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This study established a highly effective system, a controllable volumetric prover (CVP), for evaluating the responsiveness of flowmeters having various hydrodynamic principles. The CVP analyzes flowmeters' responsiveness by controlling the transient flow rate with various waveforms. The CVP is a novel system equipping various analysis methods to quantify indexes regarding flowmeter responsiveness, such as gain, time constant, harmonic distortion, and more. In this study, the system quantitatively compares the responsiveness in flowmeters with different hydrodynamic principles, such as Coriolis, tangential, and ultrasound, as application examples. The most reliable method for steady-state flow measurement, the static weighing method, evaluates the uncertainty of the flow rate control of CVP. Based on the model equation for the flow control by the CVP, the expanded uncertainty of the flow rate control by CVP is estimated as 0.15%. • The uncertainty of controllable volumetric prover is evaluated. • Flowmeters with different hydrodynamic principles are quantitatively compared. • An evaluation system is established based on several analysis methods. • A static weighing method is utilized for calibrating controllable volumetric prover. [ABSTRACT FROM AUTHOR]

In this paper, the results of an inter-laboratory comparison of two small water flow calibration facilities with extremely low uncertainty between Endress+Hauser Japan Co. Ltd. (E+H-J) and the National Metrology Institute of Japan (NMIJ) is reported. Flowrate range between 30 kg/h and 36,000 kg/h is compared. Expanded uncertainty of mass flowrate is from 0.020% to 0.025% at E+H-J and from 0.021% to 0.023% at NMIJ. In order to achieve low uncertainty, NMIJ carries out a re-evaluation of the uncertainty budget for two weighing tank systems. With advanced control of ambient temperature and calibration, the uncertainty level can be reduced to approximately half of previous levels. Results of the inter-laboratory comparison show excellent agreement for both standards, which is less than 0.018%. En values are also less than 0.52 for all examined flowrate points. These results show a high level of consistency for the facilities at both labs. To know the substantial difference, comparison is performed using corrected fitting curves between the flowrate by the test meters and the reference. As a result, significant difference between two facilities was quite small, and is estimated to be less than 0.001%. Differences in this comparison are one or two orders of magnitude lower than previous comparisons on water flow. [ABSTRACT FROM AUTHOR]

To obtain the specific values of the flowrate measurement uncertainty using the ultrasonic Doppler velocity profile (UVP) method under disturbed flow conditions, experimental measurements were performed. To generate a disturbed flow, obstacle plates were installed upstream of the test section. To estimate which experimental parameter dominates the uncertainty, parametric examinations are conducted for the obstacle plate configuration, the distance between the obstacle plates and the measurement section, the incident angle of the ultrasonic beam, and the flowrate. The maximum deviation of the measured flowrate from the reference flowrate exceeds 2% when the flowrate is measured 8 D downstream of the obstacle plate. At a distance of 25 D downstream, the deviation is within the fundamental uncertainty level of the flowrate measurement using the UVP method. Because several uncertainty factors in this examination are cross-correlated with each other, the uncertainties of these factors are evaluated independently using analysis of variance (ANOVA). The total uncertainty is 7.98%, 1.97%, and 1.14% at 8 D , 16 D , and 25 D , respectively. [ABSTRACT FROM AUTHOR]

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Abstract: The present paper describes a fundamental uncertainty analysis for a flowrate measurement in a pipe using an ultrasonic Doppler velocity profile method and an evaluation of the estimated uncertainty by an actual flow calibration. The uncertainties are estimated for internal factors originating from the measurement equipment; UVP provided by Met-Flow sa. and external factors depending on on-site measurements, such as the inclination angle of the ultrasonic transducer. The relative expanded uncertainty due to internal factors is estimated to be 0.34% with a coverage factor of 2. The relative external uncertainty including external factors is estimated to be from 0.42% to 2.13% depends on the inclination angle of the transducer. The results of the actual flow calibration under the same condition as the uncertainty analysis are within the range of uncertainty considering the internal factors. [Copyright &y& Elsevier]