1、BRITISH STANDARD BS EN ISO 5167-2:2003 Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full Part 2: Orifice plates The European Standard EN ISO 5167-2:2003 has the status of a British Standard ICS 17.120.10 BS EN ISO 5167-2:2003
2、 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 18 March 2003 BSI 18 March 2003 ISBN 0 580 41456 6 National foreword This British Standard is the official English language version of EN ISO 5167-2:2003. It is identical with ISO 5167-2:2003.
3、It, together with Parts 1, 3 and 4 of BS EN ISO 5167:2003, supersedes BS EN ISO 5167-1:1997 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee CPI/30, Measurement of fluid flow in closed conduits, to Subcommittee CPI/30/2, Pressure differential devices,
4、which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under th
5、e section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct applicat
6、ion. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monit
7、or related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN ISO title page, the EN ISO foreword page, the ISO title page, pages ii to v, a blank page, pages 1 to 47 and a back cover. The BSI c
8、opyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM ENISO51672 March2003 ICS17.120.10 SupersedesENISO51671:1995 Englishversion Measurementoffluidflowbymeansofpre
9、ssuredifferential devicesinsertedincircularcrosssectionconduitsrunningfull Part2:Orificeplates(ISO51672:2003) Mesurededbitdesfluidesaumoyendappareils dprimognesinsrsdansdesconduitesenchargede sectioncirculairePartie2:Diaphragmes(ISO5167 2:2003) DurchflussmessungvonFluidenmitDrosselgerteninvoll durch
10、strmtenLeitungenmitKreisquerschnittTeil2: Blenden(ISO51672:2003) ThisEuropeanStandardwasapprovedbyCENon20February2003. CENmembersareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelis
11、tsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheManagementCentreortoanyCENmember. ThisEuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguagean
12、dnotifiedtotheManagementCentrehasthesamestatusasthe official versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,CzechRepublic,Denmark,Finland,France,Germany,Greece, Hungary,Iceland,Ireland,Italy,Luxembourg,Malta,Netherlands,Norway,Portugal,SlovakRepublic,Spain,Sweden,Switzerland and
13、UnitedKingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2003CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.ENISO51672:2003EForeword Thisdocument(ENISO51
14、672:2003)hasbeenpreparedbyTechnicalCommitteeISO/TC30 “Measurementoffluidflowinclosedconduits“incollaborationwithCMC. ThisEuropeanStandardshallbegiventhestatusofanationalstandard,eitherbypublicationof anidenticaltextorbyendorsement,atthelatestbySeptember2003,andconflictingnational standardsshallbewit
15、hdrawnatthelatestbySeptember2003. ThisdocumentsupersedesENISO51671:1995. AccordingtotheCEN/CENELECInternalRegulations,thenationalstandardsorganizationsof thefollowingcountriesareboundtoimplementthisEuropeanStandard:Austria,Belgium,Czech Republic,Denmark,Finland,France,Germany,Greece,Hungary,Iceland,
16、Ireland,Italy, Luxembourg,Malta,Netherlands,Norway,Portugal,SlovakRepublic,Spain,Sweden, SwitzerlandandtheUnitedKingdom. NOTEFROMCMC TheforewordissusceptibletobeamendedonreceptionoftheGerman languageversion.Theconfirmedoramendedforeword,andwhenappropriate,thenormative annexZAforthereferencestointern
17、ationalpublicationswiththeirrelevantEuropean publicationswillbecirculatedwiththeGermanversion. Endorsementnotice ThetextofISO51672:2003hasbeenapprovedbyCENasENISO51672:2003withoutany modifications. ENISO51672:2003 Reference number ISO 5167-2:2003(E)INTERNATIONAL STANDARD ISO 5167-2 First edition 200
18、3-03-01 Measurement of fluid flow by means of pressure differential devices inserted in circular-cross section conduits running full Part 2: Orifice plates Mesure de dbit des fluides au moyen dappareils dprimognes insrs dans des conduites en charge de section circulaire Partie 2: Diaphragmes ENISO51
19、672:2003ENISO51672:2003iiIS-7615 O2:(3002E) I SO 3002 All irhgts seredevr iiiContents Page Foreword iv Introduction v 1 Scope 1 2 Normative references . 1 3 Terms, definitions and symbols 1 4 Principles of the method of measurement and computation. 2 5 Orifice plates . 2 5.1 Description. 2 5.2 Press
20、ure tappings. 6 5.3 Coefficients and corresponding uncertainties of orifice plates. 10 5.4 Pressure loss, 13 6 Installation requirements . 15 6.1 General. 15 6.2 Minimum upstream and downstream straight lengths for installation between various fittings and the orifice plate . 15 6.3 Flow conditioner
21、s . 20 6.4 Circularity and cylindricality of the pipe. 26 6.5 Location of orifice plate and carrier rings 27 6.6 Method of fixing and gaskets 28 Annex A (informative) Tables of discharge coefficients and expansibility expansion factors 29 Annex B (informative) Flow conditioners. 41 Bibliography . 46
22、 ENISO51672:2003iiiIS-7615 O2:(3002E) vi I SO 3002 All irhgts seredevrForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO techni
23、cal committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely w
24、ith the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft Int
25、ernational Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document m
26、ay be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 5167-2 was prepared by Technical Committee ISO/TC 30, Measurement of fluid flow in closed conduits, Subcommittee SC 2, Pressure differential devices. This first edition of ISO 516
27、7-2, together with the second edition of ISO 5167-1 and the first editions of ISO 5167-3 and ISO 5167-4, cancels and replaces the first edition of ISO 5167-1:1991, which has been technically revised, and ISO 5167-1:1991/Amd.1:1998. ISO 5167 consists of the following parts, under the general title Me
28、asurement of fluid flow by means of pressure differential devices inserted in circular-cross section conduits running full : Part 1: General principles and requirements Part 2: Orifice plates Part 3: Nozzles and Venturi nozzles Part 4:Venturi tubes ENISO51672:2003ivIS-7615 O2:(3002E) I SO 3002 All i
29、rhgts seredevr vIntroduction ISO 5167, consisting of four parts, covers the geometry and method of use (installation and operating conditions) of orifice plates, nozzles and Venturi tubes when they are inserted in a conduit running full to determine the flowrate of the fluid flowing in the conduit.
