Two Primary Standards For Low Flows Of Gases
Author(s): Robert F. Berg,Stuart A.Tison
Abstract/Introduction:
We describe two primary standards for gas flow in the range from 0.1 to 1000 mol/s. (1 mol/s 1.3448 standard cubic centimeters per minute.) The first standard is a volumetric technique in which measurements of pressure, volume, temperature, and time are recorded while gas flows in or out of a stainless steel bellows at constant pressure. The second standard is a gravimetric technique. A small aluminum pressure cylinder supplies gas to a laminar flow meter, and the integrated throughput of the laminar flow meter is compared to the weight decrease of the cylinder. The two standards differ by approximately 0.06 %. Although this exceeds the combined standard uncertainty of 0.04 %, it suggests that the error of both standards is less than 0.06 %.
Go to Download Page
Email Reference
Document ID:
B7A43146
A Novel Primary Flow Standard For Compressible Flow Calibration: Initial Testing And Calibration
Author(s): Richard W. Caron,Charles L. Britton, Tom Connolly, Casey Hodges, Thomas Kegel
Abstract/Introduction:
The operation of a primary flow standard for compressible flow calibration is typically based on either a gravimetric or volumetric method of mass determination. The gravimetric method provides a direct determination of the mass while the volumetric method utilizes measurements of density and volume to determine mass. This paper describes the initial testing and calibration of a primary flow standard designed to determine mass of gas (air) using both the gravimetric and the volumetric methods.
Go to Download Page
Email Reference
Document ID:
CF19AA35
Development Of The Primary Standard For Very Low Gas Flow Rates
Author(s): Shin-Ichi Nakao,Yoshiya Terao,Masaki Takamoto
Abstract/Introduction:
National Metrology Institute of Japan (NMIJ) has constructed a primary standard for gas flow rates less than 1 mg/min based on the dynamic gravimetric method. The whole calibration facility is set in the chamber to avoid the influences of the ambient air flow in the temperature controlled room. A gas vessel is hung from the high resolution balance and is connected to the piping outside the chamber by a Teflon tube. The vessel, with a volume of about 10 cm3, is pressurized up to 0.5 MPa at maximum. An automatic pressure controller (APC) is installed between the chamber outlet and a test flow meter (DUT) to regulate the pressure of the test gas flowing out from the vessel as a desired flow rate is obtained. The mass flow rate on the calibration can be calculated from the changing rate of mass of the gas vessel. The relative expanded uncertainty (coverage factor k2) of the primary standard developed is expected to be below 0.5 percent in the flow rate range from 1 mg/min to 0.05 mg/min.
Go to Download Page
Email Reference
Document ID:
A5EC6989
A Primary Standard Piston Prover For Measurement Of Very Small Gas Flows
Author(s): Giorgio Cignolo, Gaetano La Piana
Abstract/Introduction:
A high-accuracy prover is described, which is the new Italian national standard for gas flow rates in the range 1 mL/min to 1 L/min. The prover (full capacity: 3 liters) measures volume changes implemented by means of a massive, motor-operated piston which is introduced into (or extracted out of) a temperature-controlled ( 10 mK) chamber containing the working gas at near ambient conditions. The prover can either deliver or collect measured gas flows, depending upon the type of instrument to which it is connected piston displacements are measured by means of a laser interferometer. Motor speed is controlled in such a way that gas delivery is made at constant rate, whereas variable incoming flows can be measured at constant pressure. Owing to the accurate measurement of temperatures and pressures, the mass flow rate can be inferred to practically the same high accuracy as the volume flow rate (relative standard uncertainty: 0.013% to 0.03%).
Go to Download Page
Email Reference
Document ID:
59CEF0AB
Proving Multi-Path Ultrasonic Flow Meter In Liquid Custody Transfer Applications
Author(s): Herb Decker
Abstract/Introduction:
With the emergence of Multi-path Ultrasonic metering as liquid hydrocarbon custody transfer quality flow measurement technology there is a need for a review of proving methodology. Ultrasonics differ from current flow metering technologies, such as turbine and positive displacement meters, in that they have much quicker response times to changing flow conditions, no moving parts and become more accurate as the line size grows. In addition to the mechanical dissimilarities multi-path Ultrasonics differ as their measurements are independent of viscosity and density. These capabilities require a different approach to the traditional methods of proving. This paper explores the technology and methods for proving.
Go to Download Page
Email Reference
Document ID:
F608FE0F
The Influence Of Speed Of Sound Changes On Ultrasonic Flow Meter Calibrations
Author(s): William Freund, Klaus Zanker And Dale Goodson,James E. Hall
Abstract/Introduction:
The simple theory of the ultrasonic flow meter predicts that the flow measurement should be independent of the speed of sound in the meter. If this assumption is not valid in actual applications, errors may occur when a meter is calibrated at conditions different from its field installation. In order to quantify the effect of changes in the speed of sound, a series of carefully controlled calibrations have been performed. The first experiment consisted of calibrating an 8-inch and two 12-inch ultrasonic meters in a natural gas loop. The fluid was then changed to nitrogen, providing approximately a 16% change in the speed of sound. In addition, further calibrations were run with changes in the speed of sound introduced through changes in the temperature of the fluid. Natural gas calibrations were performed at 70 and 50 degrees Fahrenheit and nitrogen calibrations at 70 and 90 degrees Fahrenheit. For each series of calibrations, the average calibration curves were compared to determine the effect of the change. The resulting analysis showed that speed of sound changes introduced through temperature changes did not result in a change in the calibration curve for the ultrasonic meters outside of the expected reproducibility of the facility and the meters. Analysis of the calibrations taken with natural gas and nitrogen showed an average difference of 0.2% when referenced to SwRIs sonic nozzle standard. However, when the ultrasonic calibrations were referenced to the turbine meters, this difference disappeared. This supports the possibility for wet calibration of ultrasonic meters on air as well as natural gas as long as the effect of the density of the gas on the reference is taken into account.
Go to Download Page
Email Reference
Document ID:
036935F1
Ultrasonic Flow Measurements By Multipath Measuring Spoolpieces: Quadrature Integration And Tomographic Reconstruction
Author(s): m. N. Rychagov And S. A. Tereshchenko
Abstract/Introduction:
Determination of the characteristics of liquids or gases being transported through the channels of various cross-sections, in particular circular, actually represents a theoretical, computing and engineering problem which has also considerable practical interest 1, 2. One of the most important characteristics of such flows is volumetric flowrate of a liquid or gas flowing through a cross-section of the transporting channel per unit time. The attempts of investigators and companies producing measuring equipment are aimed at the economical reduction of measuring uncertainty which is caused first of all by the spatial inhomogeneity of the flows under measurement. One of the most promising approaches to the solution of this problem is carrying out so-called multipath measurements. For estimating the characteristics of the flow, a measuring data set is used which is collected in a number of parallel measuring planes. Along with the inherent advantage in accuracy as a consequence of the increase in measured data, the multipath approach has demonstrated robustness even in non-ideal flow situations. Moreover, the multipath measurements allow one to set and to solve the problem of the reconstruction of the axisymmetric distribution of the axial flow velocity component in a cross-section of the pipeline by using Abels transform. Further development of multipath approach is related with the development of the algorithms and devices for an implicit reconstruction of an arbitrary two-dimensional distribution of the axial component of the flow in a cross-section using Radons transform. This paper gives a systematic description of the approach based on multipath measurements beginning with high-precision estimation of a single characteristic of the flow, i.e., its flowrate, to the reconstruction of axisymmetric flows and further, to full tomographic reconstruction of arbitrary flows.
Go to Download Page
Email Reference
Document ID:
06DC90A9
Intelligent Ultrasonic Flowmeters
Author(s): James E. Gallagher, Michael P. Saunders
Abstract/Introduction:
Companies today are grappling with the implementation of Ultrasonic Flowmeters (USMs) in an efficient and effective manner. While the USM technology provides the user with a high level of performance if installed correctly, it also provides the user with a wealth of information about its operation. When interpreted and analyzed thoroughly, the operating data provides the user with a number of ways to determine the effectiveness of the measurement creating a benchmark for performance. This paper contains the results of experiments of USMs in natural gas service employing - Intelligent integration techniques Techniques to monitor ultrasonic flowmeters in the real world environment for troubleshooting and assurance of performance (diagnostics) The combination of these elements provides an intelligent ultrasonic flowmeter with advanced integration and diagnostic capabilities. This paper presents experimentally validated concepts, proposed by the authors, that combines superior performance under real world piping configurations with a simplified meter design that enables the user community to benefit from significantly reduced capital and operating costs. The intellectual property discussed reflects domestic and foreign patents pending of Savant Measurement Corporation for intelligent integration and diagnostics for ultrasonic flowmeters.
