Abstract: A closing body (3) which is mounted in a housing (2) in such a way that it can be axially displaced and can be pressed out of an opening position against a valve seat (4) into a closing position. The closing body (3) is rotationally symmetrical and includes, on its outer diameter (D1) in relation to its cross-section, two outer wall sections (5, 5?) which meet at an angle of less than 180°. In this way, a surrounding interference edge (26) is formed, favouring turbulence in the flow and thus a rapid increase in the dynamic pressure. When the closing body is embodied as a hollow body, a spring action also occurs, damping the closing movement.