Henk Jan Panneman, Cornelis W. Koreman, Sjoerd Toonstra, Floris Huijsmans
Gasunie Research gained their years of experience in efficient energy utilization, gas transport and gas measurement as the in-house laboratory for N.V. Nederlandse Gasunie. This company, which was an integrated gas transport and trading company until the beginning of 2002, has been one of the largest gas suppliers in Europe for several decades. As part of this company, Gasunie Research has always striven to guarantee the continuity of the gas supply, to ensure the safety of gas transport and to enhance the added value of natural gas as a fuel. Gasunie Research developed a wealth of new...
Michael Reader-Harris, Bill Brunton, Ian Nicholson, Ronnie Rushworth, David Hodges
This paper describes the test work undertaken to establish that the compliance test in ISO 5167-1:2003 is satisfactory for Venturi tubes and also to determine the required upstream lengths when a Zanker Flow Conditioner Plate is installed upstream of a Venturi tube. In essence the Zanker Flow Conditioner Plate met the compliance test upstream of a Venturi tube provided that there is at least 3 D between the plate and the upstream pressure tapping of the Venturi tube and 7 D between the plate and any upstream fitting. However, if the compliance test were to apply to flow conditioners with...
Jos G. M. van der Grinten
Metrological decisions are based on measurements that have uncertainties. Examples are car velocity measurements for law enforcement, initial verifications that lead to the decision to approve or reject an instrument, and the significance of differences found during intercomparisons. The paper shows for each of these examples the relationship between acceptance criterion, tolerance, uncertainty and confidence level. From the discussion of these examples it can be concluded that uncertainties must be known in order to evaluate the risk on an erroneous decision. Confidence levels are...
G. J. van Essen, S. Bakker, H. J. Dane
In its gas transmission system Gasunie Transport Services (in this paper further called “Gasunie”) uses hot-tap single path ultrasonic meters for process control purposes. For these meters, a number of minimal requirements has been established, relating to meter performance (accuracy, response time, reliability, output signals), operating conditions (gas properties, mechanical, environmental and safety requirements) and documentation (manufacturing log, hot-tap procedures). For many of these requirements it can be determined relatively easy whether or not they are met. However, in most...
Olivier Broca, Joël Escande, Bruno Delenne, Gérard Mouton, Pierre Gajan, Alain Strzelecki
Multipath ultrasonic flow meters have been more and more used in gas industry for the last ten years, this technology represents an interesting alternative to orifice and turbine meters. In fact, ultrasonic meters offer significant advantages such as bi-directionality, low pressure loss, large range and self-checking capabilities. Nevertheless, in some specific configurations, ultrasonic meters are still sensitive to the installation conditions. During the last decade, this topic has been widely investigated on several aspects, however many questions still remain. In Ultraflow project, Van...
Alex S. Kun, Balazs Rekasi
The tested Sonic Nozzle Prove ring System (SNPS) stepped into service at the Gas Works of Budapest almost five years ago. To keep its parameters in a dedicated and good condition a continuous checking process is carried out. During this checking process those tested were the SNPS main accuracy and repeatability, as well as the individual sonic nozzles (SN).
M. P. van der Beek, R. van den Brink, I. J. Landheer
The paper describes the recently developed "GOPP" – Gas Oil Piston-Prover. This primary standard for high-pressure gas-volume is created to realize units of volume at various pressures for the Dutch National traceability-chain of high-pressure gas-flow measurements. The paper presents the design, working principle, simulation calculations and first results to realize a calibrated rotary-piston gas-meter. Furthermore, the actual physical process is compared to simulation calculations, and temperature characteristics are discussed. With internal harmonization processes at NMi VSL with "input"...
R. van den Brink, M. P. van der Beek, I. J. Landheer
Measurement-data of laboratories participating in comparisons are often treated equivalently with respect to operational conditions and statistical impact. When analysing the comparison, this may distort some conclusions because no attention is paid to deviations caused by differences in operational conditions (e.g. pressure). A better way to perform a comparison is to transpose the sets of flow-rate data to Reynolds numbers, to make it easier to see whether or not the points are in the same Reynolds-region and thus allow for a valid comparison. Next, not all participating laboratories...
M. P. van der Beek, I. J. Landheer
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...
A. J. M. Herwijn, M. P. van der Beek, I. J. Landheer
One of the methods to realize reference values for Volume of e.g. Natural Gas at increased pressures is via a calibration under a pressure difference (i.e. with expansion). In such a process, applied since the sixties in the Netherlands, the "un-known" meter or Meter-under-Test (MuT) is compared through expansion with the "known" meter or Reference Meter (RM) at low-pressure. In a "normal" calibration-process the difference in pressure between the two compared meters is relative small and the resulting difference between the compressibility at the Reference Meter Z RM and the compressibility...