| 摘要 |
PURPOSE:To detect the leakage of gas at an early stage, by providing weirs against flow from below at plural positions to the outer surface of the side plate of an inner tank in a height direction. CONSTITUTION:L-shaped weirs 12 having downwardly directed flanges are attached to the outer surface of the side plate 1 of an inner tank at plural positions in a height direction while a plurality of ring shaped weirs 13 having different radii are concentrically provided to the under surface of the roof 5 of an outer tank. Hereupon, now, when a crack is generated in the roof 4 of the inner tank and gas is leaked into a cool keeping layer 6, the leaked gas reaches the under surface of the roof 5, and interrupted and stayed by the first weir 13. When a crack is generated in the side plate 1, the leaked gas is evaporated in a heat-insulating layer 3 and rises along the outer surface of the side plate 1 by the difference of specific gravity with seal gas, and interrupted and stayed by the weir 12 met at first. Therefore, if the stored gas component is detected from the gas sampling apparatus 14 corresponding to the stagnating weir, it can be detected that a leak is within a range between said weir and the adjacent weir in the lower side. |
