Polyurethane insulated steel pipes, also known as insulation buried pipes, are divided into outer polyethylene and inner polyurethane insulated pipes, steel sleeve steel insulated pipes, outer iron sheet and inner polyurethane insulated pipes. They are made of outer and inner polyurethane to provide insulation for the transportation of liquids through steel pipes.

Construction characteristics

1. Reduce project costs

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

2. Low heat loss, saving energy

The thermal conductivity of high-temperature prefabricated buried insulation pipes is λ=0.013-0.03kkcal m · h · oC, which is much lower than other commonly used pipeline insulation materials in the past and has a better insulation effect. Moreover, its water absorption rate is very low, about 0.2kgm2. The reason for low water absorption is that the closed cell rate of polyurethane foam is up to 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 pipelines in underground trenches, greatly reducing the overall heat loss of heating pipelines. The heat loss of the heating network is 2%, which is less than the international standard requirement of 10%.

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

High temperature prefabricated directly buried insulation pipes have a good anti-corrosion effect due to the tight bonding of the polyurethane insulation layer to the outer skin of the steel pipe, which isolates the infiltration of air and water. At the same time, its foam pores are all closed, and its water absorption is very low. Both high-density polyethylene shell and fiberglass shell have good anti-corrosion performance. Therefore, the outer skin of the working steel pipe is difficult to be eroded by external air and water.

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

Directly buried heating pipelines do not require the construction of large trenches, only the insulation pipes need to be buried underground, thus greatly reducing project land occupation, reducing excavation volume by more than 50%, and reducing civil engineering masonry and concrete volume by 90%. At the same time, insulation pipe processing and on-site trenching are carried out in parallel, requiring only on-site joints, which can shorten the construction period by more than 50%. Prefabricated buried insulation pipes are widely used in liquid and gas transportation pipelines, chemical pipeline insulation engineering, petroleum, chemical, air conditioning and ventilation pipelines, municipal engineering, etc.