Reflective optical path device of online laser gas analyzer

Abstract

The invention provides a reflective optical path device of an online laser gas analyzer. The reflective optical path device comprises a laser transmitting and receiving unit, a background removing unit, an online monitoring unit and a laser reflecting unit which are sequentially connected with one another. The laser transmitting and receiving unit comprises a tunable laser device, a first wedge lens, a reference cell, a first detector, a second detector and a third detector, and the directions of principle optical axes of the reference cell and the first detector and the direction of laser light emitted by the tunable laser device are symmetrical with one another relative to the normal of a first surface of the first wedge lens; the background removing unit comprises a second wedge lens; the laser reflecting unit comprises a third wedge lens and an optical corner reflector. The reflective optical path device has the advantages that optical distances of measured gas can be doubled, and accordingly the sensitivity and the detection limit of the analyzer can be greatly improved; the reflective optical path device is easy and convenient to mount and debug; the gas can be measured in an online manner in real time; the reflective optical path device has few optical components and is simple in structure, and optical paths can be debugged and mounted by unprofessional people.

Description

technical field [0001] The invention relates to the technical field of optics and environmental protection instruments, in particular to a reflective laser on-line gas analyzer optical path device. Background technique [0002] Laser online gas analyzer adopts tunable semiconductor laser absorption spectroscopy (Tunable Diode Laser Absorption Spectroscopy, referred to as TDLAS), and obtains the concentration of gas by analyzing the selective absorption of laser by gas. [0003] Modulated spectrum detection technology is the most widely used semiconductor laser absorption spectroscopy technology that can obtain high detection sensitivity. It sweeps the frequency range of the measured gas absorption line by rapidly modulating the laser frequency, and then adopts phase-sensitive detection The technology measures the harmonic components in the transmission spectrum after being absorbed by the gas to analyze the absorption of the gas. There are generally two ways to tune the fre...

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Problems solved by technology

[0010] Laser online gas analyzers are used for continuous industrial process and gas emission measurement, used in harsh industrial environments, such as various steel furnaces, aluminum and non-ferrous metals, chemicals, petrochemicals, cement, power generation, tobacco and straw processing, wastewater treatment And waste incineration, the existing laser online gas analyzer has poor sensitivity and high detection limit; when the site vibration is large, it will affect the reception of the detector signal, and when the vibration is too large, the signal cannot be received, requiring technicians to re-adjust, which is time-consuming and laborious; Under the condition of high dust and high particles, it is seriously disturbed by the background and cannot work normally; there are many optical components, the installation and debugging are complicated, and professional personnel are required to debug the optical path

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