Polyurethane thermal insulation pipes are structured in three layers from the inside out:

One Layer: Working Pipe Layer

In accordance with design and customer requirements, generally seamless steel pipes, spiral steel pipes, and straight seam steel pipes are selected. After being processed by shot blasting for rust removal, the steel pipes can achieve a rust removal grade of Sa2 according to GB8923-1988 standards, with a surface roughness reaching R=12.5 micrometers as per GB6060.5-88 standards.

Second Layer: Polyurethane Insulation Layer

The rigid polyurethane foam plastic liquid is injected once into the cavity formed between the steel pipe and the outer sheath using a high-pressure foaming machine, commonly known as "foam-in-place pipe".

Three Layers: High-Density Polyethylene Protective Layer

Preformed black or yellow polyethylene plastic pipes with specified wall thickness. Their functions include: 1) protecting the polyurethane insulation layer from mechanical damage by hard objects, and 2) corrosion and water resistance.