A compressor may include first and second scroll members, first and second bearings, and first and second Oldham couplings. The scroll members define compression pockets. The first bearing may define a first rotational axis about which the first scroll member rotates. The second bearing may support the second scroll member for rotation about a second rotational axis that is offset from the first rotational axis. The first Oldham coupling may include a first body and a plurality of first keys extending from the first body. The first keys may engage slots formed in the second scroll member. The second Oldham coupling is separate and distinct from the first Oldham coupling. The second Oldham coupling may include a second body and a plurality of second keys extending from the second body. The second keys may engage slots formed in a surface that rotates about the first rotational axis.

A rotor unit assembly includes a rotor unit having a chamber and a rotor located within the chamber. The rotor has a piston which extends radially outward from the main body of the rotor; and a valve flange with an aperture. The rotor unit further comprises a rotatable hub, with a cavity configured to receive the piston. The rotor unit further comprises a first low pressure port provided in a path described by the piston; a first high pressure port positioned in a path described by the valve flange aperture around the clearance volume; and a second high pressure port positioned in a path described by the cavity around the hub axis.

Rotary piston machines working volume sealing systems thereof are disclosed. They can be used in gas (air) and refrigerating compressors, heat and vacuum pumps, and internal-combustion engines. The rotary piston compressor sealing system includes radial and butt sealing bars in the rotor slots, tightened towards the working surfaces by expanders and interacting with the sealing cylinders. The radial and butt sealing bars are made from an antifriction composite material. Each sealing cylinder is configured conjointly with one end of one butt sealing bar. Variations also are disclosed. The technical result involves increasing efficiency of the sealing system and the whole compressor operation, simplification of the system production process, simplification and labor intensity reduction of the system assembly and maintenance, increasing of the working chambers leakage tightness, increasing of system reliability and durability, and improvement of compressor performance related to bleeding and the dynamic pneumatic process as a whole.

An oil-free screw compressor has a screw rotor including a screw and a shaft, a bearing supporting the shaft, a first shaft seal device disposed between the screw and the bearing and including a first seal opposite to the shaft, and a first communication portion communicating the inner periphery face and the outer peripheral face of the first shaft seal device, a second shaft seal device disposed between the first shaft seal device and the bearing and including a second seal opposite to the shaft, and a second communication portion communicating an inner periphery face and the outer peripheral face of the second shaft seal device, and a casing including an atmosphere communication portion connected to both of the first communication portion and the second communication portion on the inner peripheral face of a shaft accommodation space.

An embodiment of method used to control operation of a screw compressor of a refrigeration system may include receiving status signals regarding operation of the screw compressor of the refrigeration system. The method may further include determining an operating point of the screw compressor based upon the received status signals, and selecting a torque profile for the screw compressor based upon the operating point. The method may also include driving the screw compressor per the selected torque profile. Refrigeration systems and compressor systems suitable for implementing the method are also presented.

An embodiment of method used to control operation of a screw compressor of a refrigeration system may include receiving status signals regarding operation of the screw compressor of the refrigeration system. The method may further include determining an operating point of the screw compressor based upon the received status signals, and selecting a torque profile for the screw compressor based upon the operating point. The method may also include driving the screw compressor per the selected torque profile. Refrigeration systems and compressor systems suitable for implementing the method are also presented.

An internal gear pump (100) comprises: a rotor/torque ring comprising an internally lobed (140) rotor (130) and a torque ring (120) extending beyond at least a first end (134) of the rotor; an externally lobed (160) idler (150) encircled by the rotor; a hollow shaft (190) supporting the idler; a pressure relief element (200) positioned to shift between a first condition and a second condition; and a spring (210) biasing the pressure relief element toward the first condition from the second condition. The torque ring has at least one pressure relief port (240A, 240B) positioned so that: in the first condition, the pressure relief element blocks a path from an interior volume (235) of the pump to the pressure relief port; and in the second condition, relative to the first condition the pressure relief element does not block the path.

A positive displacement rotary motion device including in one example a pulse detonation device. Also; an indexing system for a rotor assembly where in one example the indexing system regulates the rotational location of drive rotors. In one example the rotors are configured to rotate about a shaft.

A scroll compressor, includes: a scroll compression mechanism including an orbiting scroll, a fixed scroll, and a thrust plate supporting a load of the orbiting scroll in a thrust direction; a back-pressure application mechanism that applies, as back pressure, the refrigerant gas compressed by the scroll compression mechanism to a rear surface of the thrust plate; and a floating amount restriction mechanism that restricts an amount of floating of the thrust plate caused by the back pressure. The floating amount restriction mechanism includes a restriction pin that includes a shaft part and a head part, and locks the thrust plate to the head part to restrict the amount of floating. The shaft part passes through the thrust plate and has a front end part fixed to a front housing, and the head part has a diameter larger than a diameter of the shaft part.

A gear pump includes a housing, at least one gear set and a plurality of end plates. The gear set may be positioned between the end plates so that side surfaces of the gears face corresponding side surfaces of the end plates. The side surfaces of the end plates may have a plurality of spiral grooves positioned directly adjacent the side surface of the gears. The plurality of spiral grooves may have a logarithmic shape. Thus arranged, when the gears rotate, fluid in the pump is forced along the lengths of the spiral grooves, creating a local high pressure region that forces fluid between the side surfaces of the gears and the end plates, minimizing or eliminating contact therebetween. In some embodiments the plurality of spiral grooves may be positioned on bearing surfaces of the pump instead of end plates.