Abstract: A device for detachably coupling the orifice of a branchline to a line carrying a pressure medium and having a plurality of discharge valves spaced apart from each other in the line wall, the coupling being carried out by means of a coupling device which is movable over the length of the line and contains the orifice and opens one of the discharge valves. The discharge valves are mounted in the line with magnetically actuating opening members and the coupling device is provided with a coupling element guided thereon and is provided with an automatically sealing coupling member in the coupling position with the discharge valve at the pressure side for an automatic alignment with the orifice, and an actuator which magnetically cooperates with the opening member and the coupling member.