| 摘要 |
PURPOSE:To accurately determine whether a gas detector maintains a specified set sensitivity or not with accurately learning the density of a gas when the gas detector operates, by injecting a sample gas quantitatively into a test box always to allow the determination of the density of the gas in the test box. CONSTITUTION:A gas detector GD is housed in a closed test box 4 and alcohol or the like as sample gas is supplied with a micropump 5 to the test box 4 from a sample container 7. With a pump controller 8, a fixed amount of the sample gas is injected from the micropump 5 being controlled with a CPU 9 to change the density of the gas in the test box 4. Then, upper and lower limit values at a gas density area corresponding to a set sensitivity are stored into RAMs 12 and 13 respectively while the number of pulses corresponding to the upper and lower limit values is stored into RAMs 14 and 15 respectively. Then, with the micropump 5, a fixed amount of the sample gas is injected into the test box 4 by the number of pulses corresponding to the lower limit value through a pipe 6 to bring the density in the test box 4 to he lower limit value, Thus, the CPU 9 determines whether the gas detector GD operates or not to display 18.
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