Steel outer jacket end structure of prefabricated thermal insulation pipe

The utility model relates to the technical field of thermal insulation pipes, in particular to a steel outer jacket end structure of a prefabricated thermal insulation pipe, which comprises a thermal insulation pipe and a steel pipe, the annular clamping groove is formed in the heat preservation pipe; the first flange plate is fixedly connected to the outer side of the thermal insulation pipe; the screw hole is formed in the first flange plate; the sealing ring is fixedly connected to the inner wall of the heat preservation pipe; the second flange is fixedly connected to the outer side of the steel pipe; the fastening bolt is movably connected to the interior of the second flange plate; the annular air bag is fixedly connected into the steel pipe; and the inflation inlet is fixedly connected to the annular air bag. By arranging the air bag and the sealing ring, the sealing performance of the sealed end of the heat preservation pipe is improved, and the problems that after the end of the heat preservation pipe