In the lobe profile, when a first angle formed by two line segments linking a second rotation center as a vertex and both ends of the first contour line, a second angle formed by two line segments linking the second rotation center and both ends of the second contour line, and a third 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.

A supercharger rotor with reduced rotational inertia may result in increased performance of a supercharger. The rotor may include composite material and may be extrusion molded, injection molded, or otherwise molded or laid-up. In certain embodiments, the rotor may include a core with a central portion and one or more radially extending portions. The core may be extruded or formed of stacked sheets. A molded portion of the rotor, including one or more lobes, may be molded over a corresponding one of the radially extending portions. In other embodiments, a main portion of the rotor includes one or more lobes but no central hole nor a corresponding shaft extending between ends of the main portion. Instead, stub shafts are attached to the ends of the main portion. The increased performance may include decreased noise, decreased cost, increased reliability and/or durability, increased thermal efficiency, an increased power-to-weight ratio, etc.

The invention relates to a rotary piston pump comprising a housing with a housing interior, an inlet opening, and an outlet opening; a first rotary piston which is mounted within the housing interior in a rotational manner about a first rotational axis; and a second rotary piston which is mounted within the housing interior in a rotational manner about a second rotational axis. The first rotary piston and the second rotary piston engage into each other in a region between the first and the second axis and displace liquid. The first rotary piston has a frame assembly which comprises multiple mutually spaced plates and is at least partly filled and enveloped with a polymer material.

A rotor for a positive displacement compressor assembly having a housing defining an inlet, an outlet, and a rotor cavity in communication with the inlet and the outlet. The rotor may comprise a rotor body and a porous inner core enclosed within the rotor body. The rotor may comprise a tapered rotor body having an outer radius that decreases from a first end to a second end thereof. In one form, the positive displacement compressor assembly may comprise a supercharger assembly for an internal combustion engine.

A rotor assembly having a plurality of rotor plates mounted to a shaft, and methods of construction for a rotor assembly are disclosed. Each rotor plate in the assembly may be provided with a central opening extending between the first and second sides through which the shaft extends. In one aspect, the rotor plates are provided with a plurality of lobes extending away from the central opening, wherein each of the lobes has a lobe opening extending through the thickness of the plates. In one embodiment, the rotor plates are rotationally stacked to form a helical rotor.

The present invention concerns a dry vacuum pump comprising: a drive device (1) comprising a drive shaft (3) at one end of which is fixed at least one drive wheel (4) provided to set in motion at least one belt (5); at least two parallel rotors (7, 8) each having a shaft (9, 10) provided with a rotor element (11, 12), this shaft (9, 10) being able to be driven in rotation by the belt (5) and being equipped at one of its axial ends with a toothed wheel (13, 14), this pump having the special features that: the drive wheel (4) and the belt (5) are smooth; each shaft (9, 10) of the rotor (7, 8) comprises at least one smooth section (16, 17) arranged to co-operate with the belt (5), and the toothed wheels (13, 14) of the shafts (9, 10) of the rotor (7, 8) are dimensioned and arranged to mesh with one another.

A hydrogen circulation pump for a fuel cell includes a housing, rotary shafts, and two-lobe rotors. Each of the rotors has a configuration defined by the profile defined by an arc having a radius R and extending from apex end to a first transition point, an involute curve extending from the first transition point to a second transition point, and an envelope curve formed continuously with the involute curve from the second transition point to the bottom end based on a basic circle having a radius r. A distance between the apex ends of the lobe portions of each of the rotors is D. A distance between the axes of the pair of the rotary shafts is L. The radius R is set in {(2)/16}L<R<{(2752)/56}L, and the radius r is set in L/(22)<r<0.3(2)L, and the radius r is set in /(42)L<r<1.28/(42)L, and the distance D is set in 2{L+/(42)L}<D<2.032{L+/(42)L}.