| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a multiplex piping for a low temperature fluid, efficiently eliminating heat of a vacuum pipe even if thermal load of the vacuum pipe is increased. <P>SOLUTION: The vacuum pipe 13 is provided to maintain heat insulating performance on the outside of a liquid hydrogen piping inner pipe 1 allowing liquid hydrogen to flow through the inside, and of a liquid hydrogen piping outer pipe 2, and the space between the outer pipe 2 and the vacuum pipe 13 is kept to a vacuum atmosphere 9. The vacuum pipe 13 is provided with projecting parts 10 having a substantially rectangular section and projected outward in the radial direction in two areas on the outer periphery side . At the stepped parts 10a of the projecting parts, both ends of a semi-cylindrical helium pipe 14 are fixed by welding. The space between the helium pipe 14 and the vacuum pipe 13 is filled with helium gas 7. A cooling water pipe 15 allowing cooling water 8 to flow through the inside is fixed to the outer peripheral surface 10b of the projecting part 10 by welding. <P>COPYRIGHT: (C)2004,JPO</p> |
