High Efficiency Combustion Stove

Abstract

The invention is a stove system that is portable, has a double walled external structure for the passage of air used in combustion of the fuel, which air also maintains the external surface at a cool enough temperature that it can be touched, and which air flow prevents the waste of heat laterally to the ambient air from a hot outer surface. This increases cooking efficiency, because almost all heat that reaches the air flow between the two walls is drawn right into the combustion chamber in the form of preheated air by reason of the chimney effect. Thus almost no heat can escape the outside wall except by reaching the cooking pot bottom and pot sides after passing out the cover vents as exhaust. An internal heat concentrator ring improves the overall efficiency of the burner. The stove is preferably powered with coal, and uses about half as much coal as a conventional coal fired stove resulting from cooking efficiency. Provision is made for generation of electrical energy from the excess stove heat. Additionally, special thermally designed cook pots add to the stove system to decrease food cooking time while reducing the fuel required.

We claim: 
     
         1 . A stove comprising: a double walled exterior having at least one port for drawing combustion air into a passageway between the walls; a bottom attached about its periphery to the double walled exterior; a combustion chamber in communication with the passageway to receive combustion air there from, the chamber being surrounded by the double walled exterior and passageway to minimize loss of heat laterally to ambient air and increase heating efficiency and containing a grate to support combustible fuel; and a cover to support a cooking container and allow venting of exhaust gases. 
     
     
         2 . The stove of  claim 1  which further comprises a removable bucket concentric with and disposed within the double walled exterior. 
     
     
         3 . The stove of  claim 1  in which the grate is disposed within the removable bucket and at the bottom of the combustion chamber wherein the grate forms a combustion air flow venturi to increase heating temperature. 
     
     
         4 . The stove of  claim 1  in which the cover further comprises: an annular ring having a large open center, the open center being covered when the stove is in use by a cooking container to heat it; and the venting occurring through at least one vent from which heated air exits the stove adjacent sides of the cooking container to further heat it. 
     
     
         5 . The stove of  claim 1  which further comprises a substantial opening in the center of the bottom of the stove suitable for removal of products of combustion such as ash, and which is substantially sealed off during use of the stove by its placement on a flat horizontal surface. 
     
     
         6 . The stove of  claim 1  in which the interior of the double wall exterior is shaped as a truncated cone having its largest diameter at the top, and in which the removable bucket is comprised of a tapered portion at its top and a lower cylindrical portion, the cylindrical portion being perforated by at least one aperture, and the tapered portion fitting snugly in the lower portion of the truncated cone such that the cylindrical portion projects beneath the bottom of the truncated cone and into the passageway and the at least one aperture is immersed in combustion air flow in the passageway. 
     
     
         7 . The stove of  claim 4  in which the grate is disposed at an intersection of the tapered portion and the cylindrical top of the air inlet portion of the removable bucket on tabs projecting into the bucket. 
     
     
         8 . The stove of  claim 1  which further comprises an externally adjustable air flow regulator disposed within the passageway. 
     
     
         9 . The stove of  claim 8  in which the externally adjustable air flow regulator comprises a stationary horizontal annular plate which includes a plurality of perforations and an adjustable horizontal annular plate having an adjusting tab that projects through a slot in an outer surface of the double walled exterior and having a plurality of perforations wherein a number of perforations in the stationary portion equals a number of perforations in the adjustable portion. 
     
     
         10 . The stove of  claim 1  which is sized to be portable even in use and which is cool enough in use to be carried with bare hands because of the combustion air flow in the passageway. 
     
     
         11 . A stove comprising: an outer wall having at least one port for drawing in combustion air; a bottom attached about its periphery to the outer wall; an inner wall disposed within and substantially concentric with the outer wall, forming between the outer wall and the inner wall a passageway for combustion air flow, the inner wall surrounding a combustion chamber, the combustion air flow in the passageway minimizing heat loss and increasing heating efficiency; a removable bucket concentric with and disposed within the inner wall; a grate disposed within the removable bucket and at the bottom of the combustion chamber for supporting combustible fuel and forming a combustion air flow venturi increasing heating temperature; and an annular ring cover having a large open center, the open center covered when the stove is in use by a cooking container to heat it, and the annular ring having at least one vent from which heated air exits the stove adjacent sides of the cooking container to further heat it. 
     
     
         12 . The stove of  claim 11  in which the inner wall is shaped as a truncated cone with the largest diameter as the top. 
     
