To allow a low-temperature pipe to be embedded under the ground while maintaining heat insulating function by covering the low-temperature pipe and a heat insulating material at its outer periphery side with a sheathing pipe and welding the sheathing pipe without damaging the heat insulating material.
The low-temperature pipe as an invar pipe is covered with the heat insulating material 3 and the low-temperature pipe 2 and the heat insulating material 3 at its outer periphery side are covered with the sheathing pipe 4. A plurality of spacer structures 6 are arranged at proper lengths in the longitudinal direction of the pipe for setting a preset thickness of space 5 between the heat insulating material 3 and the sheathing pipe 4. Each of the spacer structures 6 has a reinforcing plate 21 mounted on the outer periphery of the heat insulating material and a spacer member 20 mounted between the heat insulating material 3 (the reinforcing plate 21) and the sheathing pipe 4.
MORIMOTO NAOYA
NAKAMURA KEIICHI
IKEBE MASATO
HORINO SATOSHI
KISHIMOTO SETSUJI
SUMITOMO METAL IND
KAWASAKI HEAVY IND LTD
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