Doc. Number: N 733. ISO/TC 131/SC 5 Secretariat

Transcription

1 Control roducts and coonents ISO/TC 3/SC 5 Date: Assistant: RIVAULT Estelle Direct line: e.rivault@un.fr Doc. Nuber: N 733 Your contact: BUTAYE Alexandre Direct line: a.butaye@un.fr ISO/NWIP Deterination of flow-rate characteristics of coonents using coressible fluids Part 5: Test ethod to deterine ower loss in steady-state flow COMMENTS/ DECISIONS Based on the ISO roject leader roosal, it is roosed to include the odification into a searate art 5 to the standard. A NWIP is launched (see attached docuent). Ballot is to be done on ISO balloting ortal. Moreover, the roosed revision of art has to be cancelled (see doc. ISO/TC 3/SC 5 N 73). FOLLOW UP For inforation For voting before For discussion during the next eeting on SOURCE ISO/TC 3/SC 5 Secretariat Par délégation d'afnor / On behalf of AFNOR Union de Noralisation de la Mécanique - UNM 45, rue Louis Blanc F 94 Courbevoie F 938 Paris La Défense Cedex Tél 33 () Fax 33 () Internet : htt://

2 For 4: New Work Ite Proosal Circulation date: 6--8 Closing date for voting: Click here to enter text. Prooser John Berninger Reference nuber: Click here to enter text. (to be given by Central Secretariat) ISO/TC 3/SC 5 Proosal for a new PC Secretariat Alexandre Butaye, abutaye@un.fr A roosal for a new work ite within the scoe of an existing coittee shall be subitted to the secretariat of that coittee with a coy to the Central Secretariat and, in the case of a subcoittee, a coy to the secretariat of the arent technical coittee. Proosals not within the scoe of an existing coittee shall be subitted to the secretariat of the ISO Technical Manageent Board. The rooser of a new work ite ay be a eber body of ISO, the secretariat itself, another technical coittee or subcoittee, an organization in liaison, the Technical Manageent Board or one of the advisory grous, or the Secretary-General. The roosal will be circulated to the P-ebers of the technical coittee or subcoittee for voting, and to the O-ebers for inforation. IMPORTANT NOTE: Proosals without adequate justification risk rejection or referral to originator. Guidelines for roosing and justifying a new work ite are contained in Annex C of the ISO/IEC Directives, Part. The rooser has considered the guidance given in the Annex C during the rearation of the NWIP. Proosal (to be coleted by the rooser) FORM 4 New work ite roosal Version /5

3 Title of the roosed deliverable. English title: Pneuatic fluid ower Deterination of flow-rate characteristics of coonents using coressible fluids Part 5: Test ethods to deterine ower loss in steady state flow French title (if available): Transissions neuatiques --- Déterination des caractéristiques de débit des coosants traversés ar un fluide coressible Partie 5 : Méthodes d essai our déteriner la erte de uissance en régie stationnaire (In the case of an aendent, revision or a new art of an existing docuent, show the reference nuber and current title) Scoe of the roosed deliverable. A new Part 5 to the ISO 6358 series of standards to include the ethod of deterining ower loss through the coonent. Purose and justification of the roosal* A new standard is needed to deterine ower loss in neuatic valves. This is art of the energy issues that TC 3 is develoing. Energy analysis of neuatic systes will be addressed also in SC 9/WG. Consider the following: Is there a verified arket need for the roosal? What roble does this standard solve? What value will the docuent bring to end-users? See Annex C of the ISO/IEC Directives art for ore inforation. See the following guidance on justification stateents on ISO Connect: htts://connect.iso.org/ages/viewage.action?ageid=75986 Prearatory work (at a iniu an outline should be included with the roosal) A draft is attached An outline is attached An existing docuent to serve as initial basis The rooser or the rooser's organization is reared to undertake the rearatory work required: Yes No If a draft is attached to this roosal,: Please select fro one of the following otions (note that if no otion is selected, the default will be the first otion): Draft docuent will be registered as new roject in the coittee's work rograe (stage.) Draft docuent can be registered as a Working Draft (WD stage.) Draft docuent can be registered as a Coittee Draft (CD stage 3.) Draft docuent can be registered as a Draft International Standard (DIS stage 4.) Is this a Manageent Systes Standard (MSS)? Yes No NOTE: if Yes, the NWIP along with the Justification study (see Annex SL of the Consolidated ISO Suleent) ust be sent to the MSS Task Force secretariat (tb@iso.org) for aroval before the NWIP ballot can be launched. FORM 4 New work ite roosal Version /5

