| 摘要 |
<p>PROBLEM TO BE SOLVED: To mitigate the fluctuation of internal pressure of a burner by employing the re-circulation of waste gas, in case when the amount of combustion air is increased and decreased periodically to effect periodical thick and thin fuel combustion. SOLUTION: A first cyclic opening and closing valve 15 and a second cyclic opening and closing valve 17 are opened and closed alternately whereby the total flow rate of combustion air, fuel gas and combustion gas is made constant substantially while only the oxygen concentration of mixture is changed cyclicly. In this case, the first cyclic opening and closing valve 15 in a pipeline 14 for supplying combustion air is opened and the second cyclic opening and closing calve 17 in the re-circulation pipeline 16 of combustion gas is closed to make the concentration of oxygen thick while, on the contrary, the first cyclic opening and closing valve 15 is closed and the second cyclic opening and closing valve 17 is opened to make the concentration of oxygen thin.</p> |