     
         13 . The stove of  claim 11  which further comprises a substantial opening in the center of the bottom of the stove suitable for removal of products of combustion such as ash, and which is substantially sealed off during use of the stove by its placement on a flat horizontal surface. 
     
     
         14 . The stove of  claim 11  in which the removable bucket is comprised of a tapered portion at its top and a lower cylindrical portion, the cylindrical portion being perforated by at least one aperture, and the tapered portion fitting snugly in the lower portion of the truncated cone of the inner wall such that the cylindrical portion projects beneath the bottom of the cone of the inner wall and the at least one aperture is immersed in combustion air flow between the inner and outer walls. Tabs along the circumference of the bucket at the juncture of the taper and the cylinder portion that protrude outward to provide stand-off points to center the bucket and to reduce intimate contact with the inner wall of the stove to reduce the heat transfer to the inner wall. 
     
     
         15 . The stove of  claim 14  in which the grate is disposed at an intersection of the tapered portion and the cylindrical top of the air inlet portion of the removable bucket on tabs projecting into the bucket portion of the removable bucket. 
     
     
         16 . The stove of  claim 11  which further comprises an externally adjustable air flow regulator disposed within the passageway between the inner and outer walls on the top cap to cover the exhaust ports and acting as a damper as fuel and weather conditions require. 
     
     
         17 . The stove of  claim 16  in which the externally adjustable air flow regulator comprises a stationary horizontal annular plate which includes a plurality of perforations and an adjustable horizontal annular plate having an adjusting tab that projects through a slot in the outer wall and having a plurality of perforations wherein a number of perforations in the stationary portion equals a number of perforations in the adjustable portion. 
     
     
         18 . The stove of  claim 11  which is sized to be portable even in use and which is cool enough in use to be carried with bare hands because of the combustion air flow in the passageway. 
     
     
         19 . The stove of  claim 11  fitted with a thermoelectric generator to produce an electric current during stove use. Said generator consisting of a heat pipe conductor, a hot side heat sink, a thermoelectric module, a cold side heat sink and a means of dissipating the heat from the cold side and a control module. 
     
     
         20 . A control module of  claim 19  containing the electronic regulation circuit, the storage battery, the output regulator and the input and output attachment means along with the visual status and mode indicators. 
     
     
         21 . Cook pot specifically mated and designed to a stove to allow the stove to take full advantage of its design features of increased efficiency and reduced fuel consumption comprising a series of annular rings dispersed around the bottom of the pot to act as heat collectors. 
     
     
         22 . The cook pot of  claim 21  having heat collector rings of such that the pot bottom and the ring tops are in direct contact with each other to allow for the maximum heat transfer. 
     
     
         23 . The Pot of  claim 22  wherein said heat collector rings are concentric with each other and having openings spaced around each ring to allow for even heat flow distribution to all rings. 
     
     
         24 . The stove of  claim 1 , having a removable chute for adding fuel to the stove during use without removing the cooking pot. 
     
     
         25 . A chute according to  claim 24  that is inserted into the top cap of the stove and is positioned over the heat concentrator ring from which fuel pellets may be dispensed. 
     
     
         26 . A stove according to  claim 25  that has a reservoir for fuel that can be dispensed either manually or via an electro-mechanical control means. 
     
     
         26 . A stove of  claim 1  with a support means to raise the stove off the ground and allow for ease of use while in operation. 
     
     
         27 . The grate of  claim 3  where the grate opening size (mesh) is adjusted for the type of fuel being used. 
     
     
         28 . The bucket of  claim 2  wherein is disposed a support shelf raised above the grate upon which a heat concentrator ring is held. Said concentrator ring serves to direct the heat to the center of the stove and to increase the venturi effect. 
     
     
         29 . A heat concentrator ring of  claim 3 B wherein as a heat sink/radiator provides more even heat release and distribution, said ring has a central opening to focus the heat and is sized to fit snuggly to the interior diameter of the stove, and further, the heat concentrator is concave shaped to allow for proper addition of fuel pellets. 
     
     
         30 . The stove of  claim 4 , wherein exhaust vent regulators attach to said cover of and allow for the selection of vent openings as a means of adjusting the draft. 
     
     
         31 . The grate of  claim 15  which is placed in its center a perforated, cylindrical chimney section which focuses the draft and allows for proper distribution of the fuel.