Ultrasonic Sensing for Water Flow Meters and （水流量计,超声波传感）.pdf

Application Report SNIA020– April 2015 Ultrasonic Sensing for Water Flow Meters and Heat Meters Bahram Mirshab ABSTRACT Ultrasonic flow meters are gaining wide usage in commercial, industrial and medical applications. Major benefits of utilizing this type of flowmeter are higher accuracy, low maintenance (no moving parts), non- invasive flow measurement, and the ability to regularly diagnose health of the meter. This application note is intended as an introduction to ultrasonic time-of-flight (TOF) flow sensing using the TDC1000 ultrasonic analog-front-end (AFE) and the TDC7200 picosecond accurate stopwatch. Information regarding a typical off-the-shelf ultrasonic flow sensor is provided, along with related equations for calculation of flow velocity and flow rate. Included in the appendix is a summary of standards for water meters and a list of low cost sensors suitable for this application space. Topic Page 1 Introduction 2 2 Time-of-flight Measurement Sequence 3 3 Volumetric Flow Calculations 3 4 Ultrasonic Analog-front-end Integrated Solutions for Flow Measurement 5 5 Choosing an Ultrasonic Flowmeter Sensor 6 6 Measurement Accuracy Considerations 7 7 Conclusion 10 Appendix A Flow Meter Transducers and Standards 11 SNIA020– April 2015 Ultrasonic Sensing for Water Flow Meters and H