Enhanced the mechanical properties of the outer sheath.

2.Reduced the wall thickness of the outer casing.

3.Reduced the water absorption rate of the insulation layer.

4.Enhanced the closed cell rate of the insulation layer.

5. Reduced the axis eccentricity of the thermal insulation pipe.

6.Enhanced the uniformity of the overall pipeline insulation density.

7. Enhanced the compressive strength of the thermal insulation layer.

8. Reduce thermal conductivity of the insulation layer to minimize energy loss.