JPS5741470A - Multi-stage hydraulic machine - Google Patents

Abstract

PURPOSE: To drain water stagnating in the vicinity of the outside periphery of a runner at each stage and thereby enable an idling operation to be conducted for a long period of time, by providing drain valves for leakage water in a leakage water drain pipe which connects a lower cover for a high pressure stage runner and the upper wall of a return passage ring.

CONSTITUTION: The lower cover 8, 17 for the high pressure stage runner 2 and the upper wall of the return passage ring 19 are connected to each other by the leakage water drain pipe 30, in which the drain valves 24, 31 are provided. Each of the drain valves 24, 31 is designed to open a valve port 26 by depressing a valve rod 28 downward when a hydraulic pressure so high as to overcome the force of a spring 29 is applied to the head part 28b of the valve rod 28. When water leaked out from movable guide vanes 10 and the cooling water supplied to a sealing part for the runner 2 stagnate in the outside peripheral area of the runner 2, the pressure of the stagnating water opens the valve 24, is discharged into the passages between return vanes 19a of the ring 19 through the drain pipe 23, flows through a passage 22 and flows into a low pressure stage runner chamber 6 via the passages between stay vanes 15. The leakage water then stagnates at the periphery of the runner 3, from which it is drained to the exterior through the drain pipe 30.

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