Abstract: A coupling for conveying a fluid between a stationary part and a rotatable part having confronting ports centered on a rotation axis of the rotatable part has an axially extending tube fixed in the port of one of the parts and extending toward the port of the other of the parts and a control element axially slidable on the tube. The one part, the tube, and the control element form an annular chamber around the tube pressurizable for axially shifting the control element. A first slide ring is connected to the control element and carries a seal ring turned toward the port of the other part, and a second ring on the other part at the port thereof axially bears on the first slide ring so that pressurization of chamber presses the slide rings axially against each other.

Abstract: A coupling for conveying a fluid between a stationary part and a rotatable part having confronting ports centered on a rotation axis of the rotatable part has an axially extending tube fixed in the port of one of the parts and extending toward the port of the other of the parts and a control element axially slidable on the tube. The one part, the tube, and the control element form an annular chamber around the tube pressurizable for axially shifting the control element. A first slide ring is connected to the control element and carries a seal ring turned toward the port of the other part, and a second ring on the other part at the port thereof axially bears on the first slide ring so that pressurization of chamber presses the slide rings axially against each other.