© ISO 2016 Measurement of fluid flow by means of pressure differential devices inserted in circular cross section conduits running full — Part 5 Cone meters Mesure de débit des fluides au moyen d’appa[.]
INTERNATIONAL STANDARD ISO 5167-5 First edition 2016-03-01 Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full — Part 5: Cone meters Mesure de débit des fluides au moyen d’appareils déprimogènes insérés dans des conduites en charge de section circulaire — Partie 5: Cơnes de mesure Reference number ISO 5167-5:2016(E) © ISO 2016 ISO 5167-5:2016(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2016, Published in Switzerland All rights reserved Unless otherwise specified, no part o f this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission Permission can be requested from either ISO at the address below or ISO’s member body in the country o f the requester ISO copyright o ffice Ch de Blandonnet • CP 401 CH-1214 Vernier, Geneva, Switzerland Tel +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii © ISO 2016 – All rights reserved ISO 5167-5:2016(E) Contents Page Foreword iv Introduction v Scope Normative references Terms and de finitions Principles of the method of measurement and computation Cone meters 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 Expansibility (expansion) factor, ε Uncertainty o f the discharge coe fficient, C Uncertainty o f the expansibility (expansion) factor, ε Pressure loss Installation requirements 10 6.1 6.2 6.3 Field of application General shape Material and manufacture Pressure tappings Discharge coe fficient, C 5.5.1 Limits of use 5.5.2 Discharge coe fficient o f the cone meter General 10 Minimum upstream and downstream straight lengths for installations between various fittings and the cone meter 10 6.2.1 General 10 6.2.2 Single 90° bend 11 6.2.3 Two 90° bends in perpendicular planes 11 6.2.4 Concentric expander 11 6.2.5 Partially closed valves 11 Additional specific installation requirements for cone meters 11 6.3.1 Circularity and cylindricality o f the pipe 11 6.3.2 Roughness of the upstream and downstream pipe 11 6.3.3 Positioning of a thermowell 11 Flow calibration of cone meters 12 7.1 7.2 7.3 7.4 7.5 General 12 Test facility 12 Meter installation 12 Design of the test programme 12 Reporting the calibration results 13 7.6 Uncertainty analysis o f the calibration 13 7.6.1 General 13 7.6.2 Uncertainty o f the test facility 13 7.6.3 Uncertainty o f the cone meter 13 Annex A (informative) Table of expansibility (expansion) factor 14 Bibliography 15 © ISO 2016 – All rights reserved iii ISO 5167-5:2016(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies) The work o f preparing International Standards is normally carried out through ISO technical 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 with the International Electrotechnical Commission (IEC) on all matters o f electrotechnical standardization The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part In particular the different approval criteria needed for the di fferent types o f ISO documents should be noted This document was dra fted in accordance with the editorial rules of the ISO/IEC Directives, Part (see www.iso.org/directives) Attention is drawn to the possibility that some o f the elements o f this document may be the subject o f patent rights ISO shall not be held responsible for identi fying any or all such patent rights Details o f any patent rights identified during the development o f the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents) Any trade name used in this document is in formation given for the convenience o f users and does not constitute an endorsement For an explanation on the meaning o f ISO specific terms and expressions related to formity assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary in formation The committee responsible for this document is ISO/TC 30, Measurement of fluid flow in closed conduits, Subcommittee SC 2, Pressure differential devices The first edition o f ISO 5167-5 is complementary to ISO 5167-1, ISO 5167-2, ISO 5167-3, and ISO 5167-4 ISO 5167 consists of the following parts, under the general title Measurement 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 — Part 5: Cone meters iv © ISO 2016 – All rights reserved ISO 5167-5:2016(E) Introduction This International Standard, divided into five parts, covers the geometry and method o f use (installation and operating conditions) o f orifice plates, nozzles, Venturi tubes, and cone meters when they are inserted in a conduit running full to determine the flow rate o f the fluid in the conduit It also gives necessary in formation for