Performance study in fuel dispensers in the field of volume measurements

摘要

Like any type of measuring instruments used for commercial transactions, fuel dispensers, commonly known as petrol pumps, are submitted to metrological control in order to assure consumer protection and provide society in general and citizens in particular the guarantee of accurate measurements, the verification being directly linked with the volume measurement of the delivered fuel. In Portugal, the fuel dispenser approved under the MID is subject to metrological control in service taking into account its annual verification by the verification bodies, following the procedures defined by IPQ, according to specific national regulations. Presently there are 45 000 hoses of the fuel dispensers in Portugal, verified by several verification bodies equally distributed in the national territory. In order to evaluate the influence factors in volume error determination of fuel dispensers, a study using standard test measures of different type, materials and volume was designed and implemented. The uncertainty of the volume determination according to the GUM methodology was evaluated, considering different atmospheric conditions, volume variation over time, different fuel types and determination of error the in different types of standard test measures. There was some difference in performance and error determination when using different standard test measures, but in all implemented tests, the maximum permissible error was not exceeded. The results allowed simplifying the internal procedure while maintaining the accuracy of results.