| 摘要 |
PURPOSE:To prevent the occurrence of buckling on the downstream side as well as raise sucking function on the upstream side by a method in which a bellows-like expandible tube is used for the upstream side and an inflexible fitting slide tube is used for the downstream side. CONSTITUTION:When an upstream side partition valve 7a is closed, a downstream side partition valve 7b is opened, and a movable relay tube 6 is advanced (to the left), a bellows-like expandible tube 4 is extended to such up soil in a soil-charging box 1 into the tube 4. Also, when the tube 7b is closed,and the tube 7a is opened, and the tube 6 is retracted (to the right), soil and sand is moved from the inside of the tube 6 into a fixed tube 5 for discharge. The same operations are repeated thereafter. The tube 4 is used for the upstream side and an inflexible fitting slide tube 6b is used for the downstream side. The sucking function on the upstream side can thus be raised, and the occurrece of buckling on the downstream side can be prevented.
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