The welding technology of PE pipeline system is directly related to the operation effect and service life of pipeline network, in which the connection quality of PE pipe interface is very important. The interface of PE pipe is connected by hot melting and electric melting. The cost of hot melting is lower than that of electric melting, and the quality of electric melting is better than that of electric melting. Therefore, it is very important to understand and master the characteristics and advantages of PE pipe welding, and it is necessary to systematically understand and master the characteristics of electric fusion and hot fusion welding.
Electric fusion welding-welding principle.
Using a special electric fusion welding machine, the electric heating wire embedded in the inner surface of the fused pipe is heated by electrifying it, so that the inner surface of the pipe and the outer surface of the pipe are melted respectively and cooled to the required time to achieve the purpose of welding.
The principle of hot melt welding.
PE is a kind of thermoplastic material, which can generally be melted in the range of 190fu 240 ℃ (the melting temperature of different raw materials is generally different, at this time, if the melted parts at both ends of the pipe are in full contact, and appropriate pressure is applied, it can be firmly integrated after cooling, so as to achieve the purpose of fusion.
Comparison between electric melting and hot melting:
The main contents are as follows: 1. From the point of view of the mode of operation, the hot melt welding machine is relatively tedious, which requires several steps: cutting, cleaning pipe mouth, counterpart, welding heat absorption, pressure cooling and pressure relief cooling, which requires high proficiency and needs to be operated by special technicians. The electric fusion welding machine only needs to scrape off the outer oxide layer at the pipe mouth with a scraper, and the electric fusion sleeve can be welded, which is easy to operate.
2. The flexibility of electric fusion and hot fusion welding methods, the type of hot melt welding machine is different with the difference of PE pipe, and the size of hot melt welding machine increases with the increase of pipe diameter, which makes it difficult to carry when welding. For welding PE pipes with different diameters, the type of electric fusion welder is the same, and the welder is small in size and easy to carry.
3. For the welding conditions of electric fusion welding machine and hot fusion welding machine, the volume of hot fusion welding machine is relatively large, so it is not suitable for relatively narrow pipe trench, and it is more inconvenient to use hot melt welding machine for areas with large slope. Because the hot-melt welding machine needs a certain hydraulic cylinder stroke, the pipeline is relatively fixed when the dead end is connected, and the welding quality is difficult to be guaranteed because the welding stroke is not enough, so it is more difficult to use the hot-melt welding machine.
4. The welding quality of electric fusion welding machine and hot fusion welding machine, and the welding interface quality of hot fusion welding machine can be directly shown by the amount of flanging and peeling in winter vacation. The strength of the welding joint is relatively large and the welding stability is relatively high, so the quality of the welded pipeline can be basically guaranteed by checking the weld. Capacitive welding connects the two pipe ports by melting inside the electric fusion jacket. because of the package of the electric fusion sleeve, the quality of the welding interface can not be seen directly from the outside. The welding process can only be judged indirectly by the length of the indicating column of the observation hole, and the quality inspection of the welding interface can only be achieved through the pressure test of the pipeline.