Housing for paddle fan

Abstract

Air turnover in a space achieved by a paddle fan having a plurality of blades is significantly increased by mounting an assembly radially outward from the blades. The assembly has a generally vertical shroud that is substantially impervious to air flow and a directing grid attached to the shroud at a lower end thereof. The directing grid has a plurality of intersecting members to reduce cross-sectional flow area and induce laminar air flow therethrough.

1 . An assembly for improving the turnover of air in a space by a paddle fan having a plurality of blades extending a first radial distance from a centerline thereof, comprising:
 a generally vertical shroud, having an internal diameter at least at a top end thereof that is slightly larger than a diameter of the paddle fan;   a directing grid attached to the shroud at a lower end thereof, the directing grid comprising a plurality of intersecting members to reduce cross-sectional flow area; and   means for mounting the shroud radially outwardly from the fan blades.   
     
     
         2 . The assembly of  claim 1 , wherein:
 the shroud is cylindrical.   
     
     
         3 . The assembly of  claim 1 , wherein:
 the shroud is frustoconical.   
     
     
         4 . The assembly of  claim 2 , wherein:
 the mounting means attaches the shroud to the paddle fan.   
     
     
         5 . The assembly of  claim 2 , wherein:
 the mounting means attaches the shroud to a ceiling from which the paddle fan is suspended.   
     
     
         6 . The assembly of  claim 1 , wherein:
 the average airflow velocity at a point between 80 and 100% of the radial distance from the centerline to the blade tip is greater when the paddle fan is operated with the assembly in place relative to identical operation of the paddle fan without the assembly in place.   
     
     
         7 . The assembly of  claim 1 , wherein:
 a ratio of the average airflow velocity measured at a point between 80 to 100% of the radial distance form the centerline to the blade tip to the average airflow velocity measured at the centerline under the same operating conditions increases by at least a factor of 4.   
     
     
         8 . The assembly of  claim 1 , wherein:
 the internal diameter of the shroud is at least about 30 inches.   
     
     
         9 . The assembly of  claim 3 , wherein:
 the mounting means attaches the shroud to the paddle fan.   
     
     
         10 . The assembly of  claim 3 , wherein:
 the mounting means attaches the shroud to a ceiling from which the paddle fan is suspended.