Air Diffuser

Abstract

An air diffuser for use with an air feed in a heating, ventilation, and air conditioning (HVAC) system, having a rotatable plenum from which project hollow blades. Each blade has an outlet port along the blade trailing edge, such that air received from an HVAC system flows through the air diffuser and is expelled from the outlet ports, causing the blades to rotate.

What is claimed is: 
     
         1 . An air diffuser for use with an air feed in a heating, ventilation, and air conditioning (HVAC) system, the air feed having an air-feed cross-sectional area, the air diffuser comprising:
 a mount portion for mounting in association with an air feed, the mount portion having a mount portion interior for receiving air from the air feed and the mount portion interior having a mount portion interior cross-sectional area;   a plenum, rotatably connected to the mount portion, and having a plenum interior for receiving air from the mount portion interior, the plenum interior having a plenum cross-sectional area equal to or greater than the mount portion interior cross-sectional area; and   a plurality of blades projecting from the plenum, each blade having a discharge slot, with a discharge area, each of the discharge slots in fluid communication with the plenum interior, wherein the total area of all the discharge areas is between about 75% and about 95% of the mount portion interior cross-sectional area and wherein a flow of air out of the discharge slots tends to cause the plenum and blades to rotate relative to the mount portion.   
     
     
         2 . The air diffuser of  claim 1 , wherein the plurality of blades consists of four blades. 
     
     
         3 . The air diffuser of  claim 1 , wherein the total area of all the discharge areas is between about 80% and about 90% of the mount portion interior cross-sectional area. 
     
     
         4 . The air diffuser of  claim 1 , wherein the total area of all the discharge areas is about 85% of the mount portion interior cross-sectional area. 
     
     
         5 . The air diffuser of  claim 1 , wherein the plenum cross-sectional area is at least about 150% of the air-feed cross-sectional area. 
     
     
         6 . The air diffuser of  claim 1 , wherein the plenum cross-sectional area is between about 150% and about 225% of the mount portion interior cross-sectional area. 
     
     
         7 . The air diffuser of  claim 1 , wherein each blade comprises, a planar upper wall, a planar lower wall, a curved leading edge and a planar trailing edge containing the discharge slot. 
     
     
         8 . The air diffuser of  claim 7 , wherein the planar trailing edge and discharge slot each have a length and the length of the discharge slot is about 70% to 85% of the length of the planar trailing edge. 
     
     
         9 . The air diffuser of  claim 8 , wherein the discharge slot is centered along the length of the planar trailing edge. 
     
     
         10 . The air diffuser of  claim 7 , wherein:
 each blade has a proximal end adjacent the plenum and a distal end away from the plenum; and   in each blade, in terms of transition along the blade from the proximal to the distal end:
 the planar upper wall the planar lower wall converge towards each other; 
 the curved leading edge and the planar trailing edge converge towards each other; and 
 the discharge slot narrows. 
   
     
     
         11 . The air diffuser of  claim 10 , wherein the cross sectional area of each blade at the distal end is about 20% to about 40% of the cross sectional area at the proximal end. 
     
     
         12 . The air diffuser of  claim 1 , further comprising an annular seal interposed between the mount portion and the plenum for impeding the release of air there between while permitting relative rotational movement as between the mount portion and the plenum. 
     
     
         13 . The air diffuser of  claim 1  further comprising a stationary cap located adjacent the portion of the plenum opposite the mount portion. 
     
     
         14 . The air diffuser of  claim 1 , wherein the blades and plenum comprise sheet metal.