Polyurethane Insulated Pipe, full name: High-Density Polyethylene Plastic Outer Sheath Pre-Fabricated Direct Burial Insulated Pipe with Polyurethane Foam Insulation, which is sequentially assembled from the working steel pipe conveying the medium, the polyurethane insulation layer, and the polyethylene plastic outer sheath.

National standard polyurethane insulated steel pipes have a three-layer structure from inside to outside.

Layer 1: Working Steel Pipe Layer - Generally, seamless pipes (GB8163-87), spiral-welded pipes (GB9711-88; SY/T5038-92), and straight seam welded pipes (GB3092-93) are selected according to design and customer requirements. After being treated with advanced shot blasting and rust removal technology, the steel pipes can achieve a rust removal grade of Sa2 as per GB8923-1988 standard, with a surface roughness of R=12.5 micrometers as per GB6060.5-88 standard.

Second Layer: Insulating polyurethane layer - Made by injecting the liquid raw material of rigid polyurethane foam plastic into the cavity formed between the steel pipe and the outer sheath using a high-pressure foaming machine in one go. This is commonly known as the "pipe-in-pipe foaming process." Its functions include: 1) waterproofing, 2) thermal insulation, and 3) supporting the weight of the heating network. When the temperature of the conveying medium is between -50℃ and 120℃, use rigid polyurethane foam plastic as the insulation layer.

Layer 3: High-density polyethylene protective layer - Preformed black (yellow) plastic pipes with predetermined wall thickness, serving the purpose of: 1) protecting the polyurethane insulation layer from mechanical damage, and 2) preventing corrosion and water damage.

Product Structure: The pre-fabricated buried steam insulation pipe consists of a core pipe (working steel pipe), a reducing layer, an insulating layer, a reflective layer, a fastening steel strip, sliding brackets, an air layer, an outer steel pipe, spray-painted polyurethane, and wrapped glass fiber reinforced plastic.

Features:

The exterior layer is made of steel pipes, offering high strength and resistance to damage, capable of bearing substantial upper loads. To ensure longevity, anti-corrosion treatment is required for the steel sheath.

The rolling support structure design is rational, with reduced rolling friction and decreased load on the fixed supports. Its mechanical analysis principle is simple, significantly improving the stability and safety of the pipeline.

The vacuum layer completely eliminates thermal conduction and convection through air layers, reducing heat loss. Compared to an air layer structure, it can lower the outer wall temperature by 8-13°C under the same insulation thickness.

The vacuum pump device completely solves the problem of internal wall corrosion of the outer steel casing due to hot and humid air, significantly extending the service life of the buried steam pipeline. The product lifespan is increased to 30 years.