Cooling a coal burner

Abstract From the Canadian patent

For the combustion of finely-ground coal which is slow to ignite the coal is preheated before it enters the combustion chamber. The preheating can be carried out by passing cold air around the outside of the combustion chamber and then using this heated air to preheat the coal in bunkers. For this purpose the combustion chamber is provided with a hollow casing surrounding the combustion chamber proper and a partition in the hollow casing provides an annular outer space and a concentric annular inner space. A helical baffle arrangement is also provided in the inner and outer spaces to guide the cold air down the outer space and up the inner space. The coal is burned below the melting point …