Air flow capture system

Abstract

An apparatus and kit for capturing airflow from an inlet of a centrifugal fan, the centrifugal fan having a housing containing an impeller rotatable about a fan axis and an inlet passing through the housing along the centrifugal fan axis, the apparatus comprising a frame securable to the centrifugal fan housing across the centrifugal fan inlet and a capture fan rotatably supported by the frame, the capture fan having a center of rotation about the centrifugal fan axis. The apparatus further comprises an electrical generator motor operably connected to and drive by rotation of the capture fan, wherein the capture fan is rotatable in a first direction about the centrifugal fan axis by air drawn into the centrifugal fan inlet during operation of the centrifugal fan. The kit further comprises a centrifugal fan.

What is claimed is: 
     
         1 . An apparatus for capturing airflow from an inlet of a fan the apparatus comprising:
 a capture fan located upstream of said centrifugal fan,   an electrical generator motor operably connected to and drive by rotation of said capture fan;   wherein said capture fan is rotatable in a first direction by air drawn into said fan inlet during operation of said fan.   
     
     
         2 . The apparatus of  claim 1  wherein said capture fan is located in a cabinet wall surrounding said fan. 
     
     
         3 . The apparatus of  claim 1  wherein said fan comprises a centrifugal fan, the centrifugal fan having a housing containing an impeller rotatable about a fan axis and an inlet passing through the housing along the centrifugal fan axis, the apparatus further comprising:
 a frame securable to said centrifugal fan housing across said centrifugal fan inlet, 
 wherein said capture fan is rotatably supported by said frame, said capture fan having a center of rotation about the centrifugal fan axis; and 
 wherein said capture fan is rotatable in a first direction about said centrifugal fan axis by air drawn into said centrifugal fan inlet during operation of said centrifugal fan. 
 
     
     
         4 . The apparatus of  claim 3  wherein said capture fan comprises an axial fan having a central hub and a plurality of fan blades extending radially therefrom. 
     
     
         5 . The apparatus of  claim 4  wherein said plurality of fan blades of said axial fan comprise radial fan blades extending radially outward from said hub to a tip region. 
     
     
         6 . The apparatus of  claim 5  wherein each of said plurality of fan blades has a leading and a trailing edge. 
     
     
         7 . The apparatus of  claim 6  wherein said leading edge is convex. 
     
     
         8 . The apparatus of  claim 6  wherein said trailing edge is concave. 
     
     
         9 . The apparatus of  claim 5  wherein said tip region of said radial fan blades are secured to a cylindrical outer band. 
     
     
         10 . The apparatus of  claim 4  wherein each of said plurality of fan blades is skewed rearwardly from said leading edge to said trailing edge. 
     
     
         11 . A fan system for capturing airflow comprising:
 a powered fan;   a capture fan located upstream of said powered fan,   an electrical generator motor operably connected to and drive by rotation of said capture fan;   wherein said capture fan is rotatable in a first direction by air drawn into said fan inlet during operation of said powered fan.   
     
     
         12 . The fan system of  claim 11  wherein said capture fan is located within a cabinet wall of a cabinet containing said powered fan. 
     
     
         13 . The fan system of  claim 11  wherein said powered fan comprises a centrifugal fan having a centrifugal fan housing, the fan system further comprising:
 a frame adapted to span an inlet in said centrifugal fan housing and securable to said centrifugal fan housing, 
 wherein said capture fan has a center of rotation about a capture fan axis at the capture fan center, said capture fan rotatably mounted to said frame. 
 wherein said capture fan is rotatable in a first direction about said capture fan axis by air drawn into said inlet during operation of said centrifugal fan. 
 
     
     
         14 . The apparatus of  claim 13  wherein said capture fan comprises an axial fan having a hub at said capture fan center and a plurality of fan blades. 
     
     
         15 . The apparatus of  claim 14  wherein said plurality of fan blades of said axial fan comprise radial fan blades extending radially outward from said hub to a tip region. 
     
     
         16 . The apparatus of  claim 15  wherein said tip region of said radial fan blades are secured to a cylindrical outer band.