The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 05, 1999
Filed:
Sep. 02, 1997
Seiji Sakagami, Ibaraki-ken, JP;
Masahiro Mase, Tochigi-ken, JP;
Chiaki Urano, Chiba, JP;
Shinji Koyano, Misato, JP;
Yuichi Kinoshita, Kashiwa, JP;
Takashi Nagaoka, deceased, late of Tsukuba, JP;
Hitachi, Ltd., , JP;
Seiko Seiki Co., Ltd., , JP;
Abstract
A turbo vacuum pump has a rotor and magnetic bearings. The magnetic bearings are held in a housing having a suction port and an exhaust port, and support the rotor rotatably. A peripheral flow pump stage and screw pump stage are formed in the rotor, so that the pressure at the exhaust port can be at or near atmospheric pressure level. Before starting the turbo vacuum pump, the magnetic bearings are operated to displace a rotor position and to scrape off the reaction products which have deposited inside the pump. In addition, before starting the turbo vacuum pump, a stator of the pump is heated up to decrease a binding force of the reaction products. Therefore, the pump can be restarted, even if the rotor has locked by the solidification of deposited reaction products formed during stopping of the pump.