Calibration of Ultrasonic Flow meter

Calibration of Ultrasonic Flowmeter

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Calibration of Ultrasonic Flowmeter

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Calibration of Ultrasonic Flowmeter

Calibration of Ultrasonic Flow meter

To ensure the fair gas transaction at custody transfer locations, pipeline companies are looking towards the credibility and excellence of meter calibration as the main parameter to ensure the reliability of the gas.BACKGROUND

Thecalibrationlaboratoriesusetheirownpressure andtemperaturetransmittersinordertoconformto theiraccreditedprocedures.The calibration must be done under conditions representative of the actual operation of the flow meter.The calibration must be performed by a certified and traceable laboratory.

Flow meter installed at a Calibration Facility

Flow meter is installed correctly with respect to flow direction and orientation.Same output signal is used during calibration as will be used in the final installation for traceability purpose.

Before Calibration Start

The calibration process begins with the highest flow rate. The flow of the facility is slowly increased until the high flow rate is established. The stability of the systems is allowed to stabilize before any data is sampled. The facilities acquisition system provides stability indicators. This information can be reviewed both graphically and in a tabular format.

Data recorded during the calibration sampling period includes:Pressures, Temperatures, Flow rates,Gas composition.

Acquiring ultrasonic flow meter performance data (log or maintenance file) via the instrument manufacturers software.The historical data can be used to qualify the instrument output and performance in the field where a reference standard is not accessible.

After the calibration process has been completed for all requested flow points, an as-found calibration error curve can be produced and adjustment factors can be determined.CALIBRATION ADJUSTMENT AND VERIFICATION

Adjustment factor is calculated and entered into the meter configuration for every flow rate tested.

ACFH actual cubic feet per hourAGA American Gas Association10

Selecting and applying the proper flow meter for a given job requires effective cooperation between flow meter users, manufacturers and calibration facilities. Summary

They must be calibrated as close as possible to the actual conditions of use and proper compensations should be applied for any deviations from ideal conditions. The accuracy requirements for the intended measurement must be defined based on the needs of the application. It must be confirmed that the flow meter is calibrated by a laboratory which is capable of producing calibrations with such precision. Care should be taken to insure that at the time of use, the flow meter possesses a valid calibration according to the guidelines.Requirements for proper calibration and use of flow meters