An inter-stage coupling for a multi-stage vacuum booster pump may include a first coupling face configured to be received by a first adjacent stage of the multi-stage vacuum pump; a second coupling face configured to be received by a second adjacent stage of the multi-stage vacuum pump; and a recirculator comprising a recirculation inlet aperture formed in the first coupling face, a recirculation outlet aperture formed in the first coupling face, and a recirculation conduit having a recirculation valve configured to selectively fluidly couple the recirculation inlet aperture with the recirculation outlet aperture. In this way, the pressure in a stage can be relieved by fluidly coupling the outlet aperture with the inlet aperture in order to recirculate built-up gas from one part of the first stage pump to another part of the first stage pump in order to reduce the strain on the rotor.

A multi-stage rotary vane pump comprising at least two rotor elements. The rotor elements are supported by a rotor shaft. The rotor elements and the rotor shaft are in the form of a single piece.

A plurality of scroll compressors with different fixed volume indexes are connected in fluid parallel circuit and configured to selectively operate to maximize isentropic efficiency at different condensing temperatures. Different quantities of scroll compressors of different volume indexes may be selected based upon typical climate or geographic location environmental conditions to attempt to maximize efficiency. A controller may selectively operate different combinations of the compressors of different volume indexes bases up load demands and condensing temperature conditions, which may be determined in a variety of ways.

A vacuum exhaust system which exhausts gas from chambers and which comprises a plurality of branch channels for the exhaustion of the gas from the chambers, a main pipeline in the form of a confluence of the plurality of branch channels, channel open-close valves fitted to correspond with each of the said plurality of branch channels, a channel-switching valve connecting the main channel and a plurality of selection channels and allowing flow between the main channel and any one of the plurality of selection channels, a first pump which functions as a gas exhaust means in the molecular flow region of the gas and is fitted to one of the plurality of branch channels, and second pumps which function as gas exhaust means in the viscous flow region of the gas and are fitted to the plurality of selection channels.

A stacked gerotor pump is provided. The stacked gerotor pump includes a first gerotor pump defining a first inlet section and a first outlet section, a second gerotor pump defining a second inlet section and a second outlet section and a plate. The plate is interposed between the first and second gerotor pumps and defines upstream cavities respectively communicative with the first and second inlet sections, downstream cavities respectively communicative with the first and second outlet sections and a pre-pressurization hole by which the second outlet section is communicative with the first inlet section.

A rotary compressor of an embodiment has a rotating shaft, an electric motor, a compression mechanism, a balancer, and a balancer cover. The compression mechanism has a cylinder, a main bearing, and a sub-bearing. The balancer is provided on the rotating shaft on a second side of the sub-bearing in an axial direction thereof. The balancer cover covers the balancer. A lubricating oil supply path that opens on a second side end face in the axial direction is provided in the rotating shaft. A supply hole that allows the supply path to communicate with the outside of the balancer cover is formed in the balancer cover at a position facing the supply path in the axial direction. A seal mechanism that seals between the balancer cover and the rotating shaft is provided between the balancer cover and the rotating shaft while allowing relative movement between the balancer cover and the rotating shaft in the axial direction.

A compressor including a housing, and a motor including a stator to be interference fitted into and fixed to an inner circumferential surface of the housing and a rotor rotatable inside the stator. The stator includes an annular back yoke disposed inside the housing, a plurality of teeth extending radially inward from the back yoke, and a coil wound on the plurality of teeth. The back yoke includes a deformation portion compressed and deformed by the housing while the stator is interference fitted into the inner circumferential surface of the housing, a contact portion which protrudes radially outward from the deformation portion and being in contact with the housing, and a cavity formed on a radial inner side of the deformation portion into which the deformation portion is deformed.

The present disclosure relates to a two-stage rotary vane vacuum pump casing 200 that comprises an exterior surface 202 and a first plurality of cooling fins 204 (214) protruding from the exterior surface 202, wherein each cooling fin 204 (214) extends along the exterior surface 202 between a first and second cooling fin end 201a, 201b, and is a non-planar element that forms an at least partially enclosed cooling channel 206 (216) between the first and second ends 201a, 201b of the cooling fin 204 (214b). The present disclosure also provides a method of making a two-stage rotary vane vacuum pump casing 200 using extrusion and providing a removable end plate for a two-stage rotary vane vacuum pump casing 200.

The present disclosure provides a multi-stage compressor and an air conditioner having the same. The multi-stage compressor includes: a first-stage cylinder including a first-stage compression cavity and a first vane disposed in the first-stage compression cavity; a second-stage cylinder including a second-stage compression cavity and a second vane disposed in the second-stage compression cavity, wherein a refrigerant flowing out from the first-stage compression cavity enters the second-stage compression cavity; a linkage structure disposed between the first vane and the second vane, so that the second vane is capable of moving with a movement of the first vane and maintain contact with a roller in the second-stage compression cavity.

A rotary compressor includes a compression device including a compression space to accommodate a refrigerant introduced through an inlet, and configured to compress the refrigerant and to discharge the refrigerant to an outlet, a driving device to drive the compression device, a flange member to partition an inner portion of the case into a low-pressure region and a high-pressure region, and a muffler member disposed on a surface of the flange member to form a first space to store oil and a second space. The flange member includes a first hole communicating with the second space to allow the low-pressure region to communicate with the compression space, the muffler member includes a second hole which forms part of a refrigerant flow path, and at least one of the flange member and the muffler member includes a third hole which forms part of an oil flow path.