4 Indication(s) of the referred tye or tyes of deliverable(s) to be roduced under the roosal. International Standard Technical Secification Publicly Available Secification Technical Reort Proosed develoent track (4 onths) (36 onths - default) 3 (48 onths) Note: Good roject anageent is essential to eeting deadlines. A coittee ay be granted only one extension of u to 9 onths for the total roject duration (to be aroved by the ISO/TMB). Known atented ites (see ISO/IEC Directives, Part for iortant guidance) Yes No If "Yes", rovide full inforation as annex Co-ordination of work: To the best of your knowledge, has this or a siilar roosal been subitted to another standards develoent organization? Yes No If Yes, lease secify which one(s): Click here to enter text. A stateent fro the rooser as to how the roosed work ay relate to or iact on existing work, esecially existing ISO and IEC deliverables. The rooser should exlain how the work differs fro aarently siilar work, or exlain how dulication and conflict will be iniized. Power loss was not taken into consideration when develoing the ISO 6358 series. It needs to be added. An earlier NWI ballot, although successful, roosed a revision to ISO Several coents received with the ballot indicated that Part is already too large and adding the ower loss akes it unwieldly. Therefore, the roosal is being re-balloted to be a new standard; Part 5 to the ISO 6358 series. A listing of relevant existing docuents at the international, regional and national levels. Click here to enter text. A sile and concise stateent identifying and describing relevant affected stakeholder categories (including sall and ediu sized enterrises) and how they will each benefit fro or be iacted by the roosed deliverable(s) This new Part 5 to the ISO 6358 series offers a test ethod to deterine energy inforation for users of neuatic coonents. Liaisons: A listing of relevant external international organizations or internal arties (other ISO and/or IEC coittees) to be engaged as liaisons in the develoent of the deliverable(s). None known at this tie. Joint/arallel work: Possible joint/arallel work with: IEC (lease secify coittee ID) Click here to enter text. CEN (lease secify coittee ID) Click here to enter text. Other (lease secify) Click here to enter text. FORM 4 New work ite roosal Version /5

5 A listing of relevant countries which are not already P-ebers of the coittee. Click here to enter text. Note: The coittee secretary shall distribute this NWIP to the countries listed above to see if they wish to articiate in this work Proosed Project Leader (nae and e-ail address) John Berninger, Nae of the Prooser (include contact inforation) John Berninger, This roosal will be develoed by: An existing Working Grou (lease secify which one: TC 3 SC5 WG3) A new Working Grou (title: Click here to enter text.) (Note: establishent of a new WG ust be aroved by coittee resolution) The TC/SC directly To be deterined Suleentary inforation relating to the roosal This roosal relates to a new ISO docuent; This roosal relates to the adotion as an active roject of an ite currently registered as a Preliinary Work Ite; This roosal relates to the re-establishent of a cancelled roject as an active roject. Other: Click here to enter text. Annex(es) are included with this roosal (give details) Click here to enter text. FORM 4 New work ite roosal Version /5

6 ISO 6 All rights reserved Date: 6--8 ISO NP ISO/TC 3/SC 5 Secretariat: AFNOR Pneuatic fluid ower Deterination of flow-rate characteristics of coonents using coressible fluids Part 5: Test ethod to deterine ower loss in steady-state flow Éléent introductif Éléent rincial Partie n: Titre de la artie Warning This docuent is not an ISO International Standard. It is distributed for review and coent. It is subject to change without notice and ay not be referred to as an International Standard. Reciients of this draft are invited to subit, with their coents, notification of any relevant atent rights of which they are aware and to rovide suorting docuentation.

7 Coyright notice This ISO docuent is a working draft or coittee draft and is coyright-rotected by ISO. While the reroduction of working drafts or coittee drafts in any for for use by articiants in the ISO standards develoent rocess is eritted without rior erission fro ISO, neither this docuent nor any extract fro it ay be reroduced, stored or transitted in any for for any other urose without rior written erission fro ISO. Requests for erission to reroduce this docuent for the urose of selling it should be addressed as shown below or to ISO s eber body in the country of the requester: [Indicate : the full address telehone nuber fax nuber telex nuber and electronic ail address as aroriate, of the Coyright Manager of the ISO eber body resonsible for the secretariat of the TC or SC within the fraework of which the draft has been reared] Reroduction for sales uroses ay be subject to royalty ayents or a licensing agreeent. Violators ay be rosecuted. ii ISO 6 All rights reserved

