Thermal insulation steel pipe polyurethane directly buried insulation pipe, also known as "pipe in tube", has two steps, consisting of external maintenance layer of high density polyethylene, rigid polyurethane foam plastic pipe and steel pipe.

The insulating layer material is rigid polyurethane foam with density 60kg/m3 to 80kg/m3, fully filled the gap between the steel pipe and the casing, and has a certain bonding strength, so that the steel pipe, the outer sleeve pipe and the insulation layer can form a solid whole between the three. The insulation steel tube foam has excellent mechanical function and adiabatic function. Under normal conditions, it can withstand 120 degrees of temperature and is able to withstand temperature of 180 degrees after being modified or combined with other insulation materials. The insulating layer material is rigid polyurethane foam with density 60kg/m3 to 80kg/m3, fully filled the gap between the steel pipe and the casing, and has a certain bonding strength, so that the steel pipe, the outer sleeve pipe and the insulation layer can form a solid whole between the three. The insulation steel pipe foam has excellent mechanical function and adiabatic function. Under normal conditions, it can withstand 120 degrees of temperature and is modified or combined with other insulation materials.

1. Anti-corrosive coating: Maintain external steel pipe to avoid corrosion and prolong service life of steel pipe.

2. External steel pipe protection: Maintain the insulation layer from open water corrosion, support the work pipe and can withstand certain external loads to ensure the normal operation of the work pipe.

3. polyurethane foam layer: ensure the temperature of the medium and ensure the surface of the outer tube is kept at normal temperature.

4. isolation and reflective layer: ensure that the organic foam material does not enter the inorganic hard and high temperature resistant layer; reflects the local heat of the high temperature resistant layer.

5. inorganic hard insulation: high temperature, ensure the interface temperature between the organic insulation layer and ensure that the foam is not carbonized.

6. Drag Reduction Layer: Ensure free movement of hot expansion and cold contraction of working steel pipe.

7. Working steel pipe: Ensure the normal activity of the delivery medium.

It is believed that after reading the introduction of https://www.sdhpgy.com, the polyurethane insulation steel pipe manufacturer in this paper, they will have their own understanding of this aspect, and other problems can be solved well in the future.