| 摘要 |
PURPOSE:To prevent the forming of frost enhancing the cryogenic performance at a manhole by storing a bag filled with granular or powdery cold insulator such as granular or powdery perlite in an outer vessel manhole of a cryogenic tank. CONSTITUTION:In the space between an inner vessel manhole 5 and an outer vessel manhole 6, glass wool 8 is filled. In the space of the outer vessel manhole 6 projected outward from the inner manhole 5, a cloth bag 14 filled with granular or powdery cold insulator 13 such as granular or powdery perlite is stored. Such being the constitution, the cryogenic performance at the outer vessel manhole 6 enhances and frost is not formed in the vicinity X of crossing part of the outer vessel manhole 6 and the outer vessel side plate 4a. |
