Project name: Hydraulic relief of the village Düren – Echtz
Reservoir sewer made of PEHD DN 1100, L = 483 m, V = approx. 450 m³
Due to an increase in the volume of wastewater, it became necessary to extend the storm sewer within the town of Düren Echtz from DN 300 to DN 450.
Due to the high renovation costs, the old DN 300 pipeline was to be retained in the lower section on the way to the treatment plant. However, this required a solution for wastewater storage, which had to be located between the new DN 450 sewer and the DN 300 old pipe. The storage volume was calculated to be 450 m³.
The classic solution of a storage channel with a larger nominal diameter or basin shape with an integrated pump system was rejected in the planning phase because the amount of the basic investment and running costs threatened to exceed the permissible budget.
Instead, the decision was made in favor of a gravity sewer as a double line solution with 2 X DN 1100, L = 483.00 m and a volume of approx. 480 m³. Supplemented by one distributor and one unification structure each as a combination shaft. The installation of the reservoir channel was carried out in such a way that the first channel was arranged as a through channel, and the second in the shunt. After that, the DN 300 existing sewer was continued to the sewage treatment plant.
A challenge was posed by the existing depth of the existing sewers with their low gradient (0.2%), which required a high degree of accuracy during installation.
The high groundwater table and the massive stock of old trees in the pipe route meant equally high demands on the pipe system.
For this reason, it was decided to use a pipeline system made of HDPE from Hawle Kunststofftechnik as a high-load pipe, which had to be completely welded to prevent root ingrowth and to protect against infiltration and exfiltration due to the high groundwater level.
The welding system used here was the innovative IP-plus welding system from the company SABUG.
Hawle Kunststoff GmbH, based in Wiehl, Germany, produces and sells plastic pipe and manhole systems, as well as suitable fittings and connectors for private and municipal drinking water supply and wastewater disposal. The extensive range includes plastic solutions made of PP and PE-HD for use in water, wastewater, industrial and landfill technology.
The basis for the complete system is the plastic profile coiled pipe, which can be manufactured with a smooth or profiled exterior in nominal sizes DN 300 to DN 3500. Polypropylene or Polyethylenes have an enormous longevity, whereby a 100-year service life can be assumed, and are completely recyclable by type. The materials used are characterized by high chemical resistance and abrasion resistance. Thermoplastics also have very high impact resistance. Stress cracks or mechanical damage that would impair the function can therefore be virtually ruled out.
Structures made of plastic are also characterized by their low weight and a high degree of prefabrication. This enables fast and efficient laying on the construction site. In order to be able to guarantee sustainable watertightness, the individual elements are welded together.
Together with the experts from SABUG GmbH, Hawle-Kunststofftechnik as well as IH-MG, a technically high-quality complete solution was developed, which combines the advantages of plastic pipes with the system of the IP-plus welding system.
The innovative IP-plus welding system from SABUG GmbH with dynamic stress control enables the material-to-substance welding of polypropylene (PP) and PEHD sewer pipes and the associated fittings. This not only reduces the cost of pipe construction compared to conventional welding solutions, but also shortens construction time due to the quick and easy installation of the welding rings. The welding times in this case were approx. 15 min. incl. preparation. The usual supporting, holding and clamping devices can be completely dispensed with in this system.
This particularly efficient method was successfully used for the laying of the new storage sewer in Düren – Echtz.
When using this welding system, the standard rubber sealing ring is simply removed from the pipe bead and replaced with the welding ring. Modification of the existing pipe system is not necessary. The IP-Plus welding ring is preformed for easy insertion and can be inserted into the bead of the pipe without much effort.
The operation of the IP-plus welding system differs from the systems of conventional heating coil welding sleeves. Due to the design of this welding system, the joining pressure required for welding is generated during the welding process itself. The basis of the welding system is a torus made of modified PP, to which a heating wire is applied thermally. When the temperature is increased, the torus heats up and thus sets itself up, which results in a welding of the two tube partners and even tolerances, which are unavoidable with larger tube diameters, can be reliably compensated. The PE or PP material surrounding the torus, serves as welding filler. The multi-voltage welding process offers the possibility to model the temperature and the added power during the welding process to obtain a perfect welding result. Removal of the oxide layer is not necessary with this system, as this is safely destroyed by the “setting up” of the welding ring. The weld is merely cleaned with a PE/PP cleaner. This was proven, among other things, by the peeling tests at the MPFA-Leipzig. The individual packaging also guarantees high quality of the delivered IP-Plus welding rings.
By using a bar code, the required welding parameters are read into the device and processed accordingly. In conventional welding processes in the field of plastic filament welding, the voltage is kept constant during the welding process. In the multi-voltage welding process, this is changed in a defined way. Quality assurance and welder training are set high for this system. As with PE-HD heated spiral butt welding, a high standard of quality and cleanliness is essential on the construction site, when processing the components. For this reason, the specific training of welders for the IP-Plus welding system is desirable and necessary.
All proofs of the functionality of the IP-plus welding system were, of course, verified in advance by corresponding expert reports. Furthermore, the entire system has been approved by the German Institute for Building Technology (DIBt) for use in wastewater pipes. Approval : Z-42-5-553.
Client: WVER Wasserverband Eifel – Rur, Düren
Planner: Engineering office Tuttahs & Meyer, Aachen
Execution: Bauunternehmung STRABAG, Düren
Pipe manufacturer: Hawle – Kunststoff, Wiehl
Execution period: May – June 2018