Product Structure

Polyethylene outer protective pipe rigid polyurethane prefabricated directly buried insulated pipe is manufactured by using the "pipe-in-pipe" process (also known as the "two-step method"), used for transporting hot water less than 140℃. It consists of working steel pipes for transporting media, rigid polyurethane foam, high density polyethylene outer protective pipe, is tightly integrated into three parts. Alarm lines can also be added to the insulation layer according to customer requirements.

Working steel pipe: seamless steel pipe, spiral welded pipe, straight seam welded pipe. Before thermal insulation, the surface of the steel pipe shall be mechanically derusted, and the derusting level shall not be lower than the Sa2.5 level in GB/T8923.1.

Polyurethane insulation layer: Made of rigid polyurethane foam, the gap between the steel pipe and the outer protective pipe is fully filled after high-pressure mixing and injection, ensuring that the steel pipe, outer protective pipe and insulation layer form a solid whole. The density of polyurethane foam at any position of the insulation layer can reach 60kg/m³.

Outer protection tube: Made of high-density polyethylene material not lower than PE80, low-temperature ions are generated through tip discharge to corona treat the inner surface of the polyethylene outer protection tube.The surface tension after corona treatment reaches above dyn/cm, which strengthens the bonding force between the insulation layer and the outer protective pipe, improves the shear strength, and extends the service life of the insulation pipe.

 Performance Characteristics

（1）The outer protective tube adopts online corona technology to form a polar bond with the insulation layer, effectively solving the bonding delamination problem.

（2）It has good low temperature resistance and impact resistance, and can be directly buried in the frozen soil layer.

（3）High strength, good toughness, easy to weld and construct.

（4）Low thermal conductivity, strong waterproof and corrosion resistance, and can be directly buried underground or in water

（5） Long service life, under normal use conditions, it can be used in an environment of 140℃ for more than 30 years