Abstract: The present invention relates to a pressure vessel (1) for receiving samples (P) to be heated, having a reaction chamber (2) as a pressure space for the initiation and/or facilitation of chemical and/or physical pressure reactions, the reaction chamber (2) being designed for receiving a liquid (5), a magnetic disk (8) mounted rotatably about an axis of rotation in the reaction chamber (2), and a magnet arrangement (10), provided outside the reaction chamber (2), for generating a rotating magnetic field for rotationally driving the magnetic disk (8) about its axis of rotation, the magnetic disk (8) having at least one passage bore (13), which extends transversely in relation to the axis of rotation and is provided in such a way that liquid (5) received in the reaction chamber (2) is driven through the passage opening (13) by rotation of the magnetic disk (8) in order to stir the liquid (5).