Light signal intensity-based gas sensor adapting to various environments

Abstract

The invention discloses a light signal intensity-based gas sensor adapting to various environments. The gas sensor comprises a micro processor, a digital-analog converter, a laser controller, a laser device, a circulator, a photoswitch, a probe, a photoelectric detector, a trans-impedance amplifier, an operational amplifier, a narrow band filter, a digital potentiometer and an analog-digital converter. A weak signal entering the analog-digital converter and the micro processor through the narrow band filter forms a signal feedback system through the digital potentiometer, and the amplification factor is automatically changed, so that signals Af1 and Af2 which are absorbed by gas are obtained; the concentration of the gas can be obtained according to a linear relation between a ratio of the two signals and the concentration. By the use of an algorithm basis of detecting propane through a harmonic detection technology, a relation between primary and secondary harmonic signals at the central wavelength of a broad spectrum absorption peak of the propane and the concentration of the propane, and an on-site adaptive system, the problems caused by unstable factors such as optical path signal attenuation, probe dewing, interface attenuation, high humidity, an optical fiber distance and the like are solved.

Description

technical field [0001] The present invention relates to the technical field of optoelectronics, in particular to the technical field of gas sensing and volatile organic compound (VOC) detection instruments based on laser spectroscopy, and in particular to a gas sensor that adapts to various environments based on optical signal strength. Background technique [0002] Volatile organic compounds (VOCs) are one of the important objects of air quality and environmental safety monitoring in recent years. They have the characteristics of various types and complex components, and the composition of VOCs in different industries is different. In the petrochemical industry, the main components of oil and gas volatiles are alkane gases, of which propane, butane and other gases are the main components. In addition to affecting the atmospheric environment and human health, excessive oil and gas volatiles will also cause safety hazards. And its detection method is required to be able to mo...

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Problems solved by technology

[0006] In view of this, the main purpose of the present invention is to provide a gas sensor based on the intensity of the light signal to adapt to various environments, to use the harmonic detection technology to detect the algorithm basis of propane, the first harmonic signal at the central wavelength of the propane broad-spectrum absorption peak and the relationship between the second harmonic signal and the concentration of propane, the on-site adaptive system solves the problems caused by unstable factors such as optical path signal attenuation, probe condensation, interface attenuation, high humidity, and optical fiber distance

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