Patent ID: 6983851

Claim:
A filter element removably positionable between housing portions, the element including a ring of filtration media circumscribing a central axis and having first and second ends; a first end cap sealingly bonded to the first end of the filtration media, and a second end cap sealingly bonded to the second end of the filtration media; the second end cap including a central opening along the central axis of the filter element; said first end cap also including a central opening along the central axis of the filter element, said central opening of said first end cap having a smaller diameter than said central opening of said second end cap, said central opening of said first end cap bounded by an annular flange integral with said first end cap and projecting axially inward a short distance from said first end cap toward said second end cap and terminating at a point closer to said first end cap than said second end cap, said annular flange spaced radially inward from the ring of filtration media; and a series of distinct protrusions spaced radially outward from said annular flange and radially between said flange and said ring of filtration media, said protrusions permanently fixed to said first end cap and projecting axially inward from said first end cap a short distance from said first end cap toward said second end cap and remaining with the filter element when the filter element is removed from between the housing portions.