PURPOSE: To reduce an amount of discharged CO by a method wherein unburnt gas is re-introduced in a combustion chamber by means of air fed to a restriction area to burn the unburnt gas, and the unburnt gas diffused to an air introduction passage through a vent hole is oxidized by means of a catalyst body.
CONSTITUTION: During high combustion, unburnt gas and air are burnt in a well mixed state with high efficiency in a range of from a position in the vicinity of the upper end of an inner flame cylinder 6 to a position in the vicinity of the upper end part of a combustion chamber 8. The unburnt gas is burnt by means of flame fr formed above the unburnt gas. By reducing an unburnt gas amount through reduction of the exposure height of a wick 1, flame is lowered in the combustion chamber 8. Gasified gas is reduced and an unburnt gas amount is also reduced, a region of mixture with an air flow is lowered downward, and flame fs is formed in the combustion chamber 8. Most of the unburnt gas flowing in a restriction area 22 is fed in the combustion chamber 8 by means of an air flow and burnt by means of the flame fs, but a part of the unburnt gas is diffused through a vent hole 24 to an air introduction passage 25. Since an oxidizing catalyst body 27 is arranged in the introduction passage 25 above the vent hole 24, diffused CO passes through the catalyst body 27 for oxidation, and the oxidized CO rises in the air introduction passage 25, and an amount of CO discharged in the open air is reduced.
ISHIKAWA KATSUHIKO
OGINO TOSHIRO
