Excavation of trenches in the processing site of spiral submerged arc welded pipe insulation pipe

Excavation of trenches in the processing site of spiral submerged arc welded pipe insulation pipe

Inside sliding type of spiral submerged arc welded steel pipe: thermal insulation structure consists of working steel pipe, aluminium silicate, drag reduction layer, micro-porous calcium silicate, thermal insulation layer, stainless steel fastening strip, aluminium foil reflective layer, polyurethane thermal insulation layer, coated steel pipe and external anti-corrosion layer. The inner sliding heat preservation steel pipe is composed of steel pipe conveying medium + composite silicate or micro-porous calcium silicate + rigid polyurethane foam plastic + coated steel pipe + FRP shell anticorrosive protective layer structure. All kinds of pipe joint insulation treatment technology is mature and reliable. External sliding type: thermal insulation structure consists of working steel pipe, glass wool thermal insulation layer, aluminum foil reflective layer, stainless steel fastening strip, sliding guide bracket, air thermal insulation layer, external steel pipe and external anti-corrosion layer. According to the design and customer requirements, seamless steel pipe, spiral steel pipe and straight seam steel pipe are generally selected. After the surface of steel tube is treated by advanced shot peening rust removal technology, the grade of steel tube rust removal can reach Sa2 grade in GB8923-1988 standard, and the surface roughness can reach R=12.5 micron in GB6060.5-88 standard. Leakage alarm line: When manufacturing high temperature prefabricated directly buried insulation pipe, an alarm line is embedded in the insulation layer near the steel pipe. Once leakage occurs somewhere in the pipeline, through the transmission of the alarm line, it can alarm on the special detection instrument and show the exact location and degree of leakage, so as to inform the maintenance personnel to quickly deal with the leakage pipe section and ensure the safe operation of the heat network. The insulation pipe is tightly adhered to the outer skin of the steel pipe because of the rigid polyurethane foam insulation layer, which can isolate the infiltration of air and water, and can play a good anti-corrosive effect. At the same time, its foaming holes are closed and its water absorption is very small. High density polyethylene shell and FRP shell have good anti-corrosion, insulation and mechanical properties. Therefore, the outer skin of the working steel pipe is very difficult to be eroded by the outside air and water. As long as the water quality inside the pipeline is well treated, according to foreign information, the service life of high temperature prefabricated directly buried insulation pipe can reach more than 50 years, which is 3-4 times longer than that of traditional trench laying and overhead laying.