<p>Ventilating system comprises a sealing element which can be inserted into a housing (1) and has an eccentric through-bore running parallel to the axis of rotation (5). The sealing surface of the sealing element facing a ventilating element (2) is pressed towards the ventilating element in its sealed position under the action of pressure on the sealing element. Preferred Features: The sealing surface of the sealing element facing the ventilating element is surrounded by a circular rib arranged in a coaxial manner to the axis of rotation.</p>
