After completion of the cleaning and sealing of the rehabilitation section at the shaft of the main collector DN 600 the filling of the communicating pipe systems with the injection agent Tubogel 1 (T1) takes place at the lowest part of the line. To minimize disturbing effects on road traffic the gas wagon can be positioned as far as 50 m away from the shaft, as it has an accordingly long filling line.
The filling process is greatly influenced by the exfiltration rate of the injection fluid. Upon reaching the pipe crown resp. a filling height of 50 cm above the pipe bottom the filling process is interrupted for approx. 3 min. to be able to estimate the loss of fluid.
At low fluid loss the filling process continues as follows:
Filling of T1 to shaft top. The drop of the fluid level in the shaft is measured and recorded.

After approximately 30 minutes the loss of injection fluid is replaced by refilling it up to the top of the shaft. Due to the hydrostatic pressure the injection agent penetrates the leaks resp. seeps through these into the soil. The injection agent T1 remains in total approximately 45 minutes in the rehabilitation section and is then pumped out by vacuum pumps.