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, 2010
Filed:
Apr. 20, 2005
Pascal Durand, La Balme de Sillingy, FR;
Jean-françois Vuillermoz, Annecy le Vieux, FR;
Patrick Pilotti, Cran-Gevrier, FR;
Jean-françois Grosdaillon, Mures, FR;
Pascal Durand, La Balme de Sillingy, FR;
Jean-François Vuillermoz, Annecy le Vieux, FR;
Patrick Pilotti, Cran-Gevrier, FR;
Jean-François Grosdaillon, Mures, FR;
ALCATEL, Paris, FR;
Abstract
The present invention provides a multistage vacuum pump comprising at least a low pressure first stage and at least a high pressure second stage. At least one of the stages has at least one suction inlet for admitting gas to be pumped, and at least one of the stages has at least one delivery outlet that is open to the outside for exhausting pumped gas. The first and second stages communicate with each other in order to pass gas from the first stage to the second stage. The first stage operates at a flow rate that is smaller than that of the second stage. For an oil-seal rotary vane positive-displacement pump, the oil is injected into the stage having the greater flow rate.