Multi-stage taper fan-motor assembly

Abstract

A motor-driven fan assembly includes a bracket which couples to a motor assembly and includes an outlet port. A shroud assembly defines a first chamber and a second chamber and includes an inlet port, the shroud assembly is received on the bracket. A bearing-supported shaft is driven by the motor assembly, and extends through the bracket and into the shroud assembly. A first fan is coupled to the shaft and positioned in the first chamber. A second fan is coupled to the shaft and positioned in the second chamber. The first and second fan include a plurality of curved blades positioned between a flat disc and a cap, the cap defining a non-linear cross section. Rotation of the fans by the shaft results in air flow through the fan assembly. Dust is generally prevented from settling on the fan blades during operation, thereby preventing non-uniform dust buildup or breakup which may cause excessive vibration and reduce bearing and brush life.

1 . A motor-driven fan assembly, comprising:
 a motor assembly;   a bracket coupled to said motor assembly, said bracket including an outlet port;   a shroud assembly which defines at least a first chamber and a second chamber and includes an inlet port, said shroud assembly adapted to be received on said bracket;   a shaft rotated by said motor assembly, said shaft extending through said bracket and into said shroud assembly;   a first fan coupled to said shaft and positioned in said first chamber; and   a second fan coupled to said shaft and positioned in said second chamber, wherein said first and said second fan each include a plurality of curved blades positioned between a flat disc and a cap, each said cap defining a non-linear cross section.   
   
   
       2 . The fan assembly according to  claim 1 , wherein said blades are disposed on said disc in a curved sunburst arrangement radiating radially outwardly. 
   
   
       3 . The fan assembly according to  claim 1 , wherein each said blade extends from said disc to said cap. 
   
   
       4 . The fan assembly according to  claim 1 , wherein said blades are secured to said cap and said disc. 
   
   
       5 . The fan assembly according to  claim 1 , wherein said shroud assembly further comprises:
 at least a first shell and a second shell having a spacing bracket therebetween, said first shell includes a tapered wall having the same cross-sectional profile as said cap of said first fan and said second shell includes a wall having the same cross-sectional profile as said cap of said second fan.   
   
   
       6 . The fan assembly according to  claim 5  further comprising a stationary fan, said stationary fan is coupled to said spacing bracket. 
   
   
       7 . The fan assembly according to  claim 6 , wherein said stationary fan comprises a plurality of curved blades and a disc, said blades are disposed between said disc and said stationary spacing bracket. 
   
   
       8 . The fan assembly according to  claim 1 , wherein said cap of said first fan includes a first fan aperture and said cap of said second fan includes a second fan aperture and when said shaft rotates air is drawn through said first and second fan apertures and radially outward across said blades. 
   
   
       9 . A fan assembly associated with a motor assembly having a rotatable shaft, the fan assembly comprising:
 a shroud assembly which includes a first shell and a second shell having a spacing bracket disposed therebetween, said first shell including a tapered wall and said second shell having a tapered wall, said tapered wall of said first shell being curved and substantially identical to a tapered wall of said second shell, said shroud assembly adapted to receive the rotatable shaft;   a first fan adapted to be coupled to the shaft and positioned adjacent to said tapered wall of said first shell; and   a second fan adapted to be coupled to the shaft and positioned adjacent to said tapered wall of said second shell, wherein said first and said second fan include a plurality of curved blades disposed between a flat disc and a cap, each said cap being curved to match the curvature of said adjacent tapered wall.   
   
   
       10 . The fan assembly according to  claim 9 , wherein each said blade is disposed on said disc in a curved sunburst arrangement radiating radially outwardly. 
   
   
       11 . The fan assembly according to  claim 10 , wherein each said blade extends from said disc to said cap. 
   
   
       12 . The fan assembly according to  claim 10 , wherein said blades are secured to said cap and said disc. 
   
   
       13 . The fan assembly according to  claim 12 , further comprising:
 a stationary fan coupled to said spacing bracket.   
   
   
       14 . The fan assembly according to  claim 10 , wherein said stationary fan comprises a plurality of curved stationary blades and a stationary disc, said stationary blades are disposed between said stationary disc and said stationary spacing bracket. 
   
   
       15 . The fan assembly according to  claim 10 , wherein said cap of said first fan includes a first aperture and said cap of said second fan includes a second aperture and when said shaft rotates air is drawn through said first and second apertures and radially outward across said blades.