| 摘要 |
PURPOSE:To increase the ridigity of a draft tube inlet part by providing plural annular ribs on the outer periphery of the draft tube. CONSTITUTION:Plural annular ribs 22 are provided on the outer peripheral part 21a of a water wheel while distributed in the water current direction. The rib 22 is formed U-shaped in its cross section, and its opening side is welded to the upstream side outer peripheral part 21a of the draft tube. The upstream side outer peripheral part 21a of the rib 22 and the draft tube around said rib is covered with foundation concrete 26. The draft tube outer peripheral part 21a located upstream of a water sealing part 17 is increase its rigidity by the rib 22, and the rib 22 is fixed by the foundation concrete 26, so that the vibration of the outer peripheral part 21a is eliminated due to a circulating water flow from a runner vane 6 even if an off cam operation is performed. |
