CAJ | 학술논문

在气体浓度检测过程中采用特征光谱吸收法时，提高气体浓度检测精度常常需要采用高质量窄带激光器并调制其波长使其对准被测气体特征吸收峰的方法，这样大大增加了对激光器的要求及系统成本。为了在采用原有便携式、低成本固体激光器的条件下获取更高的检测精度，设计了转换窗差分吸收光学结构以及特征吸收差分比例算法。分析了特征波长位置选择的依据，给出了实现该处理算法的步骤。系统利用转换窗与吸收气室组合的方法，将非特征吸收峰位置上的光强响应通过求比值的方法约掉，从而实现了与采用窄带激光器对准特征吸收峰位置相近的检测效果。实验采用MW-IR-1650型红外激光器、SSM17-2型步进电机控制模块、C30659型红外探测器等器件，对不同浓度的甲烷气体进行测试，结果显示在200～5000 ppm之间测量相对误差基本在2.0％以内。证明了该系统具有较高的检测精度及稳定性。
재기체농도검측과정중채용특정광보흡수법시，제고기체농도검측정도상상수요채용고질량착대격광기병조제기파장사기대준피측기체특정흡수봉적방법，저양대대증가료대격광기적요구급계통성본。위료재채용원유편휴식、저성본고체격광기적조건하획취경고적검측정도，설계료전환창차분흡수광학결구이급특정흡수차분비례산법。분석료특정파장위치선택적의거，급출료실현해처리산법적보취。계통이용전환창여흡수기실조합적방법，장비특정흡수봉위치상적광강향응통과구비치적방법약도，종이실현료여채용착대격광기대준특정흡수봉위치상근적검측효과。실험채용MW-IR-1650형홍외격광기、SSM17-2형보진전궤공제모괴、C30659형홍외탐측기등기건，대불동농도적갑완기체진행측시，결과현시재200～5000 ppm지간측량상대오차기본재2.0％이내。증명료해계통구유교고적검측정도급은정성。
In the gas concentration detection process using the characteristic spectrum absorption method ,in order to improve the detection accuracy of the gas concentration ,it often has to use the high-quality narrowband modulated laser and modulate wave-length to align with the characteristic absorption peaks of measured gas .But by this way ,the cost of the laser and system re-quirements will be greatly increased .To use the existing portable ,low-cost semiconductor laser conditions ,at the same time it can obtain higher precision ,conversion window differential absorption optical structure and the algorithm of differential charac-teristic absorption ratio was designed .Selection reason of position of the wavelength characteristic was analyzed ,and steps to implement the processing algorithm were given .Systematically utilizing the combination method of conversion window and ab-sorption gas chamber ,by the method for calculating the ratio of the light intensity response ,the light intensity from non-charac-teristic absorption peak position was divided out .So it achieved a similar detecting effect was achieved that used a narrow-band laser aligned to the feature absorption peak position .Experiments adopted MW-IR-1650 infrared laser ,type SSM17-2 stepper motor control module ,C30659 infrared detectors ,and other devices .In the experiments ,different concentrations of methane gas were tested ,and experimental results show that the relative error of measurement was less than 2.0% within the range from 200 to 5 000 ppm .In summary ,it’s proved that the system has high accuracy and stability .