Polyurethane insulation pipe production technology district heating supply and return water with the introduction of its structure is generally made of high density polyethylene outer sheath or outer sheath fiberglass, rigid polyurethane foam insulation, interior steel composition. Other structures in accordance with the actual requirements of the steam pipe insulation also alarm line black pipe insulation, brackets, etc., may also need other insulation materials composite layer and so on. HDPE outer sheath of high density polyethylene outer sheath tube is divided into "two-step" and "Step" manufacturing process: the structure of urban heating pipe insulation, floor insulation pipes, prefabricated buried pipe insulation is more complex and it contains insulation air-conditioning pipe insulation, the insulation layer of insulation material is not using the general refining, but by those professional and experienced workers with a rigid foam insulation to build, so that it could have been product performance maintaining stability and security is very high.