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. 12, 1993
Filed:
May. 23, 1991
Thomas Abelen, Cologne, DE;
Lutz Arndt, Troisdorf, DE;
Winfried Kaiser, Cologne, DE;
Peter Muller, Cologne, DE;
Dieter Vorberg, Erftstadt, DE;
Leybold Aktiengesellschaft, Hanau, DE;
Abstract
A two-stage rotary vane vacuum pump includes a pre-vacuum stage having a pre-vacuum pumping chamber and an outlet valve; a main oil sump; and a first oil conduit having a first opening communicating with the main oil sump and a second opening communicating with the pre-vacuum pumping chamber. The first opening is located at a level below an operational oil level in the main oil sump. There is further provided an intermediate oil sump situated at a level above the outlet valve and being arranged for receiving oil from the pre-vacuum pumping chamber; and a second oil conduit leading from the intermediate oil sump to components of the vacuum pump to be supplied with oil. All such components are situated at a level below the intermediate oil sump.