As part of a joint development project between the Kanaltechnik Schuster GbR and HAMCO GmbH, a centralised Weak point in trenchless sewer rehabilitation The challenge was specifically addressed: the system tightness when installing UV-curing GRP hose liners (GRP = abbreviation for glass fibre plastic) must be improved. By further developing the materials of the components involved, it was not only possible to significantly reduce the leakage rate, but also to sustainably improve the energy efficiency of the entire installation process.
Initial situation
A stable and uniform operating pressure is essential for optimum UV light curing of GRP tube liners. Typically, pressures of up to 600 mbar are used to ensure that the liner is firmly attached to the old pipe wall. The resin-impregnated liner, which is under permanent internal pressure, is thus evenly compacted and cured by means of an all-round UV cold light band - a basic prerequisite for the structural integrity of the subsequent pipe system.
In practice, however, there is often a Inefficient operation due to compressed air and leakage losses. These occur in particular in the Area of the sealing surfaces of the so-called packers, which seal the pipe rehabilitation package consisting of resin-impregnated liner, separating film, UV light strip and the push/pull rod at both ends of the package against the old pipe wall.
The consequence
The volume flow required to optimise the contact of the liner with the inner wall of the pipe must be compensated for by the compressor due to leakage losses. This not only leads to increased power consumption, but also to increased wear on the compressor technology used.
Solution approach
Coating of important system components with higher UV-resistant PVC of medium hardness.
To specifically optimise system tightness, a special PVC coating was applied to the packer bodies and the relevant sealing surfaces in the project. This coating fulfils several technical functions at the same time:
- Improved surface homogeneityUnevenness and microscopic pores are reduced, minimising potential leakage paths.
- Increased adaptabilityThe coated surfaces adapt better to geometric irregularities in the old pipe.
- Reduction of micro-leaksTightness is significantly increased, particularly at critical transitions between the packer and the pipe wall.
PVC from the Covytec material series was chosen as the coating material for key system components, such as the packers, due to its outstanding properties against mechanical stress, chemical influences and the possibility of achieving even better resistance to high UV radiation by adding additives - a decisive factor in the context of UV curing.
Conclusion
The joint development project impressively demonstrates the Potential in the targeted optimisation of materials technology lies. By applying a highly resistant PVC coating, it was possible to significantly improve an existing trenchless sewer rehabilitation system - without complex design interventions.
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