LASER OPTOACOUSTIC GAS ANALYSER AND METHOD FOR MEASURING THE GAS CONCENTRATION Russian patent published in 2022 - IPC G01N21/00 

FIELD: measuring.

SUBSTANCE: laser optoacoustic gas analyser and method for measuring the gas concentration are intended to measure the concentration of one or multiple components in a gas mixture by means of the optoacoustic effect. Claimed laser optoacoustic gas analyser comprises a laser, a control board, an optoacoustic detector, an air filter, a pump, and a display for outputting the calculated concentration. The optoacoustic detector comprises a gas sample entry point, a reference optoacoustic cell, an additional optoacoustic cell, a primary optoacoustic cell, and a gas sample exit point, and is limited with fixed limiters on both sides. Laser emission passes through cells arranged in sequence on a single straight line. Microphones detecting changes in the pressure are installed in the cell walls. The primary optoacoustic cell herein comprises two buffer cavities, optical windows with an antireflective coating, an active acoustic channel and an auxiliary one. Microphones and speakers for generating an acoustic signal are installed in the channel walls. The speakers and microphones are connected to the control board. The apparatus differs from analogues by an acoustic filter being installed between the primary cell and the additional cell, and the additional optoacoustic cell being centrosymmetrical relative to the optical axis of the optoacoustic detector. In order to calculate the gas concentration, a gas sample is supplied through the sample entry point; the sample is then moved by the pump through the air filter, the entry point, the additional optoacoustic cell, the acoustic filter, the primary optoacoustic cell, the sample exit point, and the pump; consecutive propagation of laser emission through the cells is then ensured, then initiation of the acoustic wave in the sample is ensured, followed by detecting the pressure change in the sample, then performing the Fourier signal processing is by means of the control board, then calculating the concentration of the target gas, outputting the information on the display and ensuring the output of the sample.

EFFECT: higher efficiency of detecting the target gas with structural simplification of of the gas analyser.

19 cl, 6 dwg