Ventilation fan

Abstract

A ventilation fan wheel having a wheel hub. A plurality of peripheral fan blades are coupled to an outer edge of the wheel hub and spaced apart circumferentially about a rotation axis of the fan wheel. A plurality of impeller fan blades extend from the wheel hub radially between the rotation axis and the plurality of peripheral fan blades.

1 . A ventilation fan comprising:
 a scroll formed to define an interior space, an inlet opening into the interior space, and an outlet spaced apart from the inlet,   a fan wheel coupled to the scroll and arranged to lie within the interior space, and   a motor configured to drive rotation of the fen wheel about a rotation axis,   wherein the fan wheel includes a wheel hub coupled to the motor, a plurality of peripheral fan blades coupled to an outer edge of the wheel hub and spaced apart circumferentially about the rotation axis, and a plurality of impeller fan blades coupled to the wheel hub and located radially between the rotation axis and the plurality of peripheral fan blades.   
     
     
         2 . The ventilation fan of  claim 1 , wherein each of the impeller fan blades is spaced apart from the rotation axis and is arranged along a plane that does not pass thorough the rotation axis. 
     
     
         3 . The ventilation fan of  claim 2 , wherein each plane is substantially straight and parallel with the rotation axis. 
     
     
         4 . The ventilation fan of  claim 3 , wherein the each plane extends through a tangent point of one of the peripheral blades. 
     
     
         5 . The ventilation fan of  claim 2 , wherein each impeller blade has an inner end located at a first circumferential location and an outer end located at a second circumferential location offset from the first circumferential location. 
     
     
         6 . The ventilation fan of  claim 4 , wherein the outer end of each impeller blade is formed integrally with a radially inner end of a corresponding peripheral blade. 
     
     
         7 . The ventilation fan of  claim 1 , wherein each of the peripheral blades has a first, constant height and each of the impeller blades has a second, variable height. 
     
     
         8 . The ventilation fan of  claim 7 , wherein the second, variable height is less than the first, constant height. 
     
     
         9 . The ventilation fan of  claim 1 , wherein each of the impeller blades has a bottom edge that slopes toward a proximal end of the peripheral blades as the impeller blades extend radially outward away from the rotation axis. 
     
     
         10 . The ventilation fan of  claim 1 , wherein each of the impeller blades has a bottom edge that slopes toward a distal end of the peripheral blades as the impeller blades extend radially outward away from the rotation axis. 
     
     
         11 . A fan wheel for a ventilation fan, the fan wheel comprising:
 a wheel hub defining a rotational axis configured to be coupled to a motor;   a plurality of peripheral fan blades coupled to an outer edge of the wheel hub and spaced apart circumferentially about the rotational axis; and   a plurality of impeller fan blades coupled to the wheel hub and located radially between the rotation axis and the plurality of peripheral fan blades.   
     
     
         12 . The fan wheel of  claim 11 , wherein each of the impeller fan blades is spaced apart from the rotation axis and is arranged along a plane that does not pass thorough the rotation axis. 
     
     
         13 . The fan wheel of  claim 12 , wherein each plane is substantially straight and parallel with the rotation axis. 
     
     
         14 . The fan wheel of  claim 13 , wherein the each plane extends through a tangent point of one of the peripheral blades. 
     
     
         15 . The fan wheel of  claim 12 , wherein each impeller blade has an inner end located at a first circumferential location and an outer end located at a second circumferential location offset from the first circumferential location. 
     
     
         16 . The fan wheel of  claim 14 , wherein the outer end of each impeller blade is formed integrally with a radially inner end of a corresponding peripheral blade. 
     
     
         17 . The fan wheel of  claim 11 , wherein each of the peripheral blades has a first, constant height and each of the impeller blades has a second, variable height. 
     
     
         18 . The fan wheel of  claim 17 , wherein the second, variable height is less than the first, constant height. 
     
     
         19 . The ventilation fan of  claim 11 , wherein each of the impeller blades has a bottom edge that slopes toward a proximal end of the peripheral blades as the impeller blades extend radially outward away from the rotation axis. 
     
     
         20 . A fan wheel for a ventilation fan, the fan wheel comprising
 a wheel hub defining a rotational axis;   a plurality of peripheral fan blades extending from an outer edge of the wheel hub; and   a plurality of impeller fan blades coupled to the wheel hub radially inward of the peripheral fan blades.