ULTRASONIC FLOW METER

摘要

PROBLEM TO BE SOLVED: To provide a precise flow meter. SOLUTION: A transmission-side ultrasonic converter 23 (or 24) is driven at a plurality of frequencies to transmit ultrasonic waves. A plurality of zero-cross points of received waveforms received at a reception-side ultrasonic converter 24 (or 23) are detected while a trigger level is sequentially updated to determine a true ultrasonic wave propagation time Ts. The quantity of flow of a fluid is computed through the use of the determined time to accurately measure the flow velocity of the fluid and implement the precise flow meter. COPYRIGHT: (C)2004,JPO