| 摘要 |
A hydraulic machine, such as a reversible pump-turbine, is provided with an automatic air vent valve disposed in the casing area and a conduit having a valve for providing direct fluid communication between the casing area and the draft tube, in addition to compressed air means for depressing the water level within the draft tube below the runner, when the guide vanes are closed so that the runner may be rotated substantially only within air. When the runner of the hydraulic machine is rotating within the compressed air that depresses the water level and the draft tube out of the runner chamber and below the runner, water from the draft tube is fed through the valved conduit directly to the casing area, between the inlet valve and the closed guide vanes, to make up for water leaking from the side gaps of the closed guide vanes, with the conduit feed valve being open; at the same time, compressed air that leads through the side gaps of the guide vanes from the runner chamber into the casing is vented out of the casing through the automatic air vent valve.
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