pipe 7 is guided by means of inwardly angled projections at the free end portion of the pipe 9 and a plurality of spaced apart inwardly directed circumferential corrugations 19 only one of which is shown in the wall 33 of the pipe 9 to be similarly displaceable in longitudinal direction relative to the pipes 9 and 21 the duct means 3 further comprises valve means associated with the pipes to close the conduits and operable to open the conduits thereby to permit the ingress of fluids into and egress of fluids from the container through the conduits the valve means comprising a respective valve associated with each pipe and independently operable so that different combinations of the conduits can be opened for different purposes such as filling cleaning and drawing off from the container the valve associated with the outer pipe 21 and controlling the outer conduit 6 comprises a valve seat 16 provided on the connection ring of the duct means a valve body 13 arranged on the intermediate pipe 9 to be displaceable therewith and cooperable with the valve seat 16 and a spring 24 bearing on the flange 23 of the pipe 21 and urging the valve body 13 into engagement with the valve seat 16 thereby to.