engleski

Advances in gas flow measurement using weighing method

The transfer gas flow standard ROMBACH NB2 was calibrated in the Zagreb Gasworks using two different balances incorporated into the basic calibration system. The basic difference between these balances was in their resolution, i.e. 1 g for the SARTORIUS IS64FG and 0, 1 g for the SARTORIUS LA64001. Before measurements with the SARTORIUS IS64FG balance, absolute pressure sensors HBM P3MBA were calibrated using the digital barometer VAISALA PTB 220. The deadweight tester PRESSUREMENTS 6100-1L was employed for HBM P3MBA calibration before tests with the SARTORIUS LA64001 balance. In all tests, experiments were carried out for flow rates from 0, 02 m3/s to 1, 4 m3/s. Experimental results compare well with experiments previously performed in the Baden-Württemberg Office of Legal Metrology, Germany. The spread of obtained experimental values was within 0, 25% for the total range of flow rates. The measurement repeatability was within 0, 1%. The highest contributions to measurement uncertainty result from the air temperature and humidity in the tested gas flow meter and in the container. The measurement uncertainty in tests with the SARTORIUS LA64001 was smaller than in tests with the SARTORIUS IS64FG. Total measurement uncertainty was reduced when absolute pressure sensors HBM P3MBA were calibrated using the deadweight tester PRESSUREMENTS 6100-1L compared to results obtained with the VAISALA PTB 220 digital barometer.

calibration; gas flow meter; measurement uncertainty; weighing method

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