Retracting pipes

The method can be used to renovate piping systems if the diameter of the existing piping system is permitted to decrease. The set of equipment consists of the following: winch, power station – can also be performed with directional drilling and bursting device.

Depending on the diameter of the new pipe, starting and finishing pits are constructed. In the case of a DN 110 pipe, pits are generally not necessary, as the flexing radius of the pipe enables to work via existing wells. A new pipe is pulled into the existing pipe. After pulling in the pipe, the gap between the new and old pipe is filled with foam concrete or special centering rings are installed around the new pipe before pulling it in. Filling with foam concrete is not necessary if the gap between the walls of the new and old pipe is less than 1/10 of the diameter of the old pipe.

Pros (+) Cons (-)
Quick installation Diameter of the old pipe is decreased
Large extent of installing Locations of joints must be dug up
The depth of the pipe does not significantly affect the cost of installing Follows the descent of the old pipe
 Does not require special skills Overpumping and/or temporary water supply required