Impact of Regulator Noise on Ultrsonic Flow Meters in Natural Gas

The impact of pressure regulator noise on the performance of ultrasonic meters has been discussed for several years now. This is one of the problems still to be solved in ultrasonic flow metering technology. Engineers have so far attempted to solve the problem by installing complex spatial pipe arrangements at high costs to reduce interfering noise levels. The issue has been examined systematically both in field tests in the measuring station of a transportation pipeline and on the E.ON Ruhrgas high-pressure test facility in Lintorf to determine the limits of use and potential applications of an ultrasonic gas meter with chordal path layout in combination with a regulator. The tests made on a 16-inch meter in the measuring station confirmed that proper functioning of the meter with respect to pressure differential and flow rate can be guaranteed even under the most extreme conditions. For further systematic testing on the Lintorf high-pressure test facility, an 8-inch ultrasonic meter was equipped with two four-path systems working independently of each other. This approach made it possible to directly compare a system with 210 kHz ultrasonic sensors with the latest technology of 350 kHz sensors. It was found that the 350 kHz sensors are clearly less sensitive to interfering noise signals and therefore improve measurement reliability under worst case conditions. Based on auto-diagnosis parameters such as signal-to-noise ratio and performance, the meter was confirmed to be capable of clearly detecting and rejecting disturbed signals. The paper describes the test results and the information derived with respect to an expanded use of ultrasonic technology.