基本信息
摘要：1,186,957. Infrared gas analysis. SIEMENS A.G. Oct. 14, 1968 [Oct. 16, 1967], No.48507/68. Heading G1A. The concentration of carbon monoxide in exhaust gases is measured by determining the absorption by the gases of monochromatic infrared radiation from an electro-luminescent semiconductor source. Fig.2 shows a two-path system in which the measurement path comprises a pulsed electroluminescent or laser diode 23, supplied from unit 4, a through-flow chamber 14 for exhaust gases, and an infrared sensitive semi-conductor detector 5, feeding an amplifier 7, rectifier 8 and meter 9 or control means 10 for adjusting the carburretor of the engine producing the exhaust under examination. The diode 23 may be doped indium arsenide - indium antimonide body and emits radiation corresponding to a main or secondary line in the absorption spectrum of carbon monoxide. The detector 5 may be of indium antimonide, lead selenide or lead telluride. The other radiation path uses a similar detector 19 and similar circuitry and is used to maintain the wavelength of the radiation emitted by the source constant, by control of the temperature of the source, or the voltage supplied thereto. A semi-silvered mirror 18 splits the light from source 23 into two beams. In the simpler arrangement of Fig. 1 (not shown) only the measurement path is present.
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