An internal gear pump or motor includes inner and outer rotors that mesh together. An internal electric motor or generator may include a stator supported by a support element that passes through bearings of the outer rotor and the inner rotor may act as a rotor of the electric motor or generator. With or without the stator, the support element may support bearings of the inner rotor. The support element may be, for example, an eccentric shaft. Fluids may be supplied via the support element, if present, for cooling, lubrication or to flush a working fluid out of portions of the pump or motor, such as bearings. Flushing may also occur via channels in the housing with or without the presence of the support element. Axial faces of one of a pair of adjacent elements, for example the inner rotor and the outer rotor, may include portions for improved axial sealing and wearing in of the other of the pair. Fluid may enter and exit chambers between the inner and outer rotors by radial ports

A compressor 12 for use in a refrigerant circuit 11 using a refrigerating machine oil 60 being free of phosphoric ester and a refrigerant mixture inclusive of 1,1,2-trifluoroetylene includes a rolling piston 32 and a vane 33 in contact with the rolling piston 32 in a slidable manner. The rolling piston 32 and the vane 33 are formed of a base metal, the base metal being steel, and the base metal is exposed at a contact portion between the rolling piston 32 and the vane 33.

A rough-vacuum pump of dry type includes a duct formed in the stator and of which an inlet orifice is intended to be connected to at least one source of purge gas and of which at least one outlet orifice communicates with the last pumping stage communicating with the delivery and a device for injecting a heated purge gas including a heating device to at least partly heat the purge gas injected into the duct to a temperature higher than 40° C.

A liquid-injected compressor or vacuum pump device with a liquid-injected compressor or vacuum pump element (2), which includes a liquid return system (7), a motor (4) to drive the compressor or vacuum pumping element (2), a gearbox (3) provided between the motor (4) and the liquid-injected compressor or vacuum pump element (2), and a liquid separator vessel (5) in fluid connection with an outlet (6) of the compressor or vacuum pump element (2). The liquid return system (7) includes a main body (8) with a chamber in which a first compressed gas flow (11) from the liquid separator vessel (5) and a second fluid flow (15) from the gearbox (3) are mixed together to form a third fluid flow (20). The third fluid flow (20) leaves the chamber via an outlet (16) and is directed into the liquid-injected compressor or vacuum pump element (2) via the injection point (17).

A screw compressor includes a screw rotor, a casing, and a fluid supply portion to supply fluid in a membrane form into a compression chamber in the casing. The screw rotor has a male and female rotors. A male bore covering the male rotor and a female bore covering the female rotor are formed on the inner surface of the casing. An intersection line, on a higher pressure side, of the male and female bores is defined as a compression cusp. In a bore development view, a trajectory made by the first intersection of an extension line of a female lobe ridge and a male lobe ridge being moved, along with the rotation of the male and female rotors, is defined as a trajectory line. An opening of the fluid supply section to the compression chamber is positioned between the compression cusp and the trajectory line.

A compression part of a rotary compressor includes an intermediate partition plate that is arranged between an upper cylinder and a lower cylinder, an upper vane that sections an upper cylinder chamber formed within the upper cylinder into an upper suction chamber and an upper compression chamber, and a lower vane that sections a lower cylinder chamber formed within the lower cylinder into a lower suction chamber and a lower compression chamber. The intermediate partition plate is formed with an injection hole that injects a liquid refrigerant into the upper compression chamber and the lower compression chamber and an injection passage that supplies the liquid refrigerant to the injection hole. The injection passage is formed along a straight line that does not cross a rotary shaft insertion hole into which a rotary shaft is inserted.

An oil-free water-injected screw air compressor comprises a housing that encloses two rotors for generating compressed air, an air water separator for separating the water from the compressed air. Injecting water during compression can remove the heat of compression and thus enhance efficiency of compression. However, injecting water may complicate bearing lubrication. According to the present subject matter, these challenges are tackled using a sealing system for isolation of bearing lubricant from water used for cooling.

Compressor device comprising an oil-injected compressor element (2) with an outlet (4) connected via an outlet line (8) to an oil separator (9) which is connected via an injection pipe (10) to the compressor element (2), wherein controllable cooling means (15) for the oil are provided, the compressor device (1) being provided with a control unit (21) and thereto connected measuring means (22a, 22b) for controlling the cooling means (15) to control a temperature (T_uit_afsch) downstream of the oil separator (9), the measuring means (22a, 22b) including means (22a) for determining a temperature (T_uit) at the outlet (4) and a temperature sensor (22b) for determining the temperature (T_uit_afsch) downstream of the oil separator (9), the control unit (21) including a controller (25) for controlling the cooling means (15) on the basis of signals from said measuring means (22a, 22b) and on the basis of a dew point.

A rotary piston compressor/pump/blower includes a housing spatially limiting a working chamber, an intake connection for guiding fluid into the working chamber, a pressure connection for guiding the fluid out of the working chamber, and a rotor assembly having a first rotor rotatably arranged in a first working sub-chamber and a second rotor cooperating with the first rotor and rotatably arranged in a second working sub-chamber. The rotary piston compressor/pump/blower also includes a ventilation channel, formed in the housing and connected to the working chamber via a ventilation channel opening, for the temporally limited introducing of air into the working chamber, wherein the ventilation channel opening is open at least in sections, in particular completely open, in a compression phase.

A compressor system can include a lubricant injection system useful to supply lubricant to an airend. The compressor system can include a variable lubricant flow valve which can be regulated by a controller on the basis of operating conditions of the compressor system. In one form the compressor system also includes an oil separator and/or an oil cooler with or without a them al control valve. The controller can have one or more modes of operation, including a mode in which the controller regulates the flow of lubricant to the airend to increase an internal flow area of the valve when the airend is operated at an unloaded or loaded condition. In some forms the controller can regulate the lubricant flow valve and/or the thermal control valve and/or the lubricant cooler.