| 摘要 |
PURPOSE:To prevent the buckling and leak of tubes by supporting the outer periphery of a bellows-like expandible tube on the downstream side on a movable ring. CONSTITUTION:An upstream side partition valve 10a is closed, a downstream side partition valve 10b is opened,and a movable relay tube 7 is advanced (to the left). Hereupon, a bellows-like expandible tube 6a on the upstream side is extended to suck up soil and sand in a soil-charging box 1 into the tube 6a. When the valve 10b is closed, the valve 10a is opened, and the tube 7 is retracted (to the right), soil and sand is moved from the inside of the tube 7 into the tube 6b. The same operations are repeated thereafter. The periphery of the tube 6b on the downstream side is supported on a movable ring 9. The buckling and leak of the tube can thus be prevented.
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