Abstract: A method of forming a filter element is disclosed comprising the steps of preparing a plurality of upstanding pleats each having first and second pleat legs, wherein the first pleat leg of one pleat is joined to the second pleat leg of a preceding pleat by a medial pleat section; moving the upstanding pleats into an overlapped condition wherein each medial pleat section becomes part of the second leg of a preceding pleat; and forming the overlapped pleats into a cylindrical configuration.

Abstract: A method of forming a filter element is disclosed comprising the steps of preparing a plurality of upstanding pleats each having first and second pleat legs, wherein the first pleat leg of one pleat is joined to the second pleat leg of a preceding pleat by a medial pleat section; moving the upstanding pleats into an overlapped condition wherein each medial pleat section becomes part of the second leg of a preceding pleat; and forming the overlapped pleats into a cylindrical configuration.

Abstract: A filter assembly is provided which includes an outer filter sleeve formed at least in part by a plurality of pleats, an inner filter sleeve formed at least in part by a plurality of pleats, wherein the inner and outer filter sleeves define a passage therebetween. An inlet cap is secured to a first end of the inner and outer filter sleeves and it has at least one inlet port communicating with the passage, and an end cap is secured to a second end of the inner and outer filter sleeves and it has an end surface closing the passage. Methods of forming such a filter assembly are also provided.