| 摘要 |
PURPOSE:To drain water staying in a return passage connected to the outer periphery and the upper part of a low pressure stage runner chamber in a multistage hydraulic machine in a short time by lowering the water level by the drain water and the air supply by means of the centrifugal force of the runner when a hydraulic machine is transferred to an idling operation. CONSTITUTION:When the water level of the inside flow passage of the maximum stage guide vanes 15 is lowered, the vanes 15 are fully closed, and air is supplied only to the draft tube 18 of the minimum pressure stage of multistage hydraulic machine passages. After the water in the runner chamber 9 of the low pressure stage is first loweredy by supplying compressed air, the air is supplied to a return passage 20 of the upper high pressure side passage in which water is still staying, and the outer periphery of the runner chamber except the maximum stage is communicated with the draft tube 18 through drain tubes 21, 22, 31, 33. In this manner the water can be drained in a short time by the water level lowering effect by the air supplying operation from above in addition to the draining effect of the centrifugal force of the runners. |