calculating the flow rate and its associated uncertainty This International Standard is applicable only to pressure di fferential devices in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase, but it is not applicable to the measurement o f pulsating flow Furthermore, each o f these devices can only be used within specified limits o f pipe size and Reynolds number This International Standard deals with devices for which direct calibration experiments have been made su fficient in number, spread, and quality to enable coherent systems o f application to be based on their results and coe fficients to be given with certain predictable limits o f uncertainty However, for cone meters calibrated in accordance with Clause 7, a wider range of pipe size, β, and Reynolds number may be considered The devices introduced into the pipe are called “primary devices” The term primary device also includes the pressure tappings All other instruments or devices required for the measurement are known as “secondary devices” This International Standard covers primary devices; secondary devices [1][5] will be mentioned only occasionally This International Standard is divided into the following five parts: a) ISO 5167-1 gives general terms and definitions, symbols, principles, and requirements as well as methods o f measurement and uncertainty that are to be used in conjunction with ISO 5167-1, ISO 5167-2, ISO 5167-3, ISO 5167-4, and ISO 5167-5 b) ISO 5167-2 specifies requirements for orifice plates, which can be used with corner pressure tappings, D and D/2 pressure tappings 1) , and flange pressure tappings c) ISO 5167-3 specifies requirements for ISA 1932 nozzles 2) , long radius nozzles, and Venturi nozzles, d) which differ in shape and in the position of the pressure tappings ISO 5167-4 specifies requirements for classical Venturi tubes 3) e) This part o f ISO 5167 specifies requirements for cone meters and includes a section on calibration Aspects o f sa fety are not dealt with in ISO 5167 (all parts) It is the responsibility o f the user to ensure that the system meets applicable sa fety regulations 1) Orifice plates with ‘vena contracta’ pressure tappings are not considered in ISO 5167 (all parts) 2) ISA is the abbreviation for the International Federation of the National Standardizing Associations, which was succeeded by ISO in 1946 3) In the USA, the classical Venturi tube is sometimes called the Herschel Venturi tube © ISO 2016 – All rights reserved v INTERNATIONAL STANDARD ISO 5167-5:2016(E) Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full — Part 5: Cone meters Scope This part o f ISO 5167 specifies the geometry and method o f use (installation and operating conditions) o f cone meters when they are inserted in a conduit running full to determine the flow rate o f the fluid flowing in the conduit As the uncertainty o f an uncalibrated cone meter might be too high for a particular application, it might be deemed essential to calibrate the flow meter in accordance with Clause This part o f ISO 5167 also provides background in formation for calculating the flow rate and is applicable in conjunction with the requirements given in ISO 5167-1 This part o f ISO 5167 is applicable only to cone meters in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase Uncalibrated cone meters can only be used within specified limits o f pipe size, roughness, β, and Reynolds number This part o f ISO 5167 is not applicable to the measurement o f pulsating flow It does not cover the use o f uncalibrated cone meters in pipes sized less than 50 mm or more than 500 mm, or where the pipe Reynolds numbers are below × 10 or greater than 1,2 × 10 A cone meter is a primary device which consists o f a cone-shaped restriction held concentrically in the centre o f the pipe with the nose o f the cone upstream The design o f cone meter defined in this part o f ISO 5167 has one or more upstream pressure tappings in the wall, and a downstream pressure tapping positioned in the back face of the cone with the connection to a differential pressure transmitter being a hole through the cone to the support bar, and then up through the support bar Alternative designs o f cone meters are available; however, at the time o f writing, there is insu fficient data to fully characterize these devices, and there fore, these meters shall be calibrated in accordance with Clause Normative references The following documents, in whole or in part, are normatively re ferenced in this document and are indispensable for its application For dated re ferences, only the edition cited applies For undated re ferences, the latest edition o f