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:
Mar. 02, 1993
Filed:
Apr. 08, 1991
Minoru Taniyama, Ibaraki, JP;
Masahiro Mase, Tochigi, JP;
Kazuaki Nakamori, Ibaraki, JP;
Takashi Nagaoka, Tsukuba, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A vacuum pump of the present invention comprises a housing including a suction port and an exhaust port, a stator fixed in the housing, a rotor rotatably supported in the housing, and a cooling jacket provided adjacent to the stator. Gas suctioned from the suction port and having a pressure substantially equal to or close to the atmospheric pressure is exhausted from the exhaust port. A cooling fluid having a thermal conductivity less than that of water, for example, of 0.08 to 0.25 Kcal/m.h..degree.C. flows through the cooling jacket. When the gas contains aluminum chloride, the cooling fluid flows into the cooling jacket in such a manner that the temperature inside a gas conduit is maintained to be higher than the sublimation temperature of aluminum chloride. Lubrication oil may be supplied as the cooling fluid to the cooling jacket from the same supply line as lubrication oil supplied to oil lubricating bearings provided below a pump mechanism unit. A closed-loop line may be comprised of the cooling jacket, a tank, the supply line, and a return line, to thereby circulate the cooling fluid by a pump.