Ultrasonic flow meters exploit the ability of materials to propagate sound in fluids, in particular the speed of sound propagation is a characteristic that depends on the density, pressure and temperature.
Ultrasonic flow meters work with the following principle: an electrical impulse is applied to an electroacoustic transducer which transforms it into a corresponding impulse of sonic energy with a frequency between 0.5 and 5 MHz.
The impulse propagates in the fluid under examination, with a speed dependent on the speed of the fluid itself, up to the receiver where it is transformed into an electrical signal.
The ultrasonic flow meter can also be used for dirty or abrasive fluids and for pipes with large diameters, however its accuracy is influenced by the fluid regime.