Trenchless Technology: Pull-In-Place and Inversion

Pipe Relining Tools

Is most cases pipes are installed behind walls, underneath roads and concrete and beneath the ground and in hard to reach places. Accessing them for repair can be difficult. That’s where Trenchless Technology and Pipe Relining Equipment and their processes come into play. This equipment and technology allow repair of pipes in a less invasive way than the traditional excavation methods. Pipe Relining can repair leaks, cracks, root intrusions, joint displacement and deterioration of pipes. Two Pipe Relining Techniques are called Pull-In-Place and Inversion installation methods.

Below I will discuss the two methods:

  1. Pull-In-Place: The pull-in-place method is described in its name. The process begins with the resin impregnated tube to a wire or rope that has already been pre-strung through the existing pipeline from Point A to Point B. Points A & B are generally called the up-stream and down-stream access points of the fault inside the pipeline. After being carefully pulled through the pipe and the resin impregnated tube is positioned over the fault, static pressure is used to inflate the tube and hold it tightly against the host pipe. The tube is then cured using either ambient temperatures, water cure or steam curing methods. The resin thermostatically cures hard and you are left with a jointless, seamless, pipe-within-a-pipe. This is a structural repair to the host pipe and fixes the fault inside the pipeline. There are many different brands and contractors that use the pull-in-place installation method around the world.
  2. Inversion: The inversion process is installed similar to how you would roll or fold a sock. Firstly the liner is impregnated with 2 part Resin mixture. The resin impregnated liner (the sock) is then folded inward and rolled into an inversion drum. Compressed air is then used to blown through the inversion drum and the tube is inverted down the inside of the pipeline. The inverted tube then cures hard to the inside of the pipe. The Inversion process is best used on pipes in straight runs.

Both techniques have advantages and disadvantages and each have their own unique pipe relining companies and contractors!


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