1、BSI Standards PublicationBS ISO 6358-1:2013Pneumatic fluid power Determination of flow-rate characteristics of components using compressible fluidsPart 1: General rules and test methods for steady-state flowBS ISO 6358-1:2013National forewordThis British Standard is the UK implementation of ISO 6358
2、-1:2013. Together with BS ISO 6358-2:2013 and BS ISO 6358-3, it supersedes BS 7294:1990 (dual numbered as ISO 6358:1989) which will be withdrawn on publication of Part 3.The UK participation in its preparation was entrusted to Technical Committee MCE/18, Fluid power systems and components.A list of
3、organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2013. Published by BSI Standards Limit
4、ed 2013ISBN 978 0 580 71501 3 ICS 23.100.01 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2013.Amendments/corrigenda issued since publicationDate T
5、ext affectedBRITISH STANDARDBS ISO 6358-1:2013 ISO 2013Pneumatic fluid power Determination of flow-rate characteristics of components using compressible fluids Part 1: General rules and test methods for steady-state flowTransmissions pneumatiques Dtermination des caractristiques de dbit des composan
6、ts traverss par un fluide compressible Partie 1: Rgles gnrales et mthodes dessai en rgime stationnaireINTERNATIONAL STANDARDISO6358-1First edition2013-05-15Reference numberISO 6358-1:2013(E)BS ISO 6358-1:2013ISO 6358-1:2013(E)ii ISO 2013 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2013All ri
7、ghts reserved. Unless otherwise specified, no part of 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
8、either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 6358-1:2013ISO 6358-1:2013(E) ISO 2013 All rights r
9、eserved iiiForewordISO (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 technical committees. Each member body interested in a subject for
10、 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 a
11、ll 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 International Standards adopted by the technical committees are c
12、irculated 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 may be the subject of patent rights. ISO shall not be held respo
13、nsible for identifying any or all such patent rights.ISO 6358-1 was prepared by Technical Committee ISO/TC 131, Fluid power systems, Subcommittee SC 5, Control products and components.This first edition of ISO 6358-1, together with ISO 6358-2 and ISO 6358-3, cancels and replaces ISO 6358:1989, which
14、 has been technically revised. However, ISO 6358-2 and ISO 6358-3 are new standards whose scopes were not included in ISO 6358:1989.ISO 6358 consists of the following parts, under the general title Pneumatic fluid power Determination of flow-rate characteristics of components using compressible flui
15、d:Part 1: General rules and test methods for steady-state flowPart 2: Alternative test methodsThe following parts are under preparation: Part 3: Method for calculating steady-state flow-rate characteristics of assembliesBS ISO 6358-1:2013ISO 6358-1:2013(E)iv ISO 2013 All rights reservedContents Page
16、Introduction v1 Scope .12 Normative references 23 Terms and definitions .23.1 Terms and definitions related to pressures . 23.2 Terms and definitions related to temperature 23.3 Terms and definitions related to flow . 33.4 Terms and definitions related to flow-rate characteristics 33.5 Miscellaneous
17、 terms and definitions . 44 Symbols and units . 45 Test installation . 55.1 Test circuit for constant upstream pressure test . 55.2 Test circuit for variable upstream pressure test 65.3 General requirements . 75.4 Pressure-measuring tubes (items 6 and 10) . 75.5 Transition connectors (items 7 and 9)
18、 . 95.6 Special requirements 126 Test procedures 136.1 Test conditions . 136.2 Measuring procedures . 146.3 Calculation of characteristics 167 Presentation of test results 188 Identification statement (reference to this part of ISO 6358) 19Annex A (normative) Alternative test procedure .20Annex B (i
19、nformative) Flowmeter calibration 23Annex C (informative) Evaluation of measurement uncertainty .25Annex D (informative) Observations on error in test results 30Annex E (informative) Equations and graphical representations of flow-rate characteristics 41Annex F (informative) Use of practical units .
20、46Annex G (informative) Results of testing performed on commercially available pneumatic components 47Annex H (informative) Procedures for calculating critical back-pressure ratio, b, and subsonic index, m, by the least-square method using the Solver function in Microsoft Excel .57Bibliography .61BS
21、 ISO 6358-1:2013ISO 6358-1:2013(E)IntroductionIn pneumatic fluid power systems, power is transmitted and controlled through a gas under pressure within a circuit. Components that make up such a circuit are inherently resistive to the flow of the gas and it is necessary, therefore, to define and dete
22、rmine the flow-rate characteristics that describe their performance.ISO 6358:1989 was developed to determine the flow-rate characteristics of pneumatic valves, based upon a model of converging nozzles. The method included two characteristic parameters: sonic conductance, C, and critical pressure rat
23、io, b, used in a proposed mathematical approximation of the flow behaviour. The result described flow performance of a pneumatic valve from choked flow to subsonic flow, based on static pressure. This new edition uses stagnation pressure instead, to take into account the influence of flow velocity o
24、n the measurement of pressures.Experience has demonstrated that many pneumatic valves have converging-diverging characteristics that do not fit the ISO 6358:1989 model very well. Furthermore, new developments have allowed the application of this method to additional components beyond pneumatic valve
25、s. However, this now requires the use of four parameters (C, b, m, and pc) to define the flow performance in both the choked and subsonic flow regions.This part of ISO 6358 describes a set of four flow-rate characteristic parameters determined from test results. These parameters are described as fol
26、lows and are listed in decreasing order of priority:The sonic conductance, C, corresponding to the maximum flow rate (choked) is the most important parameter. This parameter is defined by the upstream stagnation conditions.The critical back-pressure ratio, b, representing the boundary between choked
27、 and subsonic flow is second in importance. Its definition differs here from the one in ISO 6358:1989 because it corresponds to the ratio of downstream to upstream stagnation pressures.The subsonic index, m, is used if necessary to represent more accurately the subsonic flow behaviour. For component
