Patent attributes
A unidirectional valve, wherein the valve comprises a valve body including a frame, a valve opening through the frame, and a valve seat extending from the frame and at least partially surrounding the valve opening. The valve further includes a valve flap having a first portion attached to the frame and an adjacent second portion free to move from a first position where the second portion is in contact with at least a part of the valve seat to a second position where at least part of the second portion is spaced from the valve seat, wherein the valve flap has a contour profile. The contoured profile may be along the length of the valve flap, between the point of attachment of the flap to the frame and the flap end, or from one flap side edge to a second side edge.
