A coated felt hose soaked in polyester or vinylester resin is inverted via existing shafts (where there are larger dimensions via smaller construction pits) using a water tower or a inversion drum with air pressure into a preliner which has previously been pulled into the pipe to be rehabilitated.
This preliner must be used without fail as the resins must not come into contact with water. The liner is kept under pressure and is cured using the appropriate methods (heating the water or introducing steam).
After curing, the system provides a structural liner which is comparable to a new pipe. In the event of groundwater ingress, preliminary sealing via punctual methods is required.
Fields of application:
- Non-pressurized pipes
- Sewerage and industry
- Dimensions between 150 mm and 2400 mm
- Circular, oval and special profiles
- Suitable for all pipe materials
- Bends and curved section rehabilitation possible
- Hot water curing: up to 600 m pipe length (depending on nominal dimensions and system)
- Steam curing: up to 250m pipe length (depending on nominal dimensions and system), shorter curing times compared to water curing
Advantages:
- Short construction time
- No pipe connections
- Very flexible in application
- Insignificant cross-section reduction (twice the wall thickness of the liner pipe)
- Installation possible via existing shafts; depending on the situation, the cone must be removed from DN 700 and a construction pit is required from DN 900.
- Shafts can be passed through with the liner
- Lateral connection can be implemented from within
- The liner is hydraulically very smooth and resistant against aggressive waste water and mechanical stresses;
Disadvantages:
- Risk of folds is possible, particularly in the event of position deviation, nominal dimensions tolerances, bending, deflection and significant drift in the old pipe;
- Use of a preliner necessary to prevent contact with polyester or vinylester resin contained in the liners (styrene is washed out on contact with water and curing is impossible)
- No adhesion with the inner pipe wall - small remaining annular space, connections and shafts must be sealed additionally to be watertight.
- Hot water curing: The drainage of process water via rain water channel or the discharge into open water channels is not adviseable (possible content of styrene)
- Steam curing: Condensation in the lower segment area with the risk of insufficient curing (measures required for drainage of condensed water)
- Wastes, in particular substrate material and resin, must be disposed of correctly.
- Not suitable for damage such as pipe collapse
- Pipe manufactured on site – compliance with high quality standards required
