Electrofusion
Benefits
Electrofusion is a rapid and simple way of permanent jointing. Using the Akafusion electrofusion couplers and equipment, pipes, fittings and prefabricated pipe sections can efficiently be assembled. An electrofusion joint is made by placing an electrofusion socket over the two weld ends and passing a specific amount of energy through the heating wire contained in the electrofusion socket. This process is very suitable for joints made on site or in tight areas.
The resistance wires lie at the surface of the coupler, a unique technical feature of the Akafusion electrofusion couplers that allows a better heat transfer during the welding process. The wires are positioned in a fusion zone. On both sides of the fusion zone a cold zone prevents the molten HDPE from outpouring thereby containing the fusion process. During the fusion process the pipe/fitting expands and touches the inner coupler wall. The electrofusion joint is made with the pressure caused by the expanding HDPE and the heat from the resistance wires. Most Akatherm products can be welded by electrofusion. Akatherm has a complete range of electrofusion couplers and electrofusion control boxes available.
Basic principles
Electrofusion is a reliable way of jointing when a proper weld has been made. The electrofusion process consists of the following steps (please refer to our Specification Manual for the complete process). Also available are our electrofusion 40-160 mm and electrofusion 200-315 mm instruction movies.
- 8 steps of the electrofusion process
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1. Preparations
Good preparation consist of making sure the electrofusion control box works properly. The inserted pipe or fitting must completely cover the resistance wires at the surface of the coupler for a good heat exchange. In order to utilize the fusion and cold zones in the pipe or fitting must be inserted to the correct depth.
2. Cutting the pipe square
The pipe ends must be cut square to ensure that the resistance wire in the coupler is completely covered by the pipe or fitting.
3. Mark surface for scraping
The insertion depth +10 mm must be marked to ensure the oxidized layer will be removed from the full welding zone.
4. Scrape pipe and mark insertion depth
The full outer surface of the pipe that will be covered by the coupler, must be scraped (approx. 0,2 mm deep) to remove any surface 'oxidation'. The insertion depth should be marked again to safeguard full insertion.
5. Clean electrofusion coupler
Before assembling the pipes into the coupler ensure that all surfaces are clean and dry.
6. Insert pipe/fitting until marked line
Ensure that the pipe is pushed into the coupler as straight as possible and up to the marked insertion depth. This will ensure that all the wires are covered with HDPE during the fusion cycle.
7. Prevent misalignment and movement
Misalignment will cause extra load on the fusion zone causing additional HDPE to melt resulting in the outpouring of HDPE or wire movement. The movement of the pipe can cause melted HDPE to flow out of the joint. This can result in wire movement and possibly a short circuit and thus a bad weld or fire hazard.
8. Welding electrofusion coupler and cooling down
Commence welding after connecting the control box to the coupler by pressing the start button. Akatherm control boxes adapt the welding time to the ambient temperature. The joint assembly should not be disturbed during the fusion cycle and for the specified cooling time afterwards.
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