Description of Process
Spiral wound pipe (SWP) comprises a method whereby a pipe or liner is formed in-situ by helically winding a PVC profile strip into a host pipe normally from an existing manhole.

A major advantage of both of these systems is that there is a hollow opening at all times along the entire length of spiral wound pipe so existing sewer flows can usually be accommodated without the use of over pumping.

Typical Applications
Suitable for all circular non-pressure pipes. The system is designed as a structural liner with a service life in excess of 50 years.

Installation
The special winding machine is positioned at the base of the access chamber and the PVC profile strip is fed into the machine from above ground. The lead end of the tube exits the winding machine and rotates as it travels down the host pipe as further turns of the helix are added. The SWP tube is of a smaller diameter than the host pipe and the rotating tube “rides over” displaced joints etc. rather being simply pulled into the pipe as with normal slip lining.

Once the smaller diameter tube has reached the other access chamber the winding machine continues to operate such that the profile lock is made to slide within itself thus progressively expanding the tube in diameter.  The process continues until the entire length has been expanded to be a tight fit (DiaFit) to the existing pipe.

Available Sizes
SWP DiaFit is available for use in pipes ranging in diameter from 225mm to 600mm.

Materials
The profiles used in SWP DiaFit linings are made from PVC which has a proven record for sewer applications.

SWP DiaFit and SWP SL brochure