Patent ID: 8585793

Claim:
A recirculation filter comprising: a. a first polymeric support layer of support material comprising fibers and a second polymeric support layer of support material comprising fibers; and, b. a fibrous layer disposed between the first polymeric support layer and the second polymeric support layer, wherein said first and second polymeric support layers are located adjacent to said fibrous layer, and wherein each of said first polymeric support layer and said second polymeric support layer is bonded through the thickness of the layer to restrict protrusion of said fibers of said first and second polymeric support layers, the bonding being continuous to define a plurality of closed cells, such that the longest span of unbonded support material between bond sites is less than a critical fiber length of said fibers, said critical fiber length being a length of fibers which if not inhibited from protruding from a surface of the recirculation filter would cause undesirable results, and wherein the first and second polymeric support layers have a bond at the perimeter of the recirculation filter.