| 摘要 |
The infrared dual beam hydrogen fluoride (HF) gas detector comprises a light source for generating a light beam, a reference filter which passes light at a wavelength in the infrared range, such wavelength light being highly not absorbed by HF gas, an HF sensing filter which passes light at a wavelength in the infrared range, such wavelength light being highly absorbed by HF gas, structure for directing the light beam through a space containing vapor under investigation and alternately through each filter, a first sensor for sensing the light transmitted through the reference filter and for generating a first signal, a second sensor for sensing the light transmitted through the HF sensing filter and for generating a second signal, first circuitry for demodulating and amplifying the first signal generated by light transmitted through the reference filter, second circuitry for demodulating and amplifying the second signal generated by light transmitted through the HF sensing filter, and a comparator for comparing the first demodulated and amplified signal with the second demodulated and amplified signal and for generating an output control signal indicative of the amount of HF gas in parts per million - meters in the vapor in the space under investigation.
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