One SICK ultrasonic flare flow meter is installed in our HP flare line and we noticed that flare flow meter reading is little bit erratic while the flow rate is high. Recently we have some upset in our propane skid so we flare it the total gas and during that time we noticed the inlet ultrasonic meter reading is less than the flare ultrasonic flare meter. The flare flow meter is corrected with pressure and temperature. Based on the DCS trend the deviation is increased with flow rate. I expect some valuable suggestion to fix this issue and why this is happening.

 

Historically in ultrasonic velocity measurement, a narrow beam or shear mode energy beam from the transmitting transducer relied on stable propagation conditions in order to hit its target - the receiving transducer. Changes in sonic velocity due to temperature or fluid composition could cause a narrow beam to miss the receiving transducer resulting in a loss of signal.

Ask the vendor how changes in medium sonic velocity are accounted for.

 

David,

You are right, and that case the reading probably will reduce from the actual reading. But in our case the high flow rate, the meter reading is showing around 30 % high flow. Is it possible?