Polyurethane Insulated Pipeline, full name: High-Density Polyethylene Plastic Outer Sheath Pre-fabricated Direct Burial Insulated Pipe with Polyurethane Foam Insulation, consisting of a working steel pipe for conveying medium, a polyurethane insulation layer, and a polyethylene plastic outer sheath, which are sequentially combined outwardly through equipment.
National standard polyurethane insulated steel pipes are structured in three layers 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 rust removal technology, the steel pipes can achieve rust removal grade 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 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 conveying medium is between -50℃ and 120℃, use rigid polyurethane foam plastic as the insulation layer.
Three Layers: High-density polyethylene protective layer, pre-fabricated black (yellow) plastic pipes with a certain wall thickness. Its functions include: 1. Protecting the polyurethane insulation layer from mechanical damage, and 2. Anti-corrosion and waterproof.
Product Structure: The pre-fabricated buried steam insulation 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, 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 substantial upper loads. To ensure longevity, anti-corrosion treatment is required for the steel sheath.
The rolling support structure design is rational, featuring low rolling friction, which reduces the load on the fixed supports. The mechanical analysis principle is simple, 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 with the same insulation thickness.
The vacuum pump system completely solves the problem of internal wall corrosion in the outer steel casing due to hot and humid air, significantly extending the service life of the directly buried steam pipeline. The product lifespan is increased to 30 years.
