| 摘要 |
849,831. Infra-red gas &c. analysers. OFFICE NATIONAL D'ETUDES ET DE RECHERCHES AERONAUTIQUES O.N.E.R.A. March 13, 1957 [April 11, 1956], No. 8233/57. Class 40(3). In an infra-red gas analyser, radiation from a source 1 is passed through a chamber 4 containing the gas to be analysed to two detector chambers 5, 6 also containing a gas to be detected, the two chambers 5, 6 being connected to a diaphragm condenser 7, 8. The radiation entering respective chambers 5, 6 is chopped by shutters 12, 13 at two different frequencies or phases and the output signal of the condenser is filtered at 14, 15 to provide two signals which represent respectively the difference in radiation received by the two detectors 5, 6 and the actual amount received by the second one 6 and these signals are compared by a potentiometer 16. |
