Method and system for detecting trace gas concentration based on spectral absorption principle

Abstract

The invention provides a method and a system for detecting the concentration of trace gas on an open optical path based on a spectral absorption principle. The system is provided with a PCB control circuit, a laser emitter and a photoelectric detector, wherein the laser emitter and the photoelectric detector are respectively connected with the PCB control circuit; wherein the PCB control circuit comprises an MCU module, an amplifying and filtering module, a phase shift and phase sensitive detection module, an ADC sampling module and a self-calibration module, a collimating lens is arranged between the laser emitter and detected gas, an aspherical mirror is arranged between the photoelectric detector and the detected gas, the aspherical mirror gathers reflected laser to the photoelectric detector, the photoelectric detector is used for measuring reflected light power. The technical problems that an existing laser detection method cannot avoid interference of environmental noise, circuits and algorithms are complex, and cost is high are solved. The method and the system can be widely applied to gas concentration detection.

Description

technical field [0001] The invention relates to a method and system for detecting trace gas concentration, in particular to a method and system for detecting trace gas concentration based on the principle of spectral absorption. Background technique [0002] Trace gas detection is a problem that human beings often face in practical activities. It is of great significance to production, environmental protection, safety, and health. Some toxic and harmful gases, such as H 2 S, CO, CH 4 Etc., extremely low concentrations can pose a threat to people's lives and property safety. For such gases, the detection method must be real-time, fast, with a low lower limit and high precision. [0003] Most of the traditional laser detection methods use TDLAS technology to emit modulated laser light to the area to be measured, and perform amplification, phase-locking, filtering, Fourier transform and other processing on the received reflected light signal, and finally according to the first...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the technical problems that the existing laser detection method cannot avoid the interference of environmental noise, the circuit and algorithm are complicated, and the cost is high, the invention provides a kind of laser detection method based on the principle of spectral absorption that can effectively avoid the interference of environmental noise, the circuit and algorithm are simple, and the cost is low. Method and system for detecting trace gas concentration

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