Development of a New Type Ultrasonic Gas Flowmeter

Abstract

In this paper, a new method on how to design ultrasonic gas flow meter is presented. Ultrasonic sensor with large area and center frequency 120kHz is selected and ultrasonic sensor driving circuit based on IRF7389 is designed to drive the sensor, the received ultrasonic signal can reach 1000mv in the distance of 30cm, thus can make the amplifying circuit easy to design. In the ultrasonic receiving circuit, the no inverting amplifier is used to realize preliminary amplification; followed by the second-order band pass filter with the center frequency for 120kHz to filter out the noise, gain adjustable amplifier circuit is designed based on digital potentiometer, ultrasonic signal after comparison circuit outputs square wave to control chip time TDC-GP2 to achieve time interval measurements. Finally, the system is calibrated and the calibration results show that the measurement accuracy is 1%.