并行激励的电磁流量计电导率测量系统研制

Design of the electromagnetic flowmeter conductivity measurement system with parallel excitation

针对现有的电磁流量计电导率测量方法测量精度低、附加激励与磁场激励分时进行,影响流量测量实时性等问题。提出一种并行激励的电磁流量计电导率测量方法,激励电路采用单路高频方波电容耦合的方式,该激励方式可与磁场激励并行激励,使得流量信号与电导率信号均可以实时测量。采用带通滤波与基于能量衰减的信号处理方法,提高了电导率测量精度和稳定性。流速实验结果表明,并行激励下可以实现电导率和流量同时测量,且在流体电导率为100μS/cm^3 mS/cm的范围内测量精度可以达到3%,水流量标定精度优于0.5级。

In view of the existing electromagnetic flowmeter conductivity measurement methods,there are problems such as low measurement accuracy,time-sharing of additional excitation and magnetic excitation,which affect the real-time flow measurement.This paper proposes a parallel excitation electromagnetic flowmeter conductivity measurement method.The single pulse square wave capacitive coupling manner is adopted in the excitation part,which can be with magnetic field excitation in parallel.The flowmeter signal and the electrical conductivity can be measured in the same time.The band-pass filter and the method based on energy attenuation are given,which improve the precision and stability of conductivity measurement.The flow velocity measurement shows that the conductivity and the flow can be measured simultaneously with parallel excitation,and the conductivity measurement is accurate to 3%within the range of 100μS/cm^3 mS/cm,the flow calibration precision is better than 0.5 level.