| 摘要 |
PURPOSE:To accurately and rapidly detect oxygen concentrantion by once exhausting remaining gas in a chamber and then introducing a gas to be detected into the chamber. CONSTITUTION:Remaining gas in a chamber 2 is once exhausted by a vacuum pump 7, a gas to be detected is then introduced throught a introducing tube 5 into the chamber 2, measured as electromotive force in the form of the difference between reference gas pressure and oxygen partial pressure, thereby measuring oxygen gas in the gas to be detected. Then, the gas is passed through a detection gas exhaust tube 6 by the pump 7, and exhausted. The pressure (exhausting pressure) in the chamber at the time of exhausting is preferably reduced as much as possible considering the later substitution of next gas to be detected, but if it is excessively reduced, the exhausting unit becomes large and expensive. On the contrary, if the exhausting amount is too little and the exhausting pressure is too high, it takes a time to substitute the gas to be detected. Accordingly, it is preferable to set the exhausting pressure to 0.1atm or lower. When the gas to be detected is introduced after the remaining gas is once exhausted, gas in the chamber 2 can be repidly replaced with the gas to be detected, and hence the oxygen concentration can be accurately and rapidly detected. |
