Enhanced the mechanical properties of the external sleeve.

2.Reduced the wall thickness of the outer casing.

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

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

5. Reduced the axis eccentricity of the insulation pipe.

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

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

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