基于超声检测的新型二元混合气体传感器  

New Type of Binary Mixed Gas Sensor Based on Ultrasonic Detection

作　　者：王飞 吴国贵 和卫星[1] 

机构地区：[1]江苏大学电气信息工程学院,江苏镇江212013

出　　处：《自动化仪表》2017年第12期77-80,共4页Process Automation Instrumentation

摘　　要：目前,国内气体浓度流量传感器存在混合气体的浓度、流量计量准确度低的问题。为解决该问题,在深入研究超声波气体流量计测量原理的基础上,准确分析了超声波计量二元混合气体浓度、流量的影响因子,提出了一种基于超声检测的新型二元混合气体传感器设计方案。以TMS320VC5402 DSP作为控制芯片,简化了硬件设计,提高了数据处理能力。采用信号有效范围检验方法,利用高精度A/D采集超声波回波信号,并运用拉伊达准则去除信号噪声。基于能量阈值法的基峰确定过零检测方法,可准确检测超声波过零点,精确计算超声波传播时间。结合理想气体状态方程等理论,计算、分析了二元混合气体浓度和流量。给出了新型二元混合气体传感器及实施方案,并对氧气、氮气组成的二元混合气体进行了试验验证。试验结果表明,该设计方案的浓度误差小于1%,流量误差小于1.2%。At present,there is a problem that the domestic gas concentration and flow sensor has a low measurement accuracy of the mixed gas concentration and flow measuring. To solve the problems, and on the basis of studying the measuring principle of ultrasonic gas flowmeter and analyzing the influencing factors on the concentration and flow measurement of binary mixed gas, a new type scheme of binary mixed gas sensor based on ultrasonic detection is proposed. With TMS320VC5402 DSP as the control chip,the hardware design is simplified,and the data processing abi l ity is improved. The method of signal valid range examination is adopted, and by using high precision A/D, the ultrasonic echo signal is acquired, and Pauta criterion is taken to remove the signal noise. A zero - crossing detection method based on the energy threshold is proposed to detect the zero - crossing point of ultrasonic wave and calculate the ultrasonic transmission time. Combined with the ideal gas state equation and other theories,the concentration and flow of binary mixed gas are calculated and analyzed. The new type of binary mixed gas sensor and the specific implementation scheme are given, and the experimental measurement of the binary mixed gas combining oxygen and nitrogen is carried out. The experimental results show that the concentration error is less than 1% ,and the flow error is less than 1.2%.

关 键 词：超声波 传感器 流量计 二元混合气体 数字信号处理器 过零检测 

分 类 号：TH7[机械工程—仪器科学与技术] TP212[机械工程—精密仪器及机械]