Over the last 20 years, ultrasonic gas meters have become the measuring instrument of choice for gas volume measurement in custody transfer. The technology owes its broad acceptance among gas transport companies to its superior measuring accuracy, reproducibility, wide measuring range and low maintenance costs.
Ultrasonic gas meters use robust sensors that generate repeatable pulses (amplitude and frequency). They also include high-speed electronics, complete with a precise timer for detection, resolution and timing of the transmission/reception of ultrasonic pulses with sufficient time domain resolution. The sensor and electronics configuration of the meter allows high pulse transmission rates. The signal propagation time measurement provides a fast integration of the gas flow velocity so that precise readings can be recorded every second.
The most important development in ultrasonic technology in recent years was the multi-path meter, which determines the average of the axial velocity components over the cross-section of a closed pipe. The design and performance of ultrasonic gas meters are defined in international standards, e.g. ISO 17089 and AGA 9. Ultrasonic gas meters are the technology of choice for custody transfer metering and are approved by MID, Measurement Canada and other national approval bodies.