Investigations concerning the applicability of ultrasonics for the measurement of the velocity and the volume of flowing liquids

The velocity of sound in a liquid is a function of the temperature, the pressure, the density, the viscosity, and the composition of the liquid. Acoustic directional and reflection effects depend on the acoustic frequency. A description is given of three ultrasonic approaches for measuring the flow rate of a liquid. The amplitude method is based upon a change in the amplitude of a supersonic beam which has been deflected as a consequence of liquid motion. Another method utilizes the phase difference between a supersonic beam traveling in the direction of liquid flow and a beam traveling in the opposite direction. The third method employs two generators which produce short supersonic pulses. Time intervals between two succeeding pulses provide an indication of the flow velocity in this approach.