Fuel stoker and furnace

摘要

A furnace having a primary heat exchange unit also providing a combustion chamber, a secondary heat exchange unit connected by an upper crossover conduit to the primary heat exchange unit, and a tertiary heat exchange unit connected by a lower V-shaped crossover conduit to the secondary heat exchange unit. A third crossover conduit connects the V-shaped crossover conduit with the primary heat exchange unit. A fly ash removal screw is located in the V-shaped crossover conduit to move fly ash therefrom through the third crossover conduit back into the primary heat exchange unit to an ash depository for removal therefrom. Vibrating means are provided between the secondary and tertiary heat exchange units to vibrate the walls thereof and dislodge clinging fly ash so that it falls into the V-shaped crossover conduit for removal by the screw conveyor. A burner assembly of the furnace includes a combustion air housing carrying a circular, stationary grate with an annular valley for carrying fuel during combustion. A central opening is connected to a fuel conveyor for introduction of fuel to the grate through the lower portion of the housing. Combustion air introduction conduits on the housing are remote from the fuel introduction passages and introduce air under pressure at the lower portion of the grate. An agitator and discharge ring is provided on the grate and is rotated on the grate by a suitable drive sprocket mechanism to agitate the fuel for more complete burning thereof and to remove burned ash.