wires 13 are to run into the space which is to be foamed between carrier pipe and jacket pipe these signaling wires 13 may be passed through one or more apertures 3 in part 1 while the space to be foamed is being filled since part 1 preferably does not have the capability to move radially with respect to the pipes 4 and 7 the position of the aperture 3 in part 1 through which the signal wires are led does not change its angle to the carrier pipe and the jacket pipe this also prevents twisting of the signaling wires with respect to the pipes if the pipes rotate in relation to part 2 which includes the apertures 8 through which the mixtures are distributed the holder may preferably be ring shaped a particularly advantageous design of the holder is shown in fig1 by way of example and will be described in more detail below the holder is ring shaped is built up from an inner ring 1 which is in contact with the carrier pipe 4 via rolling bearings 5 and has the capability to move axially and an outer ring 2 the outer ring 2 is connected with.