28、s with a fixed flow path, m is distributed around 0,5. In these cases, only the first two characteristic parameters C and b are necessary. For many other components, m varies widely. In these cases, it is necessary to determine C, b, and m.The parameter pcis the cracking pressure. This parameter is
29、used only for pneumatic components that open with increasing upstream pressure, such as non-return (check) valves or one-way flow control valves.Several changes to the test equipment were made to overcome apparent violations of the theory of compressible fluid flow. This includes expanded inlet pres
30、sure-measuring tubes to satisfy the assumptions of negligible inlet velocity to the item under test and to allow the inlet stagnation pressure to be measured directly. Expanded outlet tubes allow the direct measurement of downstream stagnation pressure to better accommodate the different component m
31、odels. The difference between stagnation pressure at upstream and downstream of component means a loss of pressure energy.For testing a component with a large nominal bore, to shorten testing time or to reduce energy consumption, it is desirable to apply the methods specified in ISO 6358-2, which co
32、vers a discharge test and a charge test as alternative test methods.ISO 6358-3 can be used to calculate without measurements an estimate of the overall flow-rate characteristics of an assembly of components and piping, using the characteristics of each component and piping determined in accordance w
33、ith this part of ISO 6358 or ISO 6358-2.It should be noted that performance characteristics measured in accordance with this edition of ISO 6358 differ from those measured in accordance with ISO 6358:1989. ISO 2013 All rights reserved vBS ISO 6358-1:2013BS ISO 6358-1:2013Pneumatic fluid power Determ
34、ination of flow-rate characteristics of components using compressible fluids Part 1: General rules and test methods for steady-state flow1 ScopeThis part of ISO 6358 specifies a steady-state method for testing pneumatic fluid power components that use compressible fluids, i.e. gases, and that have i
35、nternal flow paths that can be either fixed or variable in size, to determine their flow-rate characteristics. However, this part of ISO 6358 does not apply to components whose flow coefficient is unstable during use, i.e. components that exhibit remarkable hysteretic behaviour (because they can con
36、tain flexible parts that deform under the flow) or that have an internal feedback phenomenon (such as regulators). In addition, it does not apply to components that exchange energy with the fluid during flow-rate measurement, e.g. cylinders, accumulators, etc.Table 1 provides a summary of which part
37、s of ISO 6358 can be applied to various components.Table 1 Application of ISO 6358 test methods to componentsComponentsConstant upstream pressure testVariable upstream pressure testISO 6358-1 constant upstream pressure testISO 6358-2 charge testISO 6358-1 variable upstream pres-sure testISO 6358-2 d
38、is-charge testGroup 1 Directional control valves yes yes yes yesFlow control valves yes yes yes yesConnectors yes yes yes yesValve manifolds yes yes yes yesGroup of components yes yes yes yesGroup 2 Filters and lubricators yes no no noNon-return (check) valves yes no no noTubes and hoses yes no no n
39、oGroup 3 Silencers and exhaust oil mist separatorsno no yes yesBlow nozzles no no yes yesQuick-exhaust valves no no yes yesCylinder end heads no no yes yesThis part of ISO 6358 specifies requirements for the test installation, the test procedure, and the presentation of results for the steady-state
40、method.This part of ISO 6358 includes several test procedures, including the one described in Annex A, which is from ISO 6358:1989. Flowmeter calibration is described in Annex B. Evaluation of measurement uncertainties is described in Annex C. Observations of the error in the test results are descri
41、bed in Annex D. Equations and graphical representations of flow-rate characteristics are given in Annex E. Guidance on the use of practical units for the presentation of results is given in Annex F. Test results INTERNATIONAL STANDARD ISO 6358-1:2013(E) ISO 2013 All rights reserved 1BS ISO 6358-1:20
42、13ISO 6358-1:2013(E)using commercially available pneumatic components are given in Annex G. Guidance on calculating the flow-rate characteristics is given in Annex H.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable
43、for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 228-1, Pipe threads where pressure-tight joints are not made on the threads Part 1: Dimensions, tolerances and desig
44、nationISO 1219-1, Fluid power systems and components Graphical symbols and circuit diagrams Part 1: Graphical symbols for conventional use and data-processing applicationsISO 5598, Fluid power systems and components VocabularyISO 8778, Pneumatic fluid power Standard reference atmosphereISO 14743:200
45、4, Pneumatic fluid power Push-in connectors for thermoplastic tubesISO 16030, Pneumatic fluid power Connections Ports and stud ends3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 5598 and the following apply. The terms and definitions given in 3.1 thr
46、ough 3.3 are those for which it seems useful to emphasize the meaning. The terms and definitions in 3.4 and 3.5 are given for the purposes of this part of ISO 6358.3.1 Terms and definitions related to pressures3.1.1static pressurepressure measured perpendicularly to the flow direction without influe
47、nce of disturbancesNote 1 to entry: Static pressure can be measured by connecting a pressure-measuring device to a pressure-tapping mounting in a wall.3.1.2stagnation pressurepressure that would exist in a flowing gas stream if the stream were brought to rest by an isentropic processNote 1 to entry:
48、 In this part of ISO 6358, the static pressure measured in the pressure-measuring tubes is effectively the stagnation pressure within 6 %.3.2 Terms and definitions related to temperature3.2.1static temperaturetemperature that would be measured by a device that moves with the flowing gas at its veloc
49、ity3.2.2stagnation temperaturetemperature that would exist in a flowing gas stream if the stream were brought to rest by an isentropic processNote 1 to entry: In this part of ISO 6358, the temperature measured in the pressure-measuring tubes with either an immersed temperature probe or a probe in the side wall