1、AN AMERICAN NATIONAL STANDARDASME MFC-5.12011(Revision and Partition of ANSI/ASME MFC-5M1985)Measurement of Liquid Flow in Closed Conduits Using Transit-Time Ultrasonic FlowmetersASME MFC-5.12011(Revision and Partition of ANSI/ASME MFC-5M1985)Measurement ofLiquid Flow in ClosedConduits UsingTransit-
2、TimeUltrasonic FlowmetersAN AMERICAN NATIONAL STANDARDThree Park Avenue New York, NY 10016 USADate of Issuance: June 17, 2011This Standard will be revised when the Society approves the issuance of a new edition. There willbe no addenda issued to this edition.ASME issues written replies to inquiries
3、concerning interpretations of technical aspects of thisdocument. Periodically certain actions of the ASME MFC Committee may be published as Cases.Cases and interpretations are published on the ASME Web site under the Committee Pages athttp:/cstools.asme.org as they are issued.ASME is the registered
4、trademark of The American Society of Mechanical Engineers.This code or standard was developed under procedures accredited as meeting the criteria for American NationalStandards. The Standards Committee that approved the code or standard was balanced to assure that individuals fromcompetent and conce
5、rned interests have had an opportunity to participate. The proposed code or standard was madeavailable for public review and comment that provides an opportunity for additional public input from industry, academia,regulatory agencies, and the public-at-large.ASME does not “approve,” “rate,” or “endo
6、rse” any item, construction, proprietary device, or activity.ASME does not take any position with respect to the validity of any patent rights asserted in connection with anyitems mentioned in this document, and does not undertake to insure anyone utilizing a standard against liability forinfringeme
7、nt of any applicable letters patent, nor assume any such liability. Users of a code or standard are expresslyadvised that determination of the validity of any such patent rights, and the risk of infringement of such rights, isentirely their own responsibility.Participation by federal agency represen
8、tative(s) or person(s) affiliated with industry is not to be interpreted asgovernment or industry endorsement of this code or standard.ASME accepts responsibility for only those interpretations of this document issued in accordance with the establishedASME procedures and policies, which precludes th
9、e issuance of interpretations by individuals.No part of this document may be reproduced in any form,in an electronic retrieval system or otherwise,without the prior written permission of the publisher.The American Society of Mechanical EngineersThree Park Avenue, New York, NY 10016-5990Copyright 201
10、1 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.CONTENTSForeword ivCommittee Roster . vCorrespondence With the MFC Committee . vi1 General. 12 General Ultrasonic Flowmeter Descriptions 23 Transit-Time Flowmeter Descriptions 24 Uncertainty Sources and Uncertainty R
11、eduction . 75 Installation and Selection Guidelines . 106 Calibration, Verification, and Diagnostics . 11Figures3-1 Wetted Transducer Configurations 33-2 Protected Configuration With Both an External Mount and a Wetted SmoothBore 53-3 Acoustic Path Configurations 64-1 A Typical Cross Path Ultrasonic
12、 Flowmeter Configuration 9Tables1-1 Symbols . 31-2 Subscripts . 3iiiFOREWORDThe need for a standard describing measurement of liquid measurement of liquid flows bymeans of transit-time ultrasonic flowmeters has been recognized for many years. The ASMEStandards Committee MFC, Measurement of Fluid Flo
13、w in Closed Conduits, developed a stan-dard, ANSI/ASME MFC-5M1985 to address this need. Subsequently, it was decided to reviseand partition ANSI/ASME MFC-5M into three standards to assist the readers in understandingthe three technologies: transit time, cross-correlation, and scattering (Doppler).Th
14、is Standard applies to ultrasonic flowmeters that base their operation on the measurementof transit time of acoustic signals. This Standard concerns the volume flow-rate measurement ofa single-phase liquid with steady flow or flow varying only slowly with time in a completelyfilled closed conduit.Th
15、e next standard planned in this series, Measurement of Liquids Using Cross-CorrelationUltrasonic Flowmeters (ASME MFC-5.2M), will apply to ultrasonic flowmeters that base theiroperation on the cross-correlation of modulated acoustic signals. It will be concerned with thevolume flow-rate measurement
16、of a single-phase or multiphase liquid with steady flow or flowvarying only slowly with time in a completely filled closed conduit.The last standard planned for this series, Measurement of Liquids Using Scattering (Doppler)Ultrasonic Flowmeters (ASME MFC-5.3M), will apply to ultrasonic flowmeters th
17、at base theiroperation on the scattering (Doppler) of acoustic signals. It will be concerned with the volumeflow-rate measurement of two-phase liquid with steady flow or flow varying only slowly withtime in a completely filled closed conduit.Suggestions for improvement of this Standard are welcome.
