|Υπερηχητικά σήματα αποστέλλονται εναλλάξ προς και αντίθετα στην κατεύθυνση της ροής.
The heat meters use the highly precise ultrasonic transit time measuring principle, for which two ultrasonic sensors are externally mounted on the pipeline and connected to the electronic. The ultrasonic sensors work alternately as transmitter and receiver, and mutually send ultrasonic signals. During these transmissions, the respective signal transit times of the to-and-from signals (t1, t2) are measured.
The electronic measures the difference of the transit time of the ultrasonic signals going with and against the flow direction t1 and t2. These signals are either decelerated or accelerated by the medium flow. The difference produced in both signal transit times is proportional to the flow rate and is used together with the pipeline geometry for a precise flow calculation.