Patent ID: 6932923

Claim:
A method of making a porous filter medium adapted for use in an internal combustion engine air filter, the method comprising the steps of: heating a thermoplastic polymer to form a melt; extruding the melt through a plurality of openings in a die head; directing one or more streams of heated fluid toward the melt during extrusion to form a multiplicity of fibers and to blow the fibers toward a collection means, the collection means having a surface that includes a three dimensional profile, wherein at least one profile is removably attached to the surface of the collection means, the at least one profile having at least one fold; collecting the fibers on the surface of the collection means and utilizing the profile to mold the fibers into the porous filter medium, the porous filter medium having at least one fold; removing the at least one profile from the collection means; and removing the porous filter medium from the at least one profile.