| 摘要 |
PURPOSE:To obtain a compact, light-weight, inexpensive concentration measuring apparatus of chlorine organic solvent gas, whose measuring accuracy is high, by providing a gas sensor comprising a zirconia semiconductor. CONSTITUTION:A zirconia semiconductor contains, e.g., 90mol% or more of SnO2 and 3mol% or more of ZrO2. Small amounts of Sb2O3, Nb2O5 and the like are added into the semiconductor. A sensor X comprising the zirconia semiconductor is fixed in a detecting part 10. The relationship between the concentration of the gas detected by the detecting part 10 and the change in electric resistance indicates two-logarithm characteristics. With the increase in concentration, the scale of a meter 16 becomes narrower and hard to read. The signal is amplified by a logarithmic amplifier 12. An amplifier circuit 17 is provided only for a minute concentration range. A timer circuit 14 is provided so as to cope with the troublesome case when the response speed is slow. An electromagnetic pump is operated for a specified time, and a sample gas can be introduced into a gas chamber. A maximum value memory circuit 13 is provided in order to enhance accuracy of measurement. Therefore, the measuring time can be shortened and the highly accurate measurement can be performed. |
