In-Line Fan Assembly

Abstract

An airflow electrical generator for a duct system. The electrical generator is located outside the duct. The axle of the electrical generator is vertical to the airflow within the duct allowing the blades of the generator to be pushed downwind along the duct with the airflow. During the “upwind” movement of the blades, the blades pass outside the duct's profile into a closely fitting plenum allowing each blade to travel outside the airflow and all the low-pressure created by the movement of each blade within the plenum to pull the following blade for improved efficiency.

What is claimed is: 
     
         1 . A fan assembly engaging an airflow, said fan assembly comprising:
 a) a fan having,
 1) a central axle positioned perpendicular to the airflow, and, 
 2) a multitude of blades secured to the central axle and positioned to selectively engage the airflow, such that the blades so engaged travel in the airflow direction and cause said central axle to rotate; and, 
   b) a generally semi-circular plenum positioned external to the airflow and positioned such that during rotation of the central axle, each of said multitude of blades passes through the generally semi-circular plenum.   
     
     
         2 . The fan assembly according to  claim 1 , further including a bevel positioned to direct the airflow away from the generally semi-circular plenum. 
     
     
         3 . The fan assembly according to  claim 2 , wherein each of said multitude of blades are configured for resistance to the airflow. 
     
     
         4 . The fan assembly according to  claim 2 , wherein said central axle is positioned to extend through the plenum. 
     
     
         5 . The fan assembly according to  claim 2 , further including a duct encasing the airflow and wherein the plenum is secured to said duct. 
     
     
         6 . The fan assembly according to  claim 5 , wherein said central axle is positioned to extend through the duct. 
     
     
         7 . The fan assembly according to  claim 5 , wherein said central axle is secured to and drives a secondary mechanism. 
     
     
         8 . A mechanism comprising:
 a) a fan having a central axle positioned perpendicular to an airflow, said central axle having a multitude of blades secured thereto;   b) A semi-circular plenum positioned outside the airflow and positioned such that during rotation of the central axle, each of said multitude of blades passes through the plenum and at a different position engages the airflow; and,   c) a bevel adapted to create air pressure within the plenum less than an air pressure of the airflow.   
     
     
         9 . The mechanism according to  claim 8 , wherein each of said multitude of blades are shaped for resistance to the airflow and reduced resistance when traveling through the plenum. 
     
     
         10 . The mechanism according to  claim 9 , wherein said central axle is positioned to extend through the plenum. 
     
     
         11 . The mechanism according to  claim 9 , further including a linear duct encasing the airflow and wherein the plenum is secured to said linear duct. 
     
     
         12 . The mechanism according to  claim 11 , wherein said central axle is positioned to extend through the linear duct. 
     
     
         13 . An electrical generator comprising:
 a) a fan having,
 1) a central axle positioned perpendicular to an airflow, and, 
 2) a multitude of blades secured to the central axle and positioned to selectively engage the airflow, such that blades so engaged, travel in a direction of the airflow and cause said central axle to rotate; 
   b) an airflow free plenum positioned such that during rotation of the axle, each of said multitude of blades at some point in their rotation passes through the plenum removed from the airflow; and,   c) at least one generator secured to the central axle such that rotation of the central axle causes said at least one generator to produce electricity.   
     
     
         14 . The electrical generator according to  claim 13 , wherein each of said multitude of blades are configured for resistance to the airflow. 
     
     
         15 . The electrical generator according to  claim 14 , wherein said plenum restricts airflow therethrough. 
     
     
         16 . The electrical generator according to  claim 15  wherein said plenum has a generally semi-circular cross section. 
     
     
         17 . The electrical generator according to  claim 16 , wherein said central axle is positioned to extend into the plenum. 
     
     
         18 . The electrical generator according to  claim 16 , further including a duct encasing the airflow and wherein the plenum is secured to said duct. 
     
     
         19 . The electrical generator according to  claim 18 , wherein said central axle is positioned to extend into the duct.