8 Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO eber bodies). The work of rearing International Standards is norally carried out through ISO technical coittees. Each eber body interested in a subject for which a technical coittee has been established has the right to be reresented on that coittee. International organizations, governental and non-governental, in liaison with ISO, also take art in the work. ISO collaborates closely with the International Electrotechnical Coission (IEC) on all atters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part. The ain task of technical coittees is to reare International Standards. Draft International Standards adoted by the technical coittees are circulated to the eber bodies for voting. Publication as an International Standard requires aroval by at least 75 % of the eber bodies casting a vote. Attention is drawn to the ossibility that soe of the eleents of this docuent ay be the subject of atent rights. ISO shall not be held resonsible for identifying any or all such atent rights. ISO was reared by Technical Coittee ISO/TC 3, Fluid ower systes, Subcoittee SC 5, Control roducts and coonents. This first edition of ISO , together with ISO 6358-, ISO 6358-, ISO and ISO , cancels and relaces ISO 6358:989, which has been technically revised. However, ISO 6358-, ISO , ISO and ISO are new standards whose scoes were not included in ISO 6358:989. ISO 6358 consists of the following arts, under the general title Pneuatic fluid ower Deterination of flow-rate characteristics of coonents using coressible fluids: Part : General rules and test ethods for steady-state flow Part : Alternative test ethods Part 3: Method for calculating steady-state flow-rate characteristics of asseblies Part 4: Method for calculating effective conductance Part 5: Test ethod to deterine ower loss in steady state flow ISO 6 All rights reserved iii

9 Introduction In neuatic fluid ower systes, ower is transitted and controlled through a gas under ressure within a circuit. Coonents that ake u such a circuit are inherently resistive to the flow of the gas and it is necessary, therefore, to define and deterine the flow-rate characteristics that describe their erforance. ISO 6358:989 was develoed to deterine the flow-rate characteristics of neuatic valves, based uon a odel of converging nozzles. The ethod included two characteristic araeters: sonic conductance, C, and critical ressure ratio, b, used in a roosed atheatical aroxiation of the flow behaviour. The result described flow erforance of a neuatic valve fro choked flow to subsonic flow, based on static ressure. This new edition uses stagnation ressure instead, to take into account the influence of flow velocity on the easureent of ressures. Exerience has deonstrated that any neuatic valves have converging-diverging characteristics that do not fit the ISO 6358:989 odel very well. Furtherore, new develoents have allowed the alication of this ethod to additional coonents beyond neuatic valves. However, this now requires the use of four araeters (C, b,, and Δ c ) to define the flow erforance in both the choked and subsonic flow regions. This art of ISO 6358 describes a test ethod to deterine the ower loss of a neuatic coonent using ost of the test equient and data obtained fro the test conducted in Part. It is necessary to exand the equient to obtain a downstrea teerature; and to obtain very accurate teerature data both ustrea and downstrea A theory and develoent of the equations are given in an annex. iv ISO 6 All rights reserved

10 Pneuatic fluid ower Deterination of flow-rate characteristics of coonents using coressible fluids Part 5: Test ethod to deterine ower loss in steady-state flow Scoe This art of ISO 6358 secifies a steady-state ethod for testing neuatic fluid ower coonents that use coressible fluids, i.e. gases, and that have internal flow aths that can be either fixed or variable in size, to deterine their flow-rate characteristics and ower loss. In addition it does not aly to coonents that exchange energy with the fluid during flow-rate easureent, e.g., cylinders, accuulators, etc. This test ethod uses data obtained fro the rocedures of Part, both the constant ustrea ressure test and the variable ustrea ressure test. It is alicable to the coonents shown in Table : Table Alication of ISO 6358 test ethods to coonents Coonents Constant ustrea ressure test ISO constant ustrea ressure test ISO charge test Variable ustrea ressure test ISO variable ustrea ressure test ISO discharge test Grou Directional control valves yes no yes no Flow control valves yes no yes no Connectors yes no yes no Valve anifolds yes no yes no Grou of coonents no no no no Grou Filters and lubricators yes no no no Non-return (check) valves yes no no no Tubes and hoses yes no no no Grou 3 Silencers and exhaust oil ist searators no no no no Blow nozzles no no no no Quick-exhaust valves no no no no Cylinder end heads no no no no This art of ISO 6358 secifies requireents for the test installation, the test rocedure and the resentation of results for steady-state ethod. Develoent of the equations for ower loss, and an exale calculation, is given in Annex A. 5

11 Norative references The following referenced docuents are indisensable for the alication of this docuent. For dated references, only the edition cited alies. For undated references, the latest edition of the referenced docuent (including any aendents) alies. ISO 9-, Fluid ower systes and coonents Grahic sybols and circuit diagras Part : Grahic sybols for conventional use and data-rocessing alications ISO 5598, Fluid ower systes and coonents Vocabulary ISO 6358-, Pneuatic fluid ower Deterination of flow-rate characteristics of coonents using coressible fluids Part : General rules and test ethods for steady-state flow 3 Ters and definitions For the uroses of this art of ISO 6358, the ters and definitions given in ISO 5598 and ISO aly. An additional ter is defined below: Power loss the loss of energy er unit of tie (exressed as watts) for gas assing through the coonent. 4 Sybols and units 4. The sybols and units used throughout this art of ISO 6358 shall be in accordance with Table. vi ISO 6 All rights reserved

