1、 Advantages: it has the characteristics of high strength, impact resistance, environmental stress cracking resistance, corrosion resistance, low temperature resistance, easy welding, simple construction, strict sealing and anti leakage.
2、 Disadvantages: 1. High temperature exposure is easy to aging, not suitable for exposed overhead pipelines; 2. Outdoor storage time should not be too long (within 3 months).
The reasons for the burst of PE insulation protection pipe are as follows: 1. PE pipe is a kind of polyethylene plastic product, which can be quickly aged by sunlight exposure and high temperature baking, resulting in the decrease of PE pipe strength and elongation; 2. When the temperature is lower than 5 ℃, the PE pipe becomes brittle and the elongation decreases; after the PE pipe performance is reduced, it is subjected to the expansion force (shrinkage force) produced by impact and sudden change of temperature, which causes the insulation pipe to crack. 3. The process of injection causes the viscosity of polyurethane foam material to be too high, the fluidity is not good, and the local density is too high, which results in the burst of external protection of PE insulation.
Solutions: 1. Strengthen the level of polyurethane foam operation technology, reasonably allocate the black and white material ratio according to the temperature, and avoid working at high temperature.
2. The storage time of PE pipes should be reduced. The outdoor storage time of PE pipes should not exceed 3 months, and the finished insulation pipes should not be stored for more than one month or stored in the warehouse (where the sunlight is not directly exposed).
3. The overhead pipeline can be protected by PE, and thin iron sheet or glass fiber reinforced plastic can be set on the basis of insulation pipe to prevent direct sunlight exposure and increase service life.
Some personal suggestions on foam insulation pipe: polyurethane insulation pipe has the characteristics of good heat preservation effect, low water absorption rate, good waterproof effect and convenient interface operation. PE external protection pipe mainly plays the role of waterproof and protecting polyurethane pipe shell. According to the performance of PE pipes, when the temperature changes little, the performance of PE pipes is basically unchanged, and the performance of PE pipes can be basically guaranteed after the insulation pipes are buried in the ground. (the underground temperature changes very little). Now there are three kinds of PE pipes. The price difference between recycled PE pipes and raw PE pipes is close to double. From the perspective of application effect, they can meet the requirements of our company The PE pipe of recycled material can be used for 30 years, and the PE pipe of raw material can be used for 50 years; but how many years can our spiral welded pipe be used? In general, it is about 15 to 20 years, and the poor is about 10 years). At present, our company uses its own foam insulation pipe (recycled material PE protection pipe), and the primary network adopts the national standard outsourcing insulation pipe (raw material PE protective pipe). It is suggested that in the primary network project, the insulation pipe with diameter less than DN500 should adopt self foaming insulation pipe or recycled PE pipe shell protection insulation pipe,
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