Polyurethane insulated pipeline, full name: High-Density Polyethylene Plastic Outer Sheath Pre-Fabricated Direct Burial Insulated Pipe with Steel Pipe for Conveying Medium,聚氨酯保温层, and Polyethylene Plastic Outer Sheath, sequentially combined outward by equipment.
National standard polyurethane insulated steel pipes have a three-layer structure from inside to outside.
Layer 1: Working钢管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 processed by advanced shot blasting rust removal technology, the surface rust grade of the steel pipes can reach Sa2 level according to GB8923-1988 standard, and the surface roughness can reach R=12.5 micrometers according to GB6060.5-88 standard.
Second Layer: Insulating polyurethane layer - Formed by injecting a liquid polyurethane foam plastic into the cavity between the steel pipe and the outer sheath using a high-pressure foam machine in a single operation. 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 heating network. For conveying media at temperatures ranging from -50℃ to 120℃, use rigid polyurethane foam plastic as the insulation layer.
Layer 3: High-density polyethylene protective layer. Pre-fabricated black (yellow) plastic pipes with specified wall thicknesses, serving the dual purposes of protecting the polyurethane insulation layer from mechanical damage and providing corrosion and waterproofing.
Product Structure: The pre-fabricated buried steam insulation pipe consists of a core pipe (working steel pipe), reducing layer, insulation layer, reflective layer, fastening steel strip, sliding bracket, air layer, outer steel pipe, sprayed polyurethane, and wrapped glass fiber reinforced plastic.
Features:
The outer protective layer made of steel pipes features high strength and is not easily damaged, capable of bearing significant upper loads. To achieve a long service life, anti-corrosion treatment is required for the steel sheath pipes.
The rolling support structure design is rational, featuring minimal rolling friction, reduced load on the fixed supports, and a simple mechanical analysis principle, significantly enhancing the pipeline stability and safety.
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.
