Patent ID: 6110260
Filing Date: 2000-08-29
Classification: B01D

Abstract:
A filter for filtering particulate contaminants from an air stream, comprising:(a) a filter media for filtering the particulate contaminants from the air stream, said filter media having a first major surface and a second major surface for air flow through said filter media from said first major surface to said second major surface;(b) an air impervious indicator patch having a first major surface and a second major surface, a periphery and a center; and(c) means adapted to support said indicator patch at a desired location adjacent a portion of one of said first major surface or second major surface of said filter media;(d) wherein said indicator patch is adapted to impede the air flow through said filter media and divert the air stream so that contaminants are progressively accumulated in said filter media from said periphery towards said center of said air impervious indicator patch as an indication of use of the filter.