Ultrasonic flow meters, which are a type of volumetric flow meter, are non-intrusive flow sensors that use acoustic vibrations to measure the flow rate of a liquid. There are two types, Doppler and transit time.

Ultrasonic meters are ideal for automated wastewater applications or any dirty liquid which is conductive or water based – but will generally not work with distilled water or drinking water. These flow meters are also ideal for applications where low pressure drop, chemical compatibility, and low maintenance are all requirements.