| 摘要 |
PURPOSE:To prevent resonance by providing a window hole in a stay vane at a terminal end of a spiral casing and providing an opening area adjusting means in the window hole to change freely the characteristic frequency of standing wave of water post in the casing. CONSTITUTION:A stay vane 12 at the terminal end of a spiral casing 11 is provided with a window hole 15 the area of which can be freely changed by the operatio of a handle 19 of an adjusting device 16. When a hole is provided in the stay vane 12 at the winding end of volute, the boundary requirement of standing wave motion is changed to vary vibration frequency. Particularly, when the window hole corresponding to only about 5-10% of end area of the closed stay vane 12 is provided, the standing wave meets approximately fully-open requirement, and when this window hole area is adjusted, the standing wave has the vibration frequency changed over a wide range from open end requirement standing wave to closed end requirement one. |
