M. P. van der Beek, I. J. Landheer
"NMi TraSys", THE ULTIMATE CARRIER & MULTIPLIER FOR THE UNIT OF VOLUME FOR HIGH-PRESSURE NATURAL GAS
The paper describes the newly developed "NMi TraSys" - NMi Traceability System. This travelling carrier & multiplier of traceability has been realized to embody a significant part of the Dutch National traceability-chain for high-pressure gas-flow measurements. The number of contributions of uncertainty as well as their values, due to "copy-losses" and "installation-effects" during the traditional transfer of traceability from one facility to another, are decreased.
First results are presented about observed repeatability and reproducibility, uncertainties and consistency checks. The device will include in time, reference values of three different independently realized primary standards (viz. DDD - Dynamic Displacement Device, GOPP – Gas-Oil Piston-Prover and NMi TraSys itself). With internal harmonization processes at NMi VSL with "input" reference values from the three other primary standards, viz. DDD-conventional, DDD-extended pressure level and GOPP, the aim of 0,1% uncertainty at 4.000 m³ / h and p = 60 bar is within reach. This will improve the uncertainty as well as the stability of the Dutch National reference values considerably.
NMi TraSys will be used as a set of Travelling Reference Meters, creating an efficient availability of stable and validated Harmonized Reference Values for high-pressure gas-flow.