Abstract: A vacuum pump of the present invention comprises a housing including a suction port and an exhaust port, a stator fixed in the housing, a rotor rotatably supported in the housing, and a cooling jacket provided adjacent to the stator. Gas suctioned from the suction port and having a pressure substantially equal to or close to the atmospheric pressure is exhausted from the exhaust port. A cooling fluid having a thermal conductivity less than that of water, for example, of 0.08 to 0.25 Kcal/m.h..degree.C. flows through the cooling jacket. When the gas contains aluminum chloride, the cooling fluid flows into the cooling jacket in such a manner that the temperature inside a gas conduit is maintained to be higher than the sublimation temperature of aluminum chloride. Lubrication oil may be supplied as the cooling fluid to the cooling jacket from the same supply line as lubrication oil supplied to oil lubricating bearings provided below a pump mechanism unit.

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.