Abstract：To overcome the shortcomings of pressure loss and the need for regular calibration with gas turbine flowmeter, a mono-channel gas ultrasonic flowmeter with high-pressure resistance and low power consumption is developed.In order to solve the poor quality of the echo signal caused by the impedance mismatch of the transducer, the features of the echo signal are analyzed.A digital signal processing method based on dynamic variable threshold and zero-crossing detection is proposed to accurately locate the feature point of the echo signal.A low-power gas ultrasonic flow transmitter with STM32 as the core has been developed, and a new excitation method is designed,which can not only prevent the two-way outputs of the MOSFET circuit from being turned on at the same time, but also save the excitation power consumption.The combination of pulse cumulative upload and optimal pulse frequency division reduces the pulse upload error.The gas flow calibration experiment results show that: the developed low-power mono gas ultrasonic flowmeter meets the requirements of the indicators of level 1 accuracy, and the range ratio is 1:21.
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2022, Vol. 43 
