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:
Aug. 14, 1990
Filed:
Dec. 22, 1988
Applicant:
Inventors:
Yoshiharu Okumura, Otsu, JP;
Katsutoshi Ando, Otsu, JP;
Assignee:
Toray Industries, Inc., Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B01D / ;
U.S. Cl.
CPC ...
210748 ; 210243 ; 210491 ; 204186 ; 204188 ;
Abstract
A method for filtering liquids having a dielectric constant less than 10 is disclosed. The method includes the step of filtering a liquid through a porous layer of an electret, the electret consisting of a fibrous sheet having a surface charge density of at least 5.times.10.sup.-11 coulombs/cm.sup.2, wherein on the upstream side of the electret is laminated another porous layer having at least a porosity or an average fiber diameter greater than that of the electret layer. The upstream layer may consist of either a fibrous electret layer, or an uncharged fibrous layer.