Yilaing He, Tianjun Zhang
Papers # 2018 Las-Vegas
A new electrofusion PE belt is developed by reinforcing it with various layers of steel mesh. It’s of sandwich structure, consisting of steel mesh reinforcement, heating wire and polyethylene. One or more layers of steel mesh is encapsulated in the middle, and heating wire is embedded onto “inner side” of the belt. Just outside the heating wire, a thin film of adhesive PE resin is applied for purposes of anticorrosion and increasing water-tightness.
This belt is much stronger than PE-only electrofusion belt due to the steel mesh reinforcement, and also flexible due to its thinner wall. PE100 or PE80 can be used to produce the belt.The belt width depends on diameter of pipes to be joined, ranging from 300 to 500mm, and the diameter range of pipes it can join is from 315mm to 2600mm. The maximum operating pressure for dn315-1200mm is 16bar and the maximum operating pressure for dn > 1200mm is 12.5bar. Belts for larger diameters and higher pressures can be designed and produced upon customer’s special request.
This belt can be used for jointing new pipes as well as for repairs, and it is suitable for both pressure and non-pressure applications. It can also be used to join pipes to pipe fittings provided the pipe and the pipe fitting to be jointed are equal in outside diameter. The belt works only with pipes with smooth-wall pipe-ends. For profile pipes with corrugations, the pipe ends shall be pre-processed at factory to be smooth so that the pipes can be joined with the belts.
Pipe jointing with this electrofusion belt is easy and cheap. In on-site jointing operation, a steel clamp is used to push the belt onto the outside wall of the pipe end tightly. For local damage to pipes like holes running through pipe wall, “patching” style of repair can be done using this belt.
Short-term hydrostatic tests, burst tests and joint decohesion tests have been done on all diameters. This product has been commercially used in China for a few years. The development/technical details will be presented in the paper.