The prover is an essential reference system within metering skids, used to verify the accuracy and performance of flow meters in measuring the volumetric or mass flow rate of liquids. Over time, due to factors such as pressure variations, temperature changes, or wear and tear, the accuracy of flow meters may decline. The prover functions by passing a predefined and precisely known volume of fluid through the flow meter and comparing it with the meter’s measured value. Based on this comparison, a meter factor (correction coefficient) is calculated and applied, typically in the flow computer or in control systems such as the DCS.

Calibration results, including deviations and correction factors, are recorded and stored to ensure traceability and reliability of measurements. This process, known as proving, is essential for guaranteeing the accuracy of measurements in custody transfer of petroleum liquids.

There are different types of provers, such as bi-directional provers and compact provers, each selected depending on the type of flow meter and the specific operating conditions. Regular use of a prover not only ensures the accuracy of metering systems but also significantly contributes to extending equipment lifespan and reducing operational costs.