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:
Nov. 05, 1996
Filed:
Feb. 09, 1996
Applicant:
Inventors:
Rossella Silvani, Milan, IT;
Valerio Carsetti, Milan, IT;
Casimiro Pace, Alessandria, IT;
Padmanabhan Srinivasan, Milan, IT;
Assignee:
Ausimont S.p.A., , IT;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C10M / ;
U.S. Cl.
CPC ...
508582 ; 508588 ; 508589 ; 252 67 ; 252 69 ;
Abstract
The invention relates to a process for reducing the back migration of the most volatile fractions of perfluoropolyethers during the operation of mechanical vaccum-generating pumps which utilize perfluoropolyethers: use is made of perfluoropolyethers containing not more than 0.1% by weight of fractions having a molecular weight lower than or equal to 1,500 and not more than 1.3% by weight of fractions having a molecular weight lower than or equal to 1,800.