Measurement of Liquid Flow in Closed Conduits With Electromagnetic Flowmeters

AN A MERICAN NA TIONAL S T AND ARD

ASME MFC-16–2014

(Revision of ASME MFC-16–2007)

ASME MFC-16–2014

(Revision of ASME MFC-16–2007)

Measurement of Liquid Flow in Closed Conduits With Electromagnetic Flowmeters

AN AMERICAN NA TIONAL S T AND ARD

Two Park Avenue • New York, NY • 10016 USA

Date of Issuance: March 14, 2014

This Standard will be revised when the Society approves the issuance of a new edition.

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CONTENTS

Foreword iv

Committee Roster v

Correspondence With the MFC Committee vi

1. Scope 1

2. References 1

3. Definitions and Symbols 1

4. Theory and Measurement Technique 1

5. Flowmeter Descriptions 4

6. Application Considerations 4

7. Equipment Markings 7

8. Calibration 7

Figures

4-1 Industrial Electromagnetic Flowmeters 2

4.2-1 Examples of Electromagnetic Field (Bo) Variation With Time 3

4.3-1 Examples of Electrodes for an Electromagnetic Flowmeter 3

6.4-1 Electromagnetic Flowmeter System 5

Table

3.2-1 Symbols 2

Nonmandatory Appendices

1. Added Details Regarding Theory and Measurement Technique 9

2. Liner Material Guidelines 11

3. Manufacturer-Specified Accuracy 13

4. Calculation Examples 15

5. Bibliography 16

iii

FOREWORD

This Standard was prepared by Subcommittee 16 of the ASME Committee on the Measurement of Liquid Flow in Closed Conduits. The chair of the subcommittee is indebted to the many individuals who contributed to this document.

Electromagnetic flowmeters were introduced to the process industries in the mid 1950s. They quickly became accepted flowmeters for difficult applications. Subsequent improvements in tech- nology and reductions in cost have transformed these flowmeters into one of the leading contend- ers for general use in water-based and other electrically conducting liquid applications.

Due to differences in design of the various electromagnetic flowmeters in the marketplace, this Standard cannot address detailed performance limitations in specific applications. It covers issues that are common to all meters, including application considerations.

The flow industry has been changing from the use of the names “primary” and “secondary” to “sensor” and “transmitter.” Previous editions of ASME MFC-16 did use primary and secondary in their figures and text. This new edition uses the sensor and transmitter terminology.

Suggestions for improvement of this Standard will be welcomed. They should be sent to The American Society of Mechanical Engineers; Attn: Secretary, MFC Standards Committee; Two Park Avenue; New York, NY 10016-5990.

This revision was approved an an American National Standard on January 28, 2014.

iv

ASME MFC COMMITTEE

Measurement of Fluid Flow in Closed Conduits

(The following is the roster of the Committee at the time of approval of this Standard.)

