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 screw compressor has a slide valve movement mechanism having a cylinder provided in a casing body, a piston partitioning an interior of the cylinder into a first chamber and a second chamber, and a communication flow passage through which the second chamber communicates with a low-pressure space. The cylinder is provided with a first inflow hole, a second inflow hole, and a third inflow hole, the first chamber communicating with a high-pressure space through the first inflow hole, the second chamber communicating with the low-pressure space through the second inflow hole and the communication flow passage, the second chamber communicating with the high-pressure space through the third inflow hole. The third inflow hole is located at a position at which the third inflow hole is closed by the piston when the piston lies at a stop position at which the piston moves toward the second chamber and stops.

A compressor may include a shell, first and second scrolls, a seal assembly, a modulation control chamber, and a modulation control valve. The first scroll may include a first end plate having a biasing passage extending therethrough. The seal assembly may isolate a discharge pressure region from a suction pressure region. The seal assembly and the first scroll may define an axial biasing chamber therebetween that communicates with the axial biasing chamber and a first pocket between the first and second scrolls. The modulation control chamber may be fluidly coupled with the biasing chamber by a first passage. The modulation control valve may be fluidly coupled with the modulation control chamber by a second passage and movable between a first position allowing communication between the second passage and the suction pressure region and a second position restricting communication between the second passage and the suction pressure region.

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 high pressure compressor and a refrigerating cycle device including a high pressure compressor are provided. The high pressure compressor may include a casing in which refrigerant discharged from a compression unit or device is filled into an inner space provided with a drive motor; a suction pipe directly connected to a suction port of the compression unit; a discharge pipe in communication with an inner space of the casing; a first valve provided at the discharge pipe or the suction pipe to control a flow the discharged refrigerant from a high pressure side to a low pressure side when the drive motor is stopped; a bypass pipe connected between a discharge side and a suction side based on the compression device; and a second valve provided at the bypass pipe to move refrigerant at the high pressure side to the low pressure side through the bypass pipe, thereby allowing a differential pressure operation to continue when the compressor is stopped, to enhance energy efficiency as well as allowing a suction pressure and a discharge pressure to rapidly reach an equilibrium pressure during restart so as to efficiently perform the restart.

A method of monitoring a volume index valve of a compressor is provided. The method includes recording a first reading of an operating condition of the compressor when the volume index valve is in a first position. The method also includes switching the volume index valve to a second position. The method further includes recording a second reading of the operating condition of the compressor when the volume index valve is in the second position. The method yet further includes calculating a difference between the first reading and the second reading. The method also includes comparing the difference to a predetermined threshold difference to determine if the volume index valve is moving between the first position and the second position in a desired manner.

A compressor may include first and second scrolls, an axial biasing chamber, and a 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 control valve may be in fluid communication with the inner port, the outer port, and the axial biasing chamber. Movement of the control valve into the first position allows fluid communication between the inner port and the axial biasing chamber. Movement of the control valve into the second position allows fluid communication between the outer port and the axial biasing chamber.

A screw compressor has a slide valve movement mechanism that includes a cylinder provided in a casing body, a piston partitioning an interior of the cylinder into a first chamber and a second chamber, and a communication flow passage through which the second chamber communicates with a low-pressure space. The cylinder includes a first inflow hole, a second inflow hole, and a third inflow hole. The first chamber communicates with a high-pressure space through the first inflow hole, the second chamber communicates with the low-pressure space through the second inflow hole and the communication flow passage, and the second chamber communicates with the high-pressure space through the third inflow hole. The third inflow hole is located at a position at which the third inflow hole is closed by the piston when the piston lies at a stop position at which the piston moves toward the second chamber and stops.

A method of monitoring a volume index valve of a compressor is provided. The method includes recording a first reading of an operating condition of the compressor when the volume index valve is in a first position. The method also includes switching the volume index valve to a second position. The method further includes recording a second reading of the operating condition of the compressor when the volume index valve is in the second position. The method yet further includes calculating a difference between the first reading and the second reading. The method also includes comparing the difference to a predetermined threshold difference to determine if the volume index valve is moving between the first position and the second position in a desired manner.

A valve assembly forms a check valve for a scroll compressor including a fixed scroll having a pair of injection ports fluidly coupled to a compression mechanism. The valve assembly includes a valve body having a pair of flow paths with each of the flow paths fluidly coupled to a corresponding one of the injection ports. An injection plate has a pair of injection holes. A reed structure is disposed between the injection plate and the valve body with the reed structure including a pair of reeds. Each of the reeds is configured to selectively provide fluid communication between a corresponding one of the injection holes and a corresponding one of the injection ports. A valve gasket is disposed between the reed structure and the valve body and includes a pair of flaps with each of the flaps configured to selectively contact a corresponding one of the reeds.