Metrological performance of diaphragm gas meters with different use age

According to the current legal metrological regulation of diaphragm gas meter, domestic gas meters in China are required to pass mandatory initial verification at 20°C, and then a 10 years' legal duration is allowed without any subsequent or in-service verifications. Here, experimental study has been implemented to investigate the metrological performance and temperature adaptability of old diaphragm gas meters with different use age. Through the introduction of weighting factors, weighted mean errors are calculated to analyse the correlation between the indication errors of gas meters and their use age, as well as the relationship between the indication errors and test temperatures. Experimental results indicate that the use age of gas meters has negligible influence on their metrological performance during the 10 years' legal duration. However, the indication errors worsen as temperature varies.