A Transit Time Ultrasonic Flowmeter with a Simple Compensation Method for the Systematic Errors

Due to the nonreciprocity of the ultrasonic transducers and the time delay caused by the energy form transformation process and the signal transmission in the measurement circuit, the accuracy of transit time ultrasonic flowmeter (TTUFM) can be reduced. This work proposes a simple measurement strategy for characterizing and eliminating the systematic error components in transit time measurement. The key feature of this method is that both the transmitted signal and its reflected echo signal are recorded to calculate the upstream and the downstream transit time, and the systematic errors of the detection system can be evaluated through this process. The cross-correlation algorithm combined with parabolic intercalation is adopted to process the recorded data. Additionally, to increase the signal-to-noise ratio (SNR) of the detected ultrasonic signal, simple coded excitation pulses with dual frequency components are investigated and utilized to drive the ultrasonic transmitter, significantly improving the signal quality of the processed data. This method provides a low-cost and effective strategy to improve the measurement accuracy of the TTUFM.