the re ferenced document (including any amendments) applies ISO 4006, 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 requirements Terms and definitions For the purposes o f this document, the terms and definitions given in ISO 4006, ISO 5167-1, and the ollowing apply f © ISO 2016 – All rights reserved ISO 5167-5:2016(E) 3.1 beta edge maximum circumference of the cone Principles of the method of measurement and computation The principle of the method of measurement is based on the installation of the cone meter into a pipeline f ff upstream and downstream tappings i n wh ich a flu id i s ru n ni ng u l l F low th rough a cone me ter pro duce s a d i erenti a l pre s s u re b e twe en the T he ma s s flow rate c an b e de term i ne d b y Formu l ae (1) a nd (2 ) : qm = and β = C 1−β4 1− ε ( Dβ ) π (1) 2∆p ρ d c2 (2) D2 where dc is the diameter of the cone in the plane of the beta edge This assumes that the diameter of the pipe at the upstream tapping, DTAP, is equal to the diameter of the pipe at the beta edge, D Figure shows that as the cone diameter increases, β decreases Key flow Figure — Cone meter showing different values of β © ISO 2016 – All rights reserved ISO 5167-5:2016(E) The uncertainty limits can be calculated using the procedure given in ISO 5167-1:2003, Clause 8, except that Formula (3) should be used instead of ISO 5167-1:2003, Formula (3) δ qm qm (3) 2 2 2 2 δ dc δ Dp δρ δ C δε 2(1 + β + β ) δ D + + = + + + C ε β (1 + β ) D β (1 + β ) d c Dp ρ1 Similarly, the value o f the volume flow rate can be calculated since qV = qm ρ (4) where ρ is the fluid density at the temperature and pressure for which the volume is stated Computation o f the flow rate, which is a purely arithmetic process, is per formed by replacing the di fferent items on the right-hand side o f Formula (1) by their numerical values Formula (5) in 5.6 (or the computed values in Table A.1) gives cone meter expansibility factors (ε) The values in Table A.1 are not intended for precise interpolation Extrapolation is not permitted However, the coe fficient of discharge, C, is generally dependent on the Reynolds number, Re, which is itself dependent on qm , and has to be obtained by iteration (see ISO 5167-1:2003, Annex A for guidance regarding the choice o f iteration procedure and initial estimates) The diameters, dc and D, mentioned in Formulae (1) and (2) are the values of the diameters at working conditions Measurements taken at any other conditions should be corrected for any possible expansion or contraction o f the primary device and the pipe due to the values o f the temperature and pressure o f the fluid during the measurement As the cone meter flow rate calculation is particularly sensitive to the pipe and cone diameter values used, the user shall ensure that these are correctly entered into the flow computation calculations For example, care shall be taken to use the measured internal diameter rather than a nominal value It is necessary to know the density and the viscosity o f the fluid at working conditions In the case o f a compressible fluid, it is also necessary to know the isentropic exponent o f the fluid at working conditions NOTE The turndown o f all di fferential pressure flow meters is dependent upon the di fferential pressure range Typically, a 10:1 turndown in flow rate (equivalent to 100:1 turndown in di fferential pressure) can be achieved Cone meters 5.1 Field of application Uncalibrated cone meters can be used in pipes with diameters between 50 mm and 500 mm and with 0,45 ≤ β ≤ 0,75 Cone meters with β > 0,75 shall be calibrated Cone meters with values of β < 0,45 are not normally manu factured There are limits to the roughness and Reynolds number which shall be addressed © ISO 2016 – All rights reserved /2 ISO 5167-5:2016(E) 5.2 General shape Figure shows a section through the centreline of a cone meter Figure shows other sections shown in Figure and Figure The cone meter is made up of a pipe section of diameter, D diameter, dc, the support structure for the cone, and the tappings for differential pressure measurement f section, as per 5.2.13 5.2.1 thro ugh the meter to aid in the metro lo gy o f the co ne meter The letters us ed in the text re fer to tho s e , wh ich hou s e s the cone a s s embly with cone T he cone as s embly i s i n s ta l le d s uch th at the cone centrel i ne i s concentric to the centrel i ne o the pip e Key flow b o dy p ip e cone element support strut high pressure tapping low pressure tapping cone nose NO TE mm ≤ L ≤ D , a s de fi ne d i n 5.4.7 Figure — Geometric pro file of cone meter © ISO 2016 – All rights reserved ISO 5167-5:2016(E) 