Ultrasonic flowmeter based on Doppler effect - with acrylic prisms facing transmitter and receiver transducers

摘要

An ultrasonic flowmeter, based on the Doppler effect has, instead of the focussing lenses facing both the transmitter and the receiver of the conventional equipment, clip-on elements which alter the exit and entry angle of ultrasonic transmitter and receiver as a function of the temperature of the fluid. The pref. clip-on elements are prisms, made of acrylic resin. - The arrangement compensates any frequency fluctuations of the Doppler signal which are caused by temp. changes, without any need for complex circuitry. The accuracy of the measurements is not detrimentally affected.