Patent ID: 7329085

Claim:
An impeller suitable for use in a centrifugal pump, for handling liquid mixtures containing particulate solids, the impeller including a front shroud having opposed faces, an outer peripheral edge portion and a rotation axis, a back shroud having opposed faces, an outer peripheral edge portion and a rotation axis, a plurality of pumping vanes positioned between the front and back shroud and extending away from the rotation axis, each pumping vane having an outer peripheral edge portion, and a plurality of auxiliary vanes on the other face of at least one shroud, the auxiliary vanes each having an outer edge portion, wherein the dimension Da from the rotation axis to the outer peripheral edge portion of the shrouds is greater than the dimension Db from the rotation axis to the outer edge portion of the auxiliary vanes and wherein Da is greater than the dimension Dc from the rotation axis to the outer peripheral edge portion of the pumping vanes and wherein the dimension Da of the one of the shrouds is greater than the dimension Da of the other shroud.