Polyurethane insulated pipeline, full name: High-Density Polyethylene Plastic Outer Sheath Pre-fabricated Direct Burial Insulated Pipe with Polyurethane Foam Insulation, which is assembled by sequentially combining the working steel pipe for conveying medium, the polyurethane insulation layer, and the polyethylene plastic outer sheath.
National standard polyurethane insulated steel pipes have a three-layer structure from the inside out.
One Layer: 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 with advanced shot blasting rust removal technology, the surface rust removal grade of the steel pipes can reach Sa2 level according to GB8923-1988, and the surface roughness can reach R=12.5 micrometers according to GB6060.5-88.
Second Layer: Insulating polyurethane layer, formed by injecting the liquid raw material of rigid polyurethane foam plastic into the cavity between the steel pipe and the outer sheath with a high-pressure foaming machine in one go. 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. When the temperature of the medium being transported is between -50℃ and 120℃, rigid polyamine urethane foam plastic is used as the insulation layer.
Layer 3: High-density polyethylene protective layer, pre-fabricated black (yellow) plastic pipes with specified wall thickness. Its functions include: 1. Protecting the polyurethane insulation layer from mechanical damage by hard objects, and 2. Preventing corrosion and water damage.
Product Structure: The pre-fabricated buried steam-insulated pipe consists of a core tube (working steel pipe), a reducing layer, an insulating layer, a reflective layer, a fastening steel strip, a sliding bracket, an air layer, an outer steel pipe, spray-painted polyurethane, and wrapped glass fiber reinforced plastic.
Features:
Made with steel pipes for external protection, it boasts high strength and is resistant to damage, capable of withstanding significant overhead loads. To ensure a long service life, anti-corrosion treatment is necessary for the steel casing.
The rolling support structure design is rational, featuring low rolling friction, which reduces the load on the fixed supports. The mechanical analysis principle is straightforward, significantly enhancing the pipeline's 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 device completely solves the problem of internal wall corrosion of the outer steel casing caused by hot and humid air, significantly extending the service life of the directly buried steam pipeline. The product lifespan is increased to 30 years.
