Direct Buried Insulation Pipe Is Divided Into Three Layers From Inside To Outside

The first layer: the seamless pipe (GB8163-87) spiral welded pipe (GB9711-88; SY / T5038-92) and straight seam welded pipe are generally selected according to the design and customer requirements (GB3092-93). After the surface of the steel pipe is treated by advanced shot blasting process, the steel pipe can reach Sa 2 in GB8923-1988 standard, and the surface roughness can reach R=12.5 microns in GB6060.5-88 standard.
The second layer: polyurethane insulation layer with high pressure foam machine in the cavity formed between the steel tube and the outer protective layer once injected into the rigid polyurethane foam plastic stock solution. Namely commonly known as the "tube in the tube foaming process". Its role is waterproof, two is heat preservation, three is to support the weight of the heat net. When the temperature of the conveying medium is-50℃ - -120℃, the rigid polyureate foam plastic is used as the insulation layer.
The third layer: the high density polyethylene protective layer prefabricated into a certain black (yellow) plastic pipe wall thickness, its role is to protect the polyurethane insulation layer from mechanical hard damage, the second is anti-corrosion and waterproof.
Polyethylene jacket pipe is made of high-density polyethylene material, with extremely high mechanical strength and excellent corrosion resistance, which can protect the pipe in the process of transportation, installation and use to avoid the damage caused by external factors. The outer tube should be added with antioxidant, ultraviolet stabilizer and carbon black.