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.

An oil pump includes: a shaft member; an inner rotor configured to rotate integrally with the shaft member; an outer rotor forming a rotor chamber into which oil is sucked from a suction passage and from which the oil is discharged toward a discharge passage, between the inner rotor and the outer rotor; a body member having a recess-shaped housing chamber in which each rotor is housed so as to be rotatable about an axis; and a cover member attached so as to close the housing chamber. The rotor chamber has first and second suction ports through each of which the oil to be sucked from the suction passage passes. The oil pump includes a straightening member branching the suction passage from a main path to the first suction port side and the second suction port side.

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.

A rotary pump for delivering fluid includes: a pump housing having a low-pressure inlet and a high-pressure outlet for the fluid to be delivered; and a delivery rotor rotatable about a rotational axis in the pump housing and including a rotor base body and multiple deliverers distributed over the circumference of the rotor base body for delivering fluid from the low-pressure inlet to the high-pressure outlet. When the delivery rotor rotates, the radial and axial outer edges of the deliverers define a delivery region of the pump. The pump includes a flow channeling structure protruding axially into the low-pressure inlet in relation to the rotational axis of the delivery rotor from the pump housing wall in order to influence fluid flowing in the low-pressure inlet. The flow channeling structure arranged axially next to the delivery region and overlaps at least in portions with the delivery region in the radial direction.

In a cylinder rotary compressor, a shaft-side suction passage for circulation of a refrigerant is formed within a shaft that rotatably supports a rotor. A rotor-side suction passage is provided within the rotor so as to guide the refrigerant flowing out of shaft-side outlets formed at the outer peripheral surface of the shaft to a compression chamber. Furthermore, a rotor-side concave portion is formed at an inner peripheral surface of the rotor. A space provided within the rotor-side concave portion forms a rotor-side communication space with an appropriate shape and a capacity enough to make the shaft-side outlets communicate with a rotor-side inlet of the rotor-side suction passage, regardless of the rotation of the rotor.

A vane pump includes: a rotor configured to rotate under rotational force from a rotary shaft while supporting multiple vanes and including a curved surface portion with an arc shape centered on the rotary shaft and a rotor recess depressed from the curved surface portion toward a rotation center; a cam ring disposed so as to surround the rotor and including an inner peripheral surface facing the curved surface portion of the rotor; and an inner plate disposed on one end of the cam ring in an axial direction of the rotary shaft so as to cover an opening of the cam ring and including a suction inner recess depressed toward the rotation center relative to the curved surface portion of the rotor.

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 vane pump that includes a first communication passage that extends along an outer periphery of the cam ring and that guides a fluid that has not flowed into the first suction port from the first inflow passage to the second suction port; a second communication passage that extends along the outer periphery of the cam ring on an opposite side of the first communication passage with respect to the rotor and that guides a fluid that has not flowed into the second suction port from the second inflow passage to the first suction port; and a rectifying portion that guides the fluid from the second inflow passage so that the fluid flows into the second suction port along the outer periphery of the cam ring.

An impeller pump having a housing, which has an inlet and an outlet, and having an impeller wheel with a plurality of elastic impeller blades is described. The cross section of the inlet and/or of the outlet is substantially in the shape of a polygon on the side facing the housing interior.

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.