US Patent 7665406 Apparatus and method for combustion

To enable a burnpot for a corn burning stove to be continuously operated, the burnpot has an openable bottom with at least a first and second position, one of said at least fist and second positions being substantially closed to enable a body of combustible fuel to burn on its upper surface, the other of said at least first and second positions providing an opening, burnpot side wall portions and a top of said 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. A combustion volume is provided between said openable bottom, said side surfaces and said 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 opening. A combustion retention openable burnpot bottom to retain combustion in the burnpot when byproduct of combustion is removed through the openable bottom.