18、They should be sent to TheAmerican Society of Mechanical Engineers; Attn: Secretary, MFC Standards Committee; Three ParkAvenue; New York, NY 10016-5990.This Standard was approved as an American National Standard on January 28, 2011.ivASME MFC COMMITTEEMeasurement of Fluid Flow in Closed Conduits(The
19、 following is the roster of the Committee at the time of approval of this Standard.)STANDARDS COMMITTEE OFFICERSR. J. DeBoom, ChairZ. D. Husain, Vice ChairD. C. Wyatt, Vice ChairC. J. Gomez, SecretarySTANDARDS COMMITTEE PERSONNELC. J. Blechinger, Honorary Member, ConsultantR. M. Bough, Rolls-Royce C
20、orp.M. S. Carter, Flow Systems, Inc.G. P. Corpron, Honorary Member, ConsultantR. J. DeBoom, ConsultantD. Faber, Contributing Member, Badger Meter, Inc.C. J. Gomez, The American Society of Mechanical EngineersF. D. Goodson, Emerson Process Management/Daniel DivisionZ. D. Husain, Chevron Corp.C. G. La
21、ngford, Honorary Member, ConsultantT. O. Maginnis, ConsultantW. M. Mattar, Invensys/Foxboro Co.SUBCOMMITTEE 5 ULTRASONIC FLOWMETERSR. J. DeBoom, Chair, ConsultantG. P. Corpron, ConsultantP. G. Espina, G. E. Energy ServicesR. H. Fritz, Regency Gas ServiceB. Funck, Flexim Labs, LLCF. D. Goodson, Emers
22、on Process Management/Daniel DivisionM. J. Keilty, Endress + Hauser Flowtec AGW. M. Mattar, Invensys/Foxboro Co.vG. E. Mattingly, The Catholic University of AmericaR. W. Miller, Honorary Member, R. W. Miller however, they shouldnot contain proprietary names or information.Requests that are not in th
23、is format may be rewritten in the appropriate format by the Committeeprior to being answered, which may inadvertently change the intent of the original request.ASME procedures provide for reconsideration of any interpretation when or if additionalinformation that might affect an interpretation is av
24、ailable. Further, persons aggrieved by aninterpretation may appeal to the cognizant ASME Committee or Subcommittee. ASME does not“approve,” “certify,” “rate,” or “endorse” any item, construction, proprietary device, or activity.Attending Committee Meetings. The MFC Standards Committee regularly hold
25、s meetings thatare open to the public. Persons wishing to attend any meeting should contact the Secretary ofthe MFC Standards Committee.viASME MFC-5.12011MEASUREMENT OF LIQUID FLOW IN CLOSED CONDUITS USINGTRANSIT-TIME ULTRASONIC FLOWMETERS1 GENERAL1.1 ScopeThis Standard applies to ultrasonic flowmet
26、ers thatbase their operation on the measurement of transit timeof acoustic signals. This Standard concerns the volumeflow-rate measurement of a single-phase liquid withsteady flow or flow varying only slowly with time in acompletely filled closed conduit.1.2 PurposeThis Standard provides(a) a descri
27、ption of the operating principles employedby the transit-time ultrasonic flowmeters(b) a guideline to expected performance characteris-tics of transit-time ultrasonic flowmeters(c) a description of calibration, verification, and diag-nostic procedures(d) a description of potential uncertainty source
28、s andtheir reduction(e) a common set of terminology, symbols, definitions,and specifications1.3 Terminology and Symbols(a) Paragraph 1.3.1 lists definitions fromASME MFC-1M used in this Standard.(b) Paragraph 1.3.2 lists definitions specific to thisStandard.(c) Table 1-1 lists symbols used in this S
29、tandard.(d) Table 1-2 lists subscripts used in this Standard.1.3.1 Definitions From ASME MFC-1Maccuracy: closeness of agreement between a measuredquantity value and a true quantity value of a measurand.NOTES:(1) The concept “measurement accuracy” is not a quantity and isnot given a numerical quantit
30、y value. A measurement is saidto be more accurate when it provides a smaller measure-ment error.(2) The term “measurement accuracy” is sometimes understoodas closeness of agreement between measured quantity valuesthat are being attributed to the measurand. “Measurementaccuracy” should not be mistake
31、n for “measurementprecision.”acoustic path: path that the acoustic signals follow as theypropagate through the measurement section. There maybe one (single path) or more (multipath) acoustic paths1in the measurement section. Common transit-time pathtypes are axial, diametrical, and chordal.axial flo
32、w velocity: component of liquid flow velocity, Vax,at a point in the measurement section that is parallel tothe measurement sections axis.calibration: experimental determination of the relation-ship between the quantity being measured and thedevice that measures it, usually by comparison with atrace
33、able reference standard; also including the act ofadjusting the output of a device to bring it to a desiredvalue, within a specified tolerance, for a particular valueof the input.NOTE: This document is written with calibration defined as thedetermination of difference from a reference and the adjust
