| 摘要 |
PURPOSE:To improve the pump efficiency, by a method wherein, in an intermediate casing, a single water return vane is located opposite to a volute maximum opening part at a preceding stage, and said vane is extended to the maximum diameter of the casing to uniformize the flow in a passage formed with the water return vane. CONSTITUTION:A water return vane 7 is positiolned opposite to a volute maximum opening 1' at a preceding stage, and the water return vane 7 is extended to the maximum diameter of a casing and is caused to coincide with the maximum opening 1'. This produces an approximately equal flow in each of passages formed with their respective water return parts, and uniformizes loss incurred due to deviation of velocity of flow in a passage, and enables water to uniformly flow in vanes at their respective subsequent stages. Furthermore, this prevents production of wasteful flow in a peripheral direction, reduces the occurrence of loss, and improves the pump efficiency. Additionally, since an intermediate casing is prevented from production of vortex therein, even if a device is used in liquid of adverse quality, this permits prevention of the occurrence of a trouble in which the casing is corroded and worn into holes. |