30、It also gives necessary information for calculating the flowrate and its associated uncertainty. ISO 5167 (all parts) is applicable only to pressure differential devices in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase, but is
31、not applicable to the measurement of pulsating flow. Furthermore, each of these devices can only be used within specified limits of pipe size and Reynolds number. ISO 5167 (all parts) deals with devices for which direct calibration experiments have been made, sufficient in number, spread and quality
32、 to enable coherent systems of application to be based on their results and coefficients to be given with certain predictable limits of uncertainty. The devices introduced into the pipe are called “primary devices”. The term primary device also includes the pressure tappings. All other instruments o
33、r devices required for the measurement are known as “secondary devices”. ISO 5167 (all parts) covers primary devices; secondary devices 1)will be mentioned only occasionally. ISO 5167 consists of the following four parts. a) ISO 5167-1 gives general terms and definitions, symbols, principles and req
34、uirements as well as methods of measurement and uncertainty that are to be used in conjunction with ISO 5167-2, ISO 5167-3 and ISO 5167-4. b) ISO 5167-2 specifies orifice plates, which can be used with corner pressure tappings, D and D/2 pressure tappings 2) , and flange pressure tappings. c) ISO 51
35、67-3 specifies ISA 1932 nozzles 3) , long radius nozzles and Venturi nozzles, which differ in shape and in the position of the pressure tappings. d) ISO 5167-4 specifies classical Venturi tubes 4) . Aspects of safety are not dealt with in Parts 1 to 4 of ISO 5167. It is the responsibility of the use
36、r to ensure that the system meets applicable safety regulations. _ 1) See ISO 2186:1973, Fluid flow in closed conduits Connections for pressure signal transmissions between primary and secondary elements. 2) Orifice plates with “vena contracta” pressure tappings are not considered in ISO 5167. 3) IS
37、A is the abbreviation for the International Federation of the National Standardizing Associations, which was succeeded by ISO in 1946. 4) In the USA, the classical Venturi tube is sometimes called the Herschel Venturi tube. ENISO51672:2003vINTENRATIONAL TSANDADR IS-7615 O2:(3002E)I SO 3002 All irhgt
38、s seredevr 1Measurement of fluid flow by means of pressure differential devices inserted in circular-cross section conduits running full Part 2: Orifice plates 1 Scope This part of ISO 5167 specifies the geometry and method of use (installation and operating conditions) of orifice plates when they a
39、re inserted in a conduit running full to determine the flowrate of the fluid flowing in the conduit. This part of ISO 5167 also provides background information for calculating the flowrate and is applicable in conjunction with the requirements given in ISO 5167-1. This part of ISO 5167 is applicable
40、 to primary devices having an orifice plate used with flange pressure tappings, or with corner pressure tappings, or with D and D/2 pressure tappings. Other pressure tappings such as “vena contracta” and pipe tappings have been used with orifice plates but are not covered by this part of ISO 5167. T
41、his part of ISO 5167 is applicable only to a flow which remains subsonic throughout the measuring section and where the fluid can be considered as single phase. It is not applicable to the measurement of pulsating flow. It does not cover the use of orifice plates in pipe sizes less than 50 mm or mor
42、e than 1 000 mm, or for pipe Reynolds numbers below 5 000. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (in
43、cluding any amendments) applies. ISO 4006:1991, Measurement of fluid flow in closed conduits Vocabulary and symbols ISO 5167-1:2003, Measurement of fluid flow by means of pressure differential devices inserted in circular-cross section conduits running full Part 1: General principles and requirement
44、s 3 Terms, definitions and symbols For the purposes of this document, the terms, definitions and symbols given in ISO 4006 and ISO 5167-1 apply. ENISO51672:20031IS-7615 O2:(3002E) 2 I SO 3002 All irhgts seredevr4 Principles of the method of measurement and computation The principle of the method of
45、measurement is based on the installation of an orifice plate into a pipeline in which a fluid is running full. The presence of the orifice plate causes a static pressure difference between the upstream and downstream sides of the plate. The mass flowrate, q m , can be determined using Equation (1):
46、2 1 4 2 4 1 m C qd p = (1) The uncertainty limits can be calculated using the procedure given in Clause 8 of ISO 5167-1:2003. Computation of the mass flowrate, which is a purely arithmetic process, can be performed by replacing the different terms on the right hand side of the basic Equation (1) by
47、their numerical values. Similarly, the value of volume flowrate, V q , is calculated from: m V q q = (2) where is the fluid density at the temperature and pressure for which the volume is stated. As will be seen later in this part of ISO 5167, the coefficient of discharge, C, is dependent on the Reynolds number, Re, which is itself dependent on q m , and has to be obtained by iteration (see Annex A of ISO 5167-1:2003 for guidance regarding the choice of the iteration procedure and initial estimates). The diameters d and D mentioned in the formula are the values of
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