Polyurethane insulation is a high-performance polyether polyol combination of materials and multiple polyphenyl methyl isocyanate foam materials made by chemical reactions. Light density polyurethane insulation, high strength, thermal insulation, sound insulation, fire-retardant, cold, corrosion, non-absorbent, quick and easy excellent characteristics such as construction, has become the construction, transport, petroleum, chemical, power, refrigeration and other industrial sectors insulation, waterproof plugging and sealing indispensable material. Polyurethane insulation for thermal indoor and outdoor pipes, central heating pipes, central air conditioning ducts, chemical, pharmaceutical and other industrial pipes, cold works. Overview of polyurethane foam insulation polyurethane synthetic material since the birth of the thirties, has served as an excellent insulation material and rapid development, its scope of application has become increasingly widespread, more because of its simple construction, energy-saving effect is remarkable preservative and are largely used for a variety of heating, cooling, oil, gasoline and other transmission pipelines. Largely used for a variety of heating, cooling, oil, gasoline and other transmission pipelines. The insulation layer - poured polyurethane foam tank with live or pre-molding method spreads the steel pipe coating, the method is simple, quick efficiency. Thermal conductivity: the thermal conductivity of polyurethane foam insulation material is the lowest, thus enabling the material to reduce heat loss to a minimum. Polyurethane pipe insulation Advantages: 1, reduce project cost, according to an estimate, polyurethane pipe insulation under normal circumstances can reduce 25% of project cost (using fiberglass to make protective layer) and 10% (made of high density polyethylene protective layer) around . 2, low heat loss, energy conservation polyurethane thermal conductivity: λ = 0.013-0.03kcal / m · h · oC, much lower than other insulation materials used in the past piping, insulation effect increased by 4 to 9 times. Furthermore the water absorption is very low, about 0.2kg / m2. The reason is due to low water absorption rate of the closed cell polyurethane foam of about 92%. Low thermal conductivity and low water absorption, coupled with the insulation layer and the outside waterproof good performance of high density polyethylene or fiberglass protective shell, changing the traditional trench laying heating pipes status "wearing wet jacket", greatly reducing the heating pipes overall heat loss, heat net heat loss of 2%, far less than 10% of international standards. 3, anti-corrosion, good insulation performance, long service life due to the polyurethane rigid foam insulation layer tightly bonded steel skin, cut off from the air and water infiltration, can play a good antiseptic effect. While its foam cells are closed, and water absorption is very small. High-density polyethylene shell, fiberglass shell have good anti-corrosion, insulation and mechanical properties. Thus, the sheath is difficult to work the steel pipe subjected to the outside air and water erosion. As long as the internal water pipeline deal, according to foreign materials, the service life of up to 50 years, than the traditional trench laying, overhead laying 3 to 4 times the service life of high.