National measurement standard of liquid density unit: structure, metrological characteristics, and operation principles

Abstract

The article presents the structure, composition, operation principle, and metrological characteristics of the national primary measurement standard of liquid density unit. This measurement standard realizes the liquid density unit by reference procedure and is the basis for comparison and metrological traceability for other measurement standards of liquid density unit, that made it possible to give it the national primary standard status. Based on accuracy characteristics analysis of primary measurement standards from other countries (CMC-lines from the KCDB of the International Bureau of Weights and Measures based on key and supplementary comparisons), it is possible to prove its high metrological status and initiate international comparisons for establishing its metrological equivalence to the analogical measurement standards from other countries. Measurement standard operation algorithms (in weighting and comparing mode) and uncertainty sources contributing to the uncertainty budget of liquid density measurement, which make it possible to submit measurement results according to established international requirements, are analyzed in the publication.