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 positive displacement roots blower can include a housing having an inlet structured to receive an incoming flow of a fluid, an outlet structured to receive an outgoing flow of the fluid, and a passage. The positive displacement roots blower can also include a pair of intermeshed rotating members supported for complementary rotation within the housing, where the rotating members and the housing form respective operating volumes there between which rotate with the rotating members. Each of the respective operating volumes has the following regions: (1) open to inlet/closed to outlet; (2) closed to inlet/closed to outlet; and (3) closed to inlet/open to outlet. The passage includes a restriction and connects to at least one of the operating volumes when the at least one of the respective operating volumes is in region (2). The restriction can be a venturi feedback connecting to the outlet.

A bearing plate damper for a supercharger comprising a bearing plate, a first shaft bore and a second shaft bore in the bearing plate, a recess centered between the first shaft bore and the second shaft bore, and a perforated panel in the recess.

A positive displacement roots blower can include a housing having an inlet structured to receive an incoming flow of a fluid, an outlet structured to receive an outgoing flow of the fluid, and a passage. The positive displacement roots blower can also include a pair of intermeshed rotating members supported for complementary rotation within the housing, where the rotating members and the housing form respective operating volumes there between which rotate with the rotating members. Each of the respective operating volumes has the following regions: (1) open to inlet/closed to outlet; (2) closed to inlet/closed to outlet; and (3) closed to inlet/open to outlet. The passage includes a restriction and connects to at least one of the operating volumes when the at least one of the respective operating volumes is in region (2). The restriction can be a venturi feedback connecting to the outlet.

A pump includes a housing, a drive shaft, a centrifugal pump portion having an impeller, and a gear pump portion having first and second gears. The impeller and one of the first and second gears are mounted to the drive shaft to drive the centrifugal pump portion and the gear pump portion at the same rotational speed. The gear pump can be a crescent internal gear (CIG) pump. The drive shaft can be rotated by a magnetic drive. The drive shaft can include a longitudinal bore in fluid communication with a cavity in the magnetic drive and with a discharge of the centrifugal pump portion to circulate working fluid through the magnetic drive to cool the drive. An impeller can be coupled to an inlet of the centrifugal pump portion.

The disclosure concerns a Roots-type blower comprising a housing defining first and second transversely overlapping cylindrical chambers and at least one inlet port and an outlet port; first and second meshed, lobed rotors, each lobe having a top land sealingly cooperating with the cylindrical chambers; a plurality of control volumes for transfer of fluid, each control volume being defined by a pair of adjacent lobes on one of the rotors, and at least one of the cylindrical chambers; and blowholes formed within the cylindrical chambers in connection with meshing of the lobes of the first and second rotors. The blower further comprises at least one backflow slot extending through the housing wall of each cylindrical chamber for effecting a leakage of fluid from downstream the at least one outlet port into a control volume.

A shunt pulsation trap for a scroll compressor reduces gas pulsations, NVH and improves off-design efficiency. Generally, a scroll compressor with the shunt pulsation trap has a pair of orbiting and stationary scrolls for forming a compression chamber that moves gas pockets from a suction port to a discharge port with internal compression. The shunt pulsation trap is configured to trap and attenuate as pulsations before the discharge port and comprises a pulsation trap chamber adjacent to the compression chamber, therein housed various gas pulsation dampening means or gas pulsation containment means, at least one trap inlet port branching off from the compression chamber into the pulsation trap chamber and a trap outlet port communicating with the compressor discharge chamber after the discharge port.