High efficiency centrifugal fan

Abstract

A centrifugal fan has a blower wheel ( 12 ) with an annular array of vanes ( 15 ) mounted for rotation about an axis of rotation. Each vane has a concave leading surface with an inboard portion located more proximally to the axis of rotation having a smaller radius of curvature than an outboard portion located more distally from the axis of rotation.

1 . A centrifugal fan having an annular array of vanes mounted for rotation about an axis of rotation and with each vane having a concave leading surface with an inboard portion located more proximally said axis of rotation having a smaller radius of curvature than an outboard portion located more distally said axis of rotation.  
     
     
         2 . The centrifugal fan of  claim 1  wherein said inboard and outboard surface portions have relative radii of curvature of approximately 3 to 4.  
     
     
         3 . A centrifugal fan having a blower wheel for drawing air axially into the wheel and then radially through the wheel and with the blower wheel having an array of vanes with leading surfaces oriented at an angle of attack to air inside the wheel that varies between their inboard edges proximal to the wheel axis of rotation and their outboard edges distal to the wheel axis of rotation at a non uniform rate.  
     
     
         4 . The centrifugal fan of  claim 3  wherein said vane leading surfaces vary from an acute angle of attack adjacent their inboard edges to an obtuse angle of attack adjacent their outboard edges.