PE pipe is a new type of water supply pipe produced by extrusion molding process with polyethylene resin as the main raw material. There are three types of connection methods: thermal fusion, electrofusion and mechanical connection. PE water supply pipe has the advantages of corrosion resistance, no scaling, good water delivery hydraulic conditions, light weight, long service life (durable for 50 years), good flexibility (the elongation at break reaches 500%, and the adaptability to uneven settlement of the foundation), It has the advantages of good impact resistance and seismic performance. And the construction connection is simple, convenient and quick. Compared with ductile iron pipes and steel pipes of the same diameter, PE pipes below dn300 are more cost-effective. PE/PRR pipe production line, PVC one-out four high-speed production line, Zhangjiagang high-speed mixer.

In recent years, the application of PE/PRR pipe production line, PVC-out four high-speed production line, and high-speed mixer manufacturers in water supply engineering has grown rapidly and has become the material of water supply engineering. However, PE pipes also have disadvantages such as high temperature resistance, exposure to sunlight, large longitudinal elongation of lower pipes (close to 3%, which is more than ten times that of steel pipes), inability to locate metal detectors, high prices of PE water supply pipes, and high maintenance costs after failure. Active measures should be taken to deal with the design and construction. Common faults and causes in construction and installation are as follows:

1. Material management is not in place

(1) PE pipes and fittings are not supplied by the same manufacturer, the chemical properties are inconsistent, and the bonding at multiple hot-melt joints is not reliable.

(2) Mix PE pipes from different manufacturers.

(3) Improper storage of PE pipes, deterioration and brittleness after exposure to high temperature, reduced quality and poor quality.

2. The internal stress of the PE pipe damages the pipe after thermal expansion and cold contraction

(1) PE pipe shrinking and breaking expansion joints: expansion joints that can withstand 12 kgf/crn2 stress (1 kgf/cm'=0.1M Pa) are qualified products. The coefficient of thermal expansion and contraction of the PE pipeline is large, and the backfilling of the pipeline is not layered and compacted, which may cause the PE pipeline to shrink and break the expander after cooling down at night.

(2) The shrinkage of the PE pipe causes the socket of the ductile iron pipe to pull off: the shrinkage of the PE pipe in winter causes the socket of the ductile iron pipe to pull off, causing the pipe to leak.

(3) After the thermal expansion and elongation of the PE pipe, it is twisted and bent from the variable diameter, and under the impact of high-speed water flow for a long time, cracks and water leakage occur at the bend.

(4) After the water inside the water supply pipe freezes, the water meter joint of the PE pipe bursts and cracks.

3. Unreasonable installation of pipes

(1) The excessive welding at the hot-melt joint forms a radial necking of the water supply and drainage, and the pipeline overflows with a small amount of water, and the pipe is almost blocked, causing the user to have no water for a long time. Pay attention to the hot-melting time of PE pipes in summer and winter. If the welding time is too long, it is easy to form radial necking and affect the flow of water.

(2) The PE main pipe shrinks after cooling, causing the attached fixture to be dislocated and leaking at the tee. Cast iron clamps should not be used for PE pipe opening tee and branch pipe. It is recommended to use standard PE tee pipe fittings and use electrofusion sleeves to connect.

(3) The pipe base is not made of sand cushion, and the residual flat iron and the broken cast iron pipe will pierce the PE water supply pipe.

(4) The casing is not tightly sealed, and the domestic sewage with too high temperature soaks the PE pipe for a long time, resulting in the brittle fracture of the PE pipe after degeneration.

(5) There is a little sediment adhering to the hot-melt interface, which causes water seepage in the pipe joint.

(6) Concrete is poured on one side during the pouring of pipe buttresses and town piers, which causes the pipes to be twisted and not concentric.

(7) The valve on the main pipeline is not closed tightly to stop the water, resulting in the flow of water at the tee interface of the welded electrofusion sleeve, and the phenomenon of water seepage in the welding seam.