Calibration of flow meter

 

Calibration  of flow meter

All flow meters require an initial calibration.

 Manufacturers of the flow meter usually calibrate a  flow meter for specific service conditions. 

The need to recalibrate usually depends on how well the meter fits the application. Some liquids passing through flow meters are corrosive or acidic or abrasive. So after sometime portions of the meter will deteriorate and the performance of the meter is reduced

 

The procedure of flow meter calibration

 First flushing the transmitter.

 Flush both the impulse lines. 

Adjust the zero when there is no flow or by equalizing in case of od DP transmitter if necessary. 

Close one of the valves either H.P. or L.P. open the equalizing valve. The O/P should read zero.

For span, calibration passes a flow of known value preferably span value of flow meter, and calibrates the span.

again check zero.

Common faults in flow meter

* No power

* Impulse line leak or block

* any wear ina components

* Transmitter faulty

* mA cable faulty

* calibration not ok

* analog channel faulty


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