Apparatus and method for combustion

Abstract

To enable a burnpot for a corn burning stove to be continuously operated, the burnpot has either: (1) an openable bottom with at least a first and second position, one of the at least first and second positions being substantially closed to enable a body of combustible fuel to burn on its upper surface, the other of the at least first and second positions providing an opening, burnpot side wall portions and a top of the burnpot being shaped so as to permit a solid clinker to drop out of the opening in the openable bottom when the openable bottom is in its second position; or (2) a bottom formed as one of a series of sections of a rotatable member so that as the member rotates, it carries ash with it away from the bottom of the burnpot. A combustion volume is provided between the openable bottom or rotatable bottom, the side surfaces and the top, the combustion volume having an upper portion and a lower portion whereby a fire on a combustion surface in the lower portion burns upwardly toward the upper portion so that byproducts of combustion build on the combustion surface to cause burning fuel to burn at a higher level; the higher level having a smaller cross sectional area than the lower portion whereby the byproducts of combustion may drop as a unit out of the burnpot bottom opening. Easy to ignite fuel is moved from one hopper into the burnpot and ignited. When the temperature is high enough to ignite the harder to ignite fuel it is moved into the burnpot and the flow of easy to ignite fuel stopped.

1 . A burnpot having a burnpot bottom opening closed by a movable bottom; said moveable bottom comprising; 
 a rotatable member having a horizontal axis of revolution;    said rotatable member having a portion closing said burnpot bottom;    whereby products of combustion are temporarily supported by a surface of the rotatable member to enable a body of combustible fuel to burn on its upper surface;    a mounting structure positioned with respect to the rotatable member so that its surface always closes the burnpot at the bottom end of the burnpot and extends sufficiently beyond an opening at the lower end of the burnpot to carry the products of combustion out of the burnpot when the rotatable member is rotated.    
   
   
       2 . A burnpot in accordance with  claim 1  wherein a rotatable bottom is cylindrical and has a radius of curvature sufficiently large to provide a bottom to the burnpot that avoids excessive collection of combustible fuel at the outer edges of the burnpot bottom.  
   
   
       3 . A burnpot in accordance with  claim 2  wherein the radius of curvature of the rotatable bottom is sufficiently large with respect to the size of the burnpot bottom opening so that the distance between a lowest point on the burnpot bottom is no more than 24 inches from a highest point.  
   
   
       4 . A burnpot in accordance with  claim 1  in which the burnpot includes side wall portions and a top portion; the burnpot side wall portions and the top portion of said burnpot being shaped to permit a solid clinker to move out of the burnpot bottom opening by rotation of the rotatable member.  
   
   
       5 . A burnpot in accordance with  claim 1  wherein a combustion volume is provided between said burnpot bottom opening, side wall portions and a top; said combustion volume having an upper portion and a lower portion whereby a fire on a combustion surface in said lower portion burns upwardly toward said upper portion so that byproducts of combustion build on the combustion surface to cause burning fuel to burn at a higher level; said higher level having a smaller cross sectional area than said lower portion whereby the byproducts of combustion may drop as a unit out of said burnpot bottom opening.  
   
   
       6 . A burnpot in accordance with  claim 1  in which burnpot side wall portions include apertures through them having internal walls, each of said apertures having a corresponding diameter and internal wall thickness; said thickness being equal to the thickness of the side wall portions; said side wall portions slanting downwardly toward an openable bottom whereby air entering the side wall portions flows with velocity in the direction of said openable bottom.  
   
   
       7 . A burnpot in accordance with  claim 1  further including a control system having means for moving from a fuel feed setting to a fuel feed setting in a controlled serial sequence.  
   
   
       8 . A burnpot in accordance with  claim 7  further including a delay time between the fuel feed settings to avoid a rapid change in rates of fuel feed.  
   
   
       9 . A burnpot in accordance with  claim 1  further including at least one scraper positioned to scrape at least one of products of combustion and fuel from the rotatable member as it rotates.  
   
   
       10 . A burnpot in accordance with  claim 1  further including fragmenting members for fragmenting clinkers as the rotating member rotates.  
   
   
       11 . A method of operating a heating apparatus comprising the steps of: 
 permitting fire in the heating apparatus to burn and build up an accumulation of products of combustion;    maintaining burning coals on an upper surface of a rotatable member; and    rotating the rotatable member when the coals have built to a predetermined level, whereby the coals are removed.    
   
   
       12 . A method in accordance with  claim 11  further including the step of scrapping products of combustion from the rotatable member.  
   
   
       13 . A method in accordance with  claim 11  wherein the step of rotating the rotatable member includes the substeps of rotating a cylinder while the coals are still burning and rotating the cylinder after fuel is at least substantially burnt.  
   
   
       14 . A method in accordance with  claim 11  wherein a portion of fuel is burned at the top of the fuel before rotating the rotatable member whereby a burnpot is not overheated, the rotatable member is rotated to loosen the fuel before the burnpot is overheated and the rotatable member is rotated again to remove ash.  
   
   
       15 . A method in accordance with  claim 11  further including the step of moving from a fuel feed setting to a fuel feed setting in a controlled serial sequence.  
   
   
       16 . A method in accordance with  claim 15  further including a delay time between the fuel feed settings to avoid a rapid change in rates of fuel feed.  
   
   
       17 . A heating apparatus, including: 
 a burnpot;    a fuel feed system;    said fuel feed system including at least first and second fuel hoppers and fuel moving apparatuses in contact with said at least first and second fuel hoppers; said fuel moving apparatuses being positioned to move fuel from either said first or said second fuel hoppers into the burnpot.    
   
   
       18 . A heating apparatus in accordance with  claim 17  further including a control system and an ignition system; said control system comprising a switching system having at least a first state and a second state wherein said switching system energizes said fuel feed system to move fuel from said first fuel hopper into said burnpot and energizes said ignition system when in said first state and, when said switching system is in said second state energizes said fuel feed system to move fuel from said second fuel hopper into said burnpot.  
   
   
       19 . A heating apparatus in accordance with  claim 18  wherein said switching system switches from said first state to said second state when the temperature in the burnpot reaches an ignition temperature of the fuel in said second fuel hopper.  
   
   
       20 . A method of igniting fuel in a burnpot comprising the steps of: 
 feeding an easily ignitable fuel from a first hopper into a burnpot;    igniting the easily ignitable fuel in the burnpot; and    feeding a harder to ignite fuel to the burnpot when the temperature in the burnpot reaches an ignition temperature of the hard to ignite fuel.