Olga S. Yoshida, Nilson M. Taira
The polynomial regression model has been largely used in flow meter calibration. The document ISO 7006 - Part II describes how to adjust a polynomial expression to non linear calibration data. The Guide establishes general rules for evaluating and expressing uncertainty in measurement, but does not demonstrate methods of evaluating uncertainty in flow meter calibration. In this paper we concentrate on the uncertainty analysis for calibration of flow gas meters by using polynomial regression models. A detailed Guide analysis of this model will be given with selected examples of non linear...
Hoi Yeung, Christos E. Papadopoulos
In the natural gas market, open access along with gas brokering and marketing has resulted in multiple gas contracts through one physical measuring point. Accurate metering of natural gas has become more important than ever as de-regulation subjects pipeline companies to competition. A more competitive market is driving the need for real-time accurate electronic flow measurement. Modern electronic natural gas metering systems (ENGMS) introduced additional, though necessary, complexity in the estimation and verification of the reported results. Additionally, it becomes more and more important...
Valmir Ruis, Noemi Christina Hernandez
This paper presents main uncertainties sources, differential equations analysis and the estimation of combined uncertainty in the calibration of a compact piston prover of the IPT Flow Laboratory. The piston prover is used mainly for calibration of liquid flow meters as turbine meters, positive displacement meters and rotameters. Calibration of other types of liquid flow meters can also be performed provided its particularities are taken into account. The procedure used was the gravimetric method with static weighing using water (Water Draw) as described in ISO 4185/80 Measurement of liquid...
Josaphat Dias da Mata, Edvaldo A. Carrascosa
The new scenario for the Brazilian energetic policy points out to a steep growth on natural gas demand for diverse applications, such as electric energy generation and industrial, domestic or vehicular use. Therefore, the necessity of an intensified effort toward the improvement of the volume gas balance is increasing. Recently there was a great technological advance in this area, covering equipments and procedures, which has contributed to the reduction of measurement errors. The modern flow meters present very low uncertainty. Although new equipments have appeared on the market, the...
Valmir Ruis, N. M. Taira, José M. Câmara Brito
Orifice plates are the most common flow meters used in Brazil to measure natural gas in metering stations in processing units. This article presents the results of analysis of the present situation of gas flow metering stations according to metrological and dimensional criteria of AGA Report #3. The uncertainty analysis was made following the guidelines of the ISO Guide for Uncertainty in Measurement (ISO GUM).
Harry Dijstelbergen, Harry Bär, Henk Bellinga
The elements required to design TCC’s new high-pressure calibration facility for the least uncertainty are summarized. Results obtained during commissioning are shown, indicating the results according to the ISO Guide to the expression of Uncertainty of Measurements (GUM).
B. Bátyi, A. S. Kun, L. Kálóczy, K. Kocsmár
A Sonic Nozzle Prover System (SNPS) stepped into service at Gas Work of Budapest. After a two-years of operation a Round-robin test was made to control the basic accuracy and repeatability. The test involved the National Standard gas meter calibration system 1 and the SNPS. Also a new one - which operation just going on - based on PD master meter was tested. The calibration systems working at low pressure using vacuumed and pressure controlled flow circle. The twin meters has temperature compensators. Repeatedly obtained tests based on twin meter package pointed out reasonable results.
G. Cignolo, A. Rivetti, G. Martini, F. Alasia, G. Birello, G. La Piana
A small bell prover and a piston prover of large capacity recently installed in the new Gas Flow Laboratory of the IMGC-CNR (the national primary standards laboratory in Italy for mechanical and thermal quantities) are described. The provers have been completely revised, automated and equipped with state-of-the-art instrumentation for measurement of temperature, pressure, bell or piston displacement and time. Both provers have been calibrated again soon after installation in the new laboratory and have been used successfully in two EUROMET comparisons carried out in 1998. The paper describes...
John D. Wright, Aaron N. Johnson
Static gravimetric and static volumetric gas flow standards are both affected by uncertainty components related to the measurement of the change of mass of gas within the inventory volume. In the process of diverting gas into the collection vessel, rapid pressure and temperature changes occur in the inventory volume. A low uncertainty gas flow standard requires thorough understanding of these transients so that appropriate instrumentation, system design, and operating procedures may be developed. A thermodynamic model for the flow work phenomena is presented and compared to experimental...
Kazuto Kawakita, Marcos Tadeu Pereira
With the purpose of studying application of critical flows through small orifices in the measurement and control of very low gas flowrates, experimental investigations were carried out on a set of 22 microorifices and capillaries of circular cross sections manufactured out of ruby and stainless steel. Diameters of the orifice and capillary samples ranged from 16 µm to 427 µm, and their lengths from 254 µm to 68 mm. The microorifices were submitted to tests using air, argon, helium and carbon dioxide, and the back to the upstream pressure ratio P b / P 0 varied from unity down to about 0,1,...