connections into drainage systems fig1 a 1c illustrate one embodiment of the invention in fig1 a a sewer 1 extends in the soil 23 a feed pipe 6 discharges into the sewer 1 in the region of the site of entry 9 as an aid to understanding the usefulness of the invention the site of entry 9 has been drawn to include various types of damage such as broken out portions 13a transition gaps 13b and fissures 13c to repair the damage present at the site of entry a sewer inner pipe 3 is introduced into the sewer 1 and a feed inner pipe 7 is introduced into the feed pipe 6 the edge of the site of entry of the pipe 6 is widened by forming a recess 15a indicated by the phantom line by forming the recess broken out portions gaps and fissures present at the site of entry 9 are largely removed the forming of recess 15a can be accomplished using a milling robot or similar cutting device introduced via the feed pipe 6 preferably the feed inner pipe 7 is not guided all the way to the interior of the sewer 1 a space is maintained between the connecting end of the pipe 7 and the wall of the sewer inner pipe 3 as shown in fig1 b an injection device 16 comprising a feed duct.