高分辨NH_(3)光谱检测的气压控制系统设计

Design of air pressure control system for high resolution NH_(3) spectrum detection

基于伯努利原理设计了被测氨气气压闭环反馈控制系统,研究了低压条件下NH_(3)高分辨光谱特性。系统以被测氨气吸收池压力为控制对象,采用CDG800压力传感器测量吸收池气压,1路VT317电磁阀控制高压标准浓度氨气源增大吸收池中的气压,1路VT317电磁阀控制真空泵抽取吸收池的气体降低气压,构成了NH_(3)光谱检测的低压气路;并设计以Arduino UNO单片机为核心的压力测量、电磁阀和真空泵闭环反馈控制电路。实验结果显示,设计的气压控制系统可维持稳定时间达72 h以上,气压波动在1 torr以内;压力为3.2 torr时获得了NH3中红外波段1 103.4 cm^(-1)的6条单根吸收光谱信号,计算得到的线强与HITRAN数据库中线强数据偏差约在2.71%~4.71%之间,实现了重叠谱线完全分离,为后续的高分辨光谱研究提供了宝贵经验。

In this paper, a closed-loop feedback control system for the measured ammonia gas pressure is designed based on Bernoulli′s principle, and the high-resolution spectral characteristics of NH_(3) under low pressure conditions are studied. The system takes the measured ammonia absorption tank pressure as the control object, uses CDG800 pressure sensor to measure the absorption tank air pressure, one of the VT317 solenoid valve controls the high pressure standard concentration ammonia source to increase the air pressure in the absorption tank, and the other VT317 solenoid valve controls the vacuum pump extraction. The gas in the absorption cell reduces the pressure to form a low-pressure gas circuit for NH_(3) spectrum detection, and a closed-loop feedback control circuit for pressure measurement, solenoid valve and vacuum pump with Arduino UNO microcontroller as the core is designed. The experimental results show that the designed air pressure control system can maintain a stable time for more than 72 h, and the air pressure fluctuates within 1 torr. When the pressure is 3.2 torr, six single absorption spectrum signal in the NH3 mid-infrared band 1 103.4 cm^(-1) is obtained, and the deriation between the calculated line intensity and the line intensity data in the HITRAN database is between 2.71% and 4.71%, which achieves complete separation of overlapping spectral lines, which provides valuable experience for subsequent high resolution spectrum research.