Thermal Insulation Steel Pipe

Published:2025-05-08 | Last Updated: 2025-06-12    Views: 22

I. Definition and core of thermal insulation steel pipe

i. Core structure and application of insulated steel pipe

Insulated steel pipe is a composite industrial pipeline that achieves efficient thermal insulation, corrosion resistance and mechanical protection through a three-layer structure. It is widely used in long-distance medium transportation fields such as heating, petroleum, and chemicals.

ii. Its core components are as follows:

(1) Working steel pipe layer

Material and function: Seamless steel pipe or spiral welded pipe, the surface is shot blasted and rust-proofed (reaching Sa2 standard and coated with epoxy resin anti-corrosion layer, directly transporting high-temperature steam (≤450℃), petroleum or chemical media.

Key performance: high strength and pressure resistance, ensuring stable flow of the medium, is the functional core of the insulated steel pipe.

(2) Polyurethane foam (the hallmark material of polyurethane insulated steel pipe):

Hard closed-cell structure, density 60-80kg/m³, thermal conductivity as low as 0.016-0.027W/(m·K), effectively blocking heat transfer.

Applicable temperature: -185℃~120℃ (up to 180℃ after modification), through high-pressure foaming process, it is tightly combined with the steel pipe to form an integrated "pipe in pipe" structure (i.e. polyurethane foam prefabricated insulation pipe).

Other insulation materials (flexibly combined according to working conditions):

(3) High-density polyethylene (HDPE):

Thickness ≥ 2.5mm, waterproof, soil corrosion resistant, and mechanical impact resistant, it is the mainstream sheath for polyurethane insulated steel pipes.

Reinforcement materials (special demand scenarios):

Fiberglass reinforced plastics (FRP): Higher weather resistance and pressure resistance, suitable for marine environments or highly corrosive areas.

Galvanized iron sheet: Low cost, suitable for non-direct buried overhead pipelines.

iii. Industrial value of polyurethane foam prefabricated insulation pipes

This type of pipe is prefabricated in the factory to achieve seamless integration of the insulation layer and the steel pipe, ensuring on-site installation efficiency and quality consistency.

For example:

Central heating network: maintain temperature stability for long-distance transportation of hot water;

Petrochemical pipelines: prevent condensation or deterioration of the medium and improve safety.

II.Product features:

Good insulation: heat loss is less than 2%, with aluminum foil reflective layer and inorganic insulation layer, strong insulation effect.

High strength: can withstand 80kN/m² soil pressure, impact resistance 50J/cm², can be buried directly underground without concrete support.

Long service life: anti-corrosion design life of up to 50 years, using cathodic protection and three-layer PE cold wrap tape, good waterproof and anti-corrosion effect.

III. Comparison table of high-quality and poor-quality steel pipe insulation

IV. Application areas of pre insulated pipe

Centralized heat supply: main pipeline of urban heat network (temperature drop≤1℃/40km).

Petrochemical industry: oil pipeline in highly corrosive environment containing Cl->200ppm.

Municipal engineering: hot and cold water circulation system of underground comprehensive pipeline corridor.

V. Standard comparison table of  thermal insulated steel pipe in each country