Methods of assembling a filter

A method of making a filter comprising laying over and arranging a plurality of pleats including a filter medium into a cylindrical configuration to form a filter element having axially extending pleats, including intimately contacting a first surface of a first leg of one pleat with the first surface of an adjoining leg of said one pleat and a second surface of said first leg with the second surface of an adjoining leg of an adjacent pleat over a substantial portion of the height of the first leg and over a continuous region extending for at least approximately 50% of the axial length of the filter element, and sealing at least a first end of the filter element to prevent axial flow along the pleats at the first end.

A method of making a filter comprising forming a composite including a filter medium and a drainage layer, corrugating the composite to form a plurality of pleats, arranging the plurality of pleats into a cylindrical configuration, laying the pleats over, intimately contacting a first surface of a first leg of each of the plurality of pleats with the first surface of an adjoining leg of said pleat and a second surface of said firs leg with the second surface of an adjoining leg of an adjacent pleat over a substantial portion of the height of the first leg and over a continuous region extending for at least approximately 95% of the axial length of the pleats to form a filter element, and sealing at least a first end of the filter element to prevent axial flow along the pleats at the first end.

A method of making a filter comprising forming a composite including an upstream drainage layer, a downstream drainage layer, and a filter medium disposed between the upstream and downstream drainage layers, corrugating the composite to form a plurality of pleats, arranging the plurality of pleats into a cylindrical laid-over configuration to form a filter element having axially extending pleats, including intimately contacting a first surface of a first leg of each pleat in the filter element with the first surface of an adjoining leg of said pleat and a second surface of said first leg with the second surface of an adjoining leg of an adjacent pleat over substantially the entire height of the first leg and over a continuous region extending for at least approximately 50% of the axial length of the filter element, and sealing at least a first end of the filter element, and sealing at least a first end of the filter element to prevent axial flow along the pleats at the first end.

A method of making a filter comprising arranging a plurality of pleats to form a filter element wherein the height of each pleat is greater than (D-d)/2, D being the outer diameter at the crest of the pleat and d being the inner diameter at the root of the pleat, including intimately contacting a first surface of a first leg of one pleat with the first surface of an adjoining leg of said one pleat and a second surface of said first leg with the second surface of an adjoining leg of an adjacent pleat over a substantial portion of the height of the first leg and over a continuous region extending for at least approximately 50% of the axial length of the pleats of the filter element, and sealing at least a first end of the filter element to prevent axial flow along the pleats at the first end.