Calibrating a new Ultrasonic Flowmeter

  • Thread starter Dalamagkas Konstantinos
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Thread Starter

Dalamagkas Konstantinos

Hello..

I am working for a refinery and we are going to change a Flow Differential Pressure Transmitter with an Ultrasonic type Flowmeter in order to achieve a better accuracy because the specific measurement is taken into consideration for the calculation of CO2 emissions of the refinery. My supervisor put me in charge of that replacement. The flowmeter will be installed in a 14" fuel gas line. I searched a bit and what confuses me is the matter of the calibration. It seems that most of these flowmeters must be sent to a laboratory for their calibration. Is there any way of ins-itu calibration? And what about the matter of accuracy? My supervisor wants to "move" to an accuracy of 1%. Can this be done with a two measuring path flowmeter?

Thank you in advance for your time..
 
Hello,

If you want to calibrate a flow meter in situ, you have to have a reference of better accuracy to do so. And even this reference would have to be calibrated against another one that is close to the metrological standards for volume flow.

For this reason, most users of measuring instruments rely on the factory calibration or calibration at a metrological institute. In case of ultrasonic flowmeters, you can either have a “dry” or a more accurate “wet” calibration (with medium, for liquids mostly water is used).

The amount of paths also has to do with accuracy, as more paths give you a better view on the flow profile. 1% accuracy should be possible with a 2 path ultrasonic flow meter. For example, here is a 3 path flow meter that is specified at 0,3% accuracy for flow speeds 1…66 ft/s: http://bit.ly/LSRocf
 
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