construction site can often see such a scene: the master has just connected the PE hot melt pipe, he is holding the water pipe to flush the interface - "hurry up and cool the next step". But ask: can the PE hot melt pipe really be cooled by water? The answer is hidden in the "bones" of the PE pipe. I don't understand the "dark lightning" that may bury the pipeline for several years.

First understand the core logic of PE hot melt connection: PE pipe is a polyethylene material. The essence of hot melt connection is to heat and melt the contact surface of the pipe and the pipe fittings, so that the originally separated polyethylene molecules "melt" into one, and then slowly cool the molecules to rearrange and crystallize to form a tight "overall structure". This step is like kneading dough and steaming steamed buns - when the dough is good, it needs to be steamed slowly. If you are in a hurry to lift the lid of the pot, it will only collapse into a ball; the "crystallization" of the PE pipe also has to be done slowly, so that the strength of the interface can catch up with the pipe itself.

What's wrong with cooling with water? Quick flushing will force the surface of the interface to shrink instantly, and the polyethylene molecules inside will be "frozen" in a chaotic state before they can "stand in line". In this case, there is a huge internal stress hidden in the interface, like a spring that is bent. It may be fine at ordinary times, but over time (such as low temperature shrinkage in winter and water pressure fluctuations in summer), the stress will be slowly released. If it is light, the interface will seep water, and if it is heavy, I have seen a community. During construction, the master used water to flush all the interfaces in order to rush to work. As a result, the next winter, all the water pipes in the three buildings cracked at the interfaces, and the maintenance cost more than 100,000 yuan. It was all a disaster of "rushing out".

The correct approach is actually very simple: wait. According to the diameter of the pipe, pipes as small as 20mm have to wait 3-5 minutes; those above 110mm have to wait at least 10 minutes - the key is to let the interface "naturally cool". During the cooling process, you should also pay attention not to touch, press, or shake the interfaces, otherwise the molecules that finally lined up will be messed up again. Some people will ask: "If it rains, does it count?" In fact, passive water is not a big problem, as long as it is not actively washed with water, a small amount of water will not quickly reduce the internal temperature, and the impact is limited.

Finally, there is a misunderstanding: it is not "the faster the cooling, the better", the "slow" of the PE pipe is the key to safety. The interface of the hot melt connection is the "heart" of the entire pipeline system. If the heart does not grow well, no matter how thick the pipe is, it is useless. Instead of rushing to flush the progress, it is better to wait a few more minutes - after all, the cost of rework is much more expensive than waiting for time.

Understand this, the next time someone says "flush with water", you can tell him confidently: "This water cannot be flushed."