K. Chahine, M. Ballico
At NMIA, volumetric standards such as Brooks or bell provers are used to calibrate critical flow Venturi nozzles or “sonic nozzles”. These nozzles, which are extremely stable, are used by both NMIA and Australian accredited laboratories to establish continuous flows for the calibration of gas flow meters. For operational reasons, sonic nozzles are generally calibrated using dry air but later used with standard atmospheric air at various humidity levels either drawn or blown through the meterunder-test. Although the accepted theoretical calculations for determining the mass flow through a...
Sun Lijun, Feng Qianqian, Li Shengjie, Tang Bing, Zhang Tao
The requirement of gas flow facility with high pressure is increasing. But, the experiences of development the closed-loop high pressure facility are not enough. Critical flow sonic Nozzles gas flow facility with medium-pressure and Closed-Loop pipelines at Tianjin University Flow Lab was presented in the paper. The performance indexes, the flow loop, the uncertainty analysis of the facility were described. Discharge coefficient correction of nozzles at medium pressure and the flow rate stability control were shown in detail. The pressure of the facility is 0.3 ~ 1.6 MPa, the flow rate is...
J. Barbe, F. Boineau, F. Dijoux, T. Macé, P. Otal
LNE has ability to calibrate micro gas flow rates using the dilution method in the range from 2 μg/s to 20 μg/s of nitrogen or 0.75 μg/s to 30 μg/s of helium. In addition, a primary constant pressure flowmeter for leak rates measuring from 0.05 μg/s to 35 μg/s is also available. In order to compare these reference facilities and to validate the dilution method below 30 μg/s LNE is developing a micro flow transfer standard (μFTS) with the collaboration of ATEQ France, manufacturer of control equipment for leak test. The flowmeter consists mainly of an array of three stainless steel...
Miroslava Benkova, Bodo Mickan, Stefan Makovnik, Ivan Mikulecky
A key comparison of the gas flow standards of the National Insititutes of Metrology was conducted from December 2010 to December 2012. A rotary gas meter type Delta S-Flow G 65 was selected as transfer standard. Laboratories were compared in low pressure gas flow in the range (2 - 100) m 3 /h. Eleven NMIs took part in this key comparison and the KCRV was determined. The results demonstrated degrees of equivalence to the KCRV. Euramet comparison were organised simultaneously with the same transfer standard. Sixteen NMIs took part in this regional comparison. Regional reference value was...
Chunhui Li, Luishi Cui, Chi Wang
In NIM, the old 2 m 3 and 20 m 3 facilities were built in 1986. The temperature stability of the collection tank was easily influenced by the surroundings. So, the new 0.1 m 3 and 2 m 3 pVTt facilities were built in 2013. The collection tanks were covered in water bath. The uncertainty for the new pVTt facilities were analyzed, and the measurement capablity was verified by comparisons among the new pVTt facility, the old pVTt facility and gas flow facilities in PTB with 14 sonic nozzles.
Thomas Kegel, William Johansen
CEESI operates a gravimetric primary standard for high pressure compressible flow measurement. A program is underway to reduce the uncertainty. A knife edged balance requires human position observation; an optical sensor will provide an electronic indication. A set of ball valves transfer the flow source from a start-up supply to the gravimetric pressure vessel. The upgrade will include monitoring pressure and temperature transients while the valves reposition. A series of "trapped volumes" contain fluid that is not included in the direct mass determination, but flows through the test...
Ching-Yi Kuo, Jiunn-Haur Shaw, Chun-Min Su
A primary high pressure air flow measurement standard was constructed at Center for Measurement Standards (CMS) in Taiwan with a capacity of 18000 m3/h and pressure range of 1 to 60 bar. With present calibration setup, the temperature of air flowing through the meter under test (MUT) decreased significantly during a test. To reduce thermal effect during meter calibration, improvements have been made by expanding the upstream air storage tank from 19 m 3 to 34 m 3 , and installing a new compact sonic nozzle array (CSNA) downstream of the MUT as a new working standard (WS). A re-circulating...
Jos G. M. van der Grinten, Frans Doorman
This paper describes a unique systematic comparison of the Westerbork and EuroLoop calibration facilities. In a period of two and a half years more than 100 meter calibrations were performed with 7 meters divided over 4 packages.
M. P. van der Beek, R. van den Brink
The paper describes the design, measurement results and uncertainty analyses of the hydraulic driven piston-prover system which is in operation at VSL since 2008. The 12 meter long, 0.6 m bore piston-prover is used for the realization of Reference Values for Gas-Volume at pressures between 1 and 65 bar(a) and ‘any’ type of Gas. The principle is based on the displacement of a piston acting as a Gas-Oil separator. The standard has a flow-rate range from 5 to 230 m³/h. The system is designed to calibrate reference meters. The Calibration and Measurement Capability (CMC) of the system is proven...
R. Doihara, T. Shimada, N. Furuichi, Y. Terao
Calibrations with ethanol, water and kerosene have been conducted by using a transferable test package which consisted of positive displacement (PD), turbine (TB), Coriolis (CMF) flowmeters and a small volume prover (SVP). Flowmeter performances and establishment a temporary ethanol flow standard have been investigated. It is founded that liquid replacement in the PD and the TB induced transitions of K-factor over several days. Performances of mass and volume flow output of CMF were also evaluated.