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:
Jan. 10, 1995
Filed:
Aug. 10, 1993
Takashi Nagaoka, Tsukuba, JP;
Shinjiro Ueda, Abiko, JP;
Seiji Sakagami, Ibaraki, JP;
Akira Nishiuchi, Ibaraki, JP;
Hirofumi Sakurai, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A turbo vacuum pump has a housing provided with a suction port and a discharge port, an evacuation pump disposed in the housing for compressing a gas sucked through the suction port and discharging the compressed gas through the discharge port, and a motor for driving the evacuation pump, the motor and the evacuation pump having a common rotor. The rotor is supported at its both axial ends by bearings. A spiral grooved dynamic seal is disposed in the vicinity of the suction port and at the opposite side of the suction port to the evacuation pump. The diameter of the spiral grooved dynamic seal, at the smallest, is greater than the outside diameter of the final stage impeller of the evacuation pump.