| 摘要 |
PURPOSE:To control a raw gas to be kept constant all the time without being affected by a temperature of bubbler or concentration and saturation of the raw gas by measuring the concentration of raw gas. CONSTITUTION:A concentration of raw gas passing through a pipe system supply of raw gas is measured by measuring a propagation delay time of ultrasonic wave on the way of the pipe system supply of raw gas and then, a carrier gas volume flowing in the pipe is controlled. For example, the raw gas is introduced in a bubbler 2 and a saturated vapor gas is produced by bubbling an organic metal 3, while the raw gas is introduced in a measuring cell 4. On the other hand, the ultrasonic wave is put out by an ultrasonic transmitter 5 or vibrator and is receiver by an ultrasonic receiving set 6 and receiver. A duration from transmitting to receiving, that is, a delay time is measured by a control part 7 to obtain the concentration of gas and a required volume of the carrier gas is measured according to the above concentration degree of gas as well as the raw gas supplied to a reaction part. Thus, the raw gas supplied to the reaction part is controlled in spite of actual degrees of bubbler temperature and saturation of raw gas.
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