12 a Table Sybols and units Reference Descrition Sybol Diension a SI unit b Flow area A L Critical back-ressure ratio b ure nuber 3.4. Conductance C e L 4 TM - 3 /(s. Pa)(ANR) 3.4. Sonic conductance C L 4 TM - 3 /(s. Pa)(ANR) Subsonic index ure nuber Secific heat at constant ressure C L s Θ J/kg K Mass force conversion g' diensionless Kg /Ns - Absolute stagnation ressure ML - T - Pa c Inut ower (e.g. solenoid) P ML T 3 watt - Mass flow rate q MT - kg/s - Volue flow rate at standard reference atoshere q v L 3 T - 3 /s(anr) - Gas constant (for a erfect gas) R L T - Θ - J/(kg. K) - Absolute stagnation teerature T Θ K Absolute static teerature τ Θ K Cracking ressure c ML - T - Pa c Pressure deendence coefficient K M - LT Pa - - Mass density ρ ML -3 kg/ 3 M = ass; L = length; T = tie; Θ = teerature b The use of ractical units for the resentation of results is described in Annex F of ISO c Pa = N/ 4. The nuerals used as subscrits and the asterisk (*) used as a suerscrit to the sybols listed in Table shall be used as secified in Table 3. Table 3 Subscrits and suerscrits Suerscrit Subscrit Meaning Conditions of standard reference atoshere defined in ISO 8778, i.e.: T = 93,5 K = kpa ( bar a ) ρ =,85 kg/ 3 65% relative huidity Ustrea conditions Downstrea conditions * Conditions during choked flow tests a bar = kpa =, MPa; Pa = N/ 7

13 5 Test installation NOTE Figures and illustrate basic circuits that do not incororate all the safety devices necessary to rotect against daage in the event of coonent failure. It is iortant that those resonsible for carrying out the test give due consideration to safeguarding both ersonnel and equient. 5. Test circuit for constant ustrea ressure test 5.. If ressure-easuring tubes can be connected on the ustrea and downstrea sides of the coonent under test, a suitable test circuit as shown in Figure shall be used. NOTE See Table 4 for the key to test circuit coonents. Figure Test circuit for constant ustrea ressure test 5.. An alternative to this test circuit is shown in Annex A of ISO Test circuit for variable ustrea ressure test If the coonent under test has a connecting ort on its downstrea side, a suitable test circuit as shown in Figure shall be used. If the coonent does not have a connecting ort on its downstrea side (such as silencer), the test cannot be conducted. NOTE See Table 4 for the key to test circuit coonents. Figure Test circuit for variable ustrea ressure test viii ISO 6 All rights reserved

14 Table 4 Key to test circuit coonents shown in Figures and Key ite nuber Relevant subclause or aragrah Descrition Additional recoendations and requireents 5.3. Coressed gas source and filter - Adjustable ressure regulator 3 - Shut-off valve Preferably with a straight flow ath 4 - Flow-rate easuring device May also be laced in osition 4 (i.e. downstrea of the downstrea ressureeasuring tube ([ite ]). 5 - Teerature-easuring instruent Sensor located on axis of the ustrea ressure-easuring tube (ite 6). See 5.4. and Ustrea ressure-easuring tube Ustrea transition connector Attached to the ressure-easuring tube and coonent under test 8 - Coonent under test Downstrea transition connector Attached to the ressure-easuring tube and coonent under test 5.4 Downstrea ressure-easuring tube - Ustrea ressure gauge or transducer - Downstrea ressure gauge or transducer A differential ressure gauge or transducer,, ay be used as an alternative. 3 - Flow control valve The sonic conductance of this flow control valve shall be about four ties larger than that of the coonent under test. 4 - Baroeter Nile a Not shown in Figures and ; see Figure Close nile a Not shown in Figures and ; see Figure 4. a As an otion, a set of ush-in connectors ay also be used. 5.3 General requireents 5.3. The coonent under test shall be installed and oerated in the test circuit in accordance with the anufacturer s oerating instructions A filter shall be installed which rovides a standard of filtration secified by the anufacturer of the coonent under test A test set-u shall be constructed fro the ites listed in Table 4, excet that ite 3 is not required for the variable ustrea ressure test All connections for ressure easureent shall be arranged so that entrained liquid cannot be traed or retained; a drain ay be rovided at any locations where liquid collects. 9

