THE DEVELOPMENT OF NATIONAL BASIC STANDARD AND RESEARCH INTO METROLOGICAL CHARACTERISTICS OF KINEMATIC VISCOSITY OF LIQUID MEDIA

Abstract

This article examines the relevance of upgrading the basic standard of metrological support of the Republic of Uzbekistan; presents the results of the new standard development and the resulting scientific and practical conclusions; considers the issues of measuring kinematic viscosity, one of the most important indicators of the quality and safety of liquid media, with high metrological accuracy. The author highlights that metrological observability of measurement readings is reached by calibrating working measuring tools.
The main attention is paid to the analysis of the findings from experimental testing, device verification, intra- and inter-laboratory comparative tests, as well as from comparison of metrological traceability of viscosity with established standard samples (certified liquid). The experiments were conducted to assess metrological suitability of the measuring device. However, based on the study into viscosity hypersensitivity to such factors as temperature and density of the liquid medium, a correlation analysis was made. Findings from theoretical and experimental studies helped to confirm the suitability of metrological properties of the measuring tool for use in the calibration process and its commercialization. Nowadays, the national basic standard of the unit of kinematic viscosity has been broadly commercialized and used in the state metrology service. The developed measuring device has enabled metrological studies of working viscometers of enterprises and organizations in a wide range of temperatures and a range of viscosity scale measurements.
As a result, in accordance with the international standard ISO / IEC 17025:2017, calibration was made in an accredited laboratory to assess deviations from the basic value and the expanded measurement uncertainty. According to the proposed approach, the expanded measurement uncertainty is estimated by multiplying the standard measurement uncertainty by the coverage factor k = 2 in compliance with normal distribution, providing a coverage probability of 95%. The standard uncertainty was determined in accordance with the GUM and COOMET R / GM / 32: 2017 recommendations