▎ 摘　　要

NOVELTY - Deep geothermal thermal insulation composite pipeline comprises four-layer composite structure, and from inside to outside are inner layer base pipe, plane high thermal conductivity layer, polyethylene foam layer and outer layer pipe, and inner layer base pipe is extruded polyethylene or PERT. The plane high thermal conductivity layer is formed by winding the high thermal conductivity layer material on the outer surface of the inner layer base pipe, and the in-plane thermal conductivity of the high thermal conductivity layer material is above 400 watt per meter by Kelvin, and the vertical thermal conductivity is 15-40 watt per meter by Kelvin. The layer of hot melt adhesive is coated between the inner layer base pipe and the plane high thermal conductivity layer and between the plane high thermal conductivity layer and the polyethylene (PE) foam layer, and the outer layer pipe is a PE protective layer. USE - Deep geothermal thermal insulation composite pipeline. ADVANTAGE - The deep geothermal thermal insulation composite pipeline has achieved neither the pressure resistance of the pipe under the premise of reducing the overall thermal conductivity of the pipe, played a thermal insulation effect, enhanced thermal conductivity of the pipeline intermediate layer material along the axial direction of the pipeline, reduced the heat loss of the pipeline when transporting hot water in a low area near the ground ambient temperature, and played a certain degree of thermal insulation effect. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing deep geothermal thermal insulation composite pipeline, which involves: (a) melt-extruding PE or PERT inner pipe raw material by a single-screw extruder, where the temperature of the barrel area is 180-200℃, and the temperature of the die area is 190-200℃; (b)performing vacuum sizing, cooling; (c) extruding a layer of hot melt adhesive on the outer surface of the inner base pipe, and the extrusion temperature of the hot melt adhesive is 135-150℃; (d) winding a layer of high thermal conductivity layer material, the longitudinal winding angle of the high thermal conductivity layer material along the inner layer base pipe is 5-45°, the winding tension is 5-15 N; (e)extruding a layer of hot melt adhesive, coating on the outer surface of the high thermal conductivity layer material; (f) mixing uniformly the composition raw materials of the PE foam layer, extruding, coating on the outer side of the high thermal conductivity layer material through a coating machine, and the extrusion temperature is 180-190℃; (g) extruding the outer protective layer of PE, setting the extrusion temperature to 180-190℃; (h) shaping the pipe after the coating is finished, cutting, and rolling off the line