34、mentto align within a specified tolerance. This is common U.S. usage.It is understood that in other parts of the world some countriesand groups define calibration as only the determination of differ-ence from a reference. A second term used is calibration adjust-ment, which is to align within a spec
35、ified tolerance.cross-flow velocity: component of liquid flow velocity ata point in the measurement section that is perpendicularto the measurement sections axis.measurementsection: section of conduit in which the volu-metric flow rate is sensed by the acoustic signals. Themeasurement section is bou
36、nded at both ends by planesperpendicular to the axis of the section and located atthe extreme upstream and downstream transducer posi-tions. The measurement section is usually circular incross section; however, it may be square, rectangular,elliptical, or some other shape.nonrefractive system: an ul
37、trasonic flowmeter system inwhich the acoustic path crosses the transducer/processliquid interfaces at a right angle to the boundary surface.refractive system: an ultrasonic flowmeter in which theacoustic path crosses the conduit boundary/processliquid interfaces at other than a right angle.transit
38、time, t: time required for an acoustic signal totraverse an acoustic path.uncertainty: parameter characterizing the dispersion ofthe quantity values being attributed to a measurand,based on the information used.NOTES:(1) Measurement uncertainty is often comprised of many compo-nents: Some of these m
39、ay be evaluated by Type A evaluationASME MFC-5.12011of measurement uncertainty from the statistical distributionof the quantity values from series of measurements and can becharacterized by standard deviations. The other components,which may be evaluated by Type B evaluation of measurementuncertaint
40、y, can also be characterized by experimental stan-dard deviations derived from probability density functionsbased on experience or other information.(2) In general, for a given set of information, it is understoodthat the measurement uncertainty is associated with a statedquantity value attributed t
41、o the measurand. A modification ofthe value of this measurand may result in a modification ofthe associated uncertainty.(3) If the result of a measurement depends on the values of quanti-ties other than the measurand, the uncertainty of the measuredvalues of these quantities contribute to the uncert
42、ainty of theresult of the measurement.velocity profile correction factor, S: dimensionless factorbased on measured knowledge of the velocity profileused to adjust the meter output.verification: experimental determination of the relation-ship between the quantity being measured and thedevice that mea
43、sures it, usually by comparison with atraceable reference standard.1.3.2 Definitions Specific to This Standarddiagnostics: comparison of internal direct and derivedmeasurement values to allow the user to ascertain thecondition of the operation of the ultrasonic flowmeter.mode conversion: when an ult
44、rasonic wave passes at anoblique angle between two materials of variant acousticimpedance, mode conversion can occur. As an example,when a wedge-type transducer is coupled to the outsideof a pipe, the longitudinal waves generated by the ultra-sonic transducer produce both longitudinal and shearwaves
45、 in the pipe wall.ultrasonictransducer: a device designed to convert electri-cal signals into directed ultrasonic waves and vice versa,usually by inclusion of materials exhibiting the piezo-electric or piezomagnetic effects. When employed forflow measurement, ultrasonic transducers are com-monly ref
46、erred to simply as “transducers.” The trans-ducers transmit and receive acoustic energy. They maybe factory mounted or field mounted by clamping,threading, or bonding. Transducers may be wetted bythe liquid or be nonwetted. Wetted transducers may beflush mounted, recessed, or protruding into the flo
47、wstream. Some transducers may be removed while the lineis in service, depending on the manufacturers design.1.3.3 Symbols Used in This Standard. See Table 1-1.1.3.4 Subscripts Used in This Standard. SeeTable 1-2.2 GENERAL ULTRASONIC FLOWMETERDESCRIPTIONSThe ultrasonic flowmeter can be thought of as
48、com-prising a primary and secondary device. The primary2device consists of a measurement section, transducers,and acoustic paths. The measurement section may be awhole spool piece, or an existing section of conduit towhich transducers are installed in the field.The secondary device comprises the ele
49、ctronic equip-ment required to operate the transducers, make the mea-surements, process the measured data, and display orrecord the results. The processing section, in additionto estimating the flow rate from the measurement,should be capable of rejecting invalid measurements,noise, etc. The indicated flow rate may be the result ofone or more individual flow velocity determinations.Most meters have outputs available, either as standardfeatures or as optional equipment. Displays may showflow rate, integrated flow volume, and flow direction,and may be analog or digital. Signal