15 5.3.5 The inlet connector of the ustrea ressure-easuring tube shall have a gradual rofile to avoid disturbance of the flow Calibrate the floweter (see Annex B for inforation) before conducting the test. For tests conducted to deterine or verify catalogue data, the floweter shall have been calibrated in accordance with the best ractices of the laboratory Perfor a dead weight test of the ressure recording instruentation at least annually Instruentation in a circuit should not be located where vibration ay affect its accuracy. 5.4 Pressure-easuring tubes (ites 6 and ) 5.4. Pressure-easuring tubes that confor to Figure 3 shall be used. Tyical diensions of the ressure-easuring tubes are also secified in Table 5. The tube shall be straight, with a sooth, circular internal surface, and a constant diaeter throughout its length. The longitudinal centreline of the tube shall intersect with the centreline of the holes, and the centreline of the holes shall be noral to the longitudinal centreline. The junction of the hole with the internal surface of the tube shall have a shar edge and be free fro burrs. There shall be no obstruction or branch connection other than those secified. Key End that connects to transition connector Pressure-taing hole 3 Teerature-taing hole - necessary in the downstrea ressure easuring tube for calculating the ower loss; but not required in the downstrea ressure easuring tube to deterine flow characteristics. A teerature taing hole is necessary on the ustrea ressure-easuring tube if teerature is not easured ustrea elsewhere. Figure 3 Pressure-easuring tube x ISO 6 All rights reserved

16 Table 5 Tyical diensions of ressure-easuring tubes Diensions in illietres T a b c b b d d d 3 L L L 3 in. no. tol. no. tol. no. tol. G /8 6 4,5 8,4,76 5,5, 7,5,4 G /4 9 8,5,5,93 6,5,4,5 9,5,4 G 3/8,5,5 4,5,5,93 7,5,4,5,5,4 G / 6 6,5 8,5,93 9,4,5,4 G 3/4 3,5 4,65,7,5,4,5 3,5,4 G ,65,7,5,4,5 4,5,4 G / ,8,4 6,5,4,5,5,4 G / ,5,8,4 7,5,4,5,5,4 G ,,74 9,5,4,5 4,5,4 G / ,,74 3,4 3 9,4 G ,5,,7 5,5, ,6 a G threads in accordance with ISO 8-. b G thread length L and diensions d and L in accordance with ISO 63. c Liit deviations of tolerance class d 9 in accordance with ISO One teerature-taing hole ay be rovided on the ustrea ressure-easuring tube in accordance with Figure 3 for a teerature-easuring sensor that does not rotrude into the flow strea Because the location of the ustrea teerature sensor does not have a significant iact on the test results, the teerature sensor can be located in a convenient location ustrea fro the coonent under test. Alternate locations of the teerature sensor should be in a large-diaeter section of the suly syste iing, away fro any areas of sudden exansion When connecting ressure easuring instruents, the dead volue shall be liited as uch as ossible to avoid long resonse tie. 5.5 Transition connectors (ites 7 and 9) Transition connectors shall be ade in accordance with the diensions and requireents described in ISO Secial requireents 5.6. When the inlet and outlet orts of the coonent under test are different in structure or size fro those described above, or are different fro each other, ressure-easuring tubes and transition connectors that are suited to the relevant orts shall be used, but they shall confor in rincile to the diensions shown in 5.5 of ISO

17 5.6. Pressure-easuring tubes and transition connectors ay be joined or welded together by eans other than shown if all internal diensions in the flow ath are aintained, and the ilot fit is used between the When a transition connector interferes with the body of the coonent under test, or an adjacent connector, the variable ustrea ressure test shall be erfored. In this case, a transition connector (ite 7) shall be used with a nile (ite 5) or short tube connected to the ustrea ort. A close nile (ite 6) shall also be installed to the downstrea ort as shown in Figure 4. The inside diaeter of the nile and close nile (ites 5 and 6) should be equal to the inside diaeter d of the transition connector NOTE See Table 4 for the key to identify circuit coonents Figure 4 Test arrangeent for coonent with orts that are close to each other All secial requireents shall be recorded in the test reort. 6 Test rocedures 6. Test conditions 6.. Test fluid 6... Air should be used as the test fluid. If a different fluid is used, it shall be stated in the test reort The gas shall be filtered and conditioned to coly with the recoendations of the anufacturer of the coonent under test. 6.. Checks Periodically check that the ressure-taing holes are not blocked by liquids or solid articles Test easureents Each set of test readings shall be recorded after steady-state conditions have been reached. The variations of ressures, teerature and flow rate indications shall not exceed the liits given in the colun Allowed test conditions variation of Table Pressure, teerature and flow rate shall be easured within the easureent accuracy secified in Table 6. xii ISO 6 All rights reserved

