Patent ID: 10436210

Abstract:
An impeller which can be rotated about a rotation axis X-X, the impeller comprising a shroud having opposed inner and outer faces and an outer peripheral edge portion remote from the rotation axis, a plurality of pumping vanes projecting from the inner face of the shroud, a plurality of auxiliary vanes projecting from the outer face of the shroud, one or more of the auxiliary vanes having an inner edge which is closer to the rotation axis and an outer edge which is closer to the peripheral edge portion of the shroud, the auxiliary vanes extending in a direction between the rotation axis towards the outer peripheral edge portion of the shroud, one or more of the auxiliary vanes having a leading side and a trailing side each of which extends from the inner edge to the outer edge with an upper side spaced from the outer face of the shroud, and at least one projection extending from the trailing side of one or more of the said auxiliary vanes, and preferably each auxiliary vane.