A refrigeration cycle apparatus includes a refrigerant and a refrigeration cycle circuit. The refrigeration cycle circuit includes a compressor, and causes the refrigerant to circulate therethrough. The refrigerant is HFO-based refrigerant alone or a mixed refrigerant. In the mixed refrigerant, a mixing ratio of HFO-based refrigerant is equal to or more than 10% by weight. The compressor includes a motor. The motor includes a portion formed from a resin component. The resin component is made of PET, PA, or the like.

A screw compressor includes a casing having an outer peripheral wall, and a compression mechanism. The compression mechanism includes a screw rotor with helical grooves, a gate rotor with a plurality of gates meshing with the helical grooves, and a cylinder housing the screw rotor. The compression mechanism is disposed inward of the outer peripheral wall. The outer peripheral wall has a discharge passage through which a fluid compressed in the compression mechanism flows. The discharge passage includes an inner peripheral passage formed along an outer peripheral surface of the cylinder, and an outer peripheral passage formed along the inner peripheral passage and the outer peripheral wall. The inner and outer peripheral passages are formed so that the fluid compressed in the compression mechanism sequentially flows through the inner and outer peripheral passages.

A single-screw compressor includes a screw rotor with helical grooves, a gate rotor assembly including first and second gate rotors, and a casing housing the screw rotor and the gate rotor assembly. A rotor support member is attached to the first and second gate rotor rotors, and is rotatably supported by the casing. Each of the helical grooves of the screw rotor has a front sidewall surface and a rear sidewall surface. Each of the gates of the first gate rotor slides only on the front sidewall surface of the helical groove in which the gate has entered. Each of the gates of the second gate rotor slides only on the rear sidewall surface of the helical groove in which the gate has entered. The first and second gate rotors of the gate rotor assembly are coaxially arranged and relatively displaceable in a circumferential direction.

A single-screw compressor includes a screw rotor with helical grooves, a gate rotor assembly including first and second gate rotors, and a casing housing the screw rotor and the gate rotor assembly. A rotor support member is attached to the first and second gate rotor rotors, and is rotatably supported by the casing. Each of the helical grooves of the screw rotor has a front sidewall surface and a rear sidewall surface. Each of the gates of the first gate rotor slides only on the front sidewall surface of the helical groove in which the gate has entered. Each of the gates of the second gate rotor slides only on the rear sidewall surface of the helical groove in which the gate has entered. The first and second gate rotors of the gate rotor assembly are coaxially arranged and relatively displaceable in a circumferential direction.

A refrigeration cycle apparatus includes a refrigerant and a refrigeration cycle circuit. The refrigeration cycle circuit includes a heat exchanger and a compressor, and circulates the refrigerant. The refrigerant is a single hydrofluoroolefin (HFO)-based refrigerant or a mixed refrigerant. In the mixed refrigerant, an HFO-based refrigerant is mixed at a mixing ratio of 10% by weight or more. The compressor includes a motor. The motor includes a resin component. The resin component includes a polyimide having a terminal blocked with a terminal group.

A screw compressor includes screw and gate rotors, a cylindrical wall, and a slide valve including a valve body and a guide portion. The valve body extends in an axial direction of the cylindrical wall and has a crescent shape in a cross section in a perpendicular direction to the axial direction. A radius of curvature of an inner arc shaped curved surface of the crescent shape is substantially equal to a radius of curvature of an inner peripheral surface of the cylindrical wall. A radius of curvature of an outer arc shaped curved surface of the crescent shape is smaller than the radius of curvature of the inner arc shaped curved surface, and a central angle of the outer arc shaped curved surface is 180° or less. The guide portion allows movement of the valve body in the axial direction and restricts movement in the perpendicular direction.

A screw compressor includes screw and gate rotors, a cylindrical wall, and a slide valve including a valve body and a guide portion. The valve body extends in an axial direction of the cylindrical wall and has a crescent shape in a cross section in a perpendicular direction to the axial direction. A radius of curvature of an inner arc shaped curved surface of the crescent shape is substantially equal to a radius of curvature of an inner peripheral surface of the cylindrical wall. A radius of curvature of an outer arc shaped curved surface of the crescent shape is smaller than the radius of curvature of the inner arc shaped curved surface, and a central angle of the outer arc shaped curved surface is 180° or less. The guide portion allows movement of the valve body in the axial direction and restricts movement in the perpendicular direction.

A rotary piston and cylinder device (1) comprising a rotor (2), a stator and a shutter disc (3), the rotor comprising a piston (5) which extends from the rotor into the cylinder space, the rotor and the stator together defining the cylinder space, the shutter disc passing through the cylinder space and forming a partition therein, and the disc comprising a slot (3a) which allows passage of the piston therethrough, the slot provided between two surface portions which receive the piston therethrough,at least one of the surfaces defines a close-running region with the piston to provide a fluid seal, and for at least part of the period during which the piston passes through the slot, the close-running region is offset from a mid-plane which extends through the disc and is co-planar with the disc.

A seal assembly configured for use with a high pressure single screw compressor includes a seal body and at least one attachment structure. The at least one attachment structure fixedly attaches the seal body to the rotor of the compressor, such that the seal body is rotatable along with the rotor. The seal body has a textured outer surface which creates a labyrinthine path between the compressor housing and the seal body.

A seal assembly configured for use with a high pressure single screw compressor includes a seal body and at least one attachment structure. The at least one attachment structure fixedly attaches the seal body to the rotor of the compressor, such that the seal body is rotatable along with the rotor. The seal body has a textured outer surface which creates a labyrinthine path between the compressor housing and the seal body.