Ultrasonic

Ultrasonic transit time or ‘clamp on’ flow meters are instruments designed to measure the speed of a liquid inside a pipeline or conduit.
The principle of operation is based on measuring the time it takes for an ultrasonic signal to travel a certain distance inside a moving liquid. A transducer positioned outside the pipe generates an ultrasonic pulse that travels through the fluid to a second transducer, positioned at a known distance from the transmitter.
The meter logs the time it takes for the ultrasonic pulse to travel from the transmitter to the receiver.
Knowing the distance between the transducers and the transit time, the meter calculates the average velocity of the fluid in the pipe using a formula. Once the velocity of the fluid is determined, the meter can display and transmit the fluid flow measurement inside the pipe.