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, 1999
Filed:
Jul. 11, 1996
Larry R Nepsund, Savage, MN (US);
Kathleen A Abrahamson, Prior Lake, MN (US);
Thomas A Boeckermann, Lakeville, MN (US);
James K Elfstrand, Mounds View, MN (US);
Donaldson Company, Inc., Minneapolis, MN (US);
Abstract
A filter arrangement is provided. The filter arrangement generally includes an air filter having an upstream surface with a prefilter positioned thereon. The prefilter preferably includes at least two layers of depth media. In preferred systems, the prefilter includes two layers of depth media secured to one another by stitching. In certain preferred arrangements disclosed, the prefilter includes an upstream layer of fibrous depth media and a downstream layer of foam depth media, with the two layers stitched to one another along peripheral edges. The invention also concerns provision of prefilters, and also air filter arrangements which include housings having air filters with prefilters according to the present invention operably positioned therein. Methods of construction and use are also provided.