Patent ID: 8545589

Claim:
A filtration media pack comprising: (a) a plurality of layers of single facer media wherein the layers of single facer media comprise a fluted sheet, a facing sheet, and a plurality of flutes extending between the fluted sheet and the facing sheet and having a flute length extending from a first face of the filtration media pack to a second face of the filtration media pack; (b) a first portion of the plurality of flutes being closed to unfiltered fluid flowing into the first portion of the plurality of flutes, and a second portion of the plurality of flutes being closed to unfiltered fluid flowing out of the second portion of the plurality of flutes so that fluid passing into one of the first face or the second face of the media pack and out the other of the first face or the second face of the media pack passes through media to provide filtration of the fluid; (c) the plurality of flutes having an average flute length of less than 5 inches; and (d) the filtration media pack exhibiting a flute density (ρ) of at least 35.0 flute/inch 2 according to the formula: ρ = number ⁢ ⁢ of ⁢ ⁢ channels ⁢ ⁢ ( open ⁢ ⁢ and ⁢ ⁢ ⁢ closed ) 2 × z ⁢ - ⁢ media ⁢ ⁢ pack ⁢ ⁢ cross ⁢ ⁢ sectional ⁢ ⁢ ⁢ area wherein the number of channels is counted and the media cross sectional area is measured; and wherein the fluted sheet comprises a plurality of repeating internal peaks facing toward the facing sheet and repeating external peaks facing away from the facing sheet, said plurality of internal and external peaks comprising sharp contact points with adjacent facing sheets.