US Patent 7493770 Methods and apparatus for regulating airflow supply systems

A check valve is provided that includes a valve housing that has a side wall and a flow path therethrough, the side wall defining the flow path. The flow path includes an inlet, an outlet, and a centerline extending between the inlet and the outlet. At least one control member is positioned in the flow path and movable between a first position, wherein fluid flow through the valve housing is substantially prohibited and a second position wherein fluid flow is permitted. The side wall includes a stop configured to limit movement of the at least one control member at a pre-determined stop angle relative to the flow path centerline.