Patent ID: 8292984

Claim:
An air filter cartridge comprising: (a) a media pack surrounding an open interior and including media having first and second, opposite, ends; (b) a first end cap positioned at the first end of the media pack; (i) the first end cap having a central air flow aperture therethrough; (c) a housing seal arrangement on the first end cap; (i) the housing seal arrangement surrounding the central air flow aperture and defining an inwardly directed radial seal; (d) a second end cap on the second end of the media; (i) the second end cap including a first projection thereon extending in direction away from the first end cap to a location not surrounded by media of the media pack; (ii) the first projection comprising a continuous serpentine wall having a radially inner surface and a radially outer surface; and, surrounding an interior surface; (iii) the radially inner surface of the serpentine wall having eight inwardly convex sections and eight inwardly concave sections alternating with one another; and, (iv) the radially outer surface of the serpentine wall having eight outwardly convex sections and eight outwardly concave sections alternating with one another; and, (e) a plurality of spaced projections positioned adjacent the outer perimeter of the second end cap; (i) each one of the spaced projections being at least 10 mm long; and, (ii) each one of the spaced projections extending in a direction away from the media and the second end cap.