At the beginning of 2016 Group for volume and flow started development of calibration method for gas meters standards with liquid. Method development took place in several phases. The last phase, method validation was finished in May 2020.
Users of gas meter standard with liquid are laboratories for gas meters verification. Directorate of Measures and Precious Metals (DMDM) uses device for gas flow with critical nozzles, type TZKD 16, manufacturer JUSTUR, Slovakia, serial number: 787/2006 for calibration. Calibration is performed with direct comparison method in accordance with work instruction RU-309: Work instruction for calibration of gas meters standards with liquid using device with critical nozzles, version/edition 01/00, May 2020.
Measurements are performed in the premises of users of gas meters standards with liquid. Extended measurement uncertainty is 0,2%. Basic component of TZKD 16 device are critical nozzles (11 pieces, with different nominal flow, measuring range from 0,016 m3/h up to 7 m3/h). Critical nozzles were calibrated in SMU, Slovakia; humidity and temperature measuring instruments in DMDM, Serbia; pressure measuring instrument in HMI, Croatia which ensures traceability of measurement results to the International System of Units SI.