| 摘要 |
PURPOSE:To enable to prevent lowering of the efficiency of a volute pump or the like due to occurrence of back flow, by extending the outlet end of each vane in the manner that the extended portion of one vane and the inlet end of other vane are overlapped with each other over a predetermined angle. CONSTITUTION:Outlet end of each vane 12 is extended a proper length smoothly along the outer circumference 11a of an impeller 11, so that inlet end portion 12a of one vane 12 and an extended portion 12b at the outlet portion of other vane 12 are overlapped a predetermined angle alpha with each other along the circumference of the impeller 11. Therefore, if the circumferential length of the extension 12b is selected appropriately, it is enabled to overlap the two vanes 12 with each other always over the predetermined angle alpha, so that occurrence of back flow can be prevented and hence lowering of efficiency can be prevented accordingly. |