5.2.2 The design of the nose of the cone (for examples, see Figure 3) can be constructed as a machined component or from an elbow The nose shall be downstream of the plane of the centreline of the upstream tapping(s) It is recommended that the nose be as short as practicable These designs shown in Figure should not be considered exclusive a) Flat b) Pointed c) Curved d) Elbow Figure — Examples of different cone nose designs The pipe diameter, D, shall be measured at plane A of Figure The number of measurements value of these measurements shall be taken as the value of D in the calculations 5.2.3 s hall b e a minimum o f fo ur equally s p aced aro und the p ip e internal circum ference The arithmetic mean The pipe diameter shall also be measured at plane C of Figure (shown as DTAP in Figure 2) The number of measurements at this plane shall be at least equal to the number of pressure tappings (with a minimum of four) 5.2.4 5.2.5 N o diameter at any p o int b etween p lane C and differ from the pipe diameter, D © ISO 2016 – All rights reserved D downstream of plane A from Figure shall , by mo re than , % ISO 5167-5:2016(E) Key cone nose flow Figure — Metrology data for a cone meter 5.2.6 The internal surface of the pipe section from plane C to plane A from Figure shall be clean and smooth, and the roughness criterion, Ra, should be as small as possible and shall be less than 10 -3 D 5.2.7 f f at their widest points) The upstream frustum shall have a single internal angle, θ1 , of 26° ± 5° to the centreline of the frusta The downstream frustum shall have a single internal angle, θ2 , of 67,5° ± 2,5° to the centreline of the frusta The co ne as s emb ly s hall generally co ns is t o a circular b i rus tum (two truncated co nes j o ined 5.2.8 The cone diameter, dc, shall be measured at plane A of Figure There shall be a minimum of four meas urements equally s p aced aro und the co ne external circum ference The arithmetic mean value of these measurements shall be taken as the value of dc in the calculations No d ia me ter sh a l l d i ffer b y more than ,1 % is from the va lue o f the me an d i ame ter T h i s re qui rement s ati s fie d when the d i fference i n leng th o f any o f the me a s ure d d i ame ters requirement with respect to the mean of the measured diameters form s to the s aid 5.2.9 The beta edge shall not be sharp The radius of curvature, R1 , at the beta edge as shown in Figure 5, shall be less than the smaller of 0,2 mm and 0,000 dc © ISO 2016 – All rights reserved ISO 5167-5:2016(E) 5.2.10 The cone shall be such that two diameters situated on the same plane perpendicular to the axis o f revo lutio n no t di ffer fro m the mean diameter by mo re than , % Figure — Radius of curvature, R1 , at the beta edge shown, as examples, for fabricated and machined cones 5.2.11 The cone surface shall be clean and smooth, and the roughness criterion, Ra, shall be as small as -4 dc p o s s ib le and s hall always b e les s than × 5.2.12 The s up p o rting s tructure fo r the co ne s hall p res ent as s mall a res trictio n to the flo w as p ractical, whils t ens uring that the s tructural integrity o f the co ne meter is no t imp aired over the range o f co nditio ns anticip ated support The co ne as s emb ly may o p tio nally include gus s ets that p rovide additio nal mechanical 5.2.13 The lateral and angular deviations of the cone from the centreline of the pipe section shall be measured T he d i s tance b e twe en the wide s t p ar t o f the cone and the adj acent pip e i nterna l wa l l sh a l l b e me as u re d (see plane A of Figure 4, labelled K1 , K2 , K3 , K4 ff spaced around the external circumference of the cone The difference between each measurement and ) T here s l l b e a m i ni mum o ou r me a s u rements e qua l ly the me a n o f tho s e me as u rements sh a l l b e no gre ater tha n , % T he d i s tance b e twe en the cone no s e and the adj acent pip e i nterna l wa l l sha l l a l s o b e me a s u re d (s e e ff plane B of Figure 4, labelled J1 , J2 , J3 , J4 around the external circumference of the cone The difference between each measurement and the ) T here sh a l l b e a m i ni mu m o ou r me a s urements e qua l ly s p ace d me an o f tho s e me a s u rements s l l b e no gre ater th an , % The angular deviation of the cone shall be measured and should be no greater than 2,0° in either the horizontal (θHORZ ) or vertical (θVERT ) from the pipe centreline at the cone nose, as shown in Figure The lateral deviation of the cone shall be measured and should be no greater than 0,01 D in either the horizontal or vertical from the pipe centreline at the cone