Go to Download Page
Email Reference
Document ID:
7F823068
Flow Measurement With Microfluidic Oscillators
Author(s): Eliphas W. Simes, Rogerio Furlan,Marcos T. Pereira
Abstract/Introduction:
This paper describes the project and development of a microfluidic oscillator, which can be used in measurement and control applications with low flows of fluids. The possible applications include rapid measurement and control in areas as automatic control in industries, measurement in domestic gas storing, and chemical or biological flow mixing and analysis, among many others. In this case, the devices should possess easy maintenance, easy manipulation, and rapid response time. The device described in this work presents potential to address all these requirements. Thus, in this stage of this project, microfluidic oscillators were simulated using the commercial ANSYS 5.7 package with a two-dimensional finite element model and devices dimensions derived from those of a typical wall attachment microfluidic amplifier (control nozzle width of 50 micrometers). The results of these calculations indicate that steady-state and dynamic transient analysis are useful tools for evaluating fluidic oscillator systems in micro dimension range.
Go to Download Page
Email Reference
Document ID:
52B2F28D
AGA10 Sound Speed Equations: Background, Thermodynamic Relations, Ideal Gas And Equation Of State Methods, Uncertainty Analysis, And Calculation Flow Diagram For Natural Gas Measurement Applications
Author(s): Jeffrey L. Savidge
Abstract/Introduction:
This paper reports work that was done in anticipation of producing A.G.A. Report No.10 for the A.G.A. Transmission Measurement Committee, Task Group 13 on Sound Speed. It is built on previous research work by the author. The goal of the paper is to provide a concise description of all of the elements required to compute the sound speed of natural gases. The method presented is consistent with ISO 12213 - Part II, AGA Report No.8, and API MPMS Chapter 14.2. The paper provides background information, basic thermodynamic relations for sound speed, the ideal gas contribution and correlation, and the non-ideal gas contribution provided by the GRI high accuracy equation of state as reported in A.G.A. Report No.8. Standard thermodynamic relations for the sound speed are provided in a form that can be conveniently applied by engineers. Coupling this information to common density search algorithms provides the means to solve the equation of state and the thermodynamic relationships required to compute the sound speed. A computer flow diagram is provided to facilitate implementation of the sound speed calculation method by users. Calculated sound speed values have been compared to measured sound speed values in order to obtain uncertainty estimates in the calculated sound speed values for different natural gas mixtures. A statistical summary of the comparisons is provided. Significant limitations in the sound speed data hamper a comprehensive uncertainty analysis of the accuracy of the sound speed data and the sound speed method. More sound speed data and analysis would provide a firmer basis to establish the uncertainty in calculated sound speed values.
Go to Download Page
Email Reference
Document ID:
4B4A4FF4
A Turbine Flow Meter That Is Insensitive To Changes In Fluid Viscosity
Author(s): Paul D. Olivier
Abstract/Introduction:
Turbine meters are often used as the volumetric meter, but are very sensitive to viscosity, temperature and Reynolds Number. Figure 1 shows the classical correlation of a standard turbine meter. The ?so called? Universal Viscosity Curve shows that the meter frequency divided by the fluid kinematic viscosity is a function of the meter frequency divided by the volumetric flow rate. If the meter is operated at varying temperatures, thus, varying viscosity, the flow rate cannot be determined without knowing the viscosity. When operating at constant temperature on a specific fluid, it is not necessary to determine the viscosity so long as the meter was calibrated at the same condition. This special case is not commonly experienced. In most cases the temperature does vary. As a result, the viscosity changes, requiring the need to determine the exact viscosity of the fluid at the operating condition. While it is possible to use text book values of viscosity as a function of temperature as an input to the computations, the value of viscosity from one batch of most fluids to another change sufficiently to negate the value of the input. As a result of this limitation, shortcuts to the need to measure the viscosity are often taken by the users. Of course, all such shortcuts lead to errors in the measurement. Sometimes they are small, but at other times they are very significant. Users often don?t realize the significance of the errors. While the users are ?happy? with their results, the results could be significantly improved once the potential errors are realized.
Go to Download Page
Email Reference
Document ID:
D4EA48EC
Turbine Meter Research In Support Of The Revision Of AGA Report No. 7
Author(s): Darin L. George
Abstract/Introduction:
In support of the planned revision of American Gas Association (AGA) Report No. 7, commercial turbine flow meters have been tested at the Gas Technology Institute (GTI) Metering Research Facility (MRF). This paper presents the test results, which were obtained from the MRF Low Pressure Loop (LPL) using natural gas as the test medium. Four commercially-available turbine meters, including high-capacity meters and single-rotor and dual-rotor designs, were evaluated. The meters were tested in the three different installation configurations referenced in the current version of AGA-7. These installations included the recommended meter run configuration, the close-coupled configuration, and the short-coupled configuration. Results were compared to determine the relative measurement biases of the test meters in these three different piping arrangements. Meters were also tested with a straight length of pipe installed upstream and with the ISO 9951 high-level perturbation piping immediately upstream of the meter runs, to evaluate meter performance in the presence of asymmetric, high swirl flows. The data are presented from the perspective of proposed revisions to the AGA-7 guidelines.
Go to Download Page
Email Reference
Document ID:
75ADEE65
Performance Of Coriolis Meters In Gas Flow
Author(s): Dr David G. Stewart
Abstract/Introduction:
Coriolis meters are used widely in the oil and process industry for metering liquids. They offer many advantages in terms of accuracy, repeatability, and relatively low sensitivity to installation effects. Coriolis meters also have the advantage that they measure the mass flowrate directly, removing the need for density calculations and corrections. Recent advances in Coriolis meter technology have meant that their use in gas flow measurement has been on the increase. Indeed, high accuracy direct measurement of the mass flow of gases is now possible. This has been reflected in interest at ISO level where TC30/SC12 are currently drafting a Standard on Coriolis meters for gas applications. Most manufacturers will calibrate these meters (intended for gas) in water and simply quote a larger uncertainty for gas measurement. However, prior to this project starting there was very little independent data to support this approach. This work was designed to investigate the performance of Coriolis meters in gas. This would provide completely independent data from which conclusions can be drawn regarding their use in gas, and also whether a water calibration is sufficient. The work featured in this paper was undertaken as part of the 1999 - 2002 Flow Programme. The Flow Programme is funded by the UK governments Department of Trade and Industry (DTI), within their National Measurement System Directorate. The Flow Programme is designed to undertake generic research in flow measurement and closely related topics. In this paper results are presented from tests on two Coriolis meters from different manufacturers. The manufacturers in question have requested that at this stage the data be presented anonymously, until the project has been completed. The estimated completion date for this project is May 2002.
Go to Download Page
Email Reference
Document ID:
53FB2A7D
Installation Effects Testing Of Coriolis Flow Meters With Natural Gas
Author(s): Terrence A. Grimley
Abstract/Introduction:
The recent publication of the American Gas Association (AGA) Engineering Technical Note titled Coriolis Flow Measurement for Natural Gas Applications demonstrates the increased interest of the gas industry in the application of Coriolis meters. This paper presents the results of recent Coriolis flow meter testing with natural gas. Commercially available meters with 2- to 4-inch nominal diameters were tested in baseline configurations over a pressure range from 200 to 1000 psi. The meters represent a sample of the product line from three manufacturers (Endress+Hauser, FMC, and Micro Motion). Two-inch meters from each manufacturer were also tested with piping configurations having an upstream flow disturbance. Single and double elbow combinations (in plane, and out of plane) placed upstream of the test meter, as well as a configuration with a concentric reducer upstream, were used to create the flow disturbances. Meters were installed based on the manufacturers specification, which in some cases required no piping between the disturbance element and the meter. The work was sponsored by the Gas Technology Institute (GTI) and was performed at the GTI Metering Research Facility (MRF) at Southwest Research Institute.
Go to Download Page
Email Reference
Document ID:
409F2B01
Performance Of Wide Beam Clamp-On Ultrasonic Flowmeters In API Proving Tests Clamp-On( Custody Transfer By API Method)
Author(s): J. Baumoel
Abstract/Introduction:
The current practice of the Petroleum industry requires use of the API proving method as a means of arbitrating the value of petroleum products passed between seller and buyer. The procedures for accomplishing this Proving are written around the use of Turbine or PD flowmeters and require a defined range of repeatability between successive runs using a Small or Large Volume Prover. Periodic service of these flowmeters is indicated when their repeatability deteriorates due to wear. Interest in the use of Ultrasonic flowmeters, which are less prone to wear factors than those meters that intrude into the flow, has been manifest in the API sponsorship of trials of Ultrasonic flowmeters to determine if a new Standard for Custody Transfer Proving could be based on these meters. Accordingly, a number of manufacturers of Ultrasonic meters were invited to submit meters for test. As a result, a number of manufacturers of Wetted Transducer Ultrasonic meters submitted instruments for test. Controlotron submitted System 1010S Wide Beam Clamp-On Spool Ultrasonic flowmeters for test in three areas Crude Oil Pipelines, Refined Product Pipelines, and Liquefied Gas Pipelines. All Controlotron System 1010S Meters performed with an average deviation of less than 0.05 percent on a multiplicity of different product batches in each liquid category. No intrusive flowmeter had better performance. What is particularly exciting about the API test program is that its results show performance under actual field conditions, which cannot be replicated by laboratory testing. While laboratory tests will always remain essential for validation of manufacturing controls, it is only by field-testing that a meters susceptibility to actual conditions can be revealed. This paper details the actual data obtained using the API proving method, and presents design details of the Controlotron meter that make such performance expected, rather than surprising. It discusses how a non-intrusive Clamp-On flowmeter deals with the application conditions that attack the performance of most other flowmeter types.
