Ultrasonic flow meters use sound waves as a reliable, accurate and maintenance free method to measure the velocity of a fluid from which the volumetric flow rate can be calculated. They feature no moving parts making them more reliable and accurate while providing maintenance-free operation. Since ultrasonic signals can also penetrate solid materials, the transducers can be mounted onto the outside of the pipe offering completely non-invasive measurement eliminating chemical compatibility issues, pressure restrictions, and pressure loss.