Patent ID: 7794556

Claim:
A method for making a filter, comprising: forming a plurality of sheets of filter media, each sheet of filter media having an inlet end and an outlet end, wherein each of the plurality of sheets of filter media are formed by the steps of: thermoforming a first layer of filtration media to have a plurality of channels, the first layer having an upper surface and a lower surface; sonically welding a portion of a second layer of filtration media to the first layer of filtration media after the first layer is thermoformed to form the sheet of filtration media, wherein at least one edge of the first layer is not sonically welded to at least one edge of the second layer, wherein the sheet of filtration media has a plurality of fluid channels each having an inlet opening at the at least one edge of the first layer and the second layer and a sealed end at another end of the sheet; and securing the plurality of sheets together by applying a strip of adhesive between each upper surface of each first layer facing the second layer of another sheet of filter media stacked upon the upper surface of the first layer of the filtration media.