Measurement Library

International Symposium on Fluid Flow Measurement Publications (2009)

North American Fluid Flow Measurement Council

The Experimental Research Of Humidity On Discharge Coefficient Of Sonic Nozzles
Author(s): Chunhui Li Chi Wang Lishui Cui
Abstract/Introduction:
The modification methods of humidity effect on the discharge coefficient of sonic nozzle were summarized in this paper. The discharge coefficients of sonic nozzles were conducted in different humidity. The experimental results showed that there existed obviously difference among different modification methods, but the modification results for each method had good accordance with the results calculated from the empirical equation of ISO 9300. Keywords: sonic nozzle humidity modification method discharge coefficient
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Document ID: F444B81D

Advances In Vortex Shedding Flow Metering
Author(s): Jim Storer, Ed Schroeder, Richard Steven
Abstract/Introduction:
There is an increased importance being placed on flow metering by industry. With increasing energy costs a flow meter with a set percentage flow rate uncertainty is set to have an increasing monetary uncertainty. There is therefore a demand for reducing the uncertainty of all flow meter designs. In practice, as a flow meter uncertainty rating is only valid if there is a guarantee the meter is operating correctly, this also means there is a growing desire to improve the output verification capabilities and self diagnostics of all flow meter designs. Systems with redundancy factors are also desirable. In this paper the potential for combining vortex shedding and differential pressure (DP) meter technologies is discussed. It will be shown that combining these different technologies in one device produces a single flow metering system with distinct advantages compared to when a vortex shedding flow meter or a DP flow meter stand alone. This simple, sturdy, relatively inexpensive and reliable system meters the mass and volume flow rates as well as measuring the fluid density with no external fluid property information required. It offers enhanced output verification capabilities and allows some diagnostic capabilities.
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Document ID: 3EE3D9CF

Natural Gas Flow Measurement: Primary Standardization And Harmonization Of Reference Values. A Brazilian Perspective
Author(s): Julio Cesar Da Costa Cominges, Rui Pitanga Marques Da Silva2, Mauricio Nogueira Frota
Abstract/Introduction:
Substantial oil and natural gas findings in Brazils continental platform -including the presalt play-, call for an appraisal of flow measurement traceability and implementation of an integrated gas flow measurement infrastructure. The work reviews successful experiences of national metrology laboratories of highly industrialized economies and procedures for the realization of the SI flow measurement unit and harmonization of reference values reported by different flow labs. The current Brazilian gas flow measurement capability is also assessed. The study provides useful information to aid the country in implementing a primary standardization scheme for flow measurement.
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Document ID: 7469271C

Environmental Tests Of Gap Discharge Emitter For Use In Ultrasonic Gas Flow Measurements
Author(s): Emil Martinson And Jerker Delsing
Abstract/Introduction:
In some situations, the ability to measure gas flows can be very limited due to difficult environmental conditions. Examples of such conditions identified in real situations include very high temperatures of up to 1200C, low pressure gas, high humidity, dust, heavy surface contamination and large dimensions (1-5m pipe diameters). In this paper, we investigate the performance of the only ultrasound emitter type we expect to be able to handle the mentioned conditions. The transmitter has been developed for harsh condition gas flow measurement using the approach of transit time or sing around technology for flow metering. Tests have been performed in a real environment in the iron ore process industry. The testing environment includes gas flows with condensing moisture, moderate temperatures and heavy surface contamination. The device investigated for the emission of ultrasound uses the principle of electric gap discharge to obtain acoustic pressure waves. Since all exposed parts of the emitter can be made using high quality metal and ceramics if necessary, it can be designed for very high temperatures, with a goal of reaching around 1200C. The tests performed here are divided into two categories: the effects of long term exposure in a bad environment and the sonic performance in the same environment. The first test revealed that both emitters were capable of surviving the contamination problem and could still work after almost 1.5 months in the environment. The signal amplitude difference before and after the test was less than 5%. In some cases the signal was stronger after the test than before. The second test showed that sound signals feasible for flow measurement under high dust content and high humidity were obtained. This was shown under realistic operation conditions in an iron ore pelletizing plant. The sound path varied from 1.9 - 3m, and the temperatures were moderate, around 30-80C. From the results in these two tests it can be stated that the idea of using a gap discharge emitter in the above mentioned conditions is a promising way to generate ultrasonic pulses for flow measurements in difficult and unfriendly environments.
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Document ID: AFD26E4A

Dynamic Gravitational Standard For Liquid Flow: Model And Measurements
Author(s): I. I. Shinder And m. R. Moldover
Abstract/Introduction:
We report progress in testing a dynamic gravimetric standard using both steady and unsteady water flows. For steady flows in the range 10 kg/s to 60 kg/s, the difference between the dynamic standard and NISTs static primary standard was 0.015 % with a standard deviation of 0.033 %. To measure unsteady flows, we calibrated a rapidly-responding electromagnetic flow meter (EMF) using NISTs static standard and we also measured the time delay between the response of the EMF and the dynamic standard. Finally We verified that the response time of the weigh scale was sufficiently insensitive to the load on it. For testing, the unsteady flows averaged 12 kg/s however, these flows were either ramped or pulsed up (or down) by 5 kg/s. When integrated over the collection interval, the difference between the dynamic standard and the EMF was 0.008 % with a standard deviation of 0.012 %. This excellent agreement supports our model for the dynamic standard and justifies the further study of the dynamic standard, particularly at higher flows where the mechanical simplicity of a dynamic standard might reduce the cost of accurate measurements.
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Document ID: A0ADE17B

Examination Of Ultrasonic Flow Meter In CO2-Rich Applications
Author(s): John Lansing, Dr. Andreas Ehrlich, Toralf Dietz
Abstract/Introduction:
Exploration of less conventional natural gas sources will lead to more diverse operating conditions and compositions for natural gas measurement. One significant challenge is increased levels of CO2 in the gas. While standard applications deal with levels well below 5 mole percent, this amount may be as high as 20 mole percent, or even higher at some installations. Additionally there are some applications where CO2 is the major gas component. Re-injection of CO2 into declining oilfields will require accurate and reliable flow measurement. Such applications contain up to 60% CO2 and require an accuracy level comparable to custody transfer for natural gas. While the flow measurement is currently being done primarily using ?p devices, such as orifice meters, it would be a significant improvement to use ultrasonic meters with their increased functionality, larger turndown ratio reduced maintenance, and diagnostic capabilities. Applications such as CCS (Carbon capture and storage) with CO2 concentrations near 100% are even feasible today.
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Document ID: FC518DA8

