The stability of the temperature is particularly important during calibration. We therefore need to be able to measure the temperature accurately. In EuroLoop’s calibration facility for liquid meters, this is realized using ultrasonic sound.

Temperature measurement based on sound velocity

Ultrasonic sound is sent through the liquid by means of an ultrasonic transmitter/receiver on both sides of a pipe and its velocity calculated. Since we have determined the relationship between the temperature and sound velocity for each of the three test liquids, the temperature of the liquid can then be derived from this sound velocity value.

The method has two advantages: temperature changes are rapidly visible and the measurement through the entire pipe diameter is more representative of the average liquid temperature than a measurement at a single point.