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Vikram. Gowda, Tsyh-Tyan Yeh, Pedro I. Espina, Nhlanhla P. Yende
THE NEW NIST WATER FLOW CALIBRATION FACILITY

A static-gravimetric liquid flow calibration facility is under construction at the NIST Gaithersburg Campus. The facility is designed to calibrate flow meters from 25 mm to 400 mm in diameter, at flow rates from 8 L/min to 38,000 L/min. It incorporates a diverter valve design, which greatly reduces the uncertainty associated with the flow diversion into the collection tank. This paper details design and construction novelties of the system and outlines the expected uncertainty budget for the calibration facility.

Tsyh-Tyan Yeh, Nhlanhla P. Yende, Pedro I. Espina
THEORETICAL SELF-ERROR-CANCELLING DIVERTERS FOR LIQUID FLOW CALIBRATION FACALITIES

A design for diverter valves in gravimetric liquid flow calibration facilities is examined. The concept makes use of repeated unidirectional motions of the diverter valve to reduce errors associated with asymmetry in the diverter valve motion and in the liquid jet velocity profile. Various implementation examples are provided and their benefits are discussed. The experimental results, given in a different paper, confirm the good performance of the error free diverter design. This new diverter design has been incorporated in the new NIST calibration facility.

Bert Roos, Milovan Antonijevic
FIELD PROVING BY MICRO MOTION CORIOLIS PROVER MASS MASTER METER METHOD

Coriolis Mass Flow Meters have been used for process optimisation for more than 20 years. Refining, petrochemical, and other process industry for use in automating and optimising production processes have adopted this technology. As companies have gained more confidence and trust in Coriolis technology it was only natural that they began to apply them in fiscal service or custody transfer metering. Coriolis inherent reliability and meter factor stability as well as multi-variable versatility (mass, density, operating volume, and temperature) have helped many users lower life cycle costs and better manage loss control.
Traditionally all LPG measurements have used volume as the basis of measurements. Mass can be a better basis for trade but, until the development of Coriolis mass flowmeters, no universally acceptable Coriolis meter based metering system was generally available. Coriolis mass flowmeters are now increasingly being introduced into custody transfer and fiscal metering duties for many different types of fluid. National regulations will require uncertainties of 0.5 or even 0.1% to meet this change in technology and philosophy. The aim of this article is to provide information to set up standardized proving method and techniques for Coriolis mass flow meters used for LPG custody transfer measurement.
A large community of Coriolis users have begun applying them not only in process but also in regulated custody transfer service of LPG and other hydrocarbons. Coriolis meters are chosen by industry to provide specific measurement solutions and are now used extensively. Their applications overlap with traditional meters and they compete well in price and performance in these areas of overlap. The following article will feature this remarkable metering technology evolution and suggest one build-in on-situ proving technique to be applied. A brief synopsis of this application will follow.

Mark Lee, Aart Pruysen
ISO 17025 ACCREDITATION FOR A STANDING START FINISH (SSF) PRIMARY FLOW STAND AND THE APPLICATION TO USING CORIOLIS FLOWMETERS AS REFERENCE STANDARDS

At FLOMEKO 2000 Micro Motion, Inc. (MMI) reviewed the concept of Transfer Standard Method (TSM) flow stands for the calibration of flow instruments, in particular the uncertainty analysis for calibration of Coriolis meters. This paper is an extension of the topic, discussing in depth the issues involved with ISO 17025 accreditation, maintaining calibrations, and traceability.
The company has chosen to use Coriolis flowmeters as Global Reference Meters (GRM) to maintain the traceability on the TSM stands operating worldwide. To accomplish this ISO 17025 accreditation was successfully sought for the SSF Primary Flow Stand (PFS) that is used to calibrate the GRM’s.
This paper will discuss the experiences associated with accrediting the SSF Primary Flow Stand, the processes involved with creating a GRM, calibrating TSM stands worldwide and the implications to TSM stand uncertainty .This paper includes:
- Review of SSF Primary Flow Stand Uncertainty and Traceability
- Internal Proficiency Testing Methodology
- Practical experiences in attaining ISO 17025 accreditation
- Process for GRM calibrations
- Advantages to using the GRM process

Aart Pruysen
CALIBRATION OF 24 TON WEIGHING SCALE BY CORIOLIS MASS MASTER METER UNCERTAINTY CALCULATION IN LOAD AND IN LOAD DIFFERENCE

At the MicroMotion Flowfacilities (= division of Emerson Process Management) in Veenendaal – the Netherlands, the Coriolis MicroMotion meters are gravimetric calibrated for the European users via the standing start and stop method. These flowfacilities have a “stand uncertainty” (Calibration and Measurement Capability; CMC) of 0.03%.
The biggest scale of this facility, a 24000 kg scale for flowcapacities up till 660 t / h and based on gyroscopic balance, is calibrated since three years via a Coriolis MicroMotion mass master meter. The reason for this method is that placing 3 times 24 * 1 ton weights on the bottom of the tank is a very timely consuming task (2 days); the master meter method is much shorter in time and should hopefully lead to approximately the same uncertainty as performed with weights.
The mass master meter method has a longer traceability chain than calibrating with weights so the question was if it is feasible to get again a CMC of 0.03 % at the final end.
This paper explains the calibration method; latest results (February / March 2003) and, very surprisely, the reasons why the results are better than obtained from calibration with weights.
This paper includes:
- Theory of weighing of liquid
- Introduction of three independent factors for the weighing scale: Weighing scale factor (WSF); Buoyancy Vapour Correction (BVC) and Immersed Pipe Correction (IPC)
- Determination of the uncertainty of scale in load
- Determination of the uncertainty of scale in load-difference, based on an agreed calculation method with NMi-VSL (Dutch National Standards institute)
- Determination of the CMC of a gravimetric flowcalibration facility under operating conditions
- How to minimise CMC for a special case
- Results of this performed procedure
This paper ends with two conclusions:
- Reason why this master meter method gives a smaller uncertainty in relation to the calibration with weights
- There is a need for a well defined, written calculation method when a scale is used from one load to another load (load difference). Is currently very dependent of the involved company (authority) for the assessment.