nose, as shown in Figure 5.2.14 Consideration shall be taken in the design of the cone meter and its installation to ensure that the e ffects o f p res s ure, temp erature, and res o nance over the entire range o f co nditio ns that the flo w meter may s ee over its o p eratio nal li fe no t res ult in mechanical failure I n appl ic ation s where flow cond ition s pro duce s ign i fic a nt vibration, the u s e o f gu s s e ts i s re com mende d 5.3 Material and manufacture 5.3.1 The co ne meter may b e manu factured fro m any material, p rovided that the co ne meter is in accordance with the foregoing description and will remain so during use 5.3.2 For fabricated cones, the cone shall include pressure relief vent holes through the downstream face to ens ure the s tructural s tab ility o f the co ne under rap id p res s ure changes © ISO 2016 – All rights reserved ISO 5167-5:2016(E) 5.4 Pressure tappings 5.4.1 The upstream tapping shall be made in the form of a pipe wall pressure tapping The diameter of the upstream tapping shall be between mm and 10 mm and moreover shall never be greater than 0,1 D 5.4.2 I t i s re com mende d that the up s tre a m tappi ng b e a s s ma l l as comp atible with the fluid (for example, with its vi s co s ity and conta m i na nts) 5.4.3 The centreline of the upstream tapping(s) shall meet the centreline of the pipe At the point of break-through, the hole of the pressure tapping shall be circular The edges shall f f f f the pressure tapping 5.4.4 b e flus h with the p ip e wall and ree ro m b urrs The radius s hall no t exceed o ne- tenth o the diameter o 5.4.5 The up s tream p res s ure tap p ing s ho uld b e cylindrical over a length at leas t equal to the diameter 5.4.6 C o n fo rmity o f the p res s ure tap p ing with the two of the tapping inspection fo rego ing requirements is as s es s ed by vis ual 5.4.7 The spacing between the planes perpendicular to the pipe axis of the centrelines of the upstream pressure tapping(s) and the downstream tapping within the cone support, L, shall be a minimum of 50 mm and a maximum of D, as shown in Figure 5.4.8 The wns tream tap p ing thro ugh the co ne s hall b e cylindrical, and s hall have its centreline concentric to the centreline of the cone The diameter of this tapping shall be between 0,1 × dc and 0,2 × dc The hole of the pressure tapping shall be circular and the edges shall be free from burrs 5.5 Discharge coefficient, C 5.5.1 Limits of use A simultaneous use of extreme values for D, β, and ReD shall be avoided as otherwise the uncertainties given in 5.7 might increase 5.5.2 for D, β, and ReD, f f Clause of operation The effects of ReD, Ra/D, and β on C f f values of C f For i n s ta l l ation s outs ide the l i m its defi ne d i n d i s cha rge co e fic ient it i s ne ce s s ar y to c a l ibrate the or e ach me ter i n accorda nce with over its enti re Reynold s nu mb er range are no t ye t s u fic iently known outs ide the l i m its defi ne d i n th i s p a r t o 5.5.2 Discharge coefficient of the cone meter Cone meters as per Figure 50 mm ≤ ,45 ≤ D c a n on ly b e u s e d i n accordance with th i s p a r t o f I S O 5167 when ≤ 500 mm β ≤ ,75 × 10 ≤ ReD ≤ , × 10 Under the s e cond ition s , the va lue o f the d i s cha rge co e ffic ient, C or it to b e p o s s ible to give rel iable I S O 5167 = 0,82 , for an uncalibrated meter is C © ISO 2016 – All rights reserved ISO 5167-5:2016(E) 5.6 Expansibility (expansion) factor, ε T he e xp a n s ibi l ity (exp a n s ion) ε fac tor, ε, i s c a lc u l ate d b y me an s o f Formu l a (5 ) = − (0, 649 + 0, 696 β ) ∆p (5) κ p1 Formu la (5 ) was derive d b y Stewar t e t a l [10] Test results for determination of ε However, Formu la (5 ) i s genera l ly appl ie d to cone me ters exponent is known However, the Formu la (5 ) i s on ly appl ic able i f Va lue s o f the e xp an s ibi l ity (e xp an s ion) are given for convenience in Table A.1 5.7 for ga s e s and vap ou rs are on ly known for wh ich for r the i s entropic / p2 p1 ≥ ,75 fac tor for a range o f i s entropic exp onents , pre s s u re ratio s , a nd β Uncertainty of the discharge coefficient, C T he u ncer ta i nty o f a n u nc a l ibrate d cone me ter, as given b elow, i s relatively h igh when comp a re d to o ther I S O 5167 d i fferenti a l pre s s ure device s However, i f a flow ca l ibration i s c arrie d out as p er Clause 7, the u ncer tai nty i n d i s cha rge co e fficient i s comp arable to th at o f the s e o ther device s T here fore, for app l ic ation s re qui ri ng h igher acc u rac y, it i s re com mende d that ever y cone me ter i s c a l ibrate d over the fu l l op erationa l