A few matters easy to be ignored in UFM operation (2)

(2)Ultrasonic flow meters are not properly verified or calibrated
Any flow meter needs to be verified or calibrated before use, and it is particularly important for portable ultrasonic flow meter at this point. As we all know, there are three sizes transducers selectable for portable ultrasonic flow meter (large, medium and small), respectively used for different diameter ranges, and each group transducers, when being used with the main frame, is in a sense a separate set flow meter.

If we only do verification or calibration of the portable ultrasonic flow meter with small size transducers on only small tubes, then when we use large size transducers to measure flow rate of large pipes, it means you are measuring flow rate with a flow meter which has not been verified or calibrated, so measurement accuracy cannot be guaranteed, because the present level of technology cannot guarantee transducers’ interchangeability, moreover, differences between large size and small size transducers are also variables which cannot be ignored.

Therefore, the correct approach should be according to users’ application situation to do portable UFM verification or calibration on flow standard facility with many pipelines, which diameters are same or similar with the real application pipeline. At least to ensure that each group configured transducers have been calibrated.

On portable ultrasonic flow meter verification or calibration certificate there will be a correction factor. Calibration factor will be given for each type flow meter when doing calibration because of working principle, manufacturing and other reasons; just the names and forms are different. Portable ultrasonic flow meters, since is equipped with multiple sets of transducers for different caliber, may have several correction factors. So we should ensure the correct use of the ultrasonic flow meters when we use them to measure flow. We should develop a good habit to confirm if the correction factor set in main frame is correct before formal measurement.