| 摘要 |
An impeller for a centrifugal pump (10) which includes a front shroud and a rear shroud, the shrouds being spaced apart so as to form a plurality of passageways (18) therebetween which are separated by a plurality of impeller blades (19). The impeller has an outer diameter D2 and an inlet diameter D1. Each passageway has an inlet portion with a passageway inlet (21) having a width B1, an outlet portion (22) having a passageway outlet B2, and an intermediate portion between the inlet and outlet portions. In the inlet portion the front shroud is curved away from the rear shroud so that the passageway outlet width B2 is less than the passageway inlet width B1. A method of increasing the Best Efficiency Point flow rate comprises providing such an impeller and also providing a new front liner or throat bush (13) which has an inner wall which is complementary to the wall of the inlet portion of the impeller while retaining the same main liner or casing section (12).
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