Pipe string relining using the rolldown method is a cost-effective solution for inner cities and for long sections needing refurbishment. Lengths of up to 1000 m do not pose a problem in the range DN 100 to DN 500.

The inliner comprises standard PE pipes joined on site by butt welding. The cross-section of the inliner is reduced in the rolldown machine to allow it to be drawn into the existing pipe. Using its pairs of rollers, the machine reduces the diameter by up to 10 % at a rate of one to three metres per minute.

Following insertion, the pipe ends are closed and the inliner pressurised with water, causing it to expand and revert to its original diameter, forming a close fit with the interior wall of the host pipe. The result is a pipeline in as-new quality. The host pipe does not need to have any load-bearing capacity whatsoever thanks to the structural stability of the inliner. The PE material guarantees excellent hydraulic properties and good resistance to corrosion.

the benefits

  • Reduction method to GW 320-2
  • Fast installation thanks to line lengths of more than 1000 m
  • Suitable even for pipes that are no longer structurally stable
  • Inner pressure up to PN 16 regardless of inherent pressure resistance of host pipe
  • No heat input required for reducing diameter
  • Outstanding hydraulic properties due to smooth inner surfaces
  • No problems caused by internal corrosion
  • Cost-effective due to use of standard PE material
  • Certified specialist to DVGW (German Gas and Water Association) R 3