the bundle 3 there in order to be able to fill the complete area of the saddle pipe 7 with grouting mortar 8 a formwork pipe not shown can be temporarily put over the end 21 of the saddle pipe 7 which is sealed off against the saddle pipe 7 by a seal after the front opening of the formwork pipe is sealed off the entire cavity can be grouted the formwork pipe with the lid to seal the front opening could be removed again after the grouting mortar 8 had hardened the detachable connection between the connecting pipe 14 and the sheathing 4 in this embodiment the transition pipe 15 is illustrated in fig5 as detail v of fig4 at a larger scale on its sheathing end the connecting pipe 14 has an inner flange 23 to which an outer flange 24 of the transition pipe 15 abuts from the outside the outer flange 24 can be welded to the end of the pe transition pipe 15 the friction locked connection between the transition pipe 15 and the connecting pipe 14 is ensured by an axis parallel screw connection 25 which acts against a loose flange ring 26 the installation of the sheathing is considerably.