These systems operate in a manner similar to the non-contact radar fill level transmitter. Here, an ultrasonic transducer mounted to or near the top of the container sends out an ultrasonic pulse. When the pulse hits the surface of the liquid, it is reflected, and the sensor calculates fill level based on the time between the pulse and the return signal.
Because the speed of sound can vary depending on the gas mixtures present, it’s important to note what fumes or gases might be present in the tank when using ultrasonic fill level measurement technology.