Abstract: Since a peripheral-flow pump according to the present invention has a peripheral-flow impeller having a cylindrical staircase shape whose outer diameter increases in one direction only like a staircase, a stator, which conventionally has been of a complicated configuration composed of two pieces, can be formed into an integral molding without any deterioration in pump performance. Accordingly, the production of pumps is facilitated.

Abstract: According to the turbo molecular pump of the present invention, a regenerative pump is constructed by arcuate eddy current grooves having a predetermined angle with respect to the surface of the outer periphery of a rotor and which are circumferentially engraved in array in the rotor and an arcuate ventilating channel engraved in the circumferential direction in a stator, and a partition is defined in the stator circumferentially partitioning the ventilating channel, so that the working range on the low vacuum side may be extended.

Abstract: A turbomolecular pump for evacuating a space by a plurality of turbine grooves located on a rotor and a stator located in face-to-face relationship to the rotor, with the turbine grooves, including rotor grooves on an outer peripheral surface of a rotor extending peripherally at a predetermined angle with respect to the axis of the rotor, and stator grooves on a surface of a stator facing the rotor which extend at the same angle as the rotor grooves but are oriented in an opposite direction to the rotor grooves. The rotor grooves and stator grooves overlap in part as viewed axially of the rotor. A pumping action is performed by surfaces of blades of an axial flow turbomolecular pump and a pumping action is performed by the rotor and the bottom surface of the groove of a helical groove turbomolecular pump, whereby a high compression ratio and a high gas discharge or evacuation speed can be achieved.

Abstract: A turbomolecular pump including a casing stationary blades arranged in a plurality of stages in the casing axially thereof, rotating blades arranged between the stationary blades and located on an outer periphery of a rotor located in a central portion of the casing, and a bearing device journaling the rotor at its high vacuum and end a low vacuum end. A first permanent magnet of the fixed side having a high Curie point and a second permanent magnet of the rotor side located in juxtaposed relation to the first permanent magnet constitute a magnetic bearing of an attraction type for journaling the rotor at its high vacuum end. A pivot type hydrodynamic bearing or active magnetic bearings journal the rotor at its low vacuum end.