A flange is held by a peripheral wall of an intermediate housing member and a peripheral wall of a motor housing member. In this state, bolts are passed through the intermediate housing member and the flange and are threaded to a peripheral wall of the motor housing member, thereby integrally fixing a shaft support housing member to the intermediate housing member and the motor housing member. Thus, the shaft support housing member sufficiently receives the fastening force of the bolts. Vibration of the shaft support housing member is therefore easily suppressed. The intermediate housing member includes a peripheral wall. Thus, the intermediate housing member has a higher stiffness than in a case in which the intermediate housing member does not have the peripheral wall.

This screw compressor is provided with a screw rotor, a casing accommodating the screw rotor, and a liquid feed mechanism for feeding a liquid into an operating chamber enclosed by the casing, wherein the pitch of the screw rotor changes in the axial direction from a suction end surface toward a discharge end surface.

An air injection enthalpy-increasing scroll compressor is provided. The compressor has a main frame, a movable scroll plate and a stationary scroll plate. The movable scroll plate has a movable plate end plate and a movable scroll wrap arranged on a side end face of the movable plate end plate. A back pressure chamber is defined between the movable plate end plate and the main frame. The stationary scroll plate has a fixed scroll end plate and a stationary scroll wrap arranged on a side end face of the fixed scroll end plate. The stationary scroll wrap and the movable scroll wrap are engaged with each other to form a crescent-shaped compression cavity. The movable scroll plate and the stationary scroll plate are provided with medium pressure passages that, during the rotation of the movable scroll plate, communicate the compression cavity with the back pressure chamber.

A compression chamber includes the compression chamber partitioning member, an intermediate pressure chamber guides an intermediate pressure working fluid before injection to the compression chamber, and the intermediate pressure chamber and the compression chamber face each other with a compression chamber partitioning member interposed between the intermediate pressure chamber and the compression chamber. Further, the intermediate pressure chamber includes an intermediate pressure chamber inlet through which an intermediate pressure working fluid flows, an injection port inlet of an injection port through which the intermediate pressure working fluid is injected into the compression chamber, and a liquid reservoir formed at a position below the intermediate pressure chamber inlet, and the liquid reservoir is formed by the compression chamber partitioning member.

A sheet-shaped check valve 23 which opens and closes the injection passage 21 is placed in the check valve chamber 22, an injection discharge passage 21b portion connected to the compression chamber 13 of the injection passage 21 and the check valve chamber 22 open from an outer surface of the fixed scroll 11, a lid body 25 is attached to openings of the injection discharge passage 21b and the check valve chamber 22 such that the check valve 23 is sandwiched between the openings and the lid body 25, and the injection discharge passage 21b and the check valve chamber 22 are hermetically closed, thereby forming the injection passage 21. According to this, it is possible to provide a reliable, efficient and inexpensive compressor with an injection mechanism.

A scroll compressor is provided that can prevent liquid from being accumulated with a simple structure.

The scroll compressor includes: a fixed scroll 11; an orbiting scroll 12; and a rotation shaft 13 that extends in the horizontal direction and causes the orbiting scroll 12 to orbit relative to the fixed scroll 11, and liquid is injected to a working chamber at an intake process or to the upstream side thereof. An enclosing point P of a working chamber formed near the outer end of a fixed wrap 16 of the fixed scroll 11 is positioned below a center O of the rotation shaft 13 and at the lowest point of the contour of the working chamber having shifted to the lowest position. The fixed scroll 11 has an inclined wall surface 33 that is positioned below the center 0 of the rotation shaft 13, is made to face upward, and extends from the dust wrap 17 to the outer end of the fixed wrap 16. The inclined wall surface 33 is formed so as to be sloped down gradually from the dust wrap 17 toward the outer end of the fixed wrap 16.

A compressor may include first and second scrolls, an axial biasing chamber, and a modulation control valve. The second scroll includes an outer port and an inner port. The outer and inner ports may be open to respective intermediate-pressure compression pockets. The modulation control valve may be in fluid communication with the inner port, the outer port, and the axial biasing chamber. Movement of the modulation control valve into a first position switches the compressor into a reduced-capacity mode and allows fluid communication between the inner port and the axial biasing chamber while preventing fluid communication between the outer port and the axial biasing chamber. Movement of the modulation control valve into a second position switches the compressor into a full-capacity mode and allows fluid communication between the outer port and the axial biasing chamber while preventing fluid communication between the inner port and the axial biasing chamber.

A scroll compressor is provided that is configured to increase the amount of refrigerant injected into a target compression chamber to which refrigerant is desired to be injected. The scroll compressor has a fixed scroll that has a first base plate with an injection-pipe connection port to which an injection pipe is connected, a first injection hole that passes through the first base plate and communicates with one of the compression chambers , a communication hole that communicates with the injection-pipe connection port and the first injection hole, a second injection hole that passes through the first base plate and communicates with one of the compression chambers with which the first injection hole communicates, and a groove that is formed in a face opposite to a face on which a first scroll wrap is formed and communicates with the first injection hole and the second injection hole.

A system includes a compressor with an orbiting scroll member having a first end plate and a first spiral wrap. A non-orbiting scroll member has a second end plate and a second spiral wrap, the second spiral wrap forming a meshing engagement with the first spiral wrap to create a plurality of compression chambers between a suction port and a discharge port. A first port in communication with a first of the plurality of compression chambers selectively injects an injection fluid into the first of the plurality of compression chambers to increase a compressor capacity and selectively leaks a first compressed fluid from the first of the plurality of compression chambers to reduce the compressor capacity. A second port in communication with a second of the plurality of compression chambers selectively leaks a second compressed fluid from the second of the plurality of compression chambers to reduce a compressor capacity.

An oil-free water-injected screw air compressor comprises a housing that encloses two rotors for generating compressed air, and an air water separator for separating the water from the compressed air. Water injection can effectively cool a compressor, and some embodiments provide a sealing system for isolation of compressor bearing lubricant from water used for cooling.