| 摘要 |
PROBLEM TO BE SOLVED: To detect the concentration of a flammable gas without being affected by the influence of moisture or the like with a simple configuration by using an oxygen sensor with a solid electrolyte material, for example, of a limiting current type. SOLUTION: A first oxygen sensor 3A is provided at the downstream side of a generation source 2 of a channel 1 where air is circulated through the generation source 2 of a flammable gas for detecting oxygen concentration being shifted by the amount of oxygen consumption due to the flammable gas of circulation air containing the flammable gas, a second oxygen sensor 3B is provided at the upstream side of the generation source 2 for detecting the oxygen concentration of the circulation air without containing the flammable gas, and a gas concentration output means 4 outputs the difference in the detection signal of both the oxygen sensors 3A and 3B as the concentration of the flammable gas of air through the generation source 2, thus canceling the amount of change in the detection signal of the oxygen sensors 3A and 3B due to the fluctuation of moisture or the like and hence preventing the concentration of the flammable gas to be detected from being affected by moisture or the like. |