STANDARDS COMMITTEE OFFICERS

R. J. DeBoom, Chair

Z. D. Husain, Vice Chair

D. C. Wyatt, Vice Chair

C. J. Gomez, Secretary

C. J. Blechinger, Honorary Member, Consultant

R. M. Bough, Rolls-Royce Corp.

M. S. Carter, Flow Systems, Inc.

R. J. DeBoom, Consultant

STANDARDS COMMITTEE PERSONNEL

G. E. Mattingly, The Catholic University of America

R. W. Miller, Honorary Member, R. W. Miller & Associates, Inc.

A. M. Quraishi, American Gas Association

W. F. Seidl, Honorary Member, Consultant

D. Faber, Contributing Member, Badger Meter, Inc.

C. J. Gomez, The American Society of Mechanical Engineers

F. D. Goodson, Emerson Process Management — Daniel

Z. D. Husain, Chevron Corp.

C. G. Langford, Honorary Member, Consultant

W. M. Mattar, Invensys/Foxboro Co.

D. W. Spitzer, Contributing Member, Spitzer and Boyes, LLC

R. N. Steven, Colorado Engineering Experiment Station, Inc.

J. H. Vignos, Honorary Member, Consultant

D. E. Wiklund, Emerson–Rosemount Measurement — Rosemount

J. D. Wright, Contributing Member, National Institute of Standards and Technology

D. C. Wyatt, Wyatt Engineering

1. J. DeBoom, Chair, Consultant

   SUBCOMMITTEE 16 — ELECTROMAGNETIC FLOWMETERS

2. B. Rogers, Emerson Process Management — Rosemount

C. A. Diederichs, Emerson Process Management — Rosemount

M. J. Keilty, Endress + Hauser Flowtec AG

M. M. Lloyd, The Dow Chemical Co.

W. M. Mattar, Invensys/Foxboro Co.

R. W. Miller, Contributing Member, R. W. Miller & Associates, Inc.

1. K. Rao, Consultant

2. J. Rongione, ABB Instrumentation

3. W. Spitzer, Spitzer and Boyes, LLC

S. Y. Tung, City of Houston, Public Works and Engineering

P. A. Warburton, Yokogawa Corp. of America

D. C. Wyatt, Wyatt Engineering

v

CORRESPONDENCE WITH THE MFC COMMITTEE

General. ASME Standards are developed and maintained with the intent to represent the consensus of concerned interests. As such, users of this Standard may interact with the Committee by requesting interpretations, proposing revisions, and attending Committee meetings. Corre- spondence should be addressed to

Secretary, MFC Standards Committee

The American Society of Mechanical Engineers Two Park Avenue

New York, NY 10016-5990

https://go.asme.org/Inquiry

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the Committee Page at go.asme.org/MFCcommittee.

vi

ASME MFC-16–2014

MEASUREMENT OF LIQUID FLOW IN CLOSED CONDUITS WITH ELECTROMAGNETIC FLOWMETERS

1. SCOPE

   This Standard is applicable to industrial electromag- netic flowmeters and their application in the measure- ment of liquid flow. The electromagnetic flowmeters covered by this Standard utilize an alternating electrical current (AC) or pulsed direct-current (pulsed-DC) to generate a magnetic field in electrically conductive and electrically homogeneous liquids or slurries flowing in a completely filled, closed conduit.

   This Standard does not cover the following:

   • insertion-type electromagnetic flowmeters

   • electromagnetic flowmeters used in surgical, thera- peutic, or other health and medical applications

   • applications of industrial flowmeters involving nonconductive liquids

   • highly conductive liquids (e.g., liquid metals)

     
     

2. REFERENCES

   The following document forms a part of this Standard to the extent specified herein. The latest edition shall apply.

   ISO 13359, Measurement of conductive liquid flow in closed conduits — Flanged electromagnetic flowmeters — Overall length

   Publisher: International Organization for Standardization (ISO) Central Secretariat, 1, ch. de la Voie-Creuse, Case postale 56, CH-1211, Gene`ve 20, Switzerland/Suisse

   
   

3. DEFINITIONS AND SYMBOLS

1. Definitions

   accuracy of measurement: closeness of the agreement between the result of a measurement and a true value of the measurand.

   NOTE: Accuracy is a qualitative concept; for the quantitative concept, see uncertainty.

   calibration: the experimental determination of the rela- tionship between the quantity being measured and the device that measures it, usually by comparison with a standard, then (typically) correcting the output of that device to bring it to the desired value, within a specified tolerance, for a particular value of the input.

   flowmeter sensor: includes the flow tube, process connec- tions, electromagnetic coils, and electrodes. Flowmeter sensor is also known by other names, e.g., flowmeter sensor device, sensor device, and sensor.

   flowmeter transmitter: includes the electronic transmitter, measurement of the emfv , and, in most cases, the power for the electromagnet coils of the flowmeter sensor.

   meter factor: the number determined by liquid calibration that enables the output flow signal to be related to the volumetric flow rate under defined reference conditions; often expressed as the reciprocal of mean K-factor.

   uncertainty (of measurement): parameter, associated with the result of a measurement, that characterizes the dis- persion of the values that could reasonably be attributed to the measurand.

   verification: provision of objective evidence that a given item fulfills requirements.

   
   

   EXAMPLE: Use of independent flow calibration to confirm that performance properties and/or legal requirements of a measuring system are met.

   
   

2. Symbols

See Table 3.2-1.

4 THEORY AND MEASUREMENT TECHNIQUE

Industrial electromagnetic flowmeters are composed of the following basic components (see Fig. 4-1):

1. a nonmagnetic tube with a nonconductive inner surface

2. a magnetic field passing through the tube and perpendicular to the axis of the tube at the center of the flow tube

3. a minimum of two electrodes on opposite sides of the tube in a cross-sectional plane passing through the center of the flow tube, the straight line between these two electrodes being perpendicular to the mag- netic field at the center of the flow tube

4.1 Flow-Related Electromotive Force

Faraday’s law of induction applied to this physical configuration predicts the generation of an electromo- tive force (a voltage) between the electrodes when a

1