| 摘要 |
PURPOSE:To improve an accuracy of sensing of a condition of a lack of oxygen and further improve a response characteristic in the unit by a method wherein a combustion flame in the burner is made to be a continuous flat flame and a red heat light sensing type oxygen concentration sensor is red heated by a flame and a feeding of fuel is terminated when the output singnal is set at a desired range. CONSTITUTION:Burner 7 is formed with the flame ports 8a and 8b. The flame ports 8a are formed with an independent or separate flame Qa, respectively, and the flame ports 8b are formed with a continuous flat flame Qb. When the sensor 21 of the oxygen concentration sensor 13 is red heated by the inner flame 41 of the continuous flame Qb, the red heat light corresponding to a strength of the red heat flame, i.e. an oxygen concentration of the red heat is radiated from the inner surface of the sensor 21. The red heat light is guided to the light receiving element (not shown) through the photoconductive element 24 and then produces the terminal potential corresponding to the oxygen concentration. Thus, when the output potential is in a dangerous range of lack of oxygen, a feeding of fuel is interrupted through a control unit (not shown) and thus it is possible to provide a positive operation under a high accuracy without being affected by the soot and the like. |
