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:
Oct. 31, 1989
Filed:
Aug. 31, 1987
Todd W Johnson, St. Paul, MN (US);
Corazon C Brizuela, St. Paul, MN (US);
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Abstract
A flexible filter bag, the filter element of which is seamless and avoids prior leakage problems, is made by wrapping a flexible, preferably perforated, filtering fabric and a flexible nonfiltering transport material together onto a cylindrical mandrel to provide a tube. A thin metal ring is fitted into the tube, and the portion of the filtering fabric which extends beyond the edge of the transport material is folded inwardly around the ring to provide a cuff. A sleeve of a length about twice that of the tube is inserted into and pulled over the tube until the free ends of the sleeve are approximately coterminous with the ring-free end of the tube. The free ends of the sleeve and tube are gathered in the manner of a sausage casing and then subjected to pressure to form a seal, but the convolutions of the transport material terminate just short of the seal so as to avoid bunching at the seal.