Development Of Smart Ultrasonic Gas Flowmeter

With the rapid development of China in all walks of life,ultrasonic flowmeter is broadening the market.But there are still some problems,such as few variable period flowmeter on flow meter market,no the signal quality detecting,no way to deal with the larger interference,zero flow but not zero reading.The smart ultrasonic gas flowmeter developed in this paper can adjust the measurement period according to the flow field state,which could reflect the flow field state well.And a signal quality detection method is added,which avoid the impact of low quality signals on the measurement results.And a dynamic line fitting method is adopted to correct time,which can get flow correction.This article mainly studies from the following aspects:1,By reading a lot of related literatures,the development of ultrasonic flowmeter is understood,by understanding research status at home,using the principle of time difference method to design smart ultrasonic gas flow meter.The smart algorithm is designed to measure the time.2,The overall hardware circuit of the ultrasonic flowmeter is designed.The peripheral circuits of the timing chip,the main control chip and the computing chip are configured.And the hardware circuit modules such as ultrasonic excitation conditioning circuit,ultrasonic signal processing circuit,STOP signal processing circuit,switch switching circuit and so on are designed.3,Through the research of hardware analysis and principle,the program of smart ultrasonic gas flowmeter is designed.It mainly includes the design of the main program,the time value measurement program,the measurement period adaptive program,the low quality signal elimination program,the dynamic line fitting program,the flow value calculation and so on.4,The prototype of smart ultrasonic gas flowmeter is developed.And time value is printed through serial port to compare.And the superiority of the algorithm is analyzed.The flow rate of the prototype is measured on the sonic nozzle gas flow calibration device.The performance of the prototype is analyzed through experimental data.The error of the measured data is analyzed,the error curve is drawn,and the straight line fitting is used to correct the flow value.