Patent ID: 6042333
Filing Date: 2000-03-28
Classification: F04D

Abstract:
An impeller having a hub and a plurality of blades attached to the hub, comprisingthe hub having a front face and a rear face, and a part spherical portion between the front and rear faces,the blades having a root portion and a tip portion, the root portion being complementarily configured to the spherical portion, the blades being attached to the hub on the spherical portion by pins extending from the blades at a position between a leading edge of the blades up to a mid chord point of the blades and which extend into recesses in an upper part of the hub, the extending pins having a shoulder to strengthen the attachment of the blades to the hub, the shoulder having an upper face which is flush with the spherical portion of the hub, the upper face having a part spherical configuration to compliment the hub such that the blades can pivot without the formation of undue gaps between the root portion of the blades and the hub, and the root portion of each blade extends at least partially over the upper face of the shoulder of an adjacent blade to restrain the blades from tearing away from the hub during high speed rotation, and adjacent blades define a passageway therebetween, the passageway converging between a fluid inlet and a fluid outlet, the blades are in a spaced overlapping relationship relative to each other to define part of the passageways, and the spacings between adjacent blades adjacent trailing edges of the blades are less than the spacings between adjacent blades at the leading edges to provide the converging passageways.