| 摘要 |
PURPOSE:To obtain a well balanced detecting characteristic for the concn. of both gaseous methane and hydrogen by using a lower heater temp. for an element having lower hydrogen sensitivity and a higher heater temp. for an element having high hydrogen sensitivity. CONSTITUTION:A combustible gas detecting element 1 consists of electrodes 3, 4 fixed to a cylindrical body 2. A metallic oxide semiconductor 5 is covered on said element across both electrodes and a heater H is inserted in the body 2. The resistance value of the metallic oxide semiconductor changes when the semiconductor adsorbs combustible gas. A specified voltage is impressed to the heater to age the same until the concn. of the combustible gas in the atmosphere attains a specified level. When the temp. is raised, the detecting sensitivity of hydrogen compared with methane decreases and therefore if the heater temp. is increased for the element having the high sensitivity to, for example, hydrogen, the relatively well balanced sensitivity for both hydrogen and methane is obtd. |
