A system includes a plurality of compressors, an evaporator, an expansion device, and a system controller. The compressors may be linked in parallel. The system controller may: determine a saturated evaporator temperature, a saturated condensing temperature, and a target capacity demand; determine an estimated system capacity and an estimated power consumption for each compressor operating configuration; compare the estimated system capacity with the target capacity demand and an error tolerance value; select an optimum operating mode based on the comparisons and based on the estimated power consumption; and command activation and deactivation of the plurality of compressors to achieve the selected optimum operating mode. The optimum operating mode may be selected after the normal system logic achieves a steady state and may be selected from a group having the estimated system capacity within the error tolerance of the target capacity demand and a lowest associated power consumption value.

A scroll compressor is provided in which a center of a back pressure chamber is eccentrically disposed relative to a center of a fixed scroll. For example, the center of the back pressure chamber may be moved towards a center of an orbiting scroll at a time of discharge, thereby preventing displacement of the fixed scroll and ensuring stability in orbital movement of the orbiting scroll.

A multi-stage vacuum pump may include a sealing arrangement for sealing between the stator components of the pump. The end seals of the arrangement comprise an annular portion for sealing between end stator components and shell components and axial portions which extend from the annular portion and together with separate axial seals seal between the shell components.

The present invention relates to a compressor comprising: a muffler that provides a sealed space for guiding a refrigerant; and a resonator provided in the muffler and forming cavities separate from the sealed space to decrease vibration and noise caused by the refrigerant.

An apparatus comprising a stator and a rotor which are arranged inside a housing extending along a common longitudinal axis, wherein the stator encloses the rotor in a radial direction. A space is formed between an inside of a wall of the housing and an outside of a wall of the stator. The housing has a first housing element and a second housing element that are arranged with their contact surfaces aligned with each other thus sealing the housing. Thereby, a sealing element is arranged between the contact surfaces of the housing elements. The sealing element has the shape of an annular disc with a circumferential form and at least one sealing area. In the circumferential direction, the form corresponds to a contour of the contact surfaces. The sealing area is designed to at least partially enclose the space.

An electrical arrangement assembly is provided on the external region of a hermetic housing of a compressor. The arrangement includes an insulating box capable of housing an electrical interface between internal and external regions of the compressor including an insulating box coupled to the external region by means a hinge element having a pivot handle with an extension and a grounding tab. The grounding tab of the hinge element cooperates with a housing cradle of the insulating box when connecting the box to the housing of the compressor. A controlled angular movement between the insulating box and the hinge element results in electrical connection between a first and second set of electrical terminals of the electrical interface between the internal and external regions of the hermetic housing of the compressor.

A compressor includes a drive shaft having a main shaft and an eccentric portion, and a compression mechanism having a fitted tubular portion into which a fitted shaft portion of the drive shaft is fitted. The fitted shaft portion and the fitted tubular portion slide relative to each other with an oil film interposed between. The fitted tubular portion has first and second sliding surfaces formed as portions of an inner peripheral surface of the fitted tubular portion in the circumferential direction. The second sliding surface has a smaller axial width than the first sliding surface. A sliding portion between the fitted shaft portion and the fitted tubular portion has a gap adjacent to the second sliding surface into which a lubricating oil flows, and an oil retainer to keep the lubricating oil in the gap from flowing out toward an end surface of the fitted tubular portion.

A multistage compression system uses refrigerant and oil. The multistage compression system includes a low-stage compressor that compresses the refrigerant, a high-stage compressor that further compresses the refrigerant compressed by the low-stage compressor, refrigerant pipes that-introduce the refrigerant compressed and discharged by the low-stage compressor into a suction part of the high-stage compressor, a pressure reducing element disposed between the refrigerant pipes, an accumulator disposed between the refrigerant pipes at a downstream side of the pressure reducing element and at an upstream side of the high-stage compressor, and an oil discharge pipe. The oil discharge pipe discharges the oil in the low-stage compressor. The oil discharge pipe connects the low-stage compressor and a portion of the refrigerant pipes. The portion of the refrigerant pipes is on a downstream side of the pressure reducing element and an upstream side of the accumulator.

A multistage compression system uses refrigerant and oil. The multistage compression system includes a low-stage compressor that compresses the refrigerant, a high-stage compressor that further compresses the refrigerant compressed by the low-stage compressor, refrigerant pipes that-introduce the refrigerant compressed and discharged by the low-stage compressor into a suction part of the high-stage compressor, a pressure reducing element disposed between the refrigerant pipes, an accumulator disposed between the refrigerant pipes at a downstream side of the pressure reducing element and at an upstream side of the high-stage compressor, and an oil discharge pipe. The oil discharge pipe discharges the oil in the low-stage compressor. The oil discharge pipe connects the low-stage compressor and a portion of the refrigerant pipes. The portion of the refrigerant pipes is on a downstream side of the pressure reducing element and an upstream side of the accumulator.

A multistage compression system uses refrigerant and oil. The multistage compression system includes a low-stage compressor that compresses the refrigerant, a high-stage compressor that further compresses the refrigerant compressed by the low-stage compressor, an oil return pipe that returns the oil discharged by the high-stage compressor to the low-stage compressor, and an oil discharge pipe that discharges the oil in the low-stage compressor. The low-stage compressor includes a compression part that compresses the refrigerant, a motor that drives the compression part, and a container that houses the compression part and the motor. The container forms a high-pressure space storing compressed refrigerant. Inside of the oil return pipe and inside of the oil discharge pipe are connected to the high-pressure space.