18 Table 6 Measureent accuracy and allowed test condition variation of araeters Paraeter Measureent accuracy Allowed test condition variation Teerature ± K (flow characteristics); ±, K (ower loss) ± K Pressure ±,5% ±% Flow rate ±% ±4% NOTE See ISO/IEC Guide 98-3:8 and the Guide to the exression of uncertainty in easureent (GUM:8 fro ISO/IEC/BIPM) Flow conditions in each flow ath shall be aintained constant within the coonent while taking easureents to ensure there is no inadvertent oveent of coonent arts. 6. Measuring rocedures 6.. Requireents for testing to ublish catalogue ratings If data is to be used for ublishing ratings in a catalogue, a sale consisting of a iniu of five test units selected fro a rando roduction lot shall be tested in accordance with the following rocedures. 6.. Selection of easuring rocedure Either the rocedure described in 6..3 or the rocedure described in 6..4 shall be selected in accordance with the scoe of this art of ISO If the alternative test circuit in Annex A of ISO is used, only the rocedure described in 6..3 shall be selected, with the ressures adjusted as described in A. and A.3 of ISO Measuring rocedure for constant ustrea ressure test (see Figure ) Maintain a constant ustrea ressure,, of not less than 5 kpa (5 bar) and referably higher. Adjust the ressure regulator (ite ) as required to aintain at a constant value throughout the test for each easured oint. Measure the atosheric ressure using the baroeter (ite 4) Decrease the downstrea ressure,, to its sallest ossible value by oening the flow control valve (ite 3) to its axiu flow rate. In these conditions, ost coonents are choked. Measure ustrea teerature, T *, downstrea teerature, T, ustrea ressure, *, choked ass flow rate, q *, and downstrea ressure, * Partly close the flow control valve (ite 3) ste by ste to obtain two ore data oints in the choked flow region. Record the sae additional data as in Allow sufficient tie between settings for the syste to stabilize, because the data cannot be recorded when the flow rate varies continually Continue closing the flow control valve (ite 3) ste by ste to obtain at least five aroxiately equally-saced data oints in the subsonic flow region. For each oint, easure and record the ustrea teerature, T, downstrea teerature, T, ustrea ressure,, ass flow rate, q, and downstrea ressure,. This is a decreasing flow rate test To observe if the coonent under test has disersion or hysteresis, artly oen the flow control valve (ite 3) ste by ste to easure five oints sread out over the subsonic flow region of ressure ratio / and three oints sread out over the choked flow region. This is an increasing flow rate test. 3

19 For each oint in the subsonic flow region, easure and record the ustrea teerature, T, downstrea teerature, T, ustrea ressure,, ass flow rate, q, and downstrea ressure,. For each oint in the choked flow region, easure and record the ustrea teerature, T *, downstrea teerature, T, ustrea ressure, *, choked ass flow rate, q *, and downstrea ressure, * Measuring rocedure for variable ustrea ressure test (see Figure ) Set the ustrea ressure,, to aroxiately 5 kpa (5 bar) to ensure that the flow in the coonent under test is choked. Measure the downstrea ressure,. If the downstrea transition connector cannot connect to the coonent under test, easure the atosheric ressure as Measure the choked ass flow rate, q *, ustrea teerature, T *, downstrea teerature, T, ustrea ressure, *, and downstrea ressure, * Adjust the ressure regulator (ite ) to reduce ste by ste the ustrea ressure,, to obtain two ore data oints in the choked flow region. Record the sae additional data as in Allow sufficient tie between settings for the syste to stabilize, because the data cannot be recorded when the flow rate varies continually Continue adjusting the ressure regulator (ite ) ste by ste to obtain at least five aroxiately equally-saced data oints in the subsonic flow region. For each data oint, easure and record the ustrea teerature, T, downstrea teerature, T, ustrea ressure,, ass flow rate, q, and downstrea ressure,. This is a decreasing flow rate test. 6.3 Calculation of ower loss Deterine the ower loss fro the following equation: q R g A ' A C P Power loss = o q See annex A for conversion of stagnation teerature to static teerature. 7 Presentation of test results 7. All easureents, including the inside diaeter of the ressure-easuring tube, and the results of calculations shall be tabulated by the testing laboratory. 7. If data is to be used for ublishing ratings in a catalogue, the average of results fro the test units shall be reorted. 7.3 Describe the ower loss as a function of voluetric flow rate (see exale in Annex A). 7.4 The record of the calibration of easuring devices shall be available. 8 Identification stateent (reference to this art of ISO 6358) Use the following stateent in test reorts, catalogues and sales literature when electing to coly with this International Standard: "Power loss of neuatic coonents deterined in accordance with ISO , Pneuatic fluid ower Deterination of flow-rate characteristics of coonents using coressible fluids Part 5: Test ethod to deterine ower loss in steady state flow. xiv ISO 6 All rights reserved

