Biomass fuel stove

Abstract

Disclosed is a biomass stove for burning biomass fuel using a combustion furnace. The stove includes a gravity feed fuel holding tank for feeding biomass fuel to the furnace. The combustion furnace includes a primary combustion furnace and a secondary combustion furnace surrounding the primary combustion furnace, as well as a water jacket surrounding the secondary combustion furnace and an air jacket further surrounding the water jacket. A fuel holding device may be in the form of a rotating furnace that includes a support surface with one or more curved vanes thereon for moving gravity fed fuel. An ash removal assembly includes an adjustable ash grate and a fixed ash grate below the furnace. Adjustment of the adjustable grate relative to the fixed grate moves openings into and out of alignment such that ash from burned biomass fuel is output to an ash pan.

What is claimed is: 
     
         1 . A biomass stove for burning biomass fuel using a combustion furnace comprising:
 a fuel holding tank for feeding biomass fuel to the combustion furnace;   a rotating furnace positioned below the combustion furnace for receiving the biomass fuel from the fuel holding tank; and   a motor,   wherein the rotating furnace includes a support surface configured for rotation by the motor, the support surface constructed to hold and position biomass fuel for burning in the combustion furnace.   
     
     
         2 . The stove according to  claim 1 , wherein the support surface is provided on a circular plate, the support surface being positioned in a horizontal plane, and wherein the circular plate is connected to a vertical shaft that is configured to be driven by the motor about a vertical axis. 
     
     
         3 . The stove according to  claim 1 , wherein the fuel holding tank is a gravity-feeding fuel holding tank configured to feed biomass fuel via gravity in a generally vertical direction onto the support surface of the rotating furnace. 
     
     
         4 . The stove according to  claim 3 , wherein the support surface comprises at least one curved vane thereon to assist in circulating the gravity fed biomass fuel during rotation of the rotating furnace. 
     
     
         5 . The stove according to  claim 4 , further comprising plurality of curved vanes thereon. 
     
     
         6 . The stove according to  claim 1 , wherein the support surface comprises a plurality of openings for discharging ash from burned biomass fuel below the support surface, and wherein the stove further comprises an ash removal assembly for receiving ash from burned biomass fuel being discharged from the rotating furnace. 
     
     
         7 . A biomass stove for burning biomass fuel using a combustion furnace comprising:
 a fuel holding tank for feeding biomass fuel to the combustion furnace;   a fuel holding device for receiving the biomass fuel from the fuel holding tank and positioning biomass fuel for burning in the combustion furnace; and   an ash removal assembly positioned below the combustion furnace for receiving ash from burned biomass fuel being discharged from the fuel holding device and distributing the received ash to an ash pan positioned below the ash removal assembly;   the ash removal assembly comprising an adjustable ash grate and a fixed ash grate, the fixed ash grate positioned below the adjustable ash grate, and each grate comprising a plurality of openings therein,   wherein adjustment of the adjustable ash grate relative to the fixed ash grate moves its openings into and out of alignment with openings on the fixed ash grate such that, upon substantial alignment of the openings, ash from burned biomass fuel is output to the ash pan.   
     
     
         8 . The stove according to  claim 7 , wherein the adjustable ash grate is arranged to rotate about a vertical axis. 
     
     
         9 . The stove according to  claim 8 , further comprising a primary ash scraper and a secondary ash scraper each configured to move ash adjacent thereto, wherein the primary ash scraper is positioned above the grates, and wherein the secondary ash scraper is positioned below the grates. 
     
     
         10 . The stove according to  claim 9 , wherein the secondary ash scraper is arranged to rotate about the vertical axis. 
     
     
         11 . A biomass stove for burning biomass fuel using a combustion furnace assembly comprising:
 the combustion furnace assembly comprising:   a primary combustion furnace for burning biomass fuel;   a secondary combustion furnace surrounding the primary combustion furnace, the secondary combustion furnace having an inner wall spaced from an outer wall of the primary combustion furnace;   a water jacket surrounding the secondary combustion furnace;   an air jacket further surrounding the water jacket, and   a fuel holding device for receiving the biomass fuel and positioning biomass fuel for burning in the primary combustion furnace.   
     
     
         12 . The stove according to  claim 11 , further comprising a fuel holding tank for feeding biomass fuel to the combustion furnace, wherein the fuel holding tank surrounds the air jacket and the biomass fuel is held and fed between an outer wall of the air jacket and an inner wall of the fuel holding tank. 
     
     
         13 . The stove according to  claim 12 , wherein the fuel holding tank is a gravity-feeding fuel holding tank configured to feed biomass fuel via gravity in a generally vertical direction onto the fuel holding device. 
     
     
         14 . The stove according to  claim 11 , wherein the fuel holding device comprises a rotating furnace positioned below the primary combustion furnace and a motor, wherein the rotating furnace includes a support surface configured for rotation by the motor, the support surface constructed to hold and position biomass fuel for burning in the primary combustion furnace. 
     
     
         15 . The stove according to  claim 14 , wherein the support surface is positioned in a horizontal plane, and wherein the support surface is connected to a vertical shaft that is configured to be driven by the motor about a vertical axis. 
     
     
         16 . The stove according to  claim 15 , wherein the support surface comprises at least one curved vane thereon to assist in circulating the fed biomass fuel during rotation of the rotating furnace. 
     
     
         17 . The stove according to  claim 16 , further comprising plurality of curved vanes thereon. 
     
     
         18 . The stove according to  claim 11 , wherein the fuel holding device comprises a plurality of openings for discharging ash from burned biomass fuel therebelow, and wherein the stove further comprises an ash removal assembly positioned below the combustion furnace assembly for receiving discharged ash from burned biomass fuel and distributing the received ash to an ash pan positioned below the ash removal assembly. 
     
     
         19 . The stove according to  claim 18 , wherein the ash removal assembly comprises an adjustable ash grate and a fixed ash grate, the fixed ash grate positioned below the adjustable ash grate, and each grate comprising a plurality of openings therein,
 wherein adjustment of the adjustable ash grate relative to the fixed ash grate moves its openings into and out of alignment with openings on the fixed ash grate such that, upon substantial alignment of the openings, ash from burned biomass fuel is output to the ash pan.