A rotary compressor includes a sealed longitudinal compressor housing which is provided with a discharge portion of a refrigerant at an upper portion thereof, is provided with an inlet portion of a refrigerant at a lower portion thereof, and in which lubricant oil is stored; a compressing unit which is disposed in the compressor housing, compresses a refrigerant sucked from the inlet portion and discharges the refrigerant from the discharge portion; a motor which is disposed in the compressor housing and drives the compressing unit via a rotation shaft; and an accumulator which is attached to a side portion of the compressor housing and is connected to the inlet portion of the refrigerant. When an inner diameter of a cylinder constituting the compressing unit is referred to as Dc, a height of the cylinder is referred to as Hc, and an eccentric amount of an eccentric portion of the rotation shaft is referred to as e, Dc, Hc, and e are set so that a value obtained by an expression (e+Hc).Math.(Dce).sup.1/3/(e.Math.Hc).sup.2/3 is less than 4.1.

To reduce surface pressure acting on a tip of a winding terminal portion of a spiral wall of an orbiting scroll in a scroll compressor. In a scroll compressor 10, a thrust plate 81 and a thrust sheet 82 capable of being elastically deformed are provided between an opposing surface 237 serving as a thrust receiving part and an orbiting base plate 521 of an orbiting scroll 52. A first sealing member 83 seals between the orbiting base plate 521 and the thrust sheet 82 and a second sealing member 84 having a diameter greater than that of the first sealing member 83 seals the opposing surface 237 of a second partition wall 232 and the thrust plate 81. A back pressure chamber H5 is partitioned from a suction pressure area (space H6) by the thrust plate 81, thrust sheet 82, the first sealing member 83, and the second sealing member 84. A circular concave portion 816 is formed on a surface of the thrust plate 81 on the thrust sheet 82 side.

A scroll compressor includes a fixed scroll and a movable scroll. The fixed scroll has a spiral fixed-side wrap positioned upright on a surface of a fixed-side plate. The movable scroll is orbitably disposed to face the fixed scroll. The movable scroll has a spiral movable-side wrap positioned upright on a surface of a movable-side plate, with the movable-side wrap being configured to mesh with the fixed-side wrap. A side clearance is formed between a side surface of the fixed-side wrap and a side surface of the movable-side wrap so as to increase from an outer peripheral side toward an inner peripheral side of each of the wraps.

An air compression device includes a rotary compressor, a discharge flow channel, a release flow channel and an operation control unit. The discharge flow channel is connected to a discharge portion of the rotary compressor. The release flow channel is disposed to be connectable to the discharge flow channel. The operation control unit is configured to perform a release operation of releasing a part or all of compressed air remaining in the discharge flow channel through the release flow channel when the operation control unit controls to stop the rotary compressor.

Provided is a motor rotor which, without changing an integral fastening structure relying on swage pins, increases resistance to the excessive excitation force of the motor rotor and which can easily prevent decreases in fastening strength; a motor that uses the motor rotor, and an electric compressor are also provided. This motor rotor is provided with a cylindrical rotor core comprising multiple laminated magnetic steel sheets, end plates and balance weights laminated on both ends of the rotor core, and multiple headed swage pins which are inserted from one side and which integrally fasten the rotor core, the end plates and the balance weights. The material of the balance weight arranged to the head of the swage pin is harder than that of the swage pin, and the material of the balance weight arranged to the swage part of the swage pin is softer than that of the swage pin.

A vane pump in which noise can be suppressed is provided. A vane pump (1) includes: a housing (2) having a peripheral wall portion (200), a bottom wall portion (201), and a pump chamber (A); a rotor (3) disposed in the pump chamber (A) to be rotatable; a vane (4) disposed to be slidable in the radial direction with respect to the rotor (3) and partitioning the pump chamber (A) into working chambers (A1, A2); and a reed valve (5) that opens and closes a discharge hole (201a) of the bottom wall portion (201). A position at which the sliding direction of the vane (4) with respect to the rotor (3) is inverted from outward in the radial direction to inward is defined as a reference position (1), and a section of the pump chamber (A) on the discharge hole (201a) side with respect to the reference position (1) is defined as a discharge section (AD). A pressure relief groove (201b) is disposed in a portion of the bottom wall portion (201) corresponding to the discharge section (AD) with a clearance (E) secured between the peripheral wall portion (200) and the pressure relief groove (201b). When the vane (4) overlaps the pressure relief groove (201b), a pair of the working chambers (A1, A2) on both sides of the vane (4) in the rotational direction communicate with each other via the pressure relief groove (201b).

A submersible fluid system for operating submersed in a body of water includes an electric machine and a fluid-end. The fluid-end includes a fluid-end housing having an inlet to a fluid rotor, the fluid rotor coupled to the electric machine and carried to rotate in the housing by a bearing in the housing. A fluid separator system receives a multiphase fluid and communicates a flow of the fluid to the inlet and a substantially liquid flow extracted from the multiphase fluid to the bearing.

A scroll compressor is provided that may include a first back pressure unit that allows a refrigerant to flow from a first compression chamber to a back pressure chamber while blocking a reverse flow of the refrigerant, and a second back pressure unit that allows the refrigerant to flow from the back pressure chamber to a second compression chamber while blocking a reverse flow of the refrigerant. The first back pressure unit and the second back pressure unit may be spaced apart from each other in a direction that the compression chambers are formed. This may reduce pressure pulsation in the back pressure chamber. Also, leakage between compression chambers may be suppressed and simultaneously friction loss may be reduced by appropriately adjusting the pressure in the back pressure chamber. This is especially advantageous for enhancing compression efficiency under low load operating conditions (or in a low pressure ratio operation).

An elastic body is provided which biases one of a fixed scroll and an orbiting scroll in a direction in which the fixed scroll and the orbiting scroll are spaced away from each other. With this, upon the start-up of a compressor, a gap is formed between the fixed scroll and the orbiting scroll, and thus the startability is improved.

Provided is a scroll fluid machine that makes it possible to attenuate the bending stress applied to the base of a wall body having an inclined section. The scroll fluid machine is provided with a wall body inclined section in which the distance between the facing surfaces of an end plate of a fixed scroll and an end plate of a rotating scroll that face each other continuously decreases from the outer circumferential side toward the inner circumferential side. A mesh clearance that is a gap between wall bodies formed when the wall bodies mesh with each other is larger on the outer circumferential side of the inclined section than on the inner circumferential side of the inclined section. The mesh clearance is made larger by drawing the wall surface of a wall body further back toward the central side of the wall body in the thickness direction than the original wall surface profile thereof.