Abstract: The invention relates to a blocking and/or restricting valve having a valve housing which has a fluid system having a fluid inlet, a fluid outlet and a fluid chamber arranged therebetween, wherein the fluid chamber comprises a blocking geometry and is bounded by a barrier membrane with respect to the blocking geometry, wherein the barrier membrane is connected to a tappet on its side remote from the fluid chamber (8) such that it can be pressed toward the blocking geometry by a movement of the tappet and can be lifted thereby, and wherein the tappet is arranged in a freely floating manner in a hollow space of the valve housing.