Interflow’s Titeflow provides a die-reduction polyethylene tight fit liner that restores the pressure and flow carrying capacity of a deteriorated pressure pipeline. It is suitable for high pressure and large diameter water mains and can be installed over long lengths for diameters from 75mm up to 1,000mm.
The Titeflow process takes standard polyethylene pipes and temporarily deforms them to allow installation. Once in place, the pipes are reverted to their original diameter, allowing a wide range of diameter and pressure classes to be installed.
Strings of polyethylene pipe are butt fusion welded together above ground, then steadily and progressively winched into the host pipe through a reducing die that temporarily reduces their diameter.
The reduced diameter is maintained as long as the liner remains under the winching pressure.
Once started, the process of installation is smooth and continuous until the liner is positioned in the host pipe between the launch and winch points.
When the polyethylene liner is in place in the water main, the tension in the winch cable is released and the natural molecular memory causes the polyethylene pipe to revert to its original diameter within the bore of the host pipe. Where the original diameter of the liner is greater than the internal diameter of the deteriorated pipe, the expansion of the liner produces an interference fit.
Tight-fitting polyethylene compression fit liners installed by similar methodologies have been providing reliably renewing leaking and defective water, gas and sewer pressure mains around the world for over a decade.
Interflow recently completed a project with Titeflow to renew over 5 kilometres of 115-year-old steel water main. PN16 polyethylene pipe with a nominal external diameter of 560mm is being drawn through the Titeflow diameter-reducing dies and into the host pipe.
The 20 metre long individual lengths of polyethylene pipe are first welded into continuous before being drawn into the pipeline.
Titeflow installation requires excavation of entry and exit (winch) pits at the extremities of each continuous length being installed.
The location of these pits is determined by the requirement to minimise community disruption and they are positioned where excavation is most convenient. The ability for Titeline to be installed over long continuous winching lengths means that distances between entry and exit pits of over 600 metres have been possible.
The distance between pits can also be governed by discontinuities in the pipeline such as bends or the location of valves or other fittings. The benefits this offers over the replacement of the water main by continuous trenching are obvious.
Trenchless Technology for renewing deteriorated sewers has been accepted by Water Authorities in Australia for the past 20 years. By minimising the need for excavation, and working at times that cause minimal traffic disruption, this project is a demonstration of the benefits that Trenchless Technology can bring to watermain rehabilitation.