Abstract: A multistage pump of the type including a jacket, a shaft which is coaxial to the jacket and connected to an electric motor, and active pumping stages rigidly coupled to the shaft; each stage is formed by an impeller with a front ring and by a distribution element facing the ring with the interposition of an annular supporting element shaped like an inverted bowl; the radial-vane impellers and their distribution elements are rigidly coupled to the jacket made of a highly wearproof material, and the impellers are mounted on the shaft and can move axially or float with a preset stroke with respect to the associated bowl-shaped element, whereas at least one annular supporting and sealing element for the impeller is interposed between the front ring of each impeller and the associated bowl-shaped element, is made of a material which is more wearproof than the impellers, and is suitable to withstand the axial thrusts of the various stages and prevent any fluid seepage during pump operation.

Abstract: The subject of the invention is a casing jacket for centrifugal pumps in which the suction side connecting flange is integrated in the casing jacket and the actual suction nozzle is located inside the casing jacket. A high degree of pressure resistance is obtained by embossed, corrugation-like spaces for the suction side flange connecting means and a corresponding curved or spherical outer contour of the casing jacket.

Abstract: An impeller for a centrifugal pump is disclosed for attenuating the effects of pressure and flow surges experienced by the pump. The impeller includes a rotatable impeller shaft to which a plurality of circumferentially-spaced vanes are mounted for rotation therewith, the vanes extending outwardly relative to the impeller shaft and each including first and second axially spaced edges. First and second axially-spaced cover members are provided for the plurality of vanes, the cover members being mounted for rotation with the impeller shaft and extending outwardly relative to the axial direction of the impeller shaft. The first cover member is disposed adjacent to first edges of the vane and the second cover member is disposed adjacent to second edges of the vane so as to provide an impeller chamber between the first and second cover members which is divided into subchambers by the vanes.