| 摘要 |
PURPOSE:To prevent the change of a gas detecting element such as metallic oxide semiconductor with time by covering the gas detecting element with a sulfide removing filter. CONSTITUTION:The metallic oxide semiconductor such as SnO2 or Fe2O or the catalyst element deposited with Pd, Pt, etc. on a carrier such as Al2O3 is used as the gas detecting element 9 and is contained in a holding cylinder 8. The sulfide removing filter 6 is provided in the upper part of the cylinder 8 so that the sulfide SO2, (CH3)2S, etc. do not contact with the element 9. The filter 6 is constituted by sandwiching active carbon 1, 2 with glass filters 4, 5. Since the element 9 does not contact with the sulfide, the sensitivity thereof does not change with time and the element is capable of detecting LPG and city gas, etc. with good accuracy. |
