Issues to be noted during the construction of insulated steel pipes and coating pipes

Insulated steel pipes are mainly used to transport gases or liquids such as hot water and steam, and to reduce heat loss during transportation. They are mainly used in the field of centralized heating in daily life, transporting hot water at 50-120 degrees Celsius. In industry, there are also many media transported in pipelines that require insulation, as long as the temperature is below 120 degrees Celsius; Another widely used application is the long-distance transportation pipeline of oil. Due to its high viscosity, oil can only flow normally at a certain temperature. Therefore, polyurethane insulated steel pipes play a good role in insulation, ensuring the flow rate of oil.

1. Reduce project cost

According to relevant departments' calculations, polyurethane insulated steel pipe dual control heating pipelines can generally reduce project costs by about 25% (using fiberglass as the protective layer) and 10% (using high-density polyethylene as the protective layer).

2. Low heat loss, energy-saving

The thermal conductivity of polyurethane insulated steel pipes is λ=0.013-0.03kkcal · h · oC, which is much lower than other commonly used pipeline insulation materials in the past, and the insulation effect is improved by 4-9 times. Moreover, its water absorption rate is very low, about 0.2kgm2. The reason for the low water absorption rate is that the closed cell rate of polyurethane insulated steel pipes is as high as about 92%. Low thermal conductivity and low water absorption, combined with insulation layer and high-density polyethylene or fiberglass protective shell with good waterproof performance, have changed the traditional situation of "wet cotton jacket" for laying heating pipes in trenches. Polyurethane insulated steel pipes greatly reduce the overall heat loss of heating pipes, with a heat loss of 2% for the heating network, which is less than the international standard requirement of 10%.

3. Anti corrosion, good insulation performance, long service life

Because the polyurethane insulation layer of the steel pipe is tightly bonded to the outer surface of the steel pipe, it isolates the entry of air and water and can play an outstanding anti-corrosion role. All of its foam holes are closed, and its water absorption is very low. The high-density polyethylene shell and fiberglass shell both have outstanding anti-corrosion, insulation, and mechanical properties. Therefore, the outer skin of the homework steel pipe is difficult to be corroded by external air and water. As long as the water quality inside the pipeline is well treated, according to foreign materials, the service life of polyurethane insulated steel pipes can reach more than 50 years, which is 3-4 times longer than traditional trench laying and overhead laying.

4. Less land occupation, faster construction, favorable for environmental protection

Polyurethane insulated steel pipes do not require the construction of huge trenches, only the insulation pipes need to be buried underground, thus greatly reducing the land occupation of the project, reducing excavation volume by more than 50%, and reducing civil engineering masonry and concrete volume by 90%. Together, the processing of polyurethane buried insulation pipes and on-site trenching are carried out in parallel, requiring only on-site joints, which can shorten the construction period by more than 50%.

5. An alarm system can be set up to actively detect leaks in the pipeline network, accurately indicate the location of the problem, and proactively sound an alarm

The polyurethane insulated steel pipe is equipped with a leakage alarm line. Once a leakage occurs in a certain part of the pipeline, through the transmission of the alarm line, the precise location and degree of leakage of the insulated pipeline can be displayed on a dedicated detection instrument, so as to notify the leak detection personnel to quickly deal with the leaking pipe section and ensure the safe operation of the heating network.

The next one is about anti-corrosion and pipeline construction characteristics. Here are a few points I can summarize:

1) The inner wall of the pipeline is resistant to pollution and decay by microorganisms such as shellfish and fungi in the ocean or sewage.

2) The coating inside the pipeline is smooth, and the fluid friction resistance is lower than that of PCCP and ductile iron pipelines.

3) The anti-corrosion performance of the inner wall of the pipeline is better than that of ordinary PCCP and ductile iron pipelines.

4) The single-layer polyethylene powder thermal spray coating on the outer wall of the pipeline has strong soil corrosion resistance and is environmentally friendly.

5) The specifications of the pipeline fittings are complete and can adapt to various installation needs.

6) Pipelines can be connected using various forms such as welding, clamps, flanges, etc.

7) The direct welding joint repair and repair method is simple and reliable.

8) The design life of internal and external anti-corrosion coatings can reach over 50 years.