http://nonprofitrockstartour.com/wasp-fucking-woman-hentai 1) Butt Welding or Butt Fusion Welding
enter site 2) Electrofusion Welding
Butt Fusion Welding involves simultaneous heating of both the pipes’ ends to be joined, to a specific temperature until a melting state is reached. Then the two ends are brought together in parallel without overlapping to fuse under a certain pressure for a specific cooling time & homogeneous fusion is achieved upon cooling.
This technique of welding requires an electrically heated plate to heat the pipe ends to the required fusion temperature and is used for PE63, PE80 and PE100 grades of material for pipe of size 32mm and above of the same Standard Dimension Ratio (SDR). When joining pipes using butt-fusion techniques, the heater plate temperatures are the same for PE63, PE80 and PE100, 195ºC to 200ºC.
The Site Fusion Jointing Specification WIS 4-32-08 Issue 2, 1994 emphasizes the importance of using the butt-fusion machine to be able to control the reduced secondary ram pressures that are now required for dual pressure butt-fusion jointing. For SDR11 pipes of sizes 250mm, 280mm and 315mm and for all pipe (SDRs 11, 17.6, 26)of size 355mm and above the butt fusion pressures should be reduced after 10 seconds and therefore the use of an automatic butt fusion machine is required.
Plain pipes are joined by means of electrofusion (EF) welding involving an electrical heating coil which when electrically heated for a specific time by electrofusion welding machine, melts the surface of the pipe & fitting together resulting in a complete fusion of the pipe and the fitting. There is a barcode label on each of the Electrofusion fittings. This label includes fusion parameters (such as welding voltage and duration). Fusion parameters are transferred to the machine from this label either manually or by using the barcode reader.
follow url Advantages of Electrofusion Jointing Technique:
• there is no decrease in inner diameter of the pipe
• low weight, low cost and flexibility of the equipment
• faster joining process
• fully automated operation, so need for skilled operators is minimum
• no reduction in strength of material at jointed parts