Go to Download Page
Email Reference
Document ID:
46DF3258
Ultrasonic Mass Flowmeters Using Clamp-On Or Wetted Transducers
Author(s): Jed Matson, Charles F. Mariano, Oleg Khrakovsky, And Larry Lynnworth
Abstract/Introduction:
The relationships among sound speed c3, temperature T, pressure P and density ? have been known for a long time for many fluids. As an example of the close connection between the first two of these, consider that in 1981, Sochajewski et al. 32 reported uncertainty in water temperature of only 0.1C when obtained from c3 in a multipath ultrasonic flowmeter using wetted transducers. In one sense, the present work may be viewed as a three-step extension of that 1981 work. Step (1) goes (when practical) to clamp-on transducers to measure sound speed step (2) obtains density from sound speed step (3) multiplies the volumetric flowrate Q by density to obtain mass flowrate MF ?Q. In the present work, we used NIST data, Lemmon et al. 14 to obtain density directly from sound speed in water and in normal alkanes. For water, pressure between 50 and 70 bar has 0.1% influence on ? at 100C, and 0.33% influence at 260C. Similar data available at the time were used in setting up or running ultrasonic clamp-on flow meters in two nuclear plants in the USA. (NC, four f24? pipes & CT, two f3? pipes) to measure flow velocity V and sound speed c. Angle-beam (wedge-type) clamp-on transducers were constructed with high-temperature plastic wedges for T up to 180C (NC), and metal buffers for T up to 282C (CT). The electronic instruments used in this work have been standard one- or two-channel flowmeters. In the former case, the flowmeter utilized a program corresponding to the ? vs c3 equation. In this case, the clamp-on flowmeters output is in terms of mass flow rate. Since density is obtained from the sound speed, the instrument is a stand-alone mass flowmeter that does not require any additional T or P sensors in order to compute the mass flow rate. The present report generalizes from water to certain other pure, well-defined liquids such as normal alkanes. It also considers air (dry or moist), steam (saturated), and flare gases. The sound speed in such fluids can yield density but one must be aware of errors when interfering variables are present, e.g., salt in water, branched (non-normal) molecules in alkane, condensate in steam, or unknown amounts of nitrogen in flare gas.
Go to Download Page
Email Reference
Document ID:
E2127BAF
The Latest Development On Research Of Ultrasonic Gas Meter In China
Author(s): Yuan Pingfan, He Min, And Duan Jiqin
Abstract/Introduction:
Ultrasonic gas meter has gained extensive interest in China because of its measurement performances of high accuracy, wide turn-down ratio, as well as free pressure loss, etc. Through testing, the three subjects of research, promotion, and standardization have been formed, and they have achieved new development. In China, at Chengdu Verification Branch (CVB) for Natural Gas Flow rate of National Crude Oil Large Flow rate Measurement Station, tests on 21 ultrasonic gas meters of different types which produced by different manufacturers in different countries have been conducted against the Secondary Standard Facility, the Venturi Nozzle Bank at different pressures, and different locations. The results indicates: (1) for the same meter, the result from comparing with the secondary standard facility in CVB is consistent with the result from comparing with other authoritative measurement facilities in foreign countries (2) Since the deviations of test results are around 0.1%, so the effect of pressure on meter might be ignored (3) Because it shows about 0.5% differences between the result of meter locating at 170D downstream of a out-of plane elbow and the that of meter locating at 10D upstream, therefore, its suggested that flow meter should be wet calibrated (4) the result of simulating path broke-down indicates that the multi-path ultrasonic flow meter can diagnosis itself, and some extent compensation can be made. Meanwhile, with consulting the AGA No. 9 Report, the national standard for ultrasonic gas flow meter has been approved. At present, promotion of ultrasonic gas meter and the study on using mobile ultrasonic gas meter as transfer standard are ongoing.
Go to Download Page
Email Reference
Document ID:
46161679
Performance Evaluation Of Orifice Meter Standards For Selected T-Junction And Elbow Installations
Author(s): Marvin Weiss, Wojciech Studzinski, Joseph Attia
Abstract/Introduction:
The newly revised orifice meter standards API/ANSI-2530 and ISO-5167 introduce significantly modified meter tube lengths for installations without flow conditioners. However, some of the new recommendations were based on a limited set of data. The purpose of this paper is to provide a performance check for those installations where data were sparse or geometry was limited to a certain range of geometrical parameters. The experiments were conducted in a low-pressure air facility with various types of T-junctions, a mitered 90 elbow, and two 45 elbows in-plane with short spacers. A comparison between baseline data and selected installation configurations indicated that the recommended meter run lengths are sufficient for the majority of -ratios, even for geometric configurations which are outside the specified range of the revised standard. In general, the minimum meter run lengths recommended in the new orifice meter standards are not overly conservative.
Go to Download Page
Email Reference
Document ID:
9FF9335F
The Effect Of Diameter Steps In Upstream Pipework On Orifice Plate Discharge Coefficients
Author(s): m J Reader-Harris And W C Brunton
Abstract/Introduction:
The present requirements for the diameter of pipework upstream of orifice plates are very restrictive. According to ISO 5167-1:19911 if there is to be no additional uncertainty there must be no diameter steps in pipework greater than 0.3 per cent at any point within the upstream pipework, till the first fitting is reached. The first fitting could be more than 100D from the orifice plate, where D is the pipe internal diameter. If the pipe size is small it may be necessary to machine the whole upstream length in order to meet this requirement. However, any requirement on steps which is the same at both 2D and 50D from the orifice plate is unlikely to be necessary at both locations. Moreover, it is important to know whether an existing orifice meter could be used in a different installation and what the pipework requirements are for a laboratory calibrating an orifice meter. Previous work has been undertaken by Zedan and Teyssandier2. They installed rings of width 12.7 mm (-inch) and of various internal diameters so that the downstream face of the rings was at a distance 2D upstream of an orifice plate of diameter 50.8 mm (2 inch). Large shifts in discharge coefficient were obtained, as might be expected with steps in pipe diameter so near to the orifice plate. The aim of the work presented here is to examine the effect of steps in pipe diameter at a distance from the orifice plate greater than or equal to 5D.
Go to Download Page
Email Reference
Document ID:
E2585E5F
Universal Slotted Orifice Flow Meter Flow Coefficient Equation For Single And Two Phase Flow
Author(s): G.L. Morrison, K.R. Hall
Abstract/Introduction:
The slotted orifice flow meter has been evaluated in terms of its applicability as a two or multi phase flow meter. The response of the meter to air/water and steam/water mixtures in a horizontal pipe with flow qualities varying from 100% gas to the onset of slugging flow have been measured. A study of the orifice flow equation has shown that the discharge coefficient can be expressed as a function of the Euler number and ratio instead of the Reynolds number, ratio, and pipe diameter. This eliminates the pipe diameter and fluid viscosity from the discharge coefficient calculation resulting in a simplified relationship. Beta ratios of 0.50, 0.467, and 0.43 were considered in a 50.4mm diameter pipe with the results reducing to a common relationship. The use of the slotted orifice plate in two phase and multi phase flow meters is discussed along with the proposal of a multi-phase flow meter consisting of two different ratio slotted orifice plates placed within a fifteen pipe diameter long meter run which requires only the measurement of two pressure differentials to determine the mass flow rate and mixture density.
Go to Download Page
Email Reference
Document ID:
8519CD3A
Real World Applications Using Ultrasonic Meters Where Theyre Not Recommended
Author(s): Gordon Stobie, Klaus Zanker, Winsor Letton
Abstract/Introduction:
After almost a decade of research and development, in 1986 British Gas (BG) licensed Daniel Industries to manufacture gas ultrasonic meters according to their patented technology. The BG experience was that, for pipeline applications, these new meters offered many advantages over existing devices, such as higher turndown, no pressure drop, greater immunity to installation effects, and more. A new era in gas flow measurement was born. By 1990, however, measurement specialists whose realm of interest was farther upstream had begun to take notice of this new technology. Those whose responsibility was fiscal measurement on the production platforms of the North Sea were wondering if these advantages could be brought to bear in environments much closer to where the gas was produced, where space for metering skids was tight, the operating temperature was high, and the gas often contained entrained liquids. These measurement engineers faced daunting problems in measurement on a daily basis. Why does the measurement equipment take up half the space on the platform? Why are we measuring gas flows today that are 20% higher than they were yesterday? (Yes, yes, I know the test separator isnt working perfectly, but thats life offshore, isnt it?) Facing what seemed a never-ending series of issues, these engineers were keen to try new technology which might relieve some of these burdens. It was in this environment that Project UltraFlow was conceived. Project UltraFlow was simply the first attempt to push the application of gas ultrasonic meters beyond the place where experience and standards said they should be used. While their use was taking off in pipeline transmission applications, where documents such as AGA-9, ISO/TR 12765:1997(E), and BS-7965 suggested how the meters should be installed and used, there has never been a definitive work which could be used to describe how to proceed if the application were not so pristine. While this paper is no such definitive work, it will describe how these meters have been used in unconventional ways, and will suggest other ways they might be used to advantage in the future.
