| 摘要 |
<p>PURPOSE:To suppress erroneous detection with other gas and to make it possible to detect the concentration of low-concentration fluorocarbon gas by projecting infrared rays on a sample cell through which fluorocarbon gas passes and a comparing cell in which gas that does not absorb the infrared rays is sealed. CONSTITUTION:The infrared rays which are generated in an infrared-ray source 11 are guided into a filter 12. Only the infrared rays having the wavelength in C-F stretching vibration mode of fluorocarbon gas pass through the filter 12. Said infrared rays are projected on a sample cell 13 and a comparing cell 14. A gas to be measured incorporating fluorocarbon gas is introduced into the sample cell 13 through an inlet port 15 and exhausted through an outlet port 16. In the comparing cell 14, a gas which does not absorb the infrared rays is sealed. In this constitution, the fluorocarbon gas selectively absorbs the wavelength in the C-F stretch vibration mode. The intensities of the infrared rays which have passed through the cells 13 and 14 are separately measured and compared with a detecting means 17. Thus the signal matching the concentration of the fleon gas can be obtained.</p> |
