| 摘要 |
PURPOSE:To prevent the transfer of ballast water due to syphone phenomenon by connecting an air pipe which can communicate to the outside air with a collection pipe for each piping for supplying and discharging water from each ballast tank in the lower hull of a water lifted structure body. CONSTITUTION:A number of ballast tanks 8 are formed in the lower hull 2 of a water lifted structure body such as petroleum-oil rig, etc. An air pie 19 extending to an upper deck 1 along a column 3 is connected to the collection pipe 12 for the piping 15 for supplying and discharging water from each ballast tank 8. An air port 21 is formed through a valve 20 at the edge part on the upper deck 1 of the air pipe 19. When the structure body tilts, the front and rear ballast tanks generate syphone phenomenon through the piping 15 and the collection pipe 20, and when the ballast water shifts, air is supplied through the air pipe 19 by opening the valve 20, and the transfer of the ballast water due to the syphone phenomenon is prevented, ad the structure body a be maintained in stable state.
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