Go to Download Page
Email Reference
Document ID:
1FB679AB
Dirty Vs. Clean Ultrasonic Gas Flow Meter Performance
Author(s): John Lansing
Abstract/Introduction:
The use of ultrasonic meters (USMs) for natural gas custody applications during the past few years has increased at a remarkable rate. The growth rate increased after the publication of Measurement Canadas PS-G-E-06 Provisional Ultrasonic Specification Ref 1 and AGA Report No. 9, Measurement of Gas by Multipath Ultrasonic Meters Ref 2 in June of 1998. The many benefits of USMs have been well documented over the past few years Ref 3. With the increased population of USMs in the gas industry, many users are asking more questions about this technology. One of the issues often inquired about is the performance (accuracy) of an ultrasonic meter once the internal surface changes from the original clean calibrated condition. The accuracy of all metering devices is affected when less-than-clean, pipeline quality gas contaminates the inside of the meter, the associated piping and flow conditioner. The impact on an ultrasonic meters performance is generally thought to be less than traditional metering technologies, but little data has been published to date. Dirty versus clean meter comparisons have been conducted in the past on other types of primary meters such as orifice and turbine. As one would expect, a meters accuracy changes when it is subjected to a buildup of pipeline material such as oil, grease and mill scale. Users are now asking for results on USMs when they are subjected to these conditions. This paper discusses how the performance of an ultrasonic flow meter is impacted when it is subjected to dirty natural gas.
Go to Download Page
Email Reference
Document ID:
3F89451D
Effect Of Steps And Roughness On Multi-Path Ultrasonic Meters
Author(s): Umesh Karnik And John Geerligs
Abstract/Introduction:
The effect of upstream steps and pipe roughness on 8inch multi-path meters has been tested at the Didsbury Test Facility. Using natural gas at a pressure of around 5500kPa, the performance of the meters under the test conditions was evaluated in comparison to baseline conditions using the sonic nozzle bank as a reference flow. Flow velocities for these tests ranged from 1.5m/s to 15m/s. Concentric steps were generated with a large -ratio orifice plate resulting in steps of 1mm and 3mm dam (step) height at the flange between meter and upstream spool. For the eccentric step, an eccentric, large -ratio, orifice plate was used to generate a 2mm and 6mm eccentricity at the flange between meter and upstream spool. The flow was allowed to develop for 40D following a NOVA flow conditioner. For the roughness tests, several spools, 10D in length, were used just upstream of the meter, with measured equivalent sand grain roughness (e) varying from 80in. to 5600in. Corresponding estimates for n in the velocity power law were in the range 10.6 n 7.4. It was found that e was around 4 to 12 times greater than Ra, depending on the type of the roughness. Within an uncertainty of 0.2%, the present results show that the meter is not affected by an upstream spool piece roughness (Ra/D) of up to 0.0000625. Similarly, concentric and eccentric steps at the meter flange of up to 1% of the pipe diameter do not affect meter performance.
Go to Download Page
Email Reference
Document ID:
239C0DD2
Euler Number Based Orifice Discharge Coefficient Relationship
Author(s): Gerald L. Morrison
Abstract/Introduction:
The equations used to calculate the discharge coefficient for an orifice flow meter are complex and dependent upon the Reynolds number, pipe diameter, and orifice diameter. The general equation for the mass flow rate calculation given the discharge coefficient for an orifice flow meter is presented below:
Go to Download Page
Email Reference
Document ID:
5D1CA5C4
Ultrasonic Clamp-On Flow Measurement Of Natural Gas, Steam And Compressed Air
Author(s): Xiaolei Shirley Ao, Jed Matson, Peter Kucmas, Oleg Khrakovsky And Xuesong Scott Li
Abstract/Introduction:
Clamp-on metering of flowing liquids has been known since the 1960s, and measurements of natural gas flow using wetted transducers in contact with the gas has been known since the 1970s. The past decade has seen ultrasonic flowmetering technology gaining widespread acceptance in the petrochemical and chemical industry. Until now, a portable flowmeter using clamp-on techniques to measure the flow of industrial gases in steel pipes at low (under 8 bar or 120 psig) to medium pressure has remained elusive. This paper discusses clamp-on ultrasonic gas flow measurement equipment to measure low-pressure (above 4 bar or 60 psig) gas flow in metal pipes. Some laboratory (air and gas mixture) and field (methane) calibration data, and industrial applications for gases, saturated and superheated steam and instrument air will be presented. These are mostly in the P range of 4 bar and higher, for steel pipe diameters in the range 3-inch to 30-inch (75 to 750 mm), and bi-directional flow velocities up to 135 ft/s (40 m/s).
Go to Download Page
Email Reference
Document ID:
91165BF4
The Effect Of In-Service Velocity Profiles On Flow Measurement Systems Of Several Types
Author(s): Herb Estrada
Abstract/Introduction:
There are over 25 flow measurement systems of the chordal ultrasonic transit time type currently in service in nuclear plant feedwater systems. These systems base their flow measurements on the numerical integration of the fluid velocities projected onto 4 parallel chords that are located in accordance with the requirements of K.F. Gauss numerical integration method. The data collected by chordal meters provide not only a flow measurement but also quantitative data on the axial velocity profile and the swirl present at the meter location. Some of these chordal systems are equipped with velocity profile alarms, to alert a user to potentially significant changes in the flow field. Several recent alarms on changes in profile led to a comprehensive survey of the hydraulic configurations and operating data for 18 of these chordal systems. The data from these systems show that dynamic changes in profile are common. The survey data also indicate that profiles in locations complying with commonly accepted guidance on the installation of flow measurement systems do not conform to conventional expectations. Specifically, 10 to 15 diameters downstream of a bend, the profiles are often flatter than are those for fully developed flow in smooth pipe. Additionally, a swirl having a tangential velocity in the order of 10% of the axial velocity is often present at these locations, even though an additional distance of more than 10 diameters separates the closest non-planar feature from the upstream bend. Although the shapes of the velocity profiles may differ from conventional expectations and although they are dynamic in nature, experimental data and semi-empirical analyses demonstrate that the errors in 4 chord transit time systems produced by these effects are small-less than 0.1%. The character and variability of the velocity profiles imply more significant uncertainties for externally mounted ultrasonic systems. Because these systems are constrained by Snells Law to operate on diametral paths, their calibrations are determined by the relationship between the axial fluid velocity projected onto the diametral path and the axial velocity averaged over the pipe cross section. Since the profiles are often flatter those for fully developed flow in smooth pipe, an incorrectly assumed profile can lead to an error of 1% or more. Furthermore, the variability of the profiles can lead to time-varying calibration errors the data suggest these errors are in the 0.7% range. The presence of a large and varying swirl at locations far distant from the hydraulic features that produced it can cause significant errors in nozzle-based flow measurements. The data suggest that nozzles without flow straighteners can experience errors in the 0.7% to 2% range, depending on the beta ratio of the nozzle.
Go to Download Page
Email Reference
Document ID:
3590CE30
Performance Evaluation And Field Application Of Clamp-On Ultrasonic Cross-Correlation Flow Meter, Crossflowtm
Author(s): Yuri Gurevich, Armando Lopez, Vahid Askari, Vahid Safavi-Ardibili,David Zobin
Abstract/Introduction:
The ultrasonic cross-correlation flow meter CROSSFLOWTM is a totally non-intrusive device, which has a demonstrated accuracy of better than 0.5% and has been used successfully for measuring flows at high temperatures in nuclear power plants. It remains the only ultrasonic flow meter based on the cross-correlation principle. Although cross-correlation flow measurement technology was first proposed over twenty years ago 1-2, it is still considered a less established and a less accurate method for measuring single phase flows than the more conventional transit time approach. The reluctance to accept advances made in the development of the cross-correlation meter is primarily due to the fact that the theory behind the meter operation involves understanding of the turbulence in fluid flow, unlike a more transparent transit-time approach. However, theoretical and experimental work carried out over the past several years resulted in the derivation of the meter equations and in their validation for various measurement conditions. In addition, because of large amount of data processing required only relatively recently advances in personal computer technology and in data acquisition hardware and software allowed production of a digital meter with real-time on-line data collection capabilities. The purpose of this paper is to summarize results of meter verification in different laboratories, to compare performance of the meter with typical transit time meters and to present example of a typical field application. The remainder of the paper is organized as follows. Section 2 summarizes the physical principles of the operation of the cross-correlation flow meter. Section 3 describes results of laboratory measurements that provide verification of the technology. Finally, Section 4 deals with field application of the CROSSFLOW.
Go to Download Page
Email Reference
Document ID:
0800DE73
Flowmeter Dynamic Response Characteristics Part 1: Quantifying Dynamic Response
Author(s): David Wiklund, Marcos Peluso, Rosemount, Inc.
