Rotary slide valve

A rotary slide valve contains a delivery tube, having an inlet opening and a delivery opening, and a slide element which is mounted in the delivery tube so as to be able to rotate between a passing position and a blocking position and which possesses a passage opening. Mounted coaxially in the delivery tube is a rotatable slide tube which forms the slide element. The tube wall of the slide tube is penetrated in the radial direction by the passage opening in a blocking region. The inlet opening of the delivery tube is arranged in the wall of the latter; it communicates with the passage opening of the slide tube in the passing position of the latter and, in the blocking position of the slide tube, is closed by the blocking region.