Abstract: An axial-flow molecular pump has a first active magnetic bearing for axially supporting and controlling a pump member comprised of a set of permanent magnets on the upper end of the pump member cooperating with a set of permanent magnets fixedly mounted at the upper end of a pump housing, a first electromagnet coacting with the sets of permanent magnets and operative when energized for controlling the axial position of the pump member, and an axial sensor for detecting axial displacement of the pump member and accordingly controlling the energization of the first electromagnet. A second active magnetic bearing for radially supporting and controlling the pump member comprises a second electromagnet operative when energized for controlling the radial position of the pump member, and a radial sensor for detecting radial displacement of the pump member and accordingly controlling the energization of the second electromagnet.

Abstract: A multistage discharge type rotary vacuum pump comprises a rotor rotably mounted within a cylinder chamber and dividing the cylinder chamber into first stage and second stage working chambers. A plurality of radially extending vanes are slidably mounted in the rotor in angularly spaced relation, and the vanes undergo radial sliding movement during rotation of the rotor such that the vane tips maintain sliding contact with the cylinder chamber. Each working chamber has an inlet port at the upstream side thereof for admitting exhaust gas evacuated from a confined space during use of the pump, and an outlet port at the downstream side thereof for discharging the exhaust gas which has been compressed in the working chamber in response to rotation of the rotor. The outlet port of the first stage working chamber communicates through a discharge valve with a storage chamber, and the storage chamber communicates through a pressure-responsive discharge valve with the inlet port of the second stage working chamber.

Abstract: A refrigerator comprising a piston which is driven in a reciprocating fashion within a cylinder by the difference in pressure of working gas alternately supplied to first and second variable-volume chambers separated by said piston, a motor, a rotary valve which is attached to an output shaft of said motor and which switches a passageway for said working gas provided between said first and second variable-volume chambers alternately to a high-pressure supply side and low-pressure return side, and at the same time blocks said passageway, and a cam which is mounted on an output shaft of said motor and which guides the reciprocation of said piston in accordance with the motion of said rotary valve connected to said piston rod.

Abstract: A rotor armature assembly for an electromagnetic radial bearing for use in high rotational speed applications comprises a rotor armature fixedly connected to a rotor shaft. The rotor armature is formed of a plurality of annular magnetic plates each comprised of soft magnetic material, and a plurality of annular reinforcing plates each comprised of material having greater tensile strength than the soft magnetic material. The reinforcing plates are interposed between the magnetic plates and all of the plates are axially urged together so that adjoining plates are in frictional engagement with each other to form a laminated plate structure. The reinforcing plates frictionally restrain radial outward deformation of the magnetic plates due to centrifugal force during high speed rotation of the rotor armature assembly.

Abstract: A piezoelectric resonator element having supporting lead members projecting in opposite directions therefrom is positioned in a tubular dielectric case having tubular metal cap members affixed at opposite ends thereof and extruding beyond the ends of the case. Inner end portions of the cap members are hermetically sealed to the case. Intermediate portions of the cap members beyond the ends of the case are compressed onto end portions of the lead members to secure the resonator element in position in the case and to make electrical contact between the lead members and the metal cap members. End portions of the cap members beyond the ends of the lead members are compressed to seal the case, the sealing being effected in a vacuum so as to evacuate the interior of the case. In order further to seal the case, the outer ends of the cap members may be welded or soldered.