Directly Buried Polyurethane Insulated Steel Pipe

Update time: 2025-06-11    Views: 110

I. What is a direct-buried polyurethane insulated steel pipe?

Directly buried polyurethane-insulated steel pipes are a three-layer structure consisting of a working pipe, a polyurethane insulation layer, and a high-density polyethylene outer protective layer.  

i. Structural composition:  

(1) Working pipe: Made of seamless steel pipes or spiral welded steel pipes (such as Q235B, Q345B), these pipes feature high strength and pressure resistance, ensuring stable and reliable medium transportation.

(2) Polyurethane Insulation Layer: Tightly wraps around the working pipe, made from polyurethane foam material with a low thermal conductivity (0.02–0.03 W/(m·K)), providing excellent thermal insulation.

(3) Outer Protective Layer: Made from high-density polyethylene (HDPE), it is corrosion-resistant and waterproof, protecting the pipeline from external corrosion.

ii. Performance characteristics:

(1) Efficient insulation: The polyurethane insulation layer significantly reduces heat loss and improves thermal efficiency.

(2) Corrosion resistance: The HDPE outer protective layer resists groundwater and soil corrosion.

(3) Waterproof performance: The insulation layer is tightly bonded to the steel pipe, isolating air and moisture.

(4) Easy installation: Pre insulated pipes can be directly installed, ensuring quick and efficient construction.

iii. Application areas:

(1) Heating Systems: Used as main and branch pipelines to ensure heating efficiency and energy conservation.

(2) Petrochemical Industry: Prevents heat loss and corrosion of the medium.

(3) Municipal Engineering: Used in liquid and gas transmission networks and insulation projects.

II Insulated steel pipes structure:

III. Polyurethane insulation pipe specification table:

IV Polyurethane foam insulation pipe features:

i. Reduce project cost.

ii. Low heat loss, saving energy.

iii. Anti-corrosion, good insulation performance and long service life.

iv. It occupies less space, is quick to construct, and is conducive to environmental protection.

v. Safety.

V. Advantages of polyurethane thermal insulation steel pipe:  

i. Polyurethane insulated pipes have excellent thermal insulation properties, with heat loss reduced to just 25% of traditional pipe materials, significantly lowering costs and conserving energy.  

ii. They offer superior waterproofing capabilities and are resistant to acids, alkalis, and corrosion.  

iii. They have a long service life, lasting up to 30–50 years.

iv. Pipe diameters can vary from DN15 to DN1000; insulation thickness can range from 15 to 500 mm.

v. Widely used in heating pipelines, refrigeration pipelines, chemical pipelines, industrial pipelines, and more.

VI. Polyurethane Insulated Steel Pipe Parameter Table

VII. Insulation pipe application areas：

Insulated steel pipes are mainly used in:

i. Urban central heating: as thermal pipes to reduce heat loss;

ii. Petrochemical industry: to transport high-temperature media;

iii. Refrigeration engineering: for low-temperature insulation systems.