range o f Reynold s numb er a s i s s p e ci fie d i n Clause 5.5.2 T he rel ative u ncer tai nty o f the d i s charge co e fficient as given i n i s e qua l to % , e xpre s s e d at a % fidence level For a given flowrate , the u ncer tai nty o f the d i s charge co e fficient a nd that o f the pre d ic te d d i fferenti a l pre s s u re are d i re c tly l i n ke d C on s e quently, ca re sh a l l be ta ken with de term i ni ng β maximum differential pressure does not exceed the upper range limit of the transmitter For cone meters with values of β such that the > ,75 , the u ncer tai nty i n the u nc a l ibrate d d i s cha rge co e ffic ient h as b e en fou nd to b e gre ater tha n % 5.8 Uncertainty of the expansibility (expansion) factor, ε From avai lable data, the absolute uncertainty o f 0, 096 5.9 ε is es timated (expres s ed at a 95 % confidence level) to b e Dp (6) κ p1 Pressure loss T he pre s s u re lo s s , Δ ω , for the cone me ter de s c rib e d i n th i s p a r t o f I S O p, b y Formu la (7 ) 5167 i s approxi mately relate d to the d i fferentia l pre s s u re, Δ (7) ∆ω = (1, 09 − 0, 813 β)∆p This pressure loss is the difference in static pressure between the pressure measured at the wall on the D upstream of the nose of the cone), and that f f D downstream of the cone) up s tre am s ide o f the cone as s emb ly, at a s e c tion where the i n fluence o f the appro ach i mp ac t pre s s u re adj acent to the cone i s s ti l l negl igible (approxi mately me as u re d on the down s tre a m s ide o the cone, where the s tatic pre s s u re re cover y b y exp an s ion o the j e t may b e s idere d a s j u s t comple te d (approxi mately NOTE When comparing the permanent pressure loss of a cone meter with alternative differential pressure meter designs, it is important to compare meter designs that are sized to provide a similar range of differential pressure, rather than comparing the different meter designs with the same value of β © ISO 2016 – All rights reserved ISO 5167-5:2016(E) Installation requirements 6.1 General General installation requirements for pressure differential devices are contained in ISO 5167-1:2003, C lau s e a nd s hou ld b e for fol lowe d i n conj u nc tion with the add itiona l s p e ci fic i n s ta l lation re qui rements cone me ters given i n th i s C l au s e T he genera l re qui rements device a re given i n I S O 5167-1 : 0 , T he re qu i rements for for flow cond ition s at the pri ma r y u s e o f a flow cond itioner a re given i n I S O 5167-1 : 0 , 7.4; however, flow cond itioners a re genera l ly no t re qu i re d for cone me ters Key upstream straight length downstream straight length flow Figure — Straight lengths within cone meter 6.2 Minimum upstream and downstream straight lengths for installations between various fittings and the cone meter 6.2.1 General C one me ters are relatively i n s en s itive to com mon flow d i s tu rb ance s; however, the de s igner o f the me teri ng s ys tem s hou ld ma ke re as onable e ffor ts to m i n i m i z e flow d i s tu rb ance s where p o s s ible Un le s s it i s e xpl ic itly s tate d, the re s i s tance to flow d i s tu rb a nce s i s as s u me d to b e i ndep endent o f the line size of the cone meter The effect of an upstream disturber is relative to the meter’s performance with no disturber installed Upstream straight lengths shall be measured from the downstream end of the curved portion of the f f to the plane of the centreline of the upstream tapping(s) of the cone meter, as shown in Figure Downstream straight lengths shall be measured from the plane of the beta edge, as shown in Figure 6, f f f curved or conical portion of a reducer or expander Fittings at least D downstream of the cone meter introduce no additional errors ne are s t (or on ly) b end or the down s tre am end o to the up s tre am end o 10 the c ur ve d p or tion o the c u r ve d or ic a l p or tion o a re ducer or e xp ander the ne are s t (or on ly) b end or the up s tre am end o the © ISO 2016 – All rights reserved ISO 5167-5:2016(E) 6.2.2 Single 90° bend For 0,45 ≤ β < 0,6, a minimum of D upstream straight length is required For 0,6 ≤ β ≤ 0,75, a minimum of 6D upstream straight length is required 6.2.3 Two 90° bends in perpendicular planes For 0,45 ≤ β < 0,6, a minimum of D upstream straight length is required For 0,6 ≤ β ≤ 0,75, a minimum of 6D upstream straight length is required 6.2.4 Concentric expander With a 0,75 D to D concentric expander D upstream of a cone meter, an additional uncertainty in flow rate o f up to 0,5 % can be expected A concentric reducer is a less significant flow disturber than a