| 摘要 |
PURPOSE:To increase a degree of anticorrosion and strength against fatigue in an economic manner without making runner weight yet increase, by reinforcing an inner circumferential part of a balance hole being bored in a cover plate. CONSTITUTION:An in-and-out pressure regulating balance hole 6 is being installed in a cover plate 4. A reinforced layer 10 consisting of stainless steel or the like is installed in an inner circumferential part of this balance hole 6. This reinforced layer 10 is formed so as to have almost uniformly thickness over the whole circumference by means of padding welding. With this constitution, a runner is made resistible to stress concentration due to pulsation hydraulic pressure of high frequency. |
