Bilateral Comparison of Primary Low-Pressure Gas Flow Standards Between NIMT and CMS |
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| Chun-Min Su, Win-Ti Lin, Sutham Masri |
- Abstract:
- To verify the measurement capability and performance of the newly established primary low-pressure gas flow standard, a mercury-sealed piston prover, at the National Institute of Metrology of Thailand (NIMT), a bilateral comparison with the piston prover at the Center for Measurement Standards (CMS, Taiwan) was conducted. The piston prover at NIMT has a measurement capability of 5 mL/min to 24 L/min flow range with a relative expanded uncertainty smaller than 0.13 %, whereas that of the system at CMS is 2 mL/min to 24 L/min with 0.10 % expanded uncertainty. The transfer standard (TS) used was a set of three critical flow venturis (CFV’s) with dedicated thermometers. The TS was used at eight flow rates of dry air ranging from 42 mL/min to 14.5 L/min at 0 ℃ and 101.325 kPa (0.055 g/min to 18.87 g/min). Comparison showed that the differences in the normalized average discharge coefficient between NIMT’s measurements and the reference values based on CMS’s results were smaller than 0.06 % throughout the range of flow tested. The En values for the flow measurements at NIMT with reference to CMS were all well less than unity. The equivalence between the two participants was thus demonstrated.
- Keywords:
- Piston Prover, Critical Flow Venturis, Degree of Equivalence
- Download:
- IMEKO-TC9-2010-043.pdf
- DOI:
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