Comparison Of Five Natural Gas Equations Of State Used For Flow And Energy Measurment
Author(s): Aaron Johnson, Bill Johansen
Abstract/Introduction:
Measurements of the flow and the energy content of natural gas rely on equations of state to compute various thermodynamic properties including: 1) compressibility factor 2) critical flow factor 3) speed of sound and 4) isentropic exponent. We compare these computed properties using five equations of state (REFPROP 8, GERG-2004, AGA 8, AGA 10, REFPROP 7) for eight natural gas compositions. The molar compositions vary from 97 % methane to 80 % methane the latter has high levels of ethane, nitrogen, or carbon dioxide. These comparisons span the pressure and temperature ranges 0.1 MPa to 10 MPa and 270 K to 330 K. The five equations of state predict mutually consistent properties at low pressures. However, at higher pressures and lower temperatures inconsistencies among the speeds of sound are nearly 0.2 % and inconsistencies among critical flow factors are nearly 0.5 % for ethane-rich natural gas mixtures. For these mixtures the inconsistencies in the speed of sound are close to the AGA 9 limit of 0.2 %, and could influence ultrasonic flowmeter diagnostic capabilities that depend on accurate speed of sound predictions. In addition, the inconsistencies in the predicted values of the critical flow factor, if not resolved, could significantly reduce the accuracy of critical flow venturis when used in ethane-rich gases over select ranges of pressures and temperatures. The discontinuities discovered in the AGA 10 critical flow factors were as large as 0.075 %, and raise concerns about using this equation of state for critical flow venturi applications.
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Document ID: D89D0AB5

Refprop 8: A Proposed Standard For Natural Gas Viscosities
Author(s): William Johansen, Aaron Johnson
Abstract/Introduction:
The natural gas flowmetering community does not have a standard method to calculate viscosity. The error levels in current viscosity models frequently exceed 25 %. Moreover, one of the prevalent methods to compute viscosity produces values that are consistently smaller than measured values. This bias in viscosity computations leads to biases in the Reynolds number which ultimately result in flow measurement biases that can be 0.1 % or more. The errors in Reynolds numbers have also led to numerous flowmeters being calibrated in the wrong Reynolds number range. We demonstrate that limiting the Reynolds number errors to 5 % is sufficient to reduce flowmeter measurement biases to less than 0.028 % for commonly used flowmeters (e.g., critical flow venturis, orifice meters). We show that the NIST-maintained database REFPROP 8.1 and a viscosity model developed at CEESI both agree with published natural gas viscosity data within 5 % or less at temperatures from 270 K to 330 K and at pressures up to 12 MPa for a wide range of natural gas mixtures. Based on these results we propose that REFPROP 8.1 be adopted as the standard for calculating natural gas viscosities.
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Document ID: 0DD83AAB

The Development Of Ultrasonic Meter Performance Diagnostic Methods
Author(s): Thomas Kegel, William Johansen
Abstract/Introduction:
Check meters have been in use at the CEESI Iowa Natural Gas High Flow Facility since 1999. The check meter sizes range from 24 to 4 and range in age from 10 years to very recent acquisitions. The availability of digital data from these meters has resulted in a large body of ultrasonic meter performance data. Ultrasonic meter data mining is being conducted on behalf of the natural gas industry to examine key aspects of meter performance. Ultrasonic meter recalibration intervals and performance diagnostic methods are the focus of this paper.
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Document ID: 44B7A5C8

A New Flow And Process Test Rig At The Abb Corporate Research Center In Ladenburg, Germany
Author(s): Thomas Scholl And Jrg Gebhardt
Abstract/Introduction:
At the ABB Corporate Research Center in Ladenburg (Germany) a new water flow and process test rig (FPTR) was set up to provide scientists and engineers an ideal test environment for new flow meters and field devices. The test bench provides a wide range of possible meter flow cross sections and flow rates for fast and reliable device tests. The paper describes the concept of the flow and process test rig and gives first results from the uncertainty estimation.
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Document ID: 20C4052B

A Novel Concept Of A High Accuracy Calibration Rig
Author(s): A. Pfau, H. Hafelfinger, J. Honegger, J. Gfeller
Abstract/Introduction:
Within a project period of one and a half years a substantially improved calibration facility at Endress+Hauser Flowtecs production centre in Reinach, Switzerland, was developed, built and commissioned. The first run with a meter under test happened in March 2007. In August 2008, the facility was accredited according to ISO/IEC 17025 to within 0.015% best uncertainty covering a flow rate of 0.7t/h - 432t/h, with gravimetric reference (79kg/h - 1.2t/h, 0.021% with volumetric reference). The stated objective was to provide a facility capable of operating to a very high level of accuracy, to be employed to calibrate customers Promass 83/84F Coriolis mass flow meters fully traceable, with improved specification of 0.05%. To achieve this, a number of elements of two existing calibration rigs had to be analyzed and improved. To guarantee this low level of uncertainty of the facility, frequent calibrations-, and if necessary adjustment of the system to minimal deviation as compared to the reference (weighing system) are implemented. For that purpose, certified weights of the OIML class F2 are permanently located at the sides of the weighing tanks. Based on this concept, the calibration can be carried out fully automatically every two weeks. In this presentation the key elements of this facility, the achieved performance and the traceability to the national standard will be outlined.
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Document ID: 37444397

Highest Precision For Gas Meter Calibration Worldwide: The High Pressure Gas Calibration Facility Pigsartm With Optimized Uncertainty
Author(s): B. Mickan, R. Kramer, H. Mller And V. Strunck, D. Vieth, H.-M. Hinze
Abstract/Introduction:
Since 1993 E.ON Ruhrgas operates pigsarTM as one of the leading high-pressure gas calibration facilities worldwide. One major prerequisite for pigsarTMs very low uncertainty is the fact that the German national volumetric primary standard for high-pressure natural gas, the so-called High Pressure Piston Prover (HPPP), property of the Physikalisch-Technische Bundesanstalt, (PTB), is since 1999 an integral part of the infrastructure of pigsar. During the last few years both PTB and pigsarTM staff have continuously worked on improving the uncertainty and availability of pigsarTM. As a major result, the uncertainty of pigsarTM was reduced from initially 0,16% to currently 0,13% in the main operating regime of the facility. New projects already started are aimed at reducing this uncertainty even further down to 0,1%. This paper describes the different measures that have been or will be taken to achieve and verify these improvements.
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Document ID: 71459C6B

