Abstract:
Stoves fueled by biomass pellets are provided with a grate assembly that supports the pellets for combustion and directs combustion gas into the fire. The grate assembly includes a passive grate of unequally spaced rods. The design of the rods serves to prevent the ash and clinkers from accumulating on the grate in amounts that could reduce the flow of combustion gas into the fire.
Abstract:
A furnace has a solid fuel hopper above a combustion chamber, an ash outlet below said combustion chamber, a combustion gas outlet at or below the level of the combustion chamber, and an auger in an ash chamber below the ash opening to regulate the size of an ash pile below the combustion chamber and hence control the escape of ash or fuel or non-combustibles through the ash opening. This enables the combustion gas outlet to be covered by hot coals within the combustion chamber so that any combustion gas from the combustion chamber or any pre-combustion zone must pass through a filter of hot coals before reaching the combustion gas outlet.