Double-layer composite air pipe with good heat insulation effect

The utility model discloses a double-layer composite air pipe with a good heat insulation effect, which belongs to the technical field of composite air pipes and comprises a main pipe and two groups of inner pipes, the surfaces of the two groups of inner pipes are slidably connected with the inner wall of the main pipe, limiting components are further arranged between the inner pipes and the main pipe, and locking frames are mounted at two ends of the main pipe through positioning components; the composite air pipe is composed of the main pipeline and the two inner pipes, the two inner pipes and the main pipeline are connected together in a sliding mode, a user can adjust the overall use length of the composite air pipe by pulling the inner pipes so as to meet the installation length requirements of different installation positions in a construction site, and the device is simple in structure, convenient to use and high in practicability. After the use length of the composite air pipe is adjusted, the locking