Patent ID: 9500084
Filing Date: 2016-11-22
CPC Classification: F01D,F04D

Claim Text:
1. An impeller for increasing the pressure of a fluid circulating in an annular fluid path, the impeller comprising: a plurality of centrifugal compressor vanes circumferentially interspaced around an axis of the annular fluid path, the plurality of compressor vanes extending from a generally axially-oriented inlet to a generally radially-oriented outlet, and each having an inner edge and a free edge, the free edge of the plurality of compressor vanes being adjacent to an outer limit of the annular fluid path and extending along the annular fluid path, between the inlet and the outlet, and a hub centered around the axis of the annular fluid path, the hub having an outer hub surface to which the inner edge of the plurality of centrifugal vanes is secured, the free edge of the plurality of centrifugal vanes extending away from the outer hub surface and being free from the hub, the outer hub surface having an orientation angle with respect to the axis which varies from the inlet to the outlet by gradually increasing to reach 90°, exceeds 90° forming an axial recess in a portion of the outer hub surface associated with a back plate of the hub, and then decreases into a forward lean configuration; wherein the back plate of the hub has a rear surface forming an arch in the vicinity of the axial recess in the outer hub surface, the rear surface having a radially outer portion also having a forward lean configuration and a radially inner portion having a rearward lean configuration.