Device for the automatic opening and closing of reaction vessels

device for automatically opening and closing of reaction vessels comprising - a holder (16) for non-rotatable holding of at least one reaction vessel (13), - a Grippers (11) for gripping of a lid (12) for the reaction vessel (13), wherein the gripper (11) jaws (20, 34) for embracing the lid (12), - a Turning mechanism (10) for rotatably supporting the gripper (11), characterized in that the gripping jaws (20, 34) arranged in such a are that upon insertion the lid (12) in the area between the gripping jaws (20, 34) this of the gripping jaws (20, 34) is held by frictional engagement, and the gripper (11) no active operating device for opening and closing the Gripping jaws (20, 34)