concentric expander 6.2.5 Partially closed valves A partially closed valve should not be installed within 10 D upstream o f a cone meter Fully open, full- bore, isolation valves introduce no additional errors 6.3 Additional speci fic installation requirements for cone meters 6.3.1 Circularity and cylindricality of the pipe Over an upstream length of at least D measured from the plane of the centreline of the upstream pressure tapping(s), the pipe shall be cylindrical The pipe is said to be cylindrical when no diameter in any plane di ffers by more than % from the mean o f the measured diameters o f the pipe at 6.3.1.1 that plane The number of measurements in a plane shall be equal to a minimum of four At least one axial plane shall be examined in addition to plane C from Figure 6.3.1.2 Over a downstream length of at least D measured from the plane of the beta edge of the cone meter, the pipe shall be cylindrical The pipe is said to be cylindrical when no diameter in any plane di ffers by more than % from the mean o f the measured diameters o f the pipe at that plane The number of measurements in a plane shall be equal to a minimum of four At least one axial plane shall be examined in addition to plane A from Figure The mean diameter o f pipe where it joins the cone meter shall be within % o f the cone meter diameter, D, as defined in 5.2.3 6.3.1.3 6.3.2 Roughness of the upstream and downstream pipe The upstream and downstream pipe roughness criterion Ra shall be less than 10 -3 D over the lengths of D upstream and D downstream 6.3.3 Positioning of a thermowell If a thermowell is installed, it is recommended that its location be upstream of the straight length requirement No correction for Joule-Thomson e ffect is necessary Where a thermowell is installed in the straight length requirement or between the plane of the centreline of the upstream pressure tapping(s) and the nose of the cone, the meter shall be calibrated with the thermowell installed The thermowell shall not be installed in line with an upstream pressure tapping No correction for Joule-Thomson e ffect is necessary © ISO 2016 – All rights reserved 11 ISO 5167-5:2016(E) If a thermowell is installed downstream of the cone its location shall be between D and 15 D downstream of the plane of the beta edge Refer to 5.9 and ISO 5167-1:2003, 5.4.4.1 for guidance on calculating the temperature correction to an upstream tapping A thermowell shall not be installed within D downstream of the plane of the beta edge Flow calibration of cone meters 7.1 General For users o f cone meters o f the geometry described in this part o f ISO 5167 that require a lower discharge coe fficient uncertainty than that stated in 5.5.2 , or for users o f devices where the geometry differs from that described in this part of ISO 5167, the cone meter shall be calibrated The purpose o f a flow calibration is to determine the discharge coe fficient o f an individual cone meter and its associated uncertainty Where the geometry o f the cone meter di ffers from that described in this part o f ISO 5167, the expansibility equation given in Formula (5) shall not be used unless verified In such a case, the manu facturer o f the cone meter shall provide an appropriate equation for the expansibility (expansion) factor Calibrated meters shall only be used over the calibrated Reynolds number range 7.2 Test facility The cone meter shall be calibrated in such a manner as to ensure appropriate traceability for the user o f the cone meter for the intended application NOTE For guidance on what might be appropriate, ISO/IEC 17025 is applicable 7.3 Meter installation The cone meter should be installed with a minimum of six diameters of upstream straight length of the same nominal pipe diameter immediately preceding the cone meter Similarly, the cone meter should have a minimum of two diameters of downstream straight length of the same nominal pipe diameter immediately a fter the cone meter Flow conditioners are not required for cone meter calibration The orientation of the cone meter is irrelevant I f the cone meter in operation will be installed in pipe work that significantly di ffers from the installation guidelines in this part of ISO 5167, or if β > 0,75, the operational pipe design should be replicated at the calibration facility in order to reduce the uncertainty o f the cone meter in its installation 7.4 Design of the test programme The cone meter should be calibrated, as a minimum, over the entire Reynolds number range the meter is expected to see in operational service The test facility can calibrate the cone meter using liquid or gas, or both liquid and gas