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

National standard polyurethane insulated steel pipes are structured in three layers from the inside out.

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 advanced shot blasting and rust removal treatment, 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: Insulation layer made of polyurethane foam, which is a solid polyurethane foam plastic precursor injected once into the cavity between the steel pipe and the outer sheath using a high-pressure foaming machine. This is commonly referred to as the "pipe-in-pipe foaming process." Its functions include: 1) waterproofing, 2) thermal insulation, and 3) supporting the weight of the thermal network. When the temperature of the medium being transported ranges from -50℃ to 120℃, use rigid polyurethane foam plastic as the insulation layer.

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

Product Structure: The pre-fabricated buried steam insulation pipe consists of a core tube (working steel pipe), reducing layer, insulation layer, reflective layer, securing steel strip, sliding bracket, air layer, outer steel pipe, sprayed polyurethane, and wrapped glass fiber reinforced plastic.

Features:

The outer layer is made of steel pipes, offering high strength and resistance to damage, capable of bearing significant upper loads. To ensure a long service life, anti-corrosion treatment is required for the steel sheath.

The rolling support structural design is rational, with minimal rolling friction, reducing the load on the fixed support. The mechanical analysis principle is straightforward, significantly enhancing the stability and safety of the pipeline.

The vacuum layer completely eliminates heat 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 system completely resolves the issue of internal wall corrosion in steel casing pipes due to hot and humid air, significantly extending the service life of directly buried steam pipelines. The product lifespan is increased to 30 years.