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 method for evacuating a process space by initially evacuating the process space to a pressure limit value using two compressors operated in parallel, and on reaching or undershooting the pressure limit value, the process space is subsequently evacuated using the two compressors operated in series.

Provided is a rotary compressor excellent in energy saving performance and reliability by improving sliding performance of a sliding portion and ensuring sealability in a working chamber. An oil groove is formed at a position facing a vane end face on an end plate. The oil groove communicates with an inside of a sealed container, and is exposed in a gap between a leading end surface of a vane and an outer peripheral surface of an annular piston formed when the leading end surface of the vane is in abutment on the outer peripheral surface of the annular piston.

The present disclosure provides a product removal apparatus, a treatment system, and a product removal method that can sufficiently remove the products deposited inside a vacuum pump and also suppress corrosion of the base material of the vacuum pump. The product removal apparatus of the present disclosure includes: a sensor for measuring the temperature of the inside of a vacuum pump, the thickness of a film of a product in a flow path in the vacuum pump, or the vibration frequency of the vacuum pump; a gas supplier for supplying a gas containing hydrogen halide, fluorine, chlorine, chlorine trifluoride, or fluorine radicals to the vacuum pump; and a control device. The control device controls the gas supplier so that the supply of the gas to the vacuum pump is stopped depending on a rate of temperature increase calculated from the temperature measured by the sensor, the film thickness, or the vibration frequency.

The present disclosure describes a rotary pulsation generator having a simple structure capable of transferring fluid while implementing low noise and low vibration and having high flow of fluid and high pressure suction and discharge functions. According to the present disclosure, fluid is transferred by adjusting a width and interval of pulsation while reducing vibration caused by eccentric rotation of a rotor.

According to one embodiment, a compressor includes cylinders, a rotating shaft, bearings, discharge valve mechanisms, and mufflers. As to the mufflers, an outer contour of the muffler chamber is defined by each of an end face part which is a face part on one end side of the muffler in an axial direction of the rotating shaft, a brim part which is a face part on the other end side in the axial direction, and a side face part which joins the end face part and the brim part to each other in a cylindrical form in the circumferential direction of the rotating shaft, and one of the mufflers includes a concave part formed by denting each of the end face part and the side face part toward the inside of a muffler chamber.

A pump body assembly includes: a crankshaft, a first baffle plate and a second baffle plate. The crankshaft includes a first eccentric portion, a support shaft and a second eccentric portion which are arranged at intervals in an axial direction; the first baffle plate and the second baffle plate are arranged in sequence between the first eccentric portion and the second eccentric portion, a first round hole is arranged defined on the first baffle plate, the support shaft is arranged in the first round hole, so that the first baffle plate and the support shaft form a baffle plate bearing, and the baffle plate bearing has a stress relief structure for reducing a contact stress between the support shaft and the first baffle plate.

A compressor includes a casing having a cylindrical barrel, a compression mechanism, and an electric motor. The electric motor has a tubular stator, and a rotor disposed inside the stator. The stator has a back yoke forming an outer peripheral portion of the stator, a plurality of teeth extending radially inward, and slots. A fluid passage extends between an outer peripheral surface of the stator and an inner peripheral surface of the barrel. The fluid passage has a plurality of wide portions arranged in a circumferential direction of the stator, and a narrow portion provided between adjacent ones of the wide portions. The narrow portion has a smaller radial width than each of the wide portions. Each wide portion is provided in the outer peripheral surface of the stator and between a core cut having a recessed groove shape between the slots and the inner peripheral surface of the barrel.

According to one embodiment, a rotary shaft of a rotary compressor includes a first connection shaft and a second connection shaft. The first connection shaft has a cross-sectional shape including a first outer surface, a second outer surface, and a third outer surface. L1 represents a distance from an intersecting point located on one end side where the first outer surface and the second outer surface intersect each other to the rotation center, L2 represents a distance from an intersecting point located on an other end side where the first outer surface and the second outer surface intersect each other, to the rotation center, and L3 represents a distance from the third outer surface to the rotation center, a relationship of L1>L3≥L2 is satisfied.

A multi-stage vacuum pump comprising a stator defining multiple pumping chambers is discussed. The stator comprises a plurality of transfer channels for providing a fluid passage from an outlet port of one of the plurality of pumping chambers to an inlet port of a subsequent pumping chamber. Some of the transfer channels comprise two side channel sections on opposing sides of the stator. One of the transfer channels comprises a single side channel section on one side of the stator. The vacuum pump further comprises a gas ballast inlet channel arranged on an other side of the stator to the one side of the stator.