A compressor may include non-orbiting and orbiting scrolls, a hub plate, and primary and secondary discharge valve assemblies. The non-orbiting scroll includes a first end plate having primary and secondary discharge passages. The hub plate may be mounted to the non-orbiting scroll and may include a main body and a central hub extending axially from the main body. The central hub may include a recess and a hub aperture. The primary discharge valve assembly may include a retainer and a primary valve member. In a closed position, the primary valve member may restrict fluid flow between the discharge chamber and the primary discharge passage. The secondary discharge valve assembly may include a secondary valve member that selectively allows and restricts fluid communication between the secondary discharge passage and the hub aperture of the central hub.

A positive-displacement compressor having an automatic system for adjusting compression ratio and designed for installation in a conditioning or refrigeration system for a fluid includes a suction chamber for sucking the fluid with a variable suction pressure, a delivery chamber for delivering the fluid with a delivery pressure greater than the suction pressure, a compression chamber interposed between the suction chamber and the delivery chamber and communicating with the delivery chamber via one or more discharge ports, a compression element to compress the fluid to the compression pressure, a motor driving the compression element, and an adjusting system of the compression ratio. The adjustment system includes a mechanical valve interposed between the compression chamber and the delivery chamber that automatically varies discharge port apertures in response to a pressure differential between delivery chamber and compression chamber to instantaneously equalize compression and and delivery pressure and improve compressor efficiency.

A positive-displacement compressor having an automatic system for adjusting compression ratio and designed for installation in a conditioning or refrigeration system for a fluid includes a suction chamber for sucking the fluid with a variable suction pressure, a delivery chamber for delivering the fluid with a delivery pressure greater than the suction pressure, a compression chamber interposed between the suction chamber and the delivery chamber and communicating with the delivery chamber via one or more discharge ports, a compression element to compress the fluid to the compression pressure, a motor driving the compression element, and an adjusting system of the compression ratio. The adjustment system includes a mechanical valve interposed between the compression chamber and the delivery chamber that automatically varies discharge port apertures in response to a pressure differential between delivery chamber and compression chamber to instantaneously equalize compression and and delivery pressure and improve compressor efficiency.

A multi-stage rotary piston pump comprising two shafts in a housing, which support multiple rotary pistons. Corresponding rotary pistons form a respective rotary piston pair, wherein multiple rotary piston pairs are provided which form a respective pump stage. Neighboring pump stages are each connected to one another via connection channels. The multi-stage rotary piston pump also comprises a pump inlet that is connected to the first pump stage, as well as a pump outlet that is connected to the last pump stage. The built-in volume ratio is at least 15, so that high pumping capacities of at least 1500 m.sup.3/h can be achieved.

A scroll compressor may include an orbiting scroll; a non-orbiting scroll engaged with the orbiting scroll to form a pair of compression chambers between the orbiting scroll and the non-orbiting scroll; a back pressure chamber assembly coupled to the non-orbiting scroll to form a back pressure chamber to support the non-orbiting scroll toward the orbiting scroll; a first back pressure passage that connects a first intermediate pressure chamber in the compression chamber and the back pressure chamber; a second back pressure passage that connects a second intermediate pressure chamber having a higher pressure than the first intermediate pressure chamber and the back pressure chamber; and a back pressure control valve configured to selectively open and close the first back pressure passage and the second back pressure passage according to an operation mode. The back pressure control valve moves to a first position at which the first back pressure passage is open and the second back pressure passage is closed in a power operation, and moves to a second position at which the first back pressure passage is closed and the second back pressure passage is open in a saving operation.

A compressor is provided including a housing having a suction inlet and a discharge outlet. A compression mechanism within the housing is configured to receive a vapor at the suction inlet and to provide a compressor vapor to the discharge outlet. A volume index valve is arranged near the discharge outlet. The volume index valve includes a piston positioned within a hollow chamber and configured to move between a closed position and an open position to provide a bypass flow path from an intermediate portion of the compression mechanism to the discharge outlet. The piston is configured to move within the chamber automatically in response to the operating pressure of the vapor within the compressor.

A compressor is provided including a housing having a suction inlet and a discharge outlet. A compression mechanism within the housing is configured to receive a vapor at the suction inlet and to provide a compressor vapor to the discharge outlet. A volume index valve is arranged near the discharge outlet. The volume index valve includes a piston positioned within a hollow chamber and configured to move between a closed position and an open position to provide a bypass flow path from an intermediate portion of the compression mechanism to the discharge outlet. The piston is configured to move within the chamber automatically in response to the operating pressure of the vapor within the compressor.

Provided is a variable-capacity mechanism for a scroll compressor. The scroll compressor includes a compression mechanism. The compression mechanism includes a fixed scroll and an orbiting scroll for defining a series of compression cavities. The variable-capacity mechanism includes: a discharge channel, suitable for communicating a medium-pressure compression cavity in the compression cavities with a low-pressure region; blocking members, suitable for selectively opening or closing the discharge channel; an actuation device, including an execution member, the blocking members being connected to the execution member so as to selectively open or close the discharge channel along with the actions of the execution member. Multiple blocking members are connected to a single execution member so as to synchronously move along with the actions of the single execution member. By the variable-capacity mechanism, action synchronization of multiple blocking members can be reliably implemented. Provided is a scroll compressor including the variable-capacity mechanism.

Provided is a variable-capacity mechanism for a scroll compressor. The scroll compressor includes a compression mechanism. The compression mechanism includes a fixed scroll and an orbiting scroll for defining a series of compression cavities. The variable-capacity mechanism includes: a discharge channel, suitable for communicating a medium-pressure compression cavity in the compression cavities with a low-pressure region; blocking members, suitable for selectively opening or closing the discharge channel; an actuation device, including an execution member, the blocking members being connected to the execution member so as to selectively open or close the discharge channel along with the actions of the execution member. Multiple blocking members are connected to a single execution member so as to synchronously move along with the actions of the single execution member. By the variable-capacity mechanism, action synchronization of multiple blocking members can be reliably implemented. Provided is a scroll compressor including the variable-capacity mechanism.

A vane rotary compressor may include a cylinder provided with at least one outlet port; a plurality of bearings coupled to both sides of the cylinder in an axial direction of the cylinder to form a compression space together with the cylinder; a rotational shaft radially supported by the plurality of bearings; a roller rotatably coupled to the rotational shaft and provided with a plurality of vane slots formed in a circumferential direction, each having a first end opened to an outer circumferential surface thereof; a plurality of vanes slidably inserted into the plurality of vane slots of the roller, respectively, and protruding toward an inner circumferential surface of the cylinder to partition the compression space into a plurality of compression chambers, respectively; a discharge valve coupled to the cylinder to open and close the at least one outlet port; and at least one bypass hole formed in at least one of the plurality of bearings or formed in the cylinder to bypass a portion of refrigerant compressed in the compression chamber.