Due to its special material, PU insulated pipe will gradually expand once heated during use. Generally, there is little noticeable movement during use. If the position of such material shows some change during use, this is also quite reasonable. The insulation layer and the outer jacket are of an integral bonded structure.

　　PU insulation is typically applied between the steel pipe and the protective jacket, in the same way as for insulated pipes. Bonding them together works well, and both ends of each pipe section and compensator are left untreated. This can be useful for addressing external fixing, but at the same time it must be configured to match the external concrete anchors, ensuring that the pipeline remains in position.

　　Externally sliding PU insulated steel pipes must be fitted with supports. Each support point is a consideration. The construction area is also relatively constrained, and investment is relatively high. However, their construction periods differ and may be extended. In a changing process, they still offer a useful comparison.

　　Jinan Insulated Pipe As introduced, in field use most outer jackets themselves fall into different categories, including plastic-cased steel structures, FRP-cased steel structures, and certain steel-in-steel structures. Related practice clearly shows that internally sliding cylinder structures are not suitable for the thermal expansion of certain pipelines. Therefore, it is still necessary to adopt them according to actual conditions.