Evaluation Of Two New Volumetric Primary Standards For Gas Volume Established By Ptb
Author(s): Bodo Mickan, Rainer Kramer
Abstract/Introduction:
The PTB has been operating a bell prover as the main primary standard for gas volume with a proofed uncertainty 1 of 0.06 % for more than 25 years. In the last two years there were two new primary volumetric standards established which operates in flow rate ranges comparable with the existing bell prover. One of them is a conventional bell prover of similar construction as the old one and has therefore the identical main operating range between 1 to 65 m3/h. The second one is a new actively driven piston prover based on a so-called comparator principle 23 operating mainly between 0,04 and 4 m3/h. The paper will describe the main principles and steps for providing the traceability for these new devices as well as the experimental evaluation of the uncertainties using sonic nozzles as transfer standards. The results will be evaluated also in relation to the actual defined reference value for gas flow determined in the CCM.FF-KC6 1 and to the results of nine other inter-comparisons.
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Document ID: 62C86FBF

Ultrasonic Meter Condition Based Monitoring - A Fully Automated Solution
Author(s): John Lansing
Abstract/Introduction:
During the past several years the use of ultrasonic meters (USMs) has gained world-wide acceptance for fiscal applications. The many benefits of USMs have been documented in papers at virtually every major conference. As the cost of gas continues to increase, the significance of knowing that the ultrasonic meter is operating accurately has never been more important. The use of diagnostics to help identify metering issues has been discussed in several papers over the past few years Ref 1, 2 & 12. The traditional method of verifying whether the USM is operating accurately essentially requires using the USMs diagnostic information to help understand the meters health. This has often been referred to as Conditioned Based Maintenance, or CBM for short. Different USM meter designs require different analysis techniques, especially for the velocity profile analysis. For the field technician, it is often difficult to understand all the diagnostic features of each USM meter design. Through the years software has been developed to help determine if the meter is operating correctly or not. However, it is still very difficult to clearly define limits on some of the diagnostic parameters that translate into a quantifiable metering error. This paper will discuss two methods of providing a fully redundant self diagnosing meter. The first is a new CBM concept to assist in determining if the fiscal 4-path USM meter is operating accurately. Rather than relying entirely on the understanding and interpretation of the meters diagnostics, a meter designed with an additional built-in diagnostic path, has been developed. In this paper the meter design will be referred to as the CBM 2Plex 4+1 meter. The second is having a meter which monitors, on a real-time basis, all diagnostic parameters and then reports when one, or more, approach unacceptable values. Traditionally in the past the user would collect log files monthly and analyze them. The problem is that often the technician would overlook a problem and thus it could develop into a significant measurement error. Also, since inspections are often performed on a monthly basis, a problem can develop and it may take a month or more before the user would see this. By monitoring the diagnostics on a real-time basis, combined with the redundancy of an independent, second metering path of the CBM 2Plex 4+1 meter, all aspects of a meters health can be checked and validated without the need for monthly inspections. This not only significantly reduces operation and maintenance (O&M) expenditures, but lowers measurement uncertainty in the field.
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Document ID: CB589B6C

Mapping Of Flow Features In A Wind Tunnel
Author(s): Aline Piccato, Pier Giorgio Spazzini And Riccardo Malvano
Abstract/Introduction:
The present paper faces the problem of the flow characterization in a wind tunnel for metrological application. The wind tunnel used for the experiments, which is one of the test rigs used at I.N.Ri.M. for anemometer calibration, is first described. Section 3 describes and discusses the experimental method used for the determination of the flow features, including the calibration of the instrument (X-hot wire probe). Finally, in section 4 we present the results obtained together with a discussion about the significance of such results from a practical point of view when considering the aims of the test rig.
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Document ID: 092C8175

Aspects Of Traceability And Comparisons In Flow Measurement
Author(s): Rainer Engel, Bodo Mickan
Abstract/Introduction:
Key comparisons, in general, are necessary to prove and assure the measurement uncertainty entries in the CMC (calibration and measurement capabilities) data base held at the Bureau International des Poids et Mesures (BIPM). Due to the physical character of the measurands of fluid flow, the units of those cannot be directly transferred or traced back. Therefore, an element-by-element approach of traceability is applied. The measuring quantity that is implicitly transferring the flow units is the meter factor of the so-called transfer flowmeter that is utilized for comparison or traceability purposes. But, as fluid-flow and meter-installation effects reveal impacts on meter readings, flow comparison measurement data may, occasionally, be affected by several systematic effects. Those systematic effects can exceed in their results those that originate from general statistical processes and effects which are generally part of any measurement process. In those cases comparisons would result in inconsistent data sets among the participating laboratories. Thus, in flow unit traceability or comparison measurements, flowmeters with highly stable metering properties must be applied, whose meter factors have been qualified in a characterizing test process so that systematic factors of influence may be compensated for by applying correction factors.
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Document ID: 78C606D5

Multiphase Metering In Siberian Gas And Condensate Wells Lessons- Learnt In Multiphase Well Testing Operations Since 2006
Author(s): Bertrand Theuveny, Sergey Rosmashkin, Valery Shako, Konstantin Rymarenko, Marat Nukhaev, Roman Shchelushkin
Abstract/Introduction:
Multiphase, Condensate, Gas, Multirate Test, Vx, Flowmeter, Well Testing, Yamal, Russia. Gazprom, Achimgaz, Rospan International, Condensate bank, Hydrate, Permafrost A number of multiphase flowmeters were recently deployed in the Yamal peninsula in Northern Siberia to perform multiphase measurements of the rates of gas and condensate wells. The utilization of multiphase flowmeters in wet gas and condensate wells is relatively new, and significant progress have been made in the understanding and the quantification of multiphase flowmeter uncertainties in flow loop. Little field experience is documented to date and this paper presents field data in this very challenging domain. The operating environment combines an exceptional set of constraints ranging from high Gas Volume Fraction (up to 99.5%), water and hydrates, a large permafrost zone, tough environmental regulations, and a range of logistical constraints including difficulty of access to remoteness and communication challenges. The paper describes the metrological evaluation of the full operations - not limiting itself to the dual energy gamma Venturi multiphase flowmeter that is being used, but also to the fluid property estimation. A discussion of the specific regulatory reporting in Russia for gas wells also presents some of the particularities of these operations. The paper presents the results of testing over 50 wells since 2006- comparison to traditional and other multiphase flow metering devices are presented. Some unexpected behavior of these condensate wells are presented - confirmed by other instruments, resulting in a series of recommendations that provide a significant modification to the traditional guidelines used for the measurements of rates of gas, condensate and water in similar wells. A brief discussion on the applicability of the multiphase measurements to condensate allocation workflows concludes the paper.
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Document ID: AD1E7342

