Ebara Corporation

Ebara Densan Ltd.

Shun-ichi Aiyoshizawa

Toshiharu Nakazawa

Matsutaro Miyamoto

Hiroshi Sobukawa

Yoshinori Ojima

Tetsuma Ikegami

Shigekazu Yamamoto

Yutaka Hirakawa

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.

Liquid delivery device, method of controlling such liquid delivery

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. The second pair of opposing faces are bridged with a damping member made of an elastic material. The resulting bearing unit in such a compressive state can be used in any orientation without causing any operational problems such as those encountered when the conventional magnetic bearing is used in a horizontal orientation. The unit is easy to control and produces stable smooth operation in radial and axial directions at all times.

Bearing unit

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.

Vacuum pump apparatus having peltier elements for cooling the motor &

Growing community of inventors

Tokyo, Japan

Shun-ichi Aiyoshizawa