US Patent 7581560 Check valve

A check valve includes a housing with an inlet opening and an outlet opening along with a cage-like insert disposed therein as a support for a spring element and for guiding a closing body which can be moved against the spring element and which can be moved between a first end position, in which the spring body lies in contact with a seat to form a seal, and a second end position, in which the valve is completely open. The closing body, which is constructed cylindrically and pot-like, is guided with its cylindrical casing surface at the cage-like insert and in contact with the seat with a flat outer surface.