E. van Bokhorst, M. C. A. M. Peters, F. M. Braal
THE IMPACT OF FLOW DYNAMICS IN THE DESIGN OF FLOW METERS AND METERING STATIONS

Commercially available flowmeters are provided with a calibration certificate, based on stationary flow conditions and do not include the impact of installation effects like swirl, a-symmetry, and piping and flow dynamics. Flow pulsations, valve noise and mechanical pipe vibrations can have a considerable impact on flowmeter accuracy in gas as well as in liquid flows.
International standards like ISO, AGA and API, available for several flowmeter principles, sometimes refer to swirl, flow and piping dynamic effects, though they do not specify allowable amplitudes or frequencies.
Investigations on the impact of piping and flow dynamics on differential pressure, turbine, vortex and Coriolis flowmeters have been published at several occasions. Ultrasonic noise of control valves is well known as a potential source of errors on ultrasonic flowmeters. 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.
Several manufacturers, operating companies and engineering contractors have expressed their interest in developing a well-defined test for this type of applications. An absolute criterion for allowable pulsations or vibrations can hardly be defined as the impact on flowmeters differs for each flow metering principle and/or size. Therefore individual criteria should be developed for each type of flowmeter and its application.
TNO Flow Centre has defined a project proposal to develop a test for flow-dynamic effects on flowmeters for gas and liquid applications and manufacturers and operators are invited to participate.
In addition numerical codes like PULSIM can be applied to investigate the design of a flow metering station with respect to the impact of pulsation sources like vortex shedding at T-joints, compressors and pumps. The layout of the flow metering station or the location of the flowmeter with respect to the pulsation source is optimised. A typical project, in combination with on-site verification measurements, is presented in this paper. It is proposed to include dynamic effects as pulsations, vibrations and noise in the design stage of flow metering stations to prevent systematic errors in flow metering due to installation effects.

Rainer Engel, Hans-Joachim Baade, Andreas Rubel
PERFORMANCE IMPROVEMENT OF LIQUID FLOW CALIBRATORS BY APPLYING SPECIAL MEASUREMENT AND CONTROL STRATEGIES

PTB?s new "Hydrodynamic Test Field", which represents a high-accuracy water flow calibration facility, will serve as the national primary standard for flow measurands: volumetric and mass flow rate, respectively, and total flow measurement, i.e. the quantity of fluid (volume or mass) passing a flowmeter. Owing to this application aspect, the main design goal was to realize a total expanded measurement uncertainty as low as 0,02 % for total volumetric flow-rate measurement. To meet this decisive requirement, low-uncertainty components were combined with state-of-the-art measurement and control strategies.

Tong Meng, Ren Ping, Chen Ming
MODAL ANALYSIS OF CORIOLIS MASS FLOWMETER

Coriolis Mass Flowmeter (CMF) is true mass flowmeter, by measuring the Coriolis effect of a vibrating flow pipe. Dynamitic Analysis of CMF plays an important role in its design and application. Finite element modal analysis of CMF Assembly and flow pipe individually is presented in the paper. CAD Model of CMF Assembly is built in AutoCAD, and then imported into FEM software Msc. Marc, and rotated to generate solid FEM model. Lanczos method is adopted in the calculation. Effects of type of the flow pipe’s support are investigated. It’s presented the FEM calculations are agreed with the theory analysis of Euler beam.

M. Pusayatanont, E. H. Higham, P. J. Unsworth
ANALYSIS OF THE SENSOR SIGNAL FROM A VORTEX FLOWMETER TOT RECOVER INFORMATION REGARDING THE FLOW REGIMES

The paper discusses the effects of non-standard flow regimes on the performance of vortex flowmeters and the methods of analysing the vortex sensor signal to detect the presence of these spurious conditions in the flow, and swirling flow in particular.
This study shows that the amplitude and frequency fluctuations embedded in vortex sensor signals carry much useful information about system conditions and fluid flow regimes which can seriously impair the accuracy of measurement. The necessary signal information can be recovered by analysing the unconditioned raw vortex sensor signal i.e. utilizing data regarding fluctuations in signal amplitude and periodicity.

M. Pusayatanont, E. H. Higham, P. J. Unsworth
ANALYSIS OF THE SENSOR SIGNAL FROM A TURBINE FLOWMETER TO RECOVER INFORMATION REGARDING THE FLOW REGIMES

The paper discusses the identification of turbine flowmeter fault conditions by recovering additional information from the unconditioned sensor signal. Turbine flowmeters are characterised by their high accuracy, excellent repeatability, good linearity and wide operating range.
However, they are very sensitive to the change of flow regime and system conditions, which can degrade the flowmeter performance and, in particular, the accuracy of measurement. Four general fault conditions – erosion or damaged of the rotor blades, swirling flow, pulsating flow and two-phase flow - have been simulated and studied. The laboratory experiments provide very strong evidence that there is much useful information embedded in the sensor signal that can be recovered and used to identify the operational status of the flowmeter.
The experimental results show that additional information regarding attributes and features of flowmeter itself, as well as its operational status and the condition of the flow regime in which it is operating, can be recovered by analysis of the unconditioned sensor signal.

Page 414 of 977 Results 4131 - 4140 of 9762