Basic structure of the electric melting pipe fittings.
Electric fusion welding tools:
Electric welding machine, pipe cutting machine, scraper, grinding machine, ruler, marking pen, extrusion welding gun, plastic welding wire (for sealing).
Check that the power supply is within the range required by the welding machine, especially the generator voltage. Check whether the wire capacity meets the requirements of the output power of the welder and the grounding of the ground wire. (For the Φ250mm diameter or less pipe fittings, the power of the fused machine should be larger than 3.5KW; For the Φ315mm or more pipe fittings, the power of fused machine should be larger than 9KW. Voltage and current must always be kept in the ±0.5 range of the set value).
2. Intercept of pipes:
The end face of the pipe should be cut perpendicular to the axis with an error of less than 5 mm. If the end face of the pipe is not perpendicular to the axis, it will cause the partial weld zone to be exposed, causing welding errors such as molten material flowing into the pipe. The end face of the pipe must be sealed after the pipe is cut.
3. Welding surface cleaning:
Measure and mark the depth or weld area on the pipe with a marking. Because the polyethylene pipe is stored for a period of time, an oxide layer will be formed on the surface. Therefore, it is necessary to completely remove the oxide layer on the outer surface of the pipe and the inner wall of the pipe before welding, which will affect the welding quality and cause safety hazards. The scraping of the welding surface requires a depth of 0.1-0.2mm. After scraping, cleaning the edges and edges of the inner and outer surfaces of the pipe.
4. Socket of piped and fittings:
The cleaned electric melting pipe fittings is inserted into the pipe to be welded, and the outer edge of the pipe is flush with the marking line. When installing, the terminal of the pipe should be placed in a convenient operation position. The fitting must be under stress-free conditions with the pipe to installed together. Adjust the joint between the fitting and the pipe to the same concentricity and level, and the V shape cannot appear at the pipe. If the outer diameter of the pipe is too large, the surface of the welded end of the pipe should be scraped again to achieve proper fit. If the fitting and the pipe are too large after the socket is inserted, the hoop should be hung tightly for welding.
5. Install the centralizer:
The centralizer should play the role of tightening the socket, to make sure it is not easy to move when welding; the function of the matching gap between the pipe fitting and the pipe is to make the pipe non-deformation. Adjust the two snap rings of the centralizer to the proper position of the pipe, and it must be located behind the mark to avoid the pipe fittings being in place, tighten the snap ring nut of the centralizer, and clamp it on the pipe. Pay attention to the direction of the screw hole of the centralizer during installation, lest can not to install the righting screw.
6. The output connector connection:
The welding output end is firmly connected with the pipe fittings. If the output size is different from the pipe size, the same matching wiring plug should be used.
7. Welding records:
After entering the exact welding parameters, press the Enter key to start the welding. At the end of the welding process, the welding machine alerts you automatically. The welding parameters are recorded during welding to track and analyze the construction quality. According to the temperature of the site environment and the change of working voltage, the welding time can be properly compensated during welding. When the temperature is low, heat preservation must be done well for welding electrofusion pipe fittings.
During the welding time and cooling time, the connecting piece cannot be moved or applied with an external force, and the pipe must not be pressure tested if the connecting piece is not sufficiently cooled (not less than 24h).
1. The unevenness of the oxide layer scraping or incomplete removal, even without scraping, will lead to delamination of the welded surface and affect the connection strength of the electrofusion.
2. The ambient temperature of electric fusion welding should be between -10 °C and 40 °C. When the temperature exceeds, corresponding protective measures must be taken.
3. Insert the pipe into the middle retaining ring of the pipe fitting while maintaining the coaxiality of the pipe and the pipe fitting during the connecting process.
4. When installing the elbow, tee and other pipe fittings, the fixed pier and the thrust pier must be set to make the pipe compensation.
5. After the oxide layer is removed, the welding interval is generally less than 2 hours. If it is not welded in time, the welding surface will be reoxidized or contaminated. In the case of wind, dust, rain and snow, protective measures should be taken to prevent contamination of the welding surface.