20 Annex A (inforative) Power loss and exale data calculation Consider the energy boundary - of a neuatic valve assing air as shown in Fig. I: Fig. A Energy boundary of a neuatic valve The energy equation alied to the scheatic in Fig. A, including an energy loss, would be: (KE + PE + IE + flow work) in + Heat added + Shaft work in + EE in = (KE +PE + IE + flow work) out + Shaft work out + Energy Losses For coonents such as valves, filters and iing the shaft work is zero, and the elevation difference (PE) between inlet and outlet is negligible. Also, heat is not added. Therefore, this equation becoes: (KE + IE + flow work) in - (KE + IE + flow work) out + EE in = Energy Losses (A) These ters can be exressed as the following for a differential eleent of fluid ass: V V ( d ) I( d ) AV ( dt) ( d ) I ( d ) AV ( dt) dee d( ) g' g' Loss in (A) Where the subscrits and reresent inlet and outlet, resectively. And: g = ass-force conversion unit: kg /Ns It is roosed that this initial analysis will only consider steady state conditions. Then, the ass entering the valve will be the sae as the ass leaving: d = d = d. Equation (A) then becoes: 5

21 V V ( d) ( I I) d AV AV ( dt) d EE d( ) g' g' Loss in (A3) d Fro the continuity equation for a differential aount of ass flow: AV = q dt Then: q ( dt) d where q is ass flow rate and is constant for steady state. Substituting these into (A3): V V q ( dt) I I q ( dt) AV AV ( dt) dee d( ) g' g' Loss in (A4) Equation (A4) results in an energy loss in ters of Newton eters. Units check: Ns s kg kg s N kg kg s 3 Pa N kpa Pa s kpa s N N Since there is no shaft work, it is roosed that the energy loss be converted to ower loss. Power is the rate of energy use, so: Energy Loss Loss( dt) Power Loss = (A5) tie t For steady state conditions, all of the ters in equation (I4) are constant. Therefore: Loss( dt) V V q ( t) I I q ( t) AV AV ( t) P ( ) t t g' g' t (A6) Where: P o = electrical ower inut (e.g. solenoids). Then equation (A5) becoes: V g' V g' Power loss = q I I q AV AV Po (A7) In neuatics, the density of fluids entering and leaving a coonent is not constant. And, consequently, the velocity of the fluids entering and leaving cannot be assued to be the sae even if the flow areas are equal. Fro the erfect gas law: v = Rτ and /Rτ = /v = ρ (A8) Fro the continuity equation at steady state: q = AVρ; then V=q /Aρ = q Rτ/A (A9) xvi ISO 6 All rights reserved

22 7 (If the inlet and outlet areas of a coonent are the sae size, A = A = A.) Substituting these into equation (A7) Power loss = o P q I I A R q A R q g ) ( ' (A) Power loss = o P q I I A A g R q ' (A) Fro therodynaics, it is recognized that enthaly, h = I. Then (A) becoes: Power loss = o P q h h A A g R q ' (A) For a erfect gas: (h h ) = c (τ τ ) Where: c = coefficient of secific heat at constant ressure. Power loss = o P q C A A g R q ' (A3) A valve ust be tested in order to obtain the data necessary for equation (A3). When conducting such a test, the teerature easureents obtained are tyically stagnation values. But, the teerature ters in equation (A3) are static teeratures so a conversion is necessary. This is described by equation (A4): K KT T S 4 (A4) The constant is deterined fro: ' g R A q K (A5) γ =.4 (adiabatic constant) The factor α is a recovery factor, which is deendent on the Reynolds and Prandtl nubers. d q d d q A d q d V N R 4 4 and k c N Pr (A6) Where τ S = static teerature T T = stagnation teerature Where: μ = dynaic viscosity c = secific heat k = theral conductivity of air

23 (Eq. (A9) used in N R ) For lainar flow (N R <,), N (A7a) Pr For turbulent flow (N R >,), 3 (A7b) N Pr Table A: Variables for the recovery factor α Te. Dynaic viscosity μ Secific heat c Theral conduct. K C kg/hr. kj/kg K J/hr. K All data for this table is at atosheric ressure. The dynaic viscosity and secific heat can be assued constant with ressure. The theral conductivity (at - C), will increase aroxiately.8% fro bar to bar; at 4 C, the increase is aroxiately.%. Measured (stagnation) teeratures can be used in the table. Pneuatic Exale: Consider a test of a neuatic valve as shown in Fig. A: Fig. A Pneuatic valve in a test circuit xviii ISO 6 All rights reserved

