Swirl combustion apparatus

A water tube boiler comprising:

• a combustion chamber having a front end, a rear end and a longitudinally extending substantially cylindrical wall having an inner surface;
• means for supplying a peripheral swirl of air into the combustion chamber adjacent the inner surface of the cylindrical combustion chamber wall;
• means for supplying fuel into the combustion chamber for mixing with the swirl of air and burning in the combustion chamber to form swirling hot combustion gases in the combustion chamber;
• means for directing the swirling hot combustion gases out of the combustion chamber outlet in a direction substantially tangential to the inner surface of the cylindrical combustion chamber wall, said directing means including a combustion chamber rear end wall having an annular combustion chamber outlet for directing the swirling hot combustion gases out of the combustion chamber, said annular combustion chamber outlet having an inner outlet wall, an outer outlet wall having a diameter substantially equal to the diameter of the cylindrical wall of the combustion chamber, and a plurality of spaced radial slots extending between said inner and outer outlet walls, said slots being tilted at a selected angle from the axis normal to the longitudinal axis of the combustion chamber;
• and
• heat exchange means surrounding and extending substantially along the length of said combustion chamber for cooling the wall of the combustion chamber, the heat exchange means including a steam drum longitudinally extending parallel to and above said combustion chamber, a header longitudinally extending parallel to and below said combustion chamber, a plurality of tubes connecting said header and steam drum, said tubes being integral with said combustion chamber wall along the length of said combustion chamber on opposite sides of said chamber for circulating cooling fluid which absorbs heat from said chamber and produces steam that is exhausted from said steam drum.