20090191061 | Impeller Arrangement and Pump - The present invention relates to an improved multi-impeller arrangement and to a pump having the impeller arrangement. The impeller arrangement or impeller cluster includes at least two impellers, each impeller having an annular back plate and an annular front plate. The impellers are releasably secured together in an axially in-line series having the front plate of a first impeller at one end and the back plate of a second impeller at the other end. The second impeller includes an axial projection which extends from its back plate, through and beyond its front plate to the first impeller. The first impeller is engaged with the projection of the second impeller such that all impellers are rotatable as an assembly. | 07-30-2009 |