| 摘要 |
PROBLEM TO BE SOLVED: To adjust an axial direction water thrust force which increases along with aging deterioration of a seal part in a Francis type hydraulic machine. SOLUTION: A rotatable runner 1 having a plurality of blades 31 and a runner crown 32 attached to cover upper parts of the blades and an upper cover 10 covering an upper part of the runner crown are provided. An annular back pressure chamber 12 is formed between an upper surface of the runner crown and a lower surface of the upper cover. At least one annular seal part 14 is formed in the back pressure chamber. The back pressure chamber is divided into an annular inside back pressure chamber 12a inside of the seal part and an annular outside back pressure chamber 12b outside of the seal part. Vertical pressure acting on the runner in the back pressure chamber is roughly balanced with this construction. A communication hole 16 passing through a gap between a lower surface of the runner crown and the inside back pressure chamber side, and a means 17 adjusting flow resistance of the communication hole is provided. COPYRIGHT: (C)2006,JPO&NCIPI
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