Patent ID: 6957816

Claim:
A knife gate valve having a knife gate movable within a housing to effect opening and closing of said valve, said knife gate having oppositely facing surfaces oriented transversely to an axial direction defining flow through said valve, said knife gate valve comprising: a flexible, resilient loop mounted within said housing adjacent to said knife gate, said loop comprising: a sealing lobe extending around said loop, said sealing lobe having a deformable sealing surface facing in said axial direction and being engageable with one of said knife gate surfaces to effect a fluid tight seal when said one surface is moved into engagement with said sealing lobe to close said valve; a first channel extending around said loop and positioned opposite to said sealing lobe, said first channel facing in said axial direction away from said sealing lobe; and a second channel extending around said loop and positioned contiguous to said sealing lobe, said second channel facing inwardly of said housing.