| 摘要 |
PURPOSE:To introduce a sufficient amount of water into a runner chamber by affording communication between the runner cone chamber and a runner flow path through a balance hole to specify the profile of them. CONSTITUTION:A radial distance R1 from the center line O1 about which a runner rotates to the opening center at the runner cone chamber 10 side of the lower balance hole 12 is made equivalent or more to the radial distance R2 between the rotational center line O1 and the opening center at the runner cone chamber 10 side of the upper balance hole 11. The radial distance R2 between is determined larger than the radial distance R3 between the center line O1 of rotation and the lower end opening edge of a runner cone 9. The total sectional area of low path in the lower balance hole 12 is determined approximately equivalent or more to the sum of the total sectional area of flow path in the upper balance hole 11 and the opening area in the lower end of the runner cone 9. Thus, water flow from a runner back pressure chamber 8 can be introduced into a runner flow path 13 smoothly through both balance holes 11, 12. |
