Patent ID: 8088190

Claim:
An axial flow unitary filter element for filtering a gaseous fluid stream, said filter element comprising: a primary filter portion having an inlet face and an outlet face, said primary filter portion having a wound filter media including a plurality of closed end channels, a first group of said closed end channels opening to said inlet face and a second group of said channels opening to said outlet face; and a pre-separation filter portion, said pre-separation filter portion having an inlet face and an outlet face, said pre-separation filter portion permanently secured and fully peripherally sealed about its peripheral portions to said primary filter such that said gaseous stream entering said inlet face of said primary filter portion must first pass through said pre-separation filter portion of said filter element; wherein said pre-separation filter portion has a pre-separation filter media having larger pores than said primary filter portion so as to remove larger particles in said gaseous stream before reaching said primary filter portion; and wherein said portions of said filter element are permanently integrated such that said portions form said unitary filter element; wherein said primary filter portion further includes an elastomeric or resilient seal collar positioned at, extending circumferentially around and extending axially outwardly from said inlet face of said primary filter portion; wherein said seal collar has a radially inwardly facing interior portion of the sealing collar positioned axially outwardly beyond said inlet face of said primary filter portion; wherein said pre-separation filter portion is received within said seal collar onto said inlet face of said primary filter portion, said pre-separation filter portion completely covering said inlet face of said primary filter portion; wherein said pre-separation filter portion is adhesively secured and completely sealed about its periphery portions onto said interior portion of said seal collar.