Key comparison of liquid density standards

Abstract

Hydrostatic density determination for liquids is mainly performed by laboratories to provide means for calibrating liquid density measuring instruments such as oscillation-type density meters. From 2002 to 2005 the CIPM key comparison CCM.D-K2 ‘comparison of liquid density standards’ was carried out piloted by the PTB. The aim was to compare the results of the density determination by the participating laboratories to support entries to the CMC tables in this sub-field. To provide further laboratories the possibility to support their entries to the CMC tables at the meeting of the EUROMET Working Group on Density in 2007 this comparison was agreed on. BEV (Austria) organized the comparison supported by the PTB (Germany). For the comparison samples of pentadecane, water, tetrachloroethylene and of an oil of high viscosity were measured in the temperature range from 5 °C to 60 °C at atmospheric pressure by hydrostatic weighing. The measurements were completed in 2008. The reference values of the first reports based on the draft of the CCM.D-K2. After the official publication of the CCM.D-K2 the reference values were recalculated and the report was finalised in 2015. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Comparison of density determination of liquid samples by density meters

“…The aim of this EURAMET project was to compare the results of the liquid density determination by oscillating density meters of the participating laboratories. The results were linked to CCM.D.K-2 [4] via EURAMET Project EURAMET.M.D.K-2 "Comparison of liquid density standards" by hydrostatic weighing piloted by BEV 2008 [3]. BEV (Austria) was the Pilot Laboratory in this comparison supported by MKEH (Hungary).…”

“…The results, expanded uncertainties, the equivalence and the normalised errors for water at 20°C. Overview of the results -deuterated water at 20 °C, results in kg/m3 . The continuous blue line represents the reference value while the red lines represent its expanded uncertainty (k=2).…”