Patent ID: 6250886
Filing Date: 2001-06-26
Classification: F04D

Abstract:
An axial flow fan, comprising:a hub;a plurality of hollow airfoil sections, each comprising a sheet of alloy bent to form a leading edge and having a trailing edge formed from the joining of two long edges of the sheet, each of the long edges having a substantially continuously changing curvature, the sheet possessing a bend of a first direction adjacent one of the two long edges and a bend of a second direction adjacent the other of the two long edges, whereby each of the airfoil sections possesses a twist; andfor each airfoil section, a transition piece connecting the airfoil section to the hub, the transition piece have first and second airfoil bearing surfaces, substantially all of the bearing surfaces being in contact with an interior surface of the airfoil section, and wherein each of the bearing surfaces after joining to the airfoil section possesses a twist complementary to the twist of the airfoil section.