Patent ID: 8475556

Claim:
A filter cartridge assembly for installation into an air filter housing having an inlet connection for unfiltered air and an outlet connection for filter air, the first filter cartridge assembly comprising: a main filter cartridge comprising: a substantially rigid support tube having an axially extending sidewall with airflow apertures therethrough, said sidewall defining an axially aligned open interior therein; a filter media arranged on, surrounding and secured onto said outside surface of said support tube; an annular end cap having an open aperture in air flow communication with said open interior, said end cap secured to a first axial end of said support tube sidewall and/or said filter media; a closed end cap secured to an opposing second axial end of said support tube sidewall, said closed end cap including a centrally arranged axially outwardly extending dome member arranged in said closed end cap; an anti-rotation engagement housing member arranged on an outward facing surface of said dome member and extending axially outwardly therefrom, said anti-rotation engagement member having a radially elongated or polygonal radial cross section configured to be received into and rotationally lock to a complimentary anti-rotation opening in said filter housing; a plurality of arcuate axially extending projections on an outward facing surface of said closed end cap encircling said dome member with circumferential gaps between said projections, said projections each having pre-defined keying characteristrics including a pre-defined and arc length, wherein different ones of said arcuate axially extending projections can have different arc lengths; a pre-defined projection length measured axially relative to said outward facing surface, wherein different ones of said arcuate axially extending projections can have different projection lengths; a pre-defined arcuate projection width, wherein different ones of said arcuate projections can have different projection widths; a pre-defined gap spacing between adjacent arcuate projections, wherein different pairs of said arcuate projections can have different gap spacings; a pre-defined number of said arcuate projections on said closed end cap; wherein said pre-defined characteristics key particular intended type of said filter cartridges for use in filter housing where said filter cartridge type is intended, wherein said pre-defined characteristics are operable to prevent accidental use of a non-intended type of said filter cartridge; a continuous annular elastomeric seal arranged radially between said plurality of arcuate axially extending projections and said dome member and projecting axially outwardly from said closed end cap, said annular seal configured to radially seal against the outward facing surface of an annular sealing projection.