Numerical Simulation Of Installation Effects On A Pitot Tube
Author(s): Pier Giorgio Spazzini, Ivan Cozza
Abstract/Introduction:
In the present paper, numerical simulations of the flow around a special dynamic pressure sensor (Amplified Pitot tube), specifically designed and built as a Transfer Standard for a metrological Intercomparison, are presented and discussed. The computations allowed to obtain a good, and in some instances excellent, reproduction of the measurements. The CFD results were employed to analyze in detail the fluid dynamical phenomena around the sensor in order to clarify the reasons for some incoherences in the Intercomparison results. The indications of this preliminary work are that installation effects may play a role more important than previously expected for such cases.
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Document ID: 7EB03863

Wedge Meters With Wet Natural Gas Flows
Author(s): Richard Steven, Charlie Britton, Josh Kinney, Steve Pagano
Abstract/Introduction:
The wedge meter has been on the market for more than twenty years and is well established. The wedge meter is a generic differential pressure (DP) meter and operates according to the same physical principles as all other DP meters (e.g. the orifice plate, Venturi, cone DP meters etc.). With the primary element being a very sturdy solid wedge it has a reputation for being a rugged meter capable of being used in adverse flow conditions such as slurry flows. Therefore this paper discusses, with the aid of wet gas flow data from two independent test facilities, the potential for the wedge meter to be developed for wet natural gas flow metering.
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Document ID: A504EB85

Extending The Range Of Gas Piston Provers
Author(s): Harvey Padden
Abstract/Introduction:
Traditionally, constant-pressure gas provers have been used in the range of 5 sccm to 50 slm. Our most recent viscous-sealed provers have extended the range upward to 500 slm and downward to 0.5 sccm.
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Document ID: DCD85248

Use Of Glass Capillary For The Development Of Gas Flow Transfer Standard
Author(s): Chih-Cheng Feng, Win-Ti Lin, Cheng-Tsair Yang
Abstract/Introduction:
Critical flow Venturis (CFVs), or sonic nozzles, are widely used as gas flow transfer standards. However, their application in flow rate below 1 L/min is usually limited due to the manufacturing difficulties. Therefore, the Center for Measurement Standards (CMS) is developing a laminar flow element (LFE) type flow meter as a transfer standard. This LFE consists of a single straight glass capillary or multiple straight glass capillaries connected in parallel. Two gauges and one thermometer measured the inlet/outlet pressure and inlet temperature, respectively, and the differential pressure was restricted from 2 kPa to 100 kPa. The glass capillaries were manufactured by laser machining, resulting in consistent inner diameter and straight flow path. Characteristics of glass material also prevented the capillary from bending during installation. By means of regression, the turndown ratio of this LFE flow meter could be higher than 20 and the residual would be still within 0.11 %. The reproducibility within 0.04 % indicated that this LFE flow meter can be used as a transfer standard. Moreover, the feasibility of using a bundle of multiple LFEs to expand the flow capacity while maintaining the length of the LFEs so that the flow meter can remain compact was also demonstrated. CMS will develop a series of flow meters that cover flow rates ranging from 1 sccm to 1000 sccm.
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Document ID: 17C94EBB

Measurement Of The Main Slug Flow Parameters In A Combined Up Stream-Down Stream Two-Phase Flow
Author(s): F. Snchez Silva, m. Perez Garcia, I. Carvajal Mariscal, D. Libreros, J. G. Barbosa Saldaa
Abstract/Introduction:
Slug flow induced by the combination of a downstream and an upstream two phase flow is very common in the oil industry. This phenomenon can be dangerous for the equipment operation because it induces vibrations due to the intermittent movement of the slugs into the separators, for this reason, we have conducted an experimental research in order to measure the main parameters and understand the phenomenon which occurs in two-phase flow conduction on hilly terrains which is common in oil and geothermal industries. For the measurements we have built a loop where it is possible to change the flow conditions and the loop parameters as the length and inclination angle of the pipe sections. Three conductive probes were used for the hold-up measurement in different points all of them were designed, constructed, tested and calibrated first statically and then dynamically. A data acquisition system based on a microcontroller of FREESCALE was also developed to get information from 12 instruments with a resolution of 10 bits in real time. The system operates automatically and we can control the experiment using a PC. We have undertaken the first experimental runs for a set of four alternated sections upstream downstream. The gas and liquid flow rates to get stratified flow, were tested in order to observe the variation of hold-up of the resulting slugs, we have also observed the mechanism of severe slugging formation. In this paper we present the preliminary conclusions of the experimental results analysis. Key words: Two-phase, slug flow, hilly terrain, experimental characterization
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Document ID: B42FC186

