An improved screw-spindle pump, particularly for cooling systems, includes a first screw, a second screw and a pump housing, inside which the first screw and the second screw are rotatably housed between the first screw, the second screw and the pump housing, being defined pumping chambers adapted to move, as a consequence of the rotation of the first screw and the second screw, a fluid from a suction area to a delivery area of the pump.

The pump housing housing the first screw and the second screw is made in one piece.

A compressor which includes a male rotor assembly including an elongate male helical-shaped rotor having an axial cylindrical cavity therethrough, a stationary shaft axially aligned with the male rotor and through the cavity, a housing for housing the male rotor and its associated stationary shaft therein, wherein the shaft is fixed within the housing, and bearing means mounted within the cavity of the male rotor for bearing the friction between the rotor and the shaft as the male rotor rotates about the stationary shaft.

Disclosed herein is a high-pressure scroll compressor, in response to a discharged refrigerant flowing into a back pressure chamber, capable of directly discharging the refrigerant to a space inside a main body, and capable of maintaining an intermediate pressure of the back pressure chamber to be less than a discharge pressure of the refrigerant by separately providing a discharge flow path in the back pressure chamber. The high-pressure scroll compressor comprises a main body, a fixed scroll fixed inside the main body, an orbiting scroll engaged with the fixed scroll to perform a relative orbiting motion, and forming a compression chamber with the fixed scroll, a main frame located under the orbiting scroll and including a back pressure chamber filled with an intermediate-pressure refrigerant, a back pressure hole provided in the orbiting scroll and provided to allow the compression chamber to communicate with the back pressure chamber, a bypass portion configured to selectively bypass the refrigerant of the compression chamber to a space inside the main body, and a back pressure chamber discharge portion configured to selectively discharge the refrigerant of the back pressure chamber to the space inside the main body.

A single-stage enthalpy enhancing rotary compressor and an air conditioner having same. The single-stage enthalpy enhancing rotary compressor includes: at least one single-stage cylinder, a rotator, an upper flange, and a lower flange. The rotator is arranged inside the cylinder and is rotatable, a compression chamber is formed between the rotator and an inner peripheral wall of the cylinder, a vapor injection opening is defined in at least one of the upper flange the lower flange, and the vapor injection opening is configured to supply gas outside the compressor to the compression chamber directly. According to the present disclosure, two-stage compression is realized without adding an extra cylinder, thereby effectively enhancing a circulation of refrigerant, improving cooling performance of the air conditioner under high environmental temperatures.

A rotary compressor is provided that may include a rotational shaft, first and second bearings configured to support the rotational shaft in a radial direction, a cylinder disposed between the first and second bearings to form a compression space, a rotor disposed in the compression space and coupled to the rotational shaft to compress a refrigerant as the rotor rotates, and at least one vane slidably inserted into the rotor, the at least one vane coming into contact with an inner peripheral surface of the cylinder to separate the compression space into a plurality of regions. At least one of the first bearing and the second bearing may include first and second pockets formed on a surface facing the rotor, and at least one of the first pocket and the second pocket may be formed in an asymmetrical shape.

A screw compressor includes a screw rotor having a plurality of screw grooves, a plurality of gate rotors each including gates that mesh with the screw rotor, and a casing. The screw rotor is rotatably inserted in the casing. The casing has a cylindrical wall through which the gates pass. The screw compressor has a plurality of compression chambers inside the cylindrical wall. The plurality of compression chambers are defined by the screw rotor and the gates. The compression chambers include a first compression chamber and a second compression chamber. A fluid introduced into the casing at a suction pressure is compressed to an intermediate pressure higher than the suction pressure in the first compression chamber. The fluid at the intermediate pressure is compressed to a discharge pressure higher than the intermediate pressure in the second compression chamber.

The invention relates to a vane pump for conveying liquids, in particular viscous oils, which vane pump includes: a rotor having sliding slots in which movable vanes are held and can be countersunk in relation to a rotor radius (r); a pump housing including a pump chamber, which encloses the rotor; and an inlet and an outlet, which open into the pump chamber at at least one end face of the rotor; radial elevations protruding, with respect to the sliding slots, over the circumference of the rotor, which elevations form a rotor radius (r) on either side of the vanes that can be countersunk, and radial pockets being recessed, relative to the rotor radius (r), between the radial elevations. Within the radial elevations, recesses are formed on the at least one end face of the rotor at which the inlet and the outlet open, which recesses provide rotating anticipatory control geometry for reducing pressure spikes in the vane cells.

A pump comprises: a housing: a stator disposed inside the housing; a pump gear which is disposed to correspond to the stator and which includes an external gear and an internal gear; and a magnet disposed on the external gear, wherein the magnet includes a first outer circumferential surface, the external gear includes a second outer circumferential surface, and the curvature of the first outer circumferential surface can be smaller than the curvature of the second outer circumferential surface.

A rotary piston and cylinder device (1) comprising a rotor (2), a stator (4) and a rotatable shutter (3), the rotor comprising a piston (5) which extends from the rotor into a working chamber, the rotor and the stator together defining a working chamber, the shutter arranged to extend through the working chamber and forming a partition therein, and the shutter comprising a slot which allows passage of the piston therethrough, a bearing (20) which mounts the rotor relative to the stator, the rotor comprising a formation (12; 30) which extends substantially axially away from the chamber, and the formation being radially outward of the bearing and extending around the axis of rotation, and the formation comprising a surface which at least in part defines a space between the rotor and the stator, and at least part of that space and/or the formation overlaps in an axial direction with the bearing.

A screw rotor which is hollow has improved performance against heat, pressure, rust, and the like. A screw rotor includes a screw portion of which an outer periphery has teeth and grooves having a helical shape and extending by a predetermined length in an axial direction. A radial cross section of at least a part of the screw portion includes a cross section of an outer surface portion forming the teeth and the grooves, a cross section of an axial center portion, a cross section of a support portion that connects an axial center side of the outer surface portion and an outer diameter side of the axial center portion, and a cross section of a hollow portion formed by the support portions adjacent to each other in a rotational direction and an axial center side inner surface of a tooth bottom or a tooth tip. In at least the radial cross section of the screw portion, different members are continuously joined as an integral structure in a cross section of at least one of the axial center portion and the support portion and the outer surface portion.