| 摘要 |
895,256. Centrifugal pumps. DAN BERGMAN A.G., W. Dec. 30, 1959, No. 44329/59. Class 110 (1). [Also in Group XXXV] A submersible pump comprises a passage for the upward flow of fluid formed between an outer casing and an inner casing enclosing the driving motor, the depending shaft of which motor carries a pump impeller, and a lower portion of the outer casing forms an impeller housing and is provided with inlet and outlet guide vanes for the impeller, the lower portion and the impeller being exchangeable to adapt the pump for different operation conditions. The lower member 7 of the outer easing 1 affords a housing for the impeller 4 which is attached to a shaft 3 of an electric motor disposed within an inner casing 2. The impeller 4 draws fluid through a strainer 10 fixed to the impeller housing 7 by means of a bottom plate 11. The fluid passes between inlet and outlet guide vanes 8, 9 and along an annular passage between the casings 1, 2 and is discharged at the upper end of the pump. Axial guide ribs 13 integral with the inner casing 2 and disposed along the annular passage improve the fluid flow. They are hollow with the inner surfaces in contact with the air cooling the stator windings disposed within the inner casing 2. To adapt the pump to altered operating conditions the impeller housing 7 and impeller 4 may be exchanged for a different impeller and impeller housing having characteristics more suited to the altered operating conditions without disturbing the pump above the intermediate member 6. One such arrangement comprises a two-stage impeller and a two-part impeller housing.
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