A rotor comprises a central body configured to rotate. A lobe extends perpendicularly from the central body along an lobe axis. A curved leading periphery and a curved trailing periphery are on opposite sides of the lobe axis. A V-shaped rib spans between the curved leading periphery and the curved trailing periphery. A first hollow space is bounded by the V-shaped rib, the curved leading periphery, and the curved trailing periphery. The first hollow space is distal with respect to the central body along the lobe axis. A second hollow space is bounded by the V-shaped rib, the central body, the curved leading periphery, and the curved trailing periphery. The second hollow space is proximal with respect to the central body along the lobe axis. The rotor can comprise a plurality of stacked, stamped sheets to form a helically twisted supercharger rotor.

A compressor may include a compression mechanism, a motor, and a counterweight assembly. The motor assembly is drivingly engaged to the compression mechanism and includes a rotor driving a driveshaft. The rotor drives the driveshaft. The counterweight assembly is mounted axially onto the driveshaft of the motor assembly and has a first laminated stack of plates that includes a plurality of first plates and a plurality of second plates. Each first plate defines a first polygonal-shaped aperture that has a plurality of sides. Each second plate defines a second polygonal-shaped aperture that has a plurality of second sides. The first sides of the first polygonal-shaped apertures are rotationally misaligned with the second sides of the second polygonal-shaped apertures.

A scroll compressor including a first bearing rotatably supporting a rotary shaft relative to a casing at one side of the rotary shaft with respect to a motor, a second bearing rotatably supporting the rotary shaft relative to the casing at the other side of the rotary shaft with respect to the motor, and a third bearing rotatably supporting the rotary shaft relative to an orbiting scroll at the opposite side of the first bearing with respect to the second bearing. The distance between a first bearing center and a third bearing center is a predetermined distance, the distance between a motor center and the third bearing center is longer than the distance between the motor center and the first bearing center, and the distance between a second bearing center and the motor center is longer than the distance between the second bearing center and the third bearing center.

A pump module may include a pump rotor coupled to a rotating shaft of a motor, and a pump housing configured to accommodate the pump rotor. The pump housing includes a rotor accommodating part having an insertion groove formed therein to accommodate the pump rotor, and a cover connected with the rotor accommodating part and having a fluid sucking hole and a fluid discharging hole.

The invention provides a pump comprising a pump inlet, a pump outlet, at least two threaded rotors and a pressure controlled valve, the pressure controlled valve being capable of controlling re-circulation of fluid from the pump outlet to the pump inlet. The pressure controlled valve can be a control valve. The invention also provides a multiple stage pump assembly comprising at least two pumps arranged in series, wherein at least one of the pumps is the aforementioned pump.

A screw compressor includes compressor bodies, a motor disposed in a side of the compressor bodies, a gear box coupled to the compressor bodies and transmitting the drive force of the motor to a screw rotor, and a tubular coupling casing coupling the gear box and the motor and having horizontal axis. The coupling casing has a work hole in the horizontal direction. The work hole is used for maintaining a coupling accommodated in the coupling casing. The coupling casing has a rib extending in the up-down direction. It is thus possible to avoid reduction in the rigidity of the coupling casing with no cost increase, and to improve maintainability.

A stator assembly for a progressing cavity pump is provided. The stator assembly includes a number of stator laminates having a planar body defining a primary, inner passage and a number of outer passages, the outer passages disposed effectively adjacent the inner passage whereby the inner passage is at least partially defined by a band, wherein the band is outwardly flexible. The stator laminates are coupled to each other in a stack wherein the stator laminate body inner passages define a helical passage. The helical passage is a flexible helical passage.

A drive system for a multistage screw compressor with a first compressor stage with a first main rotor mounted on a first shaft in a torque-proof manner and a second compressor stage with a second main rotor mounted on a second shaft in a torque-proof manner. The drive system has a drive shaft for driving the shafts of both main rotors of the first and second compressor stages, wherein the driving of the shaft of the first main rotor takes place independently of the driving of the shaft of the second main rotor, so that the rotational speeds of the two main rotors can preferably be adapted independently of one another.

A modular system for producing a screw spindle pump having a housing with a drive spindle therein and at least one running spindle meshing with the drive spindle, including: a plurality of housing components including a basic housing component exhibiting a fluid inlet for the formation of a basic pump chamber, a housing pressure component exhibiting a fluid outlet, bearing the drive spindle for creating a pressure chamber, a housing cover arranged on the basic housing part for supporting running spindle, and identical intermediate housing components arrangeable in any number between the basic housing component and the housing pressure component and form an additional pump chamber in each case; and a plurality of running spindle elements including at least one running spindle base element arranged in the basic housing component, and identical running spindle extension elements arranged in the intermediate housing components.

The invention proposes a vane pump (VP) with adjustable delivery volume, which vane pump has a pump housing (G), a cam ring (KR) arranged therein, and a rotor (R) which is rotatably movably mounted therein. The vane pump (VP) has a regulating device (RV) through which the delivered pressure medium (DM) flows and which has two outlets (A1, A2) which are each connected to one of two pressure chambers (DK1, DK2) in order to charge these with regulable proportions of the pressure medium (DM), wherein, to change the eccentricity of the cam ring (KR) relative to the rotor (R), the two pressure chambers (DK1, DK2) act on the outer surface of the cam ring (KR). The vane pump (VP) has two criss-crossing control ducts (STK*, STK#) which connect in each case one of the outlets (A1, A2) to one of the two pressure chambers (DK1, DK2) in order to charge these with the regulable proportions of the pressure medium (DM). The criss-crossing control ducts (STK*, STK#) are preferably arranged in a cover (D) of the pump housing such that the control ducts (STK*, STK#) are in a criss-crossing arrangement without coming into contact with one another. By means of this design, the vane pump (VP) can be easily reconfigured for a change in rotational direction of the rotor.