Provided is a two-shaft rotary pump which is capable of improving reliability and operation efficiency by preventing an exhaust gas from flowing backward into a pump as much as possible, preventing the interior of the pump form being excessively compressed as much as possible, and suppressing temperature rise in the pump. A two-shaft rotary pump in which two rotating shafts (20, 20) provided with rotors (30, 30) are supported by bearings, such that the two rotors (30, 30) are rotated in a noncontact manner with a small clearance kept therebetween and the two rotors (30, 30) are rotated in a noncontact manner with a small clearance between an inner surface of a cylinder (50) and the two rotors, and a gas sucked into the cylinder (50) and compressed is discharged from the cylinder (50), wherein an escape hole capable of letting a part of the compressed gas escape is provided in at least one of end wall portions (52) constituting both ends of the cylinder (50) and opened in the axial direction of the rotating shafts (20, 20).

A multistage pump body comprises a first pumping chamber (20) and a second pumping chamber (21). A connecting duct (26a) puts an outlet (27) of the first pumping chamber (20) into communication with an inlet (28) of the second pumping chamber (21). A leak-tight conduit (40) is provided for the circulation of a cooling liquid. The connecting duct (26a) is a lateral duct of the multistage pump body. A heat-conducting wall (33) partially delimits the connecting duct (26a) and has an external surface (34) on the outside. At least a portion of the connecting duct (26a) passes between this external surface (34) of the heat-conducting wall (33) and the leak-tight conduit (40).

A claw pump includes: a housing; two rotating shafts which are disposed parallel; a pair of rotors respectively fixed to the two rotating shafts; a rotary drive device driving the pair of rotors; and a suction port and discharge ports formed in a partition wall of the housing. The discharge ports are constituted by a first discharge port and a second discharge port. The first discharge port is formed at a position that communicates with an initial stage compression space formed at an initial stage of a compression stroke in a compression space that is formed by joining a first pocket and a second pocket. The claw pump includes an opening/closing mechanism which opens the first discharge port when a pressure of the initial stage compression space reaches a threshold and closes the first discharge port when the pressure does not reach the threshold.

A claw pump includes: a housing; two rotating shafts which are disposed parallel; a pair of rotors respectively fixed to the two rotating shafts; a rotary drive device driving the pair of rotors; and a suction port and discharge ports formed in a partition wall of the housing. The discharge ports are constituted by a first discharge port and a second discharge port. The first discharge port is formed at a position that communicates with an initial stage compression space formed at an initial stage of a compression stroke in a compression space that is formed by joining a first pocket and a second pocket. The claw pump includes an opening/closing mechanism which opens the first discharge port when a pressure of the initial stage compression space reaches a threshold and closes the first discharge port when the pressure does not reach the threshold.

A supercharger assembly comprises a housing, a shaft bore in the housing, a shaft extending into the shaft bore, wherein the shaft comprises an axis, and a bearing assembly located between the shaft bore and the shaft. The bearing assembly comprises an outer ring. The outer ring comprises an outer face. A grease is located between the outer face of the outer ring and the shaft bore. The grease has a viscosity greater than International Standards Organization Viscosity Grade 100.

A multi-stage vacuum pump comprising: first and second half-shell stator components defining a plurality of pumping chambers and for assembly together along respective longitudinally extending faces; first and second end stator components for assembly at respective longitudinal end faces of the first and second half-shell stator components; gaskets for sealing between the first and second half-shell stator components when assembled together at the longitudinally extending faces; and O-rings for sealing between the first and second end stator components and the first and second half-shell stator components when assembled; wherein annular channels intersect longitudinal recesses and each longitudinal recess comprises a stop fixed relative to the intersection, and the gasket and the longitudinal recess are configured that when the gasket is located in the recess during assembly the gasket is biased against the stop for locating an end portion of the gasket relative to the intersection.

A rotary piston compressor/pump/blower includes a housing spatially limiting a working chamber, an intake connection for guiding fluid into the working chamber, a pressure connection for guiding the fluid out of the working chamber, and a rotor assembly having a first rotor rotatably arranged in a first working sub-chamber and a second rotor cooperating with the first rotor and rotatably arranged in a second working sub-chamber. The rotary piston compressor/pump/blower also includes a ventilation channel, formed in the housing and connected to the working chamber via a ventilation channel opening, for the temporally limited introducing of air into the working chamber, wherein the ventilation channel opening is open at least in sections, in particular completely open, in a compression phase.

In a pump chamber (12), a male rotor (20) having claw portions and a female rotor (24) having recesses into which the claw portions enter are secured to rotating shafts (18a and 18b), respectively. The female rotor is provided with hollows on an upstream side in the rotational direction of the female rotor relative to a plane L containing the rotating shafts. For the hollows, the disposed position, size and configuration are selected so that a compression pocket P and a discharge opening remain in communication with each other through the hollow throughout the time from when the compression pocket stops communicating with the discharge opening and separates from the discharge opening until the compression pocket gradually reduces to disappear, and so that the hollow stops communicating with the discharge opening at the same time as the compression pocket disappears.

A pump shaft (10; 12) and a pump member (16; 18) mountable on the shaft for rotation with the shaft have respective contact surfaces that contact when the pump member is mounted on the shaft. At least one of the contact surfaces is formed such that corrosion products of the surface are substantially incompatible with the other contact surface so that joining of the shaft and pump member at the contact surfaces by corrosion is substantially prevented. The pump shaft and pump member may be parts of a dry pump.

The present disclosure relates to vacuum pump 10 comprising a substantially hermetically sealed enclosure 40, a core pump assembly located within the enclosure 40, and an inert purge gas inlet 70 fluidly connected to the enclosure 40 for supplying inert purge gas to an interior of the enclosure 40 surrounding the core pump assembly. By providing a sealed enclosure 40 around the core pump assembly and supplying inert purge gas thereto via the inlet 70, an inert positive pressure can be applied to the core pump assembly that reduces leakage of process gas from the core pump assembly such that seals therein can be removed or reduced. In particular, the need for elastomer seals that may be expensive and not be suited to high temperature or corrosive process gas conditions can be removed.