Patent ID: 8033792
Filing Date: 2011-10-11
Classification: F04D,Y10T

Abstract:
1. A centrifugal pump impeller system for pumping fluid, including molten metal, comprising: an impeller adapted for rotating about an axis in a certain pumping direction of rotation, comprising: a circular and generally flat base; and a plurality of vanes mounted to the base, the vanes extending radially from a radially inward portion of the base to an outer-most edge of the base, each vane having a concave leading wall, a convex trailing wall, and an outer peripheral wall depending from and interconnecting the leading wall and trailing wall, the trailing wall of each vane cooperating with the leading wall of an adjacent vane to define a curved passage, wherein the trailing wall of each vane is complementary in shape to the adjacent leading wall, such that the passage has a gradually increasing cross-sectional area from a radially inward inlet to a radially outward outlet; wherein each outer peripheral wall includes a viscous drag cavity having a rearward arcuate wall which has substantially the same curvature as each vane's leading wall; wherein said impeller is rotatable about a central axis such that fluid flowing through each passage follows the curved leading wall into the same general direction as the pumping direction of rotation.