Digital liq. velocity measuring system - has transducer receiving reflected acoustic wave to provide HF pulses indicative of liq. velocity

摘要

A generator provides a relatively h.f. signal to a transmitting transducer for directing an ultrasonic wave into a conduit through which liq. is directed. A receiver transducer is disposed to receive the acoustical wave as reflected from the liq. and to provide an output signal to be amplified and demodulated to provide a train of h.f. pulses, the frequency of which is indicative of the velocity of the liq. The train of pulses is applied to a counter and a decoder to provide a signal to a display. A timing circuit is provided for enabling the generator, the counter and the decoder for a first, relatively short period of time, made dependent upon the cross-sectional area (or diameter) of the conduit through which the liq. is directed.