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:
Dec. 12, 1989
Filed:
Sep. 09, 1988
Applicant:
Inventors:
Assignee:
Firma Carl Freudenberg, Weinheim/Bergstr., DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B03C / ; G11C / ;
U.S. Cl.
CPC ...
55156 ; 55482 ; 55487 ; 55DI / ; 55307 ; 55400 ;
Abstract
A multilayer filter pack includes at least three adjacent layers of fibrous material, each of which is permanently electrically charged and not more than 10 mm thick. The upstream and middle layers are formed from fibers having a fiber diameter that decreases from layer to layer in the direction of flow and are arranged at a packing density that increases from layer to layer in the direction of flow. The third layer has a fiber diameter and packing density that is approximately equal to the fiber diameter and packing density of the first layer. The multilayer filter pack is particularly well suited for use in air-purifying systems and breath protection filters.