초록 ▼

Disclosed is a change indicator for a filter for use in a gaseous circulation system, such as a forced air heating and cooling system. The change indicator includes an air impervious patch that is secured to the filter. The portion of the filter media adjacent to the change indicator changes appeara

Disclosed is a change indicator for a filter for use in a gaseous circulation system, such as a forced air heating and cooling system. The change indicator includes an air impervious patch that is secured to the filter. The portion of the filter media adjacent to the change indicator changes appearance in response to the accumulation of contaminants at a much slower rate than the remainder of the air filter. The accumulation of contaminants progresses inwardly from the region adjacent the periphery of the change indicator towards the region adjacent to the center. Once the appearance of the filter media beneath the change indicator fully changes from periphery to the center, that is an indication that the air filter is in need of cleaning or replacement.

대표청구항 ▼

[ What is claimed is:] [1.] 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 med

[ What is claimed is:] [1.] 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.