| 摘要 |
PURPOSE:To prevent the variation in the min. detected particle size accompanied by the variation in the temp. of specimen gas, by performing at least either one of the temp. control of the specimen gas, the temp. control of saturated steam and the control of a mixing ratio. CONSTITUTION:A thermostatic device 14 is provided to the front stage of a mixing chamber 4 in order to control specimen air 1 to definite temp., and a temp. sensor 15, a heater 7 and a temp. controller 16 controlling both of them perform the temp. control of saturated steam. The temp. sensor 15 and a flow controller 18 control the mixing ratio of specimen air 1 and saturated steam. By carrying out at least either one of three controls are mentioned above, the variation in the min. detected particle size accompanied by the variation in the temp. of specimen air due to a circumferential condition can be suppressed. By this method, the reliability in the measurement of ultrafine particles by a condensation nucleate counter can be enhanced markedly.
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