Abstract/Introduction:
A common method for selecting a flowmeter is to compare how the devices under consideration perform using a specified set of metrics. Perhaps the most universally employed metric is the uncertainty in the measurement of the flow rate. The measurement uncertainty of a flowmeter is an easily understood parameter and is usually specified by manufacturers. Moreover, the uncertainty is relatively straightforward to verify in the laboratory under conditions in which the flow profile is controlled and the flow rate is steady. A more meaningful comparison of the devices can be made if their response to flow transients is included as a metric. Such a comparison is complicated by incomplete and sometimes incorrect specification of the dynamic response characteristics of flowmeters. The purpose of this paper is to describe a method for determining the dynamic response performance characteristics of flowmeters and quantify these characteristics for a number of different flowmeter technologies.
Go to Download Page
Email Reference
Document ID:
C5023856
Flowmeter Dynamic Response Characteristics Part 1: Quantifying Dynamic Response
Author(s): David Wiklund, Marcos Peluso, Rosemount, Inc.
Abstract/Introduction:
A common method for selecting a flowmeter is to compare how the devices under consideration perform using a specified set of metrics. Perhaps the most universally employed metric is the uncertainty in the measurement of the flow rate. The measurement uncertainty of a flowmeter is an easily understood parameter and is usually specified by manufacturers. Moreover, the uncertainty is relatively straightforward to verify in the laboratory under conditions in which the flow profile is controlled and the flow rate is steady. A more meaningful comparison of the devices can be made if their response to flow transients is included as a metric. Such a comparison is complicated by incomplete and sometimes incorrect specification of the dynamic response characteristics of flowmeters. The purpose of this paper is to describe a method for determining the dynamic response performance characteristics of flowmeters and quantify these characteristics for a number of different flowmeter technologies.
Go to Download Page
Email Reference
Document ID:
51E65DDC
Dynamic Measurement Of Volumes In Hydrocarbons Pipelines
Author(s): Luc Catherine
Abstract/Introduction:
TRAPIL owns and operates the first ever built and major network of multiproducts pipelines in Europe. To comply with the highest standards in terms of security of operations and of dynamic measurements of volumes for custody transfer, TRAPIL has implemented original and high metrological quality measuring systems to determine volumes of hydrocarbons carried by pipelines in the respect of international standards and local regulations. These objectives have been reached in a close work and confidence between manufacturers, french legal metrological services and TRAPIL.
Go to Download Page
Email Reference
Document ID:
AB7EB841
The Advantages Of Venturi Nozzles Working At Critical Flow In Metrology Of Gas Flow Under Pressure And Application To Gas Metering
Author(s): F Vulovic, J.P. Vallet
Abstract/Introduction:
This communication presents the experience feedback of Gaz de France and of CESAME LNE Ouest on the use of venturi nozzles working at critical flow (or sonic nozzles) as transfer standards for the flow metering of gases under pressure, in addition to the recent developments effected on this type of standard. The means of calibration implemented in each laboratory for connecting the sonic nozzles are described, as are the secondary benches on which the regulatory gas meter tests are performed.
Go to Download Page
Email Reference
Document ID:
8293D4E5
Development Of Mfc Calibrator With Sonic Venturi Nozzle
Author(s): Masao Hayakawa,Takeshi Yakuwa
Abstract/Introduction:
Thermal type Mass Flow Controllers (MFCs) are frequently used to measure or control small mass flow rate of gases in many fields, especially in the semiconductor field. However, the flow values measured or controlled by MFCs vary from device to device. The Hirai Company developed The MR100 series - mass flow meters which can calibrate an MFC directly, and are traceable to the National Standard. The MR100 series is composed of a sensor unit with an ISO- type sonic Venturi nozzle and a display unit. There are various kinds of sensor units for different kinds of gases or flow rates, and the sensor unit and display units can be interchanged freely. The MR100 series measures a mass flow with the expanded uncertainty (expanded factor: k2) of less than 0.3%. If these new MFC calibrators are introduced to the calibration facilities of MFC manufacturers, the reliability of the MFC calibration will be improved.
Go to Download Page
Email Reference
Document ID:
F6F6E439
Proposal Of Fluid Dynamical Standard Fds() For Gas Flow-Rate
Author(s): Masahiro Ishibashi
Abstract/Introduction:
There is no exception, when establishing a flow-rate standard, to employ a mass or volume measurement together with a time measurement to follow its definition exactly. Of course, the gas flow-rate standard is involuved in the same situation, but it has a uniqueness that the values established by the primary standards are transferred to the next levels via critical flow Venturi nozzles (CFVNs) in almost all cases. Therefore, CFVNs are practically controlling the qualities of almost all gas flow-rate measurements in the fields. Based on experiences at NRLM (now re-organized as AIST) on CFVNs for more than a decade, the author proposes here a new gas flow-rate standard system, which is flowing from CFVNs themselves. In this new system, the quantity flow-rate is calculated from one of the most important parameter of the flow itself, that is, flow velocity. Therefore, the quantity gas flow-rate will have escaped from being derived from basic units far from the nature of flow. The new standard will be named as Fluid Dynamical Standard (FDS), since the quantity is derived from the fluid dynamics.
Go to Download Page
Email Reference
Document ID:
D024B93F
Uncertainty Analysis Of A High-Speed Dry Piston Flow Prover
Author(s): Harvey Padden
Abstract/Introduction:
This paper discusses a novel high-speed piston prover that uses a clearance seal to achieve very low uncertainties. We will review the instruments design and provide an uncertainty analysis for three sizes of our internal reference provers, designed for flows of 10 ml/min to 50 L/min. Their expanded single-reading uncertainties at 2X coverage range from 0.064% to 0.073%. The instrument also has the capability to average a number of readings, potentially reducing the above uncertainties by a significant amount. Traditional constant-displacement piston provers utilize mercury piston seals and low piston velocities. They have long been used as primary calibration devices for gases at low flow rates. Our design is based on our DryCal production design and it eliminates the seal. The attraction of such a device is its combination of primary (dimensionally-based) flow measurement, simplicity and high speed and small size. However, this instrument has unique uncertainty sources that must be analyzed and controlled. Uncertainty considerations for such a device include (among others) piston leakage, precise characterization of measured volume and the dynamics of a high-velocity underdamped free piston. Fortunately, the high speed of the device and the availability of a stable flow source allow sufficient data for a Type A analysis of the most significant uncertainties (75% to 88% of total u2).
Go to Download Page
Email Reference
Document ID:
6C67A39B
Dynamical Effects In Expanding Volume Flow Calibrators
Author(s): Thomas O. Maginnis
Abstract/Introduction:
Standard flow calibrators using the constant pressure expanding volume method employ a circular cylinder as the collection volume, with the volume expansion occurring parallel to the axis. The volume of gas collected in a given time is related to the measured axial displacement through a meter Kfactor, (with dimensions of volume per unit axial displacement), that corresponds geometrically to the average interior cross-sectional area of the cylinder. These instruments as used rarely take advantage of the displacement flexibility arising from the translational symmetry, but typically operate between geometrically fixed start and stop points. It is usually assumed that the motion occurs with constant velocity between these points, i.e. that any startup transients rapidly die out. Any residual acceleration of the movable mass that seals the collected gas in this range will degrade the desired uniform linear expansion of the collection volume at constant flow and limit accuracy. A simple dynamical analysis shows that such systems are vulnerable to sustained oscillation in the absence of adequate damping.
Go to Download Page
Email Reference
Document ID:
5E62DD96
A Test Certificate On The Impact Of Piping And Flow Dynamic Effects On Flowmeter Accuracy In Gas And Liquid Flows
Author(s): E. Van Bokhorst, M.C.A.M. Peters
Abstract/Introduction:
Each commercially available flowmeter is normally provided with a calibration certificate. This certificate is based on stationary flow conditions and does not include any flow dynamic effects. Well-known installation dynamic effects like flow pulsations, valve noise and mechanical pipe vibrations can have a considerable impact on flowmeter accuracy in gas as well as in liquid flows. Several investigations have been published in the past on the impact of flow dynamic effects on differential pressure, turbine, and vortex and Coriolis flowmeters 1,2,3,4. Recent publications indicate that ultrasonic flowmeters may also be influenced by low-frequency pulsations 5. Further ultrasonic noise of control valves is well known as a potential source of errors on this type of flowmeter. The impact of mechanical pipe vibrations on vortex and Coriolis flowmeters can result in large errors if vibrations occur in the operating range of the flowmeter. Investigations on several commercially available flowmeters of this type have reported these phenomena for vortex and coriolis flow meters International standards like ISO, AGA and API available for several flowmeters sometimes refer to flow and piping dynamic effects like flow pulsations, transients or pipe vibrations, though they do not specify allowable amplitudes or frequencies.
