The direct-buried prefabricated insulation pipe is made of tightly combined steel pipe (working pipe), rigid polyurethane foam (insulation layer), Liaoning spiral pipe high-density polyethylene outer casing (protection layer).
Overview: Directly buried prefabricated insulation pipes are made of tightly combined steel pipes (working pipes), rigid polyurethane foam (insulation layer), high-density polyethylene outer casing (protection layer).
The first layer of directly buried prefabricated insulation pipe: working steel pipe layer
According to the design customer requirements, generally choose seamless pipe (GB8163-87) spiral welded pipe (@ GB9711-88; SY / T5038-92) straight welded pipe (GB3092-93). After the surface of the steel pipe is processed by the advanced shot blasting derusting process, the derusting grade of the steel pipe can reach Sa2 grade in the GB8923-1988 standard, the surface roughness can reach R = 12.5 microns in the GB6060.5-88 standard.
Directly buried second layer of prefabricated insulation pipe: polyurethane insulation layer
The high-pressure foaming machine is used to inject the rigid polyurethane foam plastic liquid into the cavity formed between the steel pipe the outer sheath at one time. It is commonly known as "tube-in-tube foaming process". Its function is one is waterproof, the other is heat preservation, the third is to support the weight of the heating network. When the temperature of the conveying medium is: -50 ℃ -120 ℃, rigid polyurethane foam is selected as the heat preservation layer.
The third layer of directly buried prefabricated insulation pipe: high-density polyethylene protective layer
Pre-made black (yellow) plastic pipes with a certain wall thickness. Its function is to protect the polyurethane insulation layer mechanical hard objects to prevent corrosion.