| 摘要 |
The pump has one or more impellers (8, 8a) on a shaft (7) driven directly by an electric motor (3). Each impeller has radial blades (10) between front and back plates. The front and back plates have thickened projections (20) through which there are axial holes (18) connecting the blade passages (16) with the spaces (11, 11a) between the front and back plates and the casing. These admit discharge pressure into the spaces in front of and behind the impeller and thus provide an axial equalising force to maintain the axial position of the impeller. The outlets (19) from the connecting passages are close to the sides of the casing so that they form throttle orifices which adjust the pressures in the spaces (11, 11a) to keep the impeller balanced axially. |
