CASE STUDIES
Pulling the liner pipe into the host pipe
Rehabilitating surface water drainage in Wimbledon
Works were recently carried out on a Public Sewer Services site in Copse Hill Park, Wimbledon, southwest London, UK. A poorly installed 375 mm diameter twin wall plastic pipe was significantly deformed.
The site comprised mature woodland, meadow land, a park area, playing fields, a nature reserve, swale and footpaths. The area also exhibited delicate soil conditions as well as a fragile ecosystem. The acidic soil type attracted unique plants and wildlife. Residents from the affluent surrounding area were also concerned about any works that were required as there are very few green spaces accessible to them.
With limited site access and the stakeholder restriction on any excavation, options for a purely trenchless method were sought. After considering various options, discussions with rehabilitation systems provider Picote Solutions identified a solution using its new Flexi-Sliplining system.
Flexi-Sliplining system
The Flexi-Sliplining system utilises German manufactured Flexirohr pipe with tooling designed by Picote. The pipe has a corrugated outer skin so there is minimal use of oil in its production, resulting in a much-reduced overall weight and therefore the installation is also free of potential toxic waste. The corrugated pipe is DIBt certified and has been utilised in several European countries as well as South America.
The major advantage of the system is that no excavation is needed in an installation between two manholes (in sizes <800 mm diameter). This offers a huge advantage compared with traditional PE sliplining as no lead-in trench is required. The structure of the pipe allows it to negotiate smaller bends in the host pipe, should they exist. The Flexi-Sliplining system can be used for host pipes between DN100 to DN300.
Installation is achieved by connecting the liner pipe to a winch cable which pulls it through the host pipe at a rate of up to 8 m (26 ft) per minute. Once installed the ends of the pipe are fixed in the manholes at either end. The system has also pull-resistant couplings for any pipe connections.
One innovative addition to the Flexi-Sliplining system is the new pipe welding system. Picote R&D has developed unique tools for this welding process, including: a new welding rig, welding inserts, pipe cutters, pulling heads and welding balls. Also, the equipment helping the installation via pulling in of the pipe has been significantly redesigned. All of these new tools
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make the installing process easier, faster and more efficient. The tools are simple, light-weight and have good ergonomics. The Hurner welding rig used is specially adapted for Flexi-Sliplining with a barcoding system, so that users can determine the temperature and time for each weld.
Wimbledon Installation
Given these advantages, the Flexi-Sliplining systems it was chosen for the Wimbledon project. PSS mobilised its experienced specialist pipe bursting team with bursting equipment to work in conjunction with the Picote team and equipment to install a new replacement pipe.
Utilising a Picote welding rig, Picote Battery winch, winch plate and guide poles, Picote pipe guide, Picote Flexi-pipe cutter, Hurner welding rig, and a Picote Lower guide, three surface
The Flexi Line apparatus set up at the launch manhole
| December 2023 |
www.draintraderltd.com
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