Steel sets of steel insulation tube is divided into three levels from the inside to the outside
First layer: the work of steel pipe layer design and customer requirements is generally used in seamless pipe (GB8163-87) spiral welded pipe (GB9711-88; SY/T5038-92) and Longitudinal (GB3092-93). The processing of the steel pipe surface after shot blasting process, rust, steel grade up to GB8923-1988 standard of Sa2, surface roughness up to GB6060.5-88 R = 12.5 microns.
The second layer: polyurethane insulation with high-pressure foaming machine in the cavity formed by the pipe between the outer casing of a one-time injected into the liquid of rigid polyurethane foam made. Commonly known as the "tube in tube foaming process." Its role in First waterproof, insulation, support hot net weight. When the transmission medium temperature: -50 ℃ -120 ℃, the choice of rigid poly semicarbazide ester foam as insulation layer.