in separate tests to cover the required Reynolds number range The calibration data of a cone meter is not transferrable to another cone meter If the meter has multiple sets of tappings, each set shall be calibrated as if it were a separate meter Extrapolation of the calibration shall not be permitted A minimum o f six test points shall be taken approximately evenly spread across the Reynolds number range, with a minimum o f three data points taken for each test point to demonstrate the repeatability of the data 12 © ISO 2016 – All rights reserved ISO 5167-5:2016(E) 7.5 Reporting the calibration results The calibration test report shall provide both tabulated and graphical results of the differential pressure, Reynolds number, and discharge coe fficient values The discharge coe fficient versus Reynolds number relationship determined in the calibration process shall be implemented according to the user’s requirements If this relationship is not constant to within the user’s tolerance, then a non-constant mathematical expression should be used which will require an iterative solution Consistent with 7.4, the user shall not extrapolate this mathematical expression 7.6 Uncertainty analysis of the calibration 7.6.1 General All uncertainties calculated as part o f this flow calibration shall be stated to a 95 % confidence level 7.6.2 Uncertainty of the test facility The uncertainty o f the instrumentation used by the test facility shall be calculated and recorded for each test point o f the flow calibration The uncertainty in the flow measurement shall be computed from this data utilizing a method detailed in either ISO 5168 or ISO/IEC Guide 98-3 (GUM) Both the chosen method and the results shall be recorded in the calibration report Where both liquid and gas tests are separately used to cover the Reynolds number range, the uncertainties of each test facility for the relevant test points shall be clearly detailed in the calibration report 7.6.3 Uncertainty of the cone meter The calibration procedure and the calculated uncertainty o f the cone meter under test shall be recorded in the calibration report As so few measurements are taken at each Reynolds number, an appropriate statistical methodology shall be used, as, for instance, standard deviation should only be used for larger data sets © ISO 2016 – All rights reserved 13 ISO 5167-5:2016(E) Annex A (informative) Table of expansibility (expansion) factor Table A.1 — Cone meters — Expansibility (expansion) factor, ε β β4 Expansibility (expansion) factor, ε, for p /p equal to 0,98 0,450 0,500 0,550 0,600 0,650 0,700 0,750 0,041 0,062 0,091 0,129 0,178 0,240 0,316 1,000 1,000 1,000 1,000 1,000 1,000 1,000 0,988 0,988 0,988 0,987 0,987 0,986 0,985 0,450 0,500 0,550 0,600 0,650 0,700 0,750 0,041 0,062 0,091 0,129 0,178 0,240 0,316 1,000 1,000 1,000 1,000 1,000 1,000 1,000 0,989 0,989 0,989 0,988 0,988 0,987 0,986 0,450 0,500 0,550 0,600 0,650 0,700 0,750 0,041 0,062 0,091 0,129 0,178 0,240 0,316 1,000 1,000 1,000 1,000 1,000 1,000 1,000 0,990 0,990 0,989 0,989 0,989 0,988 0,987 0,450 0,500 0,550 0,600 0,650 0,700 0,750 0,041 0,062 0,091 0,129 0,178 0,240 0,316 1,000 1,000 1,000 1,000 1,000 1,000 1,000 0,991 0,991 0,991 0,991 0,990 0,990 0,989 0,96 0,94 for κ = 1,2 0,977 0,966 0,976 0,965 0,976 0,964 0,975 0,963 0,974 0,961 0,972 0,959 0,971 0,956 for κ =1,3 0,979 0,968 0,978 0,968 0,978 0,967 0,977 0,965 0,976 0,964 0,974 0,962 0,973 0,959 for κ =1,4 0,980 0,971 0,980 0,970 0,979 0,969 0,978 0,968 0,977 0,966 0,976 0,965 0,975 0,962 for κ =1,66 0,983 0,975 0,983 0,975 0,982 0,974 0,982 0,973 0,981 0,972 0,980 0,970 0,979 0,968 0,92 0,9 0,85 0,8 0,75 0,954 0,953 0,952 0,950 0,948 0,945 0,942 0,943 0,942 0,940 0,938 0,935 0,932 0,927 0,915 0,913 0,910 0,907 0,903 0,898 0,891 0,887 0,884 0,881 0,876 0,871 0,864 0,855 0,858 0,855 0,851 0,846 0,838 0,830 0,818 0,958 0,957 0,956 0,954 0,952 0,949 0,946 0,947 0,946 0,945 0,943 0,940 0,937 0,933 0,921 0,920 0,917 0,914 0,910 0,905 0,899 0,895 0,893 0,890 0,886 0,881 0,874 0,866 0,869 0,866 0,862 0,857 0,851 0,843 0,832 0,961 0,960 0,959 0,957 0,955 0,953 0,950 0,951 0,950 0,949 0,947 0,944 0,941 0,937 0,927 0,925 0,923 0,920 0,917 0,912 0,906 0,903 0,901 0,898 0,894 0,889 0,883 0,875 0,879 0,876 0,872 0,868 0,861 0,854 0,844 0,967 0,966 0,965 0,964 0,962 0,960 0,958 0,959 0,958 0,957 0,955 0,953 0,950 0,947 0,938 0,937 0,935 0,933 0,930 0,926 0,921 0,918 0,916 0,914 0,910 0,906 0,901 0,895 0,898 0,895 0,892 0,888 0,883 0,877 0,869 NOTE Table A.1 is given for convenience The values given are not intended for precise interpolation Extrapolation is not permitted 14 © ISO 2016 – All rights reserved