Acoustic fluid flowmeter using spaced transducers - includes signal generating and analysing circuitry measuring phase difference between sine wave signals

摘要

Acoustic fluid flowmeter has a pair of transducers at positions in a fluid conduit spaced along the conduit for transmitting acoustic signals in the upstream and downstream directions alternatively. Each signal consists of a gated burst of a measurement frequency with each transducer when acting as a receiving transducer, feeding signals through a narrow band filter. The filtered signals are used to produce respective continuous sine wave signals. The phase difference between the sine wave signals is measured from which the velocity of the fluid in the conduit is derived.