Abstract: A screw pump includes a casing having inlet and outlet ports and a pump rotor rotatably mounted in the casing and having screw threads communicating with said inlet and outlet ports. The pump rotor is rotated by a reversible speed-controllable motor, typically a DC brushless motor, mounted in the casing to deliver a liquid such as a chemical solution from the inlet port through a liquid passage defined by the screw threads to the outlet port.

Abstract: A turbomolecular pump evacuates gas in an apparatus (or a chamber) by means of a rotor having blades and/or spiral grooves which rotates at a high speed. The turbomolecular pump includes a casing housing a rotor and a stator therein, a pumping section comprising the rotor and the stator, a valve element capable of opening or closing an intake port of the casing, and a supporting member for supporting the valve element. The supporting member extends through at least one of the rotor and the stator. The turbomolecular pump further includes an actuating mechanism for actuating the valve element, and the actuating mechanism is provided at a side opposite to the intake port with respect to the rotor.

Abstract: A magnetic bearing unit is disclosed which comprises a rotor supported in a radial direction by magnetic effects generated by permanent magnets arranged within a passive radial magnetic bearing and supported in an axial direction by an actively-controlled axial magnetic bearing. The unit also comprises a movable member arranged between the stator and rotor, and the passive magnetic member is arranged between the movable member and the rotor. At least first and second pairs of axially opposing faces are provided on the stator and the movable member respectively. A biasing means is in functional association with the movable member for forcing the movable member to shorten a spacing between the first pair of opposing faces. The first pair of opposing faces is formed with a recess having a curved cross sectional shape on each of the opposing faces, and a plurality of balls having a radius not more than a radius of the recess are disposed in the recess.

Abstract: A vacuum pumping apparatus is presented having a Peltier element based device to provide a dual role of cooling for bearings/drive-motor and heating for sections prone to depositing reaction products. A housing (7) having the bearing and motor sections is provided with a Peltier element based device (20) to absorb the waste heat generated in the bearings and the drive motor, and transfer the waste heat to another section (17) of the apparatus to be released. The released heat may be used to heat that section of the device to facilitate vacuum processing, wherein reaction products are prone to sublime and deposit.

Abstract: A displacement sensing circuit for sensing a displacement of a measured object without any contact with the measured object. A detecting coil is disposed relative to the measured object to be capable of changing its inductance in response to a displacement of the measured object from a predetermined position. An output signal from the detecting coil is passed through a band-pass filter. The filter has a frequency band width which is equal to at least twice the upper limit of a response frequency of the sensing circuit, thereby outputting a signal less influenced by a noise. An output from the band-pass filter is detected to provide a signal corresponding to the displacement of the measured object.