Final report on the supplementary comparison Euromet.M.P-S2 (bilateral comparison) in the pressure range from 30 Pa to 7000 Pa

Abstract

A bilateral comparison was carried out in order to test the degree of equivalence between the newly established pressure balances of the Czech Metrological Institute and the Physikalisch-Technische Bundesanstalt (PTB). The comparison was carried out without using a transfer standard, but with a differential capacitance diaphragm gauge as an indicator of the small differential pressure between the two pressure balances when the target pressures were generated in the two systems. The Czech Metrological Institute brought its force balanced piston gauge FPG by the DHI company to the site of the PTB pressure balance, which was a Furness Rosenberg system FRS 5 by the Furness company. In the range under comparison from 30 Pa to 7000 Pa full equivalence was obtained with the En value ranging from 0.01 to 0.47.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 EUROMET, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Gravimetric flow standard in the vacuum and hermetic modes

“…A possible solution is a transportation of the whole primary standard to a partner laboratory, and to accomplish a direct comparison of the two standards. This solution was well proved during our comparison of low pressures; see [21][22][23]. That is why we designed the vacuum vessel with an emphasis on its portability; see figure 2.…”

Reduction of the uncertainty of the PTB vacuum pressure scale by a new large area non-rotating piston gauge

“…The bilateral comparison with CMI [5] in the range 30 Pa to 7 kPa aimed at the validation of the pressures with their respective measurement uncertainties. Due to the different lay-outs of the FPG [1,2] and the FRS5, common systematic errors are rather improbable, which made this comparison more useful than with two identical systems.…”