| 摘要 |
PURPOSE:To regulate the position of a head through switching of a valve, by a method wherein a pair of right and left injection nozzles, being open in water, which are connected through the respective valves to a feed pipe for feeding pressurized water to the injection nozzle for excavation of a drag-head, are located to the head. CONSTITUTION:A drag-head 4 of a drag suction dredger has nozzles 11 for excavation of soil in a sea bottom and an injection water feed pipe 10 connected to the injection nozzles 11 through a valve 14. The injection water feed pipe 10 is branched through a branch pipe 12 into a pair of a right and a left branch pipe, and the branch pipes are open in water through their respective values 13a and 13b. Either of the branch pipes and the injection nozzle 11 are selectively communicated with the injection water feed pipe 10 to regulate the position of the drag-head 4. This enables prevention of the occurrence of extra excavation and improvement of dredging efficiency. |
