Abstract: A valve mechanism having at least one movable valve member for sealing of a valve opening in a housing. Movements of the individual movable valve members are accomplished essentially parallelly to, and perpendicularly to, the seat surface of the valve during the opening and closing of the valve. In order to achieve high forces and low wear in the movement carried out with aid of a slot guide which guide serves to transmit forces during, and in the direction of, the opening and closing, the slot guide comprises slots which are formed in a drive plate, which slots cooperate with and overlap complementary slots in the movable valve members.