| 摘要 |
PURPOSE:A gas filter, obtained by preparing tin oxide under specific condition, capable of burning combustible gases other than CO in a mixed gas of CO- containing combustible gases with O2-containing gas to permeate the CO in an unburned state and useful as a CO sensor. CONSTITUTION:A catalyst containing stannous oxide and stannic oxide is prepared and the resultant powder is filled in a thin cylinder 2 having two opened ends covered with silica cloth to give a filter 1, which is kept at, e.g. 350 deg.C. A mixed gas of CO and combustible gases other than CO, particularly H2, etc., and a gas containing O2 sufficient to burn the at least the combustible gases other than the CO, e.g. air, is flowed from one opened end. Since the tin oxide has a much higher activity of oxidizing H2 than that of oxidizing CO, the combustible gases other than the CO are burned and the CO is permeated in the unburned state. Thereby the filter 1 can be placed before a commercially available gas sensor 3 to provide a CO sensor. |