Go to Download Page
Email Reference
Document ID:
4F947580
CFD Simulation Of Three Double-Elbow Pipe Flows
Author(s): Cheng-Tsair Yang, Jian-Yuan Chen, Jiunn-Haur Shaw
Abstract/Introduction:
Flow structures are essential information in studying flowmeter installation effects. Experiments by LDV and PIV are frequently adopted to measure velocity profiles. Nevertheless, the measurements by use of those sophisticated facilities consume too much resource and time. Computational fluid dynamics (CFD) provides an alternative of investigating pipe flow structure and its influences on flowmeter performance. After testifying the reliability of the CFD scheme, we simulated the flows in three piping configurations--a U-type in-plane pipeline, an S-type in-plane pipeline, and a 90 out-of-plane pipeline. Flow fields with an Etoile flow straightener were also simulated subsequently. The simulated flow fields agreed well with the measured data by LDV, indicating the applicability of the two codes. By comparing the flows to those with and without an Etoile flow straightener, we concluded that the straightener suppressed the swirl effectively but postponed the flow to a fully developed condition as described by many experiments from different laboratories.
Go to Download Page
Email Reference
Document ID:
88B19831
Software Tools To Simplify The Application Of Probabilistic Uncertainty Methods Monte( Carlo Simulation)
Author(s): Martin Basil,Donald Sutherland
Abstract/Introduction:
The paper describes a software system that simplifies the propagation of uncertainty using the Monte Carlo Simulation (MCS) technique. This is used to model oil and gas measurement, processing and allocation systems to find the financial exposure of the allocation. These uncertainty methods are also well suited to recent proposals for Uncertainty Based Allocation (UBA). Fluid flow is invariably derived from a functional relationship between a number of measurements and this must be taken into account when analyzing flow measurement uncertainty. These complex relationships are often further compounded when the results are cascaded into another system such as a oil or gas pipeline allocation system. Determining the uncertainty of these systems is problematic with conventional Root Sum Square (RSS) uncertainty methods. The MCS uncertainty methods described here provide a reliable systematic method of determining allocation uncertainty.
Go to Download Page
Email Reference
Document ID:
8F82B6D6
Uncertainty Analysis Of A Volumetric Primary Standard
Author(s): Thomas Kegel
Abstract/Introduction:
In 1969 CEESI began operation of a volumetric primary calibration system for use with compressible fluids. Efforts are underway to expand the existing uncertainty analysis based on new data and a review of the original results. Four issues involved with that uncertainty analysis are discussed in some detail in this paper. The first consists of a more rigorous analysis of the original volume determination process. Second, the newest dry air equation of state is applied to the limited pressure and temperature range. The third subject is a model of the diverter valve used to begin and end the calibration process. Finally, the unique aspects of propagating uncertainty components associated with density are considered.
Go to Download Page
Email Reference
Document ID:
8B3E784D
Custody Transfer Metering In The Liberalised European Market
Author(s): Dr. Klaus Altfeld
Abstract/Introduction:
Over recent years, gas trading in Europe has undergone significant quantitative and structural change. This is particularly evident when one compares the integrated European gas transmission pipeline network of 1970 with that of 2000 (Figures 1 & 2) and looks at the development of natural gas consumption in western Europe (Figure 3). While the gas industries of the early 1970s served mainly home markets, with little or no trade across borders, todays industry shows a marked Europeanisation. Prominent signs of European integration in the gas industry include the Interconnector between the UK and Belgium, the link between North Africa and Italy, the pipelines connecting the Nordic countries Denmark and Sweden to the integrated European network and the Spanish / Portuguese pipeline from Cordoba to Lisbon. The internationalisation of gas trade is closely entwined with developments in gas measurement because the commodity natural gas is being traded in ever growing quantities, with energy measurement becoming more and more accurate. Improvements in this field are not only due to more sophisticated technologies (ultrasonic gas meters, process gas chromatographs etc.) and fundamental studies (S-GERG equation etc.), but are also the result of international cooperation, harmonisation and the establishment of common codes and standards. This paper describes the development of techniques currently used to measure large natural gas flows at newly built stations and the procedures employed for meter verification and calibration. New developments in the measurement of gas property variables (particularly the superior calorific value) are also described and discussed.
Go to Download Page
Email Reference
Document ID:
7AAEDCC2
Traceability And Uncertainty Of The German National Flow Rate Measurement Standard Pigsar
Author(s): Wolfram Bremser, Werner Hasselbarth, Uwe Hirlehei, Hans-Jrgen Hotze, And Gudrun Wendt
Abstract/Introduction:
The high-pressure gas flow meter test facility pigsar operated by Ruhrgas AG serves for testing and calibration of turbine-wheel and ultrasonic meters for natural gas in the pressure range between 14 and 50 bar and flow rates ranging from 8 to 6500 m3/h. Pigsar is the national standard of high-pressure natural gas flow. It represents and disseminates the unified German-Dutch reference value for the unit of volume for high-pressure natural gas. The uncertainty analysis of the test facility presented here was one of the main pre-requisites for the creation of the harmonised reference value.
Go to Download Page
Email Reference
Document ID:
FD9AF7A4
Uncertainty Analysis Of A Large Scale Calibration Facility
Author(s): Thomas Kegel
Abstract/Introduction:
In March of 1999 CEESI completed construction of a natural gas calibration facility located in Clear Lake, Iowa. The facility is designed for the calibration of large (up to 30?, 760 mm) high pressure (1200 psi, 830 bar) natural gas meters. The facility has three test sections, 20? (508 mm), 24? (610 mm), and 30? (760 mm) in diameter. The flow to a test section is measured with an array of ten 12? (472 mm) turbine meters. A broad range of flowrates can be achieved by flowing simultaneously through multiple meters. Efforts are underway to expand upon the uncertainty analysis performed when the facility was built, this paper discusses a number of issues associated with that effort. The discussion begins with a review of the initial calibration of the flow standards. The discussion continues with three programs designed to maintain traceability and reduce uncertainty. The first is statistical process control based on ultrasonic meter check standards. A new program, turbine swap testing, is described and preliminary results are presented. The third involves applying statistical process control techniques to pressure and temperature measurement. The discussion concludes by proposing a unique approach to propagating uncertainty components.
Go to Download Page
Email Reference
Document ID:
2244F6AB
Electromagnetic Flowmeters Of The Large Diameter And Their Dry Graduation
Author(s): Velt I.D.,Yanzuo Sun,Lianke Li
Abstract/Introduction:
To measure the water flow and /or the heat supply in the large size pipeline electromagnetic flow meter with three inserted electromagnetic local velocity sensors is recommended. The necessity of the design, the principle of operation, the features and the advantages of this flow meter are described in this paper. The flow sensors and this kind of flow meter can be calibrated by simulation method without stopping water flow in the pipeline. The practical application and experiments have shown that the solution for the problem of water flow measurement in the pipeline with large diameter (400 to 4000 mm) is very successful. In this paper the theory and the practice of this flow meter, its dry calibration technique and influence factors are reported and analyzed in detail. More and more accurate and reliable means for water flow measurement in the large size pipes are required to solve problems in environmental protection and to improve large power plants, heat objects and irrigation systems. This task is related to water flow measurement in pipes with diameters from 500 up to 3000 mm and even larger. The volumetric flow rate is ranging from 1,0 up to 50m3/s. The presence of sand, silt and waterweeds in the water is possible. The water velocity does not exceed 1.5-3.5 m/s. The pipelines are located as a rule under ground. The access for installation of flow meters is usually possible in the place most inconvenient for measurements: on the outlet of a pump and downstream of a bend or on the pipeline downstream of a valve which is located underground in a well. In these places the velocity distribution of flow is asymmetric, that essentially complicates conditions of measurements.
Go to Download Page
Email Reference
Document ID:
BAF34B1A
Experimental Wet Gas Data For A Herschel Style Venturi
Author(s): Charles Britton, Walt Seidl, Josh Kinney
Abstract/Introduction:
A facility description is given of a test loop that flows both hydrocarbon gases and hydrocarbon liquids. The methodology of measuring the mass rate of flow in both the gas and liquid phases is presented. Experimental data on a 100 mm (4 inch) pipe size, 0.4 Beta, Herschel venturi is presented with varying gas and liquid velocities, liquid load, and gas density. The over-registration of the venturi meter due to the presence of liquids is compared to the results from other investigators.
Go to Download Page
Email Reference
Document ID:
11D04734
Field Performance Of Dual Energy Spectral Gamma Ray / Venturi Multiphase Flowmeters
Author(s): Bertrand Theuveny, Dr. Bruno Pinguet, Dennis Pittman, Gerard Segeral, And Birger Velle Hanssen
Abstract/Introduction:
Dual energy spectral gamma ray - venturi multiphase flow meters have evolved significantly over the last five years. Improvements have been achieved in the meters reliability and metrological performance. The experience gathered during the deployment of the spectral gamma ray detectors has enabled recent engineering developments to achieve superior stability and resolution. We have quantified the need for metrological performance in permanent installations, and present the consequences of the lack of long-term stability and resolution of various nuclear detectors. The effect of these factors is also illustrated on the flowrate computations. A specific nuclear detector has been developed for the multiphase flowmetering applications and its stability and resolution performance is illustrated. The forty-year experience in design and manufacturing of downhole and spatial nuclear detectors has enabled a rapid development of this new technology. The metrological performance of the dual energy gamma - venturi meters are not merely demonstrated through various flow loop results and field qualification tests, but the summary of the field performance in a mobile well testing application is also shown. Installation recommendations are made and specific commissioning procedures are summarized. The experience gathered during the testing of a large variety of wells and fluids (from dead oil to gas wells) illustrates the field performance reliability of this type of multiphase flowmeter. The overall reliability of such system is quantified. A discussion of the extension of this technology to higher gas volume fractions (85-100%) shows the potential and limitations to the application of wet gas metering. This is supported by results obtained in the field and in a flow loop.
