| 摘要 |
<p>The present invention enables an easy injection of bubbles to the whole lower part inside a ballast tank, reliably with low cost, by respectively forming a bubble cutting part and a bubble injecting part into multiple tubular parts having predetermined length by forming multiple penetration holes in the outer periphery; forming a flange part with an expanded diameter in both ends of each tubular part of the bubble cutting part; forming a flange part with a reduced diameter in both ends of each tubular part of the bubble injecting part; and forming multiple penetration holes in a blind flange by combining the blind flange in each flange part of the bubble injecting tubular part and the bubble cutting part which are arranged in the front end, to manufacture the bubble cutting part and the bubble injecting part through casting such as lost wax process.</p> |