Investigation Of Temperature Influences On Gas Meters
Author(s): Rainer Kramer, Bodo Mickan, Fritz Mgerle, Roland Schmidt
Abstract/Introduction:
As basically known for each kind of measuring instrument, the measurement deviation of gas meters depends from a list of influence values. In the last 2 decades input perturbations as well as the gas pressure (which leads to different gas densities and hence Re - numbers) were major subjects of interest. The gas temperature have to be investigated as an important influence figure because the application of gas meters may differ much from the calibration temperature. The impact of the temperature depends from the technique used for the flow or volume measurement in the meter. The investigation of temperature effects on gas meters is needed increasingly for type testing of meters used for custody transfer, the estimation of temperature influences on the measurement uncertainties especially if used as flow standard and the evaluation of performance figures claimed by the manufacturers. The European regulations on Measuring Instruments (MID) require the investigation of all influences and hence of the gas and the environment temperature on the behavior of gas meter as part of the conformity assessment. PTB as a notified body for MID assessments wants to carry out the metrological key tests itself, other tests will be accepted, if they are done by accredited test laboratories for instance. In order to follow this policy PTB developed and realised a test rig for temperature tests in a range between -45 C up to 80 C. The main features of the test facility as well as the chosen technical solutions will be described in the paper. The facility was designed to investigate all kind of gas meters as well as flow standards like critical nozzles up to a flow rate of 300 m3/h at standard conditions. The rig is able to stabilise the temperature in a test chamber in which the MUT is installed as well as the temperature of the test gas separately. For this the test gas flows through a heat exchanger which is equipped with an own it temperature control system. In order to avoid ice creation especially in the heat exchanger, the test gas is dried down to a dew point of - 60 C. The design uses preferably critical nozzles as flow standards which are installed under ambient condition in the test hall. By this approach a total uncertainty of U 0,2 % (k2) is reached for the flow rate at the conditions of the MUT (Q 0,1 m3/h, -25 C up to 60 C). First results of the investigation of laminar flow elements, wet gas meters (drum type) and mass flow elements based on a thermal principle are described. The results show considerable influences, which may be eliminated by appropriate correction approaches.
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Document ID: D87CC1A3

Thermal Capillary Tube Mass Flow Sensing For Low Flow Metrology Transfer Standards
Author(s): Thomas O. Maginnis
Abstract/Introduction:
Flow calibration requires 1) the ability to establish and maintain a precisely constant flow at any desired value 2) the ability to measure any such constant flow with high accuracy, relative to a primary flow standard. Much effort has been devoted to part 2) developing transfer standards with the necessary accuracy, but often the calibration result is limited instead by part 1) the inability to maintain sufficiently constant steady flows, as evidenced by the noise on the flow signal. Thus flow measurement and flow control are synergistic arts, and high proficiency in both is required for superior flow calibration. In the 35 years since their commercialization, thermal mass flow controllers have become the dominant flow measurement technology for gas flow measurement and control in the semiconductor industry, but are little known or understood outside that venue. In flow range, the technology covers a span from 3 SCCM full scale to more than 100 LPM. In the lowest flow ranges, below 100 sccm , no other continuous flow measurement technology is comparable in cost, accuracy, and flow resolution. Despite the clear commercial dominance of this flow sensing technology for the low end of the gas flow range, it remains relatively unexploited for flow metrology applications. Why? Existing semiconductor industry flow controller designs are specialized for small size, rapid response to a control setpoint change, low cost, moderate accuracy (1%), ultra-clean gas delivery and ability to operate with the most corrosive gases. Successful design for this commercial environment involves design tradeoffs that degrade flow turndown, flow resolution, and the repeatability required for a metrology grade transfer standard flow controller that could facilitate high accuracy automated flow calibrations at low flows. Also, the absence of an adequate published physical theory of operation of the thermal sensing technology severely limits the ability of metrology institutes to design or develop such transfer standards for themselves. This paper will review the potential of the thermal capillary tube flow sensing technology for high turndown, high performance gas flow controllers as calibration transfer standards in low to moderate gas flow ranges (100 SLPM).
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Document ID: 5B9780CB

Application Of Uncertainty Analysis To Balance Optimization Of Fluid Flow Networks
Author(s): Juan m. Ortiz A., John F. Velosa C.
Abstract/Introduction:
This paper describes the methodology for balance improvement in the natural gas transmission network at TGI (Transportadora de Gas Internacional). The approach is based on the application of uncertainty analysis on two levels. A first micro-scale level, defined by the uncertainty budget of the flow measurement systems, and a second macro-scale level, related to the uncertainty associated with the result of the balance for the entire network. A cyclic process is applied to simulate the effects of the different improvement actions both on the original flow measurement systems uncertainty and the balance uncertainty. The process ends when a given improvement action do not show a significant change in the uncertainty associated. With the application of this methodology has been possible to program an optimal investments plan, oriented to obtain better balances in a short-term.
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Document ID: 9ACF5C62

The Humidity Effect On Air Flow-Rates In A Critical Flow Venturi Nozzle
Author(s): J.M. Lim, B.H. Yoon, Y.K. Oh, Kyung-Am. Park
Abstract/Introduction:
Critical Flow Venturi Nozzle (CFVN) is usually calibrated with dry air. But CFVNs in the industry and calibration service centers are used to measure flow-rates of humid air. ISO 9300 suggests the calculation method of humidity effect from dry air discharge coefficient of CFVN. Thus it is important to confirm and check ISO calculation method of humidity effect on the CFVN and isentropic analysis. A CFVN (with the throat diameter 0.8 mm) was calibrated with dry air (with the dew point -40 C) in a primary air flow standard system, mercury sealed piston prover, of KRISS. A portable dry piston prover was used as a reference meter and also calibrated in the primary standard system with dry air. The repeatability of this dry piston prover was confirmed with the deviation less than 0.05 %. The CFVN was tested with this dry piston prover using humid air. For high humid air, the humidity effect on the CFVN was quite different among this experimental results, ISO and isentropic analysis. But for low humid air, the difference was small.
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Document ID: 6DF2E2F0

Eliminating Elbow Flow Turbulences From Metering Piping Systems
Abstract/Introduction:
Flow turbulence caused by piping elbows can cause cavitation, vibration, flow separation, two-phase flow, erosion and corrosion in piping systems. When this flow turbulence reaches a flow meter, it can lead to damage to the flow meter and inaccurate flow meter measurements. Most meter measurement inaccuracies can be traced directly to the flow turbulence created by the last piping elbow located close to the inlet side of the meter. Good piping design states that there should be at least 10 to 30 diameters (depending on the meter?s inlet piping diameter) of straight pipe after the elbow and before the meter, to eliminate the flow turbulence created by the elbow. In almost all cases, there is not enough room for a 10 to 30 diameter straight run of pipe between the elbow and the meter. A set of stationary rotation transformation vanes located before the elbow will eliminate the centrifugal effect of the elbow flow and make the elbow flow behave as if the elbow wasn?t there, turning the elbow into the equivalent of a straight length of pipe. The stationary vanes will create uniform controlled flow stream lines inside the piping elbow, removing the requirement for the 10 to 30 diameter straight length of pipe. The controlled elbow flow stream lines have been demonstrated effectively for sometime. This paper brings this technology to the metering industry. This paper will provide actual elbow flow measurements, numerical simulation results, and a laboratory demonstration.
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Document ID: 05437D02