24 Sale test data fro a ½ orted valve was recorded fro a test on 8 Oct., as shown in the Excel sreadsheet of Table A. Initial calculations are shown below: d = 7.7 A = A = A = (7.7) (π/4) = 6.6 Interolating fro Table A at C: μ =.655 kg/hr. c =.5 kj/kg K k = 93. J/hr. K Fro Eq. (A6): N R 4q d 4q kg 6in. in. hr. 4,5. 6 kg (7.7).655 hr. q (A Ex) Fro the data, it is observed that q >, therefore all of the flow is turbulent. Then, equation (I7b) is alicable: c k 3 kg J hr. 3 kgk J 93. hr.k 3 N 3 Pr.89 (A Ex) 6 kg in. N q 87 q R s in. 6 kg K q K.4.89 A g N,47 ' 3 kg A K A Pa.4 Pa Ns Values of K ust be calculated for both the inlet and outlet sides. Teeratures for both sides are then calculated fro equation (A4). Finally, the ower loss is deterined fro Eq. (A3): kg N q 87 in. in. kgk 36s kg PL A 6 Ns 3 kj N.5 ( ) K kgk kj K 6 Pa Pa N 4 q (A Ex3) 3 kg 6 in. whr. 6 in. hr. 3.6 N (A Ex4) q Power loss = 9,669 q A 6.75 watts P o = (electrical ower inut) is considered zero for this exale. (A Ex5) Table A shows the calculations fro an Excel sreadsheet. 9

25 Note that a ¼ K teerature adjustent was ade to the downstrea teerature easureents to avoid negative results. This is a reasonable adjustent in view of instruent accuracy, which was not in accordance with Table 6 at the tie of the test. Voluetric flow rate at standard conditions is deterined fro: q = AVρ = q v ρ since ρ = /Rτ = /Rτ where the subscrit denotes standard conditions ( = kpa; τ = C). N K q qr kg in. 3 kgk l qv q 4. 5q 3 in 6s 3 N Pa Pa l s (A Ex6) A grah of the results is shown in Fig. A3 below. Fig. A3 Test results for Power Loss Table A also has two coluns highlighted in red and blue, deonstrating the aount of ower loss attributed to the kinetic energy ortion (in red) and enthaly ortion (in blue). This corresonds to the ters likewise coloured in equation (A Ex5) reeated below: Power loss = q watts 9,669 q (A Ex5) A 6.75 Note that these are differences between inlet and outlet conditions. xx ISO 6 All rights reserved

26 Table A - Test data and calculations Inlet Press. kpa abs. Outlet Press. kpa abs. In Te. C T o Stagnation Original Adjusted Stagnation Static Static In Te. Reynolds K in K out In Te. K T o No. / K / K K T Out. Te. C T o Out. Te. C T o Out. Te. K T o Mass flow G kg/in. N R Out. Te. K T ΔT Power loss watts first ter Power loss watts nd ter Power loss watts , E E , E E ,66.635E 6.954E ,59.64E E ,53 4.E E ,8 4.87E 6.6E , E 6.577E Sonic , E 6.559E region ,8 6.96E E Ustrea flow rate Q ls ,338.94E 6.358E ,3.843E E , E E , E 6.9E , E 6.579E Sonic , E 6.33E region , E E , E E ,86.9E 6.48E ,97.59E E ,54 4.E E , E E Sonic ,77 5.8E 6.863E region ,39 5.E 6.963E ,65 5.4E E

27 Annex B (inforative) Floweter calibration B. General The floweter is a delicate easuring instruent and shall be checked frequently. A floweter ay have two levels of calibration: a) A riary calibration, erfored in accordance with legal etrology rules, resulting in a calibration curve associated with a easureent uncertainty. Fro this, a calibration table or a set of functions is used for corrections to the floweter readings when used in a laboratory. b) A secondary calibration checking erfored by coarison to a riary device, which erits verifying that recision and bias continue to be under adequate control. These verifications can be ade frequently and quickly and can use reference devices such as fixed orifice or, referably, Venturi nozzles. B. Reference devices Critical flow Venturi nozzles are widely used as floweters, check standards, and transfer standards. The oularity of these devices is a result of their excellent long-ter reroducibility, sile geoetric design, straightforward alication, and well understood hysics. The floweter calibration check in this annex coares the floweter readings to those of the reference Venturi nozzles. ISO 93 secifies the geoetry and ethod of use (installation in a syste and oerating conditions) of critical flow Venturi nozzles (CFVN) used to deterine the ass flow rate of a gas flowing through a syste. B.3 Floweter calibration checking rocedure B.3. B.3. B.3.3 B.3.4 B.3.5 A tyical set-u for a calibration is shown in Figure B., but other arrangeents are ossible: Record the baroetric ressure. As flow asses through the syste, record the ressures and teeratures. Coare the floweter readings to those of the reference device. Preare correction factors to aly to the floweter readings for use during testing. xxii ISO 6 All rights reserved

28 3 4 5 Key air suly floweter being calibrated 3 reference Venturi nozzle 4 flow control valve 5 exhaust to atoshere B.4 Alication to test data Figure B. Circuit for floweter calibration Aly the correction factors to the flow easureents ade during a test run, and use the corrected results as the final data. 3