Go to Download Page
Email Reference
Document ID:
D689EB7D
Development Of An API Recommended Engineering Practice For Use Of Wet-Gas Flowmeters For Subsea Allocation Of Hydrocarbons
Author(s): Thomas Hassold Robert Webb, Winsor Letton
Abstract/Introduction:
A Technical Advisory Group (TAG) has been chartered by the Subsea Equipment Sub-Committee of the Upstream Committee of API to develop a Recommended Engineering Practice (RP) to cover the application of wet-gas meters in subsea developments in the Gulf of Mexico (GoM). This work began in March 2001 and should be completed by the end of the second quarter of 2002. API approval will be sought in mid 2002. This paper discusses various aspects of measurement and meter operation which form the basis of the RP.
Go to Download Page
Email Reference
Document ID:
D412E7A4
Pigsar- The Extended Test Facility And New German National Primary Standard For High Pressure Natural Gas
Author(s): Bodo Mickan, Rainer Kramer, Hans- Jrgen Hotze, Dietrich Dopheide, Ruhrgas Ag
Abstract/Introduction:
PIGSAR? is the National Primary Standard of Germany for high pressure natural gas and is operated by Ruhrgas AG, Germany. Under supervision of the Physikalisch-Technische Bundesanstalt PTB1, PIGSAR? is responsible for maintaining and disseminating the unit of volume for natural gas under high pressure conditions since 12th May 1999. With respect to the contract of PTB and NMi VSL2 (The Netherlands) signed 2nd June 1999 1, the new Dutch-German harmonised reference gas cubic meter were established and has been disseminated since November 1999. The paper describes the extended test facility PIGSAR? and its measuring capabilities. The operation range of the test facility allows to calibrate gas meters in a pressure range of 16 to 50 bar and at flow rates under actual working conditions of 8 to 6500 m3/h in the whole pressure range. With this capabilities PIGSAR? is quite unique in Europe. If compared with other high pressure gas facilities world-wide, PIGSAR offers most appropriate calibration capabilities for industrial use. This will be documented here by a comparison with operation ranges of other test facilities.
Go to Download Page
Email Reference
Document ID:
A5B29D8E
Comparison Test Program Liquid Flow Measurement Final Results Cenam - Ptb - NIST
Author(s): Jose Lara, Dario A. Loza, Heinz Luchsinger
Abstract/Introduction:
This comparison-test program (1997/1998) CENAM - PTB - NIST was in order to assess the Mexican primary standard for liquid flow measurement. This program was initiated by CENAM to establish and maintain satisfactory liquid flow measurement in Mexico. In the future this program could be expanded to the international flow measurement community to include other Latin America laboratories. The estimated uncertainty for CENAMs volumetric flow rate facility is nearly constant over the range of 300 L/min to 2 100 L/min ( 0,12 % with a coverage factor k2). We expected that the results differences among NIST, PTB and CENAM were inside CENAMs uncertainty limits, however the test results from the first phase of the comparison denoted that K factor differences were bigger than the ones we expected. The three national laboratories use the gravimetric technique. The test results of this comparison program are presented graphically.
Go to Download Page
Email Reference
Document ID:
5C3EB16C
Intra-Comparison Of A Water Flow Calibration System Using The New NEL Twin-Orifice Transfer Assembly
Author(s): Dr. Lung-Hen Chow
Abstract/Introduction:
The laboratory shall have quality control procedures for monitoring the validity of tests and calibrations undertaken as to ISO/IEC 17025:2000. Participation in interlaboratory comparison or proficiency-testing programs is a part of the aforementioned monitoring, which shall be planned and reviewed to assure the quality of test and calibration results. In Feb./Mar. 2001 our water flow calibration facility representing the national water flow measurement standard (Center for Measurement Standards/ITRI) in Taiwan finished another intercomparison between water facilities using the new NEL 200 mm transfer standard with Perforated plate flow conditioner. This intercomparison was approved by Euromet as the international comparison project 574, which was initiated by NEL/UK, proposed calibrations starting from KRISS/Korea in Sept. 2000, then ITRI, SIPAI/China, NEL, IPT/Brazil, finally back to NEL in Sept./Oct. 2001. Later at the CIPM/BIPM KC activities arrangement meeting of fluid flow measurement sector (Istanbul, April 2001), CENAM/Mexico was announced to join this round of comparison testing as an additional participating laboratory. The flow range of our water system in service using gravimetric method covers from (12 to 480) m3/h with pipe size of (50 to 250) mm and we have been keeping recalibration of retained reference flowmeters in long/short-term periods as the Chapter 5.9 of ISO 17025 address.
Go to Download Page
Email Reference
Document ID:
D4B89E44
Improved Flow Measurement By Application Of Signal Analysis Tools, Now Available
Author(s): M.C.A.M. Peters, F.M. Braal, F.J.P. Verhelst
Abstract/Introduction:
Flow measurement devices are impacted by flow disturbances such as piping vibrations, flow pulsations, cavitating flow, swirl and other velocity profile distortions. These effects can significantly reduce the accuracy of flow measurement or the flow signal can even be lost for some types of flow devices. Examples are ultrasonic flow meters in a noisy environment, e.g. caused by leaking valves, or vortex flow meters in a pulsating flow or a vibrating environment. In earlier research projects it has been shown 1,2,3, that flow disturbances can have a measurable effect on the sensor signal and that application of signal analysis may help to detect and correct for these disturbances. In particular in vortex flow meters, ultrasonic, electromagnetic and Coriolis meters the application of signal analysis improves the performance of the meter The main aim of applying signal analysis tools in flow meters is to improve the accuracy of the flow meter under non-ideal flow conditions 4. However, a second application is the identification of the cause of the flow distortion, such as pumps or compressors, valves or related process instrumentation or unwanted installation conditions. This may lead to applications where the flow meter assists in monitoring the condition of process equipment and installations, without loss of performance.
Go to Download Page
Email Reference
Document ID:
C6F41C57
Flowmeter Manufacture: Some Observations On Variation And Robustness
Author(s): Roger C Baker And Michael J Gregory
Abstract/Introduction:
The quality of an instrument, and thus its ultimate accuracy will be affected by the nature of the manufacturing process. In this paper, which provides a progress report, we review reported work on variation in flowmeter manufacture, and we look at cases where small variation appears to be possible in the production process. The concept of robustness is that the design reduces the effect of variation in manufacture and application. Much work has been done over the past 20 years or more to identify the effect of application. In this context we look at the implications of some of the work. In developing an instrument it is important to avoid embedded items that cannot be fully tested until the instrument is complete, and may, at that stage, call for the finished product to be rejected. It is, therefore, important to estimate the impact of product tolerances on the performance of the instrument. Calibration is a major part of the manufacturing process, and reducing the time and cost should reduce the meter cost. Design changes may reduce the need for calibration. Changed manufacturing tolerances, alternative calibration techniques, or digital signal processing, may offer alternatives. The manufacturing process will be influenced by the tendency for software to replace hardware in new instrument design, which may, in turn, allow simplification of the components, and tuning out of variation. Manufacturers use of CD-ROMs as part of the communication with the customer may give way to e-mail links for feedback on products. In conclusion we comment on the implications for quality following from the control of variation.
Go to Download Page
Email Reference
Document ID:
F0A007A5
Recent And Likely Developments In Flow Measurement
Author(s): Roger C Baker
Abstract/Introduction:
This paper attempts to summarise the considerable published work in flow measurement that has taken place over the past five or so years. The author has reviewed the literature5 and brought together over 200 references. This task was to bring up to date the work in his Flow Measurement Handbook4. A large number of papers have been included, but many others have been missed, or omitted to keep the review within a reasonable length. In this paper an attempt is made to identify the most important trends in that period. The dominant factors are identified: management aspects such as application, cost of ownership, audit and maintenance developments in meter design, and the dominance of three: the electromagnetic, ultrasonic and Coriolis meters for wet gas and multiphase flows industrial developments market and manufacture. In conclusion the paper suggests likely future trends: New types of flowmeter are likely to appear to complement the 100+ types already on offer, and manufacturers will attempt to offer a range for all applications. Multiphase flowmeters will continue to be developed for component flow rates, wet gas, and water-in-oil. Computational Fluid Dynamics (CFD) solutions might be capable of replacing rig testing in the near future. Previously insoluble applications problems are now within the scope of new materials. Modern developments in sensors and in signal processing may call for a review of existing meter designs. The power of digital methods to analyse signals is likely to affect meters increasingly, not least multiphase meters. Information technology will affect all stages from initial interpretation of the signal, through bus systems and interface to computers. It will also influence the modelling of the metered networks. Taking the whole manufacturing process from identification of product, through design to marketing, sales and product maintenance, we are likely to see much greater attention to reducing variation and waste, and increasing quality, over the next 10 years.
