Pipe technical points: large diameter PE pipe construction control points

Polyethylene (PE for short) is a thermoplastic resin made by polymerization of ethylene.

Insoluble in general solvents at room temperature, tiny water absorption, excellent electrical insulation. ​The Polyethylene (PE) pipe has become the world's second largest plastic pipe after PVC-U pipe, widely used in the construction of urban infrastructure projects.

China HDPE parts factory put forward that PE tube has excellent chemical stability and a long service life. Under the condition of buried, the service life of PE pipe can reach further than 50 years. It has excellent weather resistance and good comprehensive mechanical properties. Construction is convenient, and its advantages are more obvious when the construction period is tight and the construction conditions are poor.

Large diameter PE buried pipe plays an essential role in the construction of urban infrastructure projects.

Large diameter PE pipe construction general provisions
PE pipe welding is the most essential part in the whole construction process, especially in the trenchless process, such as welding caused by problems the loss is usually calculated in millions. Therefore, in the construction process, we must step by step, closely grasp the quality of construction. During the whole construction period, PE pipe welding needs to use two different welding methods. For PE pipes smaller than D63, socket connection is required, that is, pipe fittings are used for pipe connection. PE pipes larger than D63 need to be connected in docking mode. That is, the pipes are connected by heating through a special welding machine.

Correct construction method
I. Preparation before welding

1, wash the oil joint, properly connect and weld the parts;

2. ​check the wash heating plate to confirm whether the voltage meets the requirements of the welder;

3. ​check and clean the heating plate;

4. ​set technical parameters accurately according to welding process;

​two, pipe construction steps

1. Pipe clamping shall be in place and port position shall be cleaned to eliminate residual water quality, soil and other debris;

2. ​pipe milling and calibration to ensure a sterile and barrier-free site. Do not touch the milling port directly after milling to avoid contamination. And calibrate pipe ports. Avoid milling deflection heating is not in place (normally, the end face of the pipe should be milled again after adjustment to ensure the pipe alignment);

3. ​pipe heating. When the heating plate reaches 220°, it is properly placed in the middle of two pipes for pipe heat absorption. When absorbing heat, remember to use drag pressure. After the heat absorption time is satisfied, the heating plate can be switched quickly to avoid the heat loss and pollution of the port surface after placing and switching for too long.

4. In the flanging stage, after heating through the port, butt the pipe quickly until flanging and flanging reaches the outer wall of the pipe (pressure relief is not allowed here);

5. ​in the cooling stage, the welding port needs to be cooled to ensure the welding quality after the welding is completed. This process is natural cooling, not through cold water or other physical cooling. Until the pipe port is cool.

Eight factors affecting welding quality
1. The port is not milled;

2. ​there are oil stains, dust or heating plates that are not clean at the pipe port;

3, the heating plate temperature is too high or low (normal temperature 220±10°);

4, the heating plate heating time is too long or short (theoretical calculation time "S": outer diameter/SDR * 10);

5, the heating plate switching time is prolonged;

6. ​the docking pressure is too large or too narrow;

7. ​welding pipes with different wall thickness at the same time;

8. ​the cooling time is too short or the pressure holding cooling is not carried out effectively;

Leave a Comment