Improved Meter Performance Characterizations For Liquid And Gas Turbine Meters
Author(s): G. E. Mattingly
Abstract/Introduction:
Increasingly, todays liquid and gas turbine meter users seek high accuracy performance in extremely wide ranges of fluid and flow conditions. While liquid turbine meters need high accuracy across extremely wide ranges of fluid viscosity for equitable custody transfer of costly fluids such as oil or LPG and for satisfactory fuel measurements in engine monitoring and performance testing, gas turbine meters need high accuracy across extremely wide ranges of gases and pressure to equitably sell and distribute natural gas or, for example, to handle hydrogen gas in future energy systems. Over all of these conditions, calibration results should satisfactorily characterize meter performance over the widest feasible turndown - i.e., the maximum to minimum flow rate ratio. Initially, turbine meter designers achieved turndowns of 10 or 20 to 1 on flow rate, for the specific liquid viscosity or for the specific gas and pressure used in the calibration. However, when liquid viscosity or gas pressure differed from calibration values, turbine meter turndowns decreased or meter uncertainty increased or both, thus reducing the meters rangeability.
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Document ID: 00B12412

Field Application Comparison Conditioning Type Orifice Plates (4-holed) And Generic Cone Meters
Author(s): Mark W. Davis, Philip A. Lawrence
Abstract/Introduction:
Allocation measurement of produced hydrocarbon gas in the upstream area require different measurement techniques and strategies than those used for standard pipeline quality gas measurement due to the nature of the fluids in the system. Wet gas, hydrate formation, liquid slugging, well clean-up debris and short meter runs all add to the difficult task of collecting meaningful data from High Pressure Full Well Stream (HPFWS) allocation metering points. Various meter types have been employed for these flow regimes in order to meet the necessary accuracy requirements and the arduous duty that normally occurs in these applications. This paper details the real world experience of such a allocation metering system operating in Wyoming, USA that has wide ranging environmental patterns from below - 30 deg F (-34 deg C) in the winter to + 90 deg F (+32 deg C) in the summer all which can have an impact on the measurement. The operational experience and differences between the two metering technologies, conditioning orifice plate versus cone will be detailed. Meter selection criteria will be discussed based on facility design constraints in accordance with regulatory and environmental requirements, allocation accuracy needs, along with sustainable and cost effective approaches for implementation. Data from the field operator will be shown together with performance, calibration data and computational fluid dynamic imagery (CFD) for some meter types that were and are now being fitted to meet the operators measurement philosophy.
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Document ID: 2D07A4F1

Measurement Of Forward And Reverse Natural Gas Flows In Closed Conduits By Differential Pressure Cone Flow Meters And Ultrasonic Meters
Author(s): Philip A Lawrence, Larry Whitaker
Abstract/Introduction:
The use of differential pressure type meters to measure accurately a bi-directional gas flow in a pipeline can have major measurement uncertainty issues due to the geometric difference in the differential producer element shape when used in the reverse direction. Meter discharge coefficients may be different in these particular cases for geometric devices such as concentric,square edged and flange tapped orifice flow meters and Venturi meters. Current national and international measurement standards state that bi-directional flow measurement is not permitted using orifice plate type flow meters for a good measurement uncertainty and that meter runs dedicated for each direction must be used in this application. This paper details the recent experience and testing of differential pressure cone meters used to measure high pressure natural gas to custody transfer standards and as check meters for the CTM Gas Ultrasonic Meters (USMs) at a natural gas storage and transmission facility in New Mexico USA The cone meters mentioned in this paper were supplied for the field application, and were independently tested using High Pressure Natural Gas Product at a nationally certified test facility in the USA. The provisional testing and a feasibility study was done on smaller diameter meters with water to demonstrate and prove the application at an international certified independent laboratory in the far east. A user in-field data set comparison will be shown between the bi-directional cone meters and the bidirectional ultrasonic meters used for the custody transfer measurement on the site. The resulting test and installation data demonstrates that the use of cone meters in a bi-directional configuration works well and is a real world cost effective alternative method to an old issue. The paper will not mention any trade names and will only use generic names and terminology
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Document ID: 97CAD221

Diagnostic Capabilities Of P? Cone Meters
Author(s): Richard Steven DP Diagnostics
Abstract/Introduction:
Differential Pressure (or DP) flow meters have simple and relatively sturdy designs. This combination of simplicity and ruggedness make them both relatively inexpensive and reliable devices. Furthermore, their simplicity makes their operating principles easily understandable. For these reasons they are one of the most popular generic flow meter types. A DP Diagnostics ?P cone meter sketch is shown in Figure 1, with a cut away of the meter wall to reveal the differential pressure producing cone element. Cone DP meters are growing in popularity due to their proven immunity to the effects of most flow disturbances both upstream and downstream of the meter. That is, unlike most meter designs, the cone DP meter does not need extensive upstream and downstream straight pipe lengths, or flow conditioners, to meter the flow rate accurately. Therefore, the cone DP meter can be, and is, installed in many pipe work locations where no other flow meter could operate successfully (i.e. to a low uncertainty).
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Document ID: 7C5A3C4E

Measurement & Diagnostic Capabilities Of Clamp-On Ultrasonic Flow Meters
Author(s): Dr. Mathias Panicke
Abstract/Introduction:
Ultrasonic clamp-on flow meters offer great flexibility to the user, this in part due to the fact that they are non-invasive and installed on the outside of a pipe. Applications used to be limited, but with the developments in transducer technology and the introduction of micro-processor based signal processing technology their reliability and range of measurement tasks have expanded to difficult hydrocarbon based liquids and gases. The evaluation of the gathered measurement data, and its reliability, are as important as the measuring values themselves. For this reason ultrasonic flow meters (USFM) inherently offer extensive self-diagnostic possibilities, both during the installation process as well as for long-term monitoring. This article presents these diagnostic capabilities as well as some of the special challenges some hydrocarbon based liquids and gas measurement pose for clamp-on USFMs.
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Document ID: 28FA666D

