Disclosed is a scroll compressor including stationary and movable scroll members engaged with each other. The stationary scroll member defines first and second air inlets and first and second air outlets. A first compression path is formed between the first air inlet outlet, and a second compression path is formed between the second air inlet outlet. The scroll compressor further includes a bypass passage for selectively communicating, at least one of the first and second compression paths with a suction pressure area of the compressor. First and second back pressure cavities are formed on a side of the stationary scroll member facing away from the movable scroll member. The first back pressure cavity is in communication with the first compression path by means of a first back pressure passage. The second back pressure cavity is in communication with the second compression path by means of a second back pressure passage

It is assumed that a distance between a center portion of fixed scroll end plate and an outer peripheral portion at a distal end of fixed spiral wrap of fixed scroll is Ds, and that a distance between a center portion of orbiting scroll end plate and a portion included in a bottom face of an orbiting spiral wrap of orbiting scroll and facing the outer peripheral portion at the distal end of the fixed spiral wrap of the fixed scroll is Do. Further, assuming that an orbiting radius of orbiting scroll is , the orbiting radius being a distance between a center of eccentric shaft and a center of driving shaft, a relationship Ds+Do is satisfied.

A suction side end part of a suction guide passage and a discharge side end part of a discharge guide passage are opposed to each other with a gap therebetween. At a deviation angle at which contraction of a pump chamber starts, an outer peripheral part of the discharge side end part is formed along an inner tooth, and an inner peripheral part of the discharge side end part is formed along an outer tooth. A working tool that rotates and cuts circularly is moved around on a pump housing in a single continuous line to form an outline of the discharge guide passage, thereby forming the discharge guide passage. The working tool is moved around on the pump housing in a single continuous line to form an outline of the suction guide passage, thereby forming the suction guide passage.

A vane pump includes: a suction port configured to guide working oil to a pump chambers; a discharge port configured to guide the working oil discharged from the pump chambers; and a notch formed from an opening edge portion of the suction port towards a reversing direction of a rotation direction of a rotor, wherein the pump chambers each communicates with the suction port through the notch during a course of the transition from the state, in which the pump chamber is in communication with the discharge port, to the state, in which the communication with the discharge port is shut off, as the rotor is rotated.

A flange for a pump comprises first and second faces and a passageway for cryogenic fluid flow extending from the first face to the second face and at least one of (1) the passageway is for a pipe and comprises a first portion of a first diameter and a second portion of a second diameter greater than the first diameter, wherein when the pipe has an outer diameter that is smaller than the second diameter a gap is formed between the pipe and the passageway where the pipe passes through the second portion; and (2) a first annular groove in one of the first face and the second face and extending around the passageway, wherein the first annular groove in cooperation with the passageway forms a bellows. The gap and bellows increase the thermal resistance between the passageway and the flange, and the bellows allows for flexure during thermal contractions of the flange reducing thermal stress on welded fluid seals.

An oil pump includes: an inner rotor including external teeth; an outer rotor including internal teeth; a housing configured to accommodate the inner and outer rotors; an inlet port formed in the housing and configured to guide oil into a pump chamber between the external and internal teeth; an outlet port formed in the housing and configured to guide the oil to the outside of the pump chamber; and a discharge hole formed in the housing and configured to guide bubbles in the oil to the outside of the pump chamber. The discharge hole communicates with the pump chamber earlier than a timing when the pump chamber and the outlet port communicate with each other. The outlet port communicates with the pump chamber later than a timing when the pump chamber has a maximum volume.

A gas meter with a rated maximum flow capacity of greater than 3,000 CFH (Cubic Feet per Hour)for example, between 3,500 CFH and 7,000 CFHis provided with 2-inch flange connectors. One or more undercuts are provided in the meter body to promote satisfactory performance in terms of, for example, differential pressures at the meter inlet and outlet.

An electric pump includes a motor unit rotationally driving a drive shaft, and a pump unit. The pump unit includes a pump rotor that sends the fluid by a driving force of the driving shaft, and a pump housing that surrounds at least one side of the pump rotor. The pump housing includes an attachment surface extending in the axial direction and in contact with an attached body, first and second flow paths respectively on the suction side and the discharge side, and a fixing location within the attachment surface and fixed to the attached body by a fixing member within a maximum outer shape of the motor housing as viewed in the axial direction. Opening locations of the first and second flow paths are displaced from each other in the axial direction on the attachment surface.

A scroll compressor includes a housing and a compression mechanism. The compression mechanism includes a compression chamber. The housing includes an intermediate pressure chamber into which refrigerant having an intermediate pressure is introduced from an external refrigerant circuit. The intermediate pressure is higher than a suction pressure of refrigerant drawn into the compression chamber and lower than a discharge pressure of the refrigerant discharged from the compression chamber. The intermediate pressure chamber and the compression chamber in a process of compression are connected to each other by an injection passage. The injection passage includes a muffler.

The motor comprises an internal rotor having an external lob; an external rotor outside the internal rotor and having an internal lob engaging the external lob; and an inlet port and an outlet port. An inner diameter of the inlet port is less than a diameter of a dedendum circle of the internal rotor, and an outer diameter of the inlet port is greater than a diameter of a dedendum circle of the external rotor. An inner diameter of the outlet port equals the diameter of the dedendum circle of the internal rotor. An outer diameter of the outlet port equals the diameter of the dedendum circle of the external rotor. The inner diameter of the inlet port is less than the inner diameter of the outlet port. The outer diameter of the inlet port is greater than the outer diameter of the outlet port.