Patent ID: 7997425

Claim:
A fluted filter media construction comprising: (a) a fluted sheet of filter media comprising a wave pattern of ridges and troughs; (b) a facing sheet of filter media adhered to the fluted sheet and wherein the fluted sheet and the facing sheet form a plurality of flutes extending there between; (c) sealant provided between the fluted sheet and the facing sheet; (d) the plurality of flutes extending between the fluted sheet and the facing sheet comprises a center indented fold pattern that seals the plurality of flutes to the passage of unfiltered air, the center indented fold pattern comprising an indent in each flute, to be closed, at or near an apex of each flute that forms an indented flute portion and a pair of ridges comprising a first ridge and a second ridge, at least one of the first ridge or the second ridge comprising a fold in a direction toward the facing sheet, the center indented fold pattern comprising a flat first layer resulting from the indented flute portion secured to the facing sheet, and a second layer pressed against the flat first layer, the second layer comprising the at least one of the first ridge or the second ridge folded against the flat first layer.