Go to Download Page
Email Reference
Document ID:
35F392C4
High Performance Flow Conditioners Bring Unparalleled Accuracy To Metering Stations
Author(s): James E. Gallagher
Abstract/Introduction:
By including flow conditioning in their latest metering station design standards, the American Petroleum Institute (API), American gas Association (AGA), and International Standards Organization (ISO) have recognized this as a technology that helps to insure previously unattainable flow measurement accuracy. Recent developments in the field of High Performance Flow Conditioner technology have created a paradigm shift in both the design and the application of natural gas custody transfer metering stations. Whether Orifice, Turbine, or Ultrasonic flowmeter applications, High Performance Flow Conditioners have brought increased accuracy and simplified installations to the industry at large. This paper discusses the High Performance Flow Conditioner technology, its application, and recent calibration results from a number of calibration facilities in North America. In addition, the paper will discuss the integration of a High Performance Flow Conditioner with an Acoustic Filter element that doubles as an Anti-Swirl device.
Go to Download Page
Email Reference
Document ID:
74999299
Ldv Calibrator For The Air Speed Standard Between 1.3 To 40 M/S
Author(s): Noboru Kurihara, Yoshiya Terao, Masaki Takamoto
Abstract/Introduction:
National Metrology Institute of Japan (NMIJ, formerly NRLM) developed a laser Doppler velocimeter (LDV) calibrator as the primary national standard for air speed between 1.3 and 40 m/s. A schematic of the presented system is shown in Fig.2. The calibrator has a rotor, shown in Fig.3, with single fine wire simulating the tracer particle, and can obtain the calibration factor in the same velocity range as that of the wind tunnel measurement by generating various velocities from the rotation. Newly developed technique enables the diameter measurement of the wire orbit in moving condition resulting in quite small calibration uncertainty. The orbit diameter in movement was measured with an optical linear scale as the distance of a rotor traversing and the influence of wire deformation was minimized. A measurement control volume of tested LDV was used to detect the wire orbit position. The calibration factor of tested LDV decided as a ratio of wire velocity to the average frequency of the Doppler burst signal.
Go to Download Page
Email Reference
Document ID:
9F41900C
Development Of A Servo Pd Oil Flowmeter For A Transfer Standard
Author(s): Takashi Shimada, Yoshiya Terao, Masaki Takamoto, Seigo Ono, Shingo Gomi
Abstract/Introduction:
A new servo PD flowmeter was developed in order to achieve wide rage ability, a long-term stability, and high accuracy in oil flow measurement. At first, the characteristic of the flow inside the flowmeter was investigated through flow visualization by using a transparent flowmter model. Secondary, a servo control system was constructed in order to compensate for mechanical friction and to control the leakage from the clearance. Finally, the performance of the new servo flowmeter was investigated for several kinds of oil. These results show that the error of the flowrate is better than 0.2 % over 1:10 of flow range. This newly developed servo PD has been selected as a transfer standard for a new calibration facility for hydrocarbon flow at NMIJ. These flowmeters in 50, 100, and 150 mm diameter are used at the flowrate range between 3 to 30, 7.5 to 75, and 30 to 300 m3/h, respectively.
Go to Download Page
Email Reference
Document ID:
9BC5B603
Doppler Global Velocimetry Dgv() For Flow Metrology At Ptb
Author(s): Harald Mller, Thomas Lehmacher, Volker Strunck, Dietrich Dopheide
Abstract/Introduction:
DGV is presented as an optical whole filed acquisition technique for the measurement of three dimensional velocity vector fields in pipes. The aim is to show that DGV, which has originally been used as whole field technique for high flow velocities in wind tunnels, is also a promising technique for lower flow velocities up to 30 m/s for flow metrology in pipe configurations. The described facility at PTB can be used for the investigation of installation effects on flow meters to reduce the error shift of gas meters as well as for first flow rate measurements based upon the definition of the volume flow rate independently on velocity field perturbations.
Go to Download Page
Email Reference
Document ID:
560B4A29
Field Experience In The Calibration Of Piston Provers
Author(s): Noemi Christina Hernandez, Valmir Ruis And Marcos Tadeu Pereira
Abstract/Introduction:
Custody transfer of liquid petroleum fluids is an important issue in the commercial relations inter companies, and the keystone subject is the metering station. Small errors could be responsible for enormous amounts of money transferred not correctly from sellers to buyers or vice-versa, and for this reason there is a permanent need for calibration, adjust and evaluation of the measurement quality of all custody transfer stations. In Brazil, which produces around 1 million barrels per day, an error of 0.2% in the fiscal metering (only the first metering) represents approximately US 20 millions per year. Unfortunately the actual figure of uncertainty is much higher than this. In almost all the custody transfer stations in Brazil ballistic or compact provers are used in the verification and calibration of the flow meters responsible for the measurement of liquid volume. These flow meters are normally turbine meters or positive displacement meters. The role of the provers is therefore crucial in the measurement chain, and it is necessary to know their error and uncertainty within stiff limits.
Go to Download Page
Email Reference
Document ID:
E4AFC67F
Calibration Of Volume Standards For Flow Rates Of Hot Water Up To 120 m/h At Temperatures Up To 180 C
Author(s): J.-F. March
Abstract/Introduction:
Heat district suppliers demand carefully constructed and calibrated flow sensors of heat meters at temperatures above 100 C. For this reason a test facility for hot water flows had been installed at PTB generating volume flow rates up to 120 m/h at temperatures up to 180 C. The fundamental mass-time method (gravimetric standard method 1) is available only below 80 C because of the losses in mass due to evaporation. Above this temperature only closed test facilities operating under pressure are therefore suited. Because of the large technical difficulties encountered at high temperatures a test facility using the gravimetric standard method is not yet available. For the determination of the flow rates above 100 C in such test facilities, neither primary nor calibrated reference flow rate standards are known up to now. The aim of this work was to calibrate a secondary volume standard, serving in the PTB hot water test facility for the determination of the volume with a relative uncertainty of less than 0.2 % in the temperature range between 20 C and 180 C and at the flow rates between 50 m/h and 120 m/h. The relative uncertainty of 0.2 % is the upper limit according to DIN EN 1434 2 for the volume uncertainty of test facilities for class 2 heat meters. Numerous investigations of flow meters have shown that the 4 AOT 1) turbine flow meters have the best measuring performance. The relative uncertainties concerning volume measurements with these flow meters, proved in a test facility with the mass-time method in the temperature range from 20 C to 80 C and at flow rates between 50 m/h and 180 m/h amount to less than 0.1 % 3. It will be shown, that the aim of calibrating an AOT flow meter, called AOT #1, as a secondary standard had been reached at temperatures above 80 C by determining the relative variations of the calibration factors using a laser Doppler velocimeter (LDV) combined with a novel one-point relative method discussed in detail in 4.
Go to Download Page
Email Reference
Document ID:
5DF5BD07
Dynamic Weighing - Improvements In Gravimetric Liquid Flowmeter Calibration
Author(s): Dr. Rainer Engel
Abstract/Introduction:
In fabricating flowmeters, the meters calibration is its final and accuracy determining step that comprises a great time consumption relative to its completion from its single component parts. Thus calibration (unless the respective time of calibration for a flow meter is not minimized) may represent a relevant contribution to fabrication costs. High-accuracy liquid flow calibration facilities are generally based upon static weighing gravimetric systems with flying start and finish. Even due to the fact that industrial liquid flow calibration facilities are successfully utilizing dynamic weighing, they still are being estimated to be less accurate than static weighing calibration systems. In international standards, static weighing has been preferred instead of dynamic weighing due to its estimated higher accuracy. This estimation has been based upon a rough mechanical model of an one-beam scale. The state of the art in the field of dynamic weighing liquid flow calibration, charging from the international standards, is still being represented by a theoretical foundation dating back about 40 years (1).
Go to Download Page
Email Reference
Document ID:
FAECF1F8
On-Line Telecalibration Between German National Primary High-Pressure Natural Gas Standard Pigsar And 5th Isffm In Washington
Author(s): Rainer Kramer, Hans-Jrgen Hotze, Bodo Mickan, Dietrich Dopheide Physikalisch Technische- Bundesanstalt Ptb And National Lab Pigsar
Abstract/Introduction:
During the symposium PTB and pigsar, the national standard for natural gas at high pressure demonstrated their telecalibration capabilities of gas meters on-line. The presentation included a direct TV- connection to pigsar in order to get an impression on the calibration activities in pigsar (Germany) and at a second visualisation showing different software screens necessary to explain the process of calibration and supervision of a gas meter under test. The presented software was the original software used by PTB and national lab pigsar for the daily calibrations and activities since January 2002. After a short introduction to explain the situation and special problems in Germany the software presentation have been started by opening of pigsars control screen. This screen shows a list of all calibration carried out by pigsar after the installation of the software in January 2002.
Go to Download Page
Email Reference
Document ID:
99609B17