The Design, Development, And Performance Of A Multi-Viscosity Flow Calibration Facility
Author(s): Bobbie Griffith, Terry Cousins, Don Augenstein
Abstract/Introduction:
This paper describes the development, design and performance of a large capacity, multiviscosity, oil flow measurement facility. The facility was constructed primarily to calibrate custody transfer quality flow meters produced by Cameron. The facility can produce world class calibrations for any type of volumetric liquid meter. The facility is a pressurized circulating system that uses one of three different hydrocarbon fluids. These fluids have nominal viscosities of 1.5, 16 and 150cSt. A 10 cubic meter prover forms the calibration basis, with master metering to enable a wider range of flowrates, particularly at the high flows. The paper shows in detail the uncertainty analysis for all of the methods of calibration, as well as the process that enabled the facility to obtain both NMI certification and ISO 17025 accreditation. Two particular features of this facility are described, along with their implications. First, temperature control of better than 0.1 Deg C during calibration. This temperature control has allowed a greater understanding of flowmeters as well enabling very high quality calibrations, compared to most other available facilities. Second, the care and attention to detail with the hydraulic design allowed the facility to far exceed the proposed design flow rates, allowing a greater range of meter calibrations than in the original specification.
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Document ID: FD16B251

Blow-Down Tests Confirm Accurate Critical Flow Venturi Measurements During Transients
Author(s): John D. Wright
Abstract/Introduction:
Critical flow venturis (CFVs) can be used to measure flow under transient pressure, temperature, and flow conditions with k 2 uncertainties of 0.4 % or less. Blow-down tests transferred 630 g of nitrogen during a 100 s interval from an unregulated cylinder (initially at 10 MPa) through a CFV into a known collection volume. Fast pressure and temperature sensors monitored the inlet to the CFV. The integrated CFV mass flows, ? m?? dt , averaged 0.38 % smaller than the mass ??V of the collected gas. To reduce temperature transients at the CFV, a heat exchanger was added upstream of it. The heat exchanger reduced the percentage difference ? m?? dt /(??V) - 1 to 0.04 %. Accurate measurements of transient flows require careful measurements of the gas temperature near the throat of the CFV and careful attention to thermal effects on the CFV discharge coefficient. We conclude that a properly instrumented critical nozzle can be used
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Document ID: F8AEA6AC

Experimental Study On Cavitating Venturi For Preventing Severe Accidents In Nuclear Power Plants
Author(s): Ki Won Lim, Jaeheun, Rho
Abstract/Introduction:
When a severe accident occurs in a nuclear reactor, a sufficient amount of water must be supplied to prevent a steam explosion. A water volume of 1135 m3 must be supplied at a rate in the range of 122 m3 / h to 170 m3 / h to stabilize the system. However, high steam pressure in the steam generator (SG) causes difficulty in supplying an appropriate volume of water. Use of a Cavitating Venturi (CV) allows a liquid flowrate to be fixed. This flowrate is independent of downstream pressure. If choking occurs in the liquid flow, downstream pressure changes cannot be transmitted through the barrier, and only an upstream pressure can increase the flowrate. However, the collapse of the vapor cavity generates severe noise and also causes pipe vibration, which destroys the piping and destabilizes operation. In this study, a designed CV is proposed for reducing the noise and the pipe vibration. Testing was carried out in the range of 54 m3 / h to 148 m3 / h under practical conditions. The noise generated from the bubble collapse was measured as from 94 dBA to 123 dBA with the tested flowrates. According to the experimental results, the designed CV showed improved characteristics for stable operation of a nuclear power plant.
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Document ID: 3048E848

Experiences With Sonic Nozzles Used For Different Gases And Wide Range Of Pressure And Temperature Conditions
Author(s): Bodo Mickan, Rainer Kramer
Abstract/Introduction:
In the past years sonic nozzles were used in several inter-comparisons as transfer standards (e.g. 1, 2) and are assumed as the most stable artefacts. Nevertheless, the aim of the flow community to establish inter-comparisons including facilities with different operating ranges, different gases and wide ranges of temperature and pressure conditions needs a careful evaluation of the potential artefacts for such inter-comparisons. In this respect the influences of the operating conditions to the calibration values of sonic nozzles will be discussed in this paper and conclusions will be made. The base for the discussion in this paper is a set of measurements with sonic nozzles operated in a pressure range between 80 kPa and 5000 kPa, a temperature range of -2C to 23C and with gases humid air, dry air, nitrogen and natural gas.
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Document ID: C006B497

Ultrasonic Meter Recalibration Program
Author(s): Stephen English, Joel Clancy
Abstract/Introduction:
Ever since multi-path ultrasonic meters were approved for custody transfer measurement of natural gas, there has been on ongoing debate as to whether they should be periodically recalibrated, and if so, how frequently? Atmos Energy Corporation has chosen to be proactive in answering these questions for themselves by implementing an ultrasonic meter recalibration program. This program uses a fleet of dedicated ultrasonic meters that allows for the exchange and recalibration of its installed ultrasonic meters with minimal impact on operations.
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Document ID: 371509CB

Calibration Facilities For Water Flowrate In Nmij
Author(s): Noriyuki Furuichi, Yoshiya Terao, Masaki Takamoto
Abstract/Introduction:
Water flow calibration rigs in NMIJ are represented. In response to a recent requirement of an actual flow calibration, NMIJ has expanded the calibration flowrate for water flow. For the small flowrate range, the calibration rig with 10 kg weighing system was developed. The expanded uncertainty of this calibration rig is 0.035%. For the large flowrate, the calibration rig which can control the temperature was also developed. Then, the flowrate range is expanded from 0.002 m3/h to 12,000 m3/h. The expanded uncertainty of this calibration rig is 0.077%. In this paper, the overview of calibration facility of water flowrate in NMIJ and the detail of the new calibration rigs are described.
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Document ID: BB607370

Novel Diverter Mechanism For Water Flow Facility
Author(s): Chun-Lin Chiang, Yi-Lin Ho, Jian-Yuan Chen, Cheng-Tsair Yang, Jiunn-Haur Shaw
Abstract/Introduction:
Fluid flow diverters are essential elements in high-accuracy liquid flow calibration facilities using static gravimetric method coupled with a flying-start-and-finish operating mode. In such flow systems, flow stability and flow velocity profile passing through a drain nozzle and to the diverter module influence the accuracy of flow measurement. Consequently, the design and construction of a diverting mechanism with its feeding pipe section contribute dearly to the total measurement uncertainty of a standard calibration facility. A novel diverter composed of a width-variable nozzle and an electro-driven module was developed for the small water flow calibration system at Center for Measurement Standards (CMS). Test results showed that the new diverter increased the measurement capacity and lowered the timing error. This paper described the design and of the new diverter and its real test results verifying a performance that fulfilled our needs.
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Document ID: 02F96AAD

Verifying Gusm Accuracy And Stability Using Control Limits Established For Advanced Diagnostics
Author(s): Daniel J Hackett,
Abstract/Introduction:
Gas ultrasonic flow meter diagnostics have been used in the last several years to not only monitor the health of the flow meter but to indicate potential dynamic flow disturbances that left unchecked can slowly lead to increased measurement uncertainty. Understanding the diagnostics available is one key to providing user actionable recommendations to resolve alarms or alerts. However, there are additional steps a user should initially take to avoid potential problems from installation and to identify the magnitude of the shift in specific diagnostic parameters.
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Document ID: A73556C7

Validating The Accuracy Of Multi-Path Transit Time Ultrasonic Flowmeters
Author(s): Don Augenstein, T. Cousins
Abstract/Introduction:
Transit time ultrasonic flow meters (UFMs) employing multiple chordal paths are now applied in many industries. One recent development is the nuclear industry using Cameron Caldon Ultrasonics (CCU) UFMs to improve their calorimetric determination instrumentation. This improvement is part of a program called Measurement Uncertainty Reduction Uprate or MUR. The MUR allows nuclear power plants to increase their licensed power levels by as much as 1.7%, using multi-path meters. A nuclear power plants calorimetric determination requires accurate knowledge of the feedwater flow rate and temperature. Cameron Caldon Ultrasonics UFMs for the nuclear industry, known as the LEFMCheckPlus (8 path), can be used to determine both parameters with accuracies of 0.3% and 0.3C respectively. Due to the feedwater flow measurement accuracy requirement, Cameron Caldon Ultrasonics calibrates their nuclear flowmeters in a full scale plant model. These models provide opportunities to perform parametric tests that quantify the sensitivity of multi-path UFMs to upstream hydraulics. Over the past 10 years, Caldon Ultrasonics has performed their laboratory calibration tests at the Alden Research Laboratory (Holden, Massachusetts, USA). These calibration tests included a range of meter sizes and upstream piping configurations. The multi-path transit time technology has demonstrated insensitivity to upstream and downstream configurations that include elbows, manifolds, and Y branches. Metrics such as flatness ratio (FR) and swirl rate are used to characterize the velocity profile. These metrics also validate the meter factor determined at Alden Laboratory by relating the field installation to the laboratory calibration.
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Document ID: 3884EFF0

Reducing Installation Effects On Ultrasonic Flow Meter
Author(s): Jan G Drenthen, Martin Kurth, Jeroen Klooster, Marcel Vermeulen
Abstract/Introduction:
Over the past decade, ultrasonic flow meter have gained rapidl a wide acceptance. Main reasons for this are the high repeatability combined with zero pressure loss and extended diagnostics features. During this period meter with difeerent path configurations have been put into the market, each of them trying to obtain the highest accuracy and a multiple of papers have been published on the performance of these meters at the calibrations laboratories. Many of the show (often mlutipoint linearization) almost ideal striaght lines with errors close the the repeatability of the lab.
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Document ID: 76E6BA97

Testing Of Generic Differential Pressure Cone Meters To API 22.2 Test Protocol Part 1.0 Water().
Author(s): Philip A Lawrence, Dr. N.W Sung
Abstract/Introduction:
During 2003 a standard was developed by the American Petroleum Institute (API) Manual of Petroleum Measurement Standards (MPMS) Chapter 5.7 Working Group, entitled Differential Pressure Flow Measurement Devices. It was subsequently moved and changed to Chapter 22, Section 2, and is now called API chapter 22.2 the differential test protocol. This paper details the work done on various sizes of differential pressure cone meters at the FCC Ltd Independent water test laboratory near to Seoul in South Korea. The paper will detail the results for baseline and perturbation testing performed at the laboratory using their gravimetric system traceable to Korean National Standards through KOLAS and KRIS. The demonstration of the laboratories alignment to the RG (Reader-Harris-Gallagher) equation will be shown and also results from a recently available technique called PIV particle image velocimetry which is a laser optical method used to obtain instantaneous velocity measurements and related properties in fluids. This technique was used to determine that the velocity profile in the pipe was fully developed thus enabling the RG equation to be validated effectively in the calibration system. Figure-1a The line velocity profile effects where shown by using a computer generated nomogram - Figure 1b The system was also used during the test to view the fluid flow dynamics through a cone meter that was installed in a clear view flexi-glass pipe.
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Document ID: C6BDC209

The ISO 5167 Compliant Design Venturi - A Summary Of Calibration Experience
Author(s): Thomas Kegel
Abstract/Introduction:
This paper organizes and analyzes the results of 59 venturi meters calibrated using compressed air. The inlet diameters range from 0.37 to 17.25 inches, the beta ratio range is between 0.26 and 0.75, the calibration pressures range from 14 to 450 psia. The results are preliminary and the analyses are continuing.
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Document ID: 17E0C7F0

An In-Situ Verification Technology For Coriolis Flowmeters
Author(s): Timothy J. Cunningham
Abstract/Introduction:
Structural Integrity Meter Verification is a robust new Coriolis verification technology which uses the onboard electronics to very accurately measure the stiffness of the flowtubes. The flow tube stiffness is directly related to the flow calibration factor and is uninfluenced by process conditions. Meter Verification compares the measured stiffness to the factory baseline stiffness to confirm that the flow calibration factor is unchanged from the factory value. Structural Integrity Meter Verification also performs additional electronics and software checks to ensure accurate measurement. This new technology allows users to save money and reduce downtime by verifying Coriolis meters in situ. Sometimes Coriolis meters are used with corrosive fluids that can etch away the tube or with erosive fluids that can cause localized thinning of the tubes. In these applications the precision and accuracy of the Coriolis flowmeter outweighs the replacement costs. A Coriolis meter has been deliberately corroded while tracking the flow calibration factor and the stiffness. Finite element analysis was used to analyze the relationship between stiffness and flow calibration factor for erosive applications. Meter Verification results for these cases are compared to the experimental and analytical data.
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Document ID: 51631080


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