They are high technology natural gas meters with wide measurement range, which are used in the main natural gas measurement stations at city entrances.  It is used only for control purposes currently and is not subject to bill in accordance with the legislation in our country.  Working pressure can increase up to 100 bars.  Transducers, which can send and receive ultrasonic waves, are placed on top of the meter in couples, and there are models with 3, 4 or 5 couples.

Working Principle:

Inner side of the meter is completely a straight tube, and transducers are placed in couples in holes that are opened on specific calculated parts.  These transducers send ultrasonic waves to the gas passing through the meter and show how much gas has passed through by calculating sending and receiving times of these waves.  It does not require any maintenance since it has no mechanical part in it.  In the event of failure in transducers, they can be replaced with special equipment under pressure and this eliminates the requirement to cut the gas in case of failure.