Abstract: A filter cartridge comprising an elongated sheet of porous filter material folded into an array of primary pleats is further folded to define secondary pleats which are tucked between the primary pleats. The secondary pleats define tapered portions at the top and bottom of the filter media, thereby reducing the width of the pleats at the top and bottom thereof to a width less than the primary width of the pleats, to thereby minimize the amount of sealant required to seal the ends of the pleats. The secondary pleats also resist radial and circumferential collapse of the pleats during filtering.

Abstract: The end caps of a filter element are formed on the element by dispensing a photo-initiated polymer in a transparent mold, setting the end of the filter media array in the mold, exposing the mold to ultraviolet light for a time sufficient to cure the polymer, and then stripping the mold from the finished end cap. Accordingly, the time of 60-75 seconds required to cure prior art Plastisol end caps is reduced to a few seconds necessary to cure the end caps made from the photo-initiated polymer. The end caps have been designed with reinforcing ribs to minimize the amount of polymer required while still maintaining necessary hoop strength to retain the media in place.

Abstract: A liquid filter includes a housing having a pressure chamber portion in which a filtering media is carried and a support engaging portion which attaches the housing to the engine upon which the filter is mounted. The support engaging portion includes a radially projecting section which mounts the usual gasket which effects a seal between the housing and a sealing surface on the engine. The radially projecting portion cooperates with the portion of the housing containing the filter to define a circumferentially extending groove therebetween, which isolates the gasket from the distorting forces generated in the housing by hydraulic pressure.

Abstract: A liquid filter for an internal combustion engine includes a filter cartridge housed within an outer shell closed by an end member. The end member provides a central outlet opening and circumferentially spaced inlet openings circumscribing the outlet opening and spaced radially therefrom. An annular fixture is mounted on the end closure between the outlet opening and the inlet openings and supports a circumferentially extending seal. The seal includes a central portion which seals between the fixture and the cartridge, and also includes a first radially projecting deflectable portion which prevents drainback of liquid filtrate through the inlet openings upon engine shutoff, and also includes a second deflectable portion which controls bypass flow. The fixture further includes axially projecting members which are engaged by the filter cartridge to hold the latter in fluid-tight engagement with the valve member.