Design and Implementation of an External Clamped Ultrasonic Flowmeter based on Time Difference Method

The external clamp-type ultrasonic flowmeter is widely used in the measurement of industrial liquids because of its advantages. In this paper, an external clamping liquid ultrasonic flowmeter based on the time difference method is designed. The system is built with TDC-GP22 chip as the core. The driving square wave is generated through the TDC-GP22 transmission channel, and the driving circuit is sent to improve the amplitude of the signal to drive the ultrasonic transducer. Enter TDC-GP22 to calculate the time difference; MCU adopts STM32F103 chip, the main function is to control TDC-GP22, measure according to the prescribed rhythm, read the measurement results and submit them to the main control board of ultrasonic flowmeter through serial port; Finally, the experimental circuit board has been tested on the flow calibration platform, including the circuit routine functional test, the standard test after painting the pipe wall and the high temperature test. The test results show that the system has good linearity and repeatability, high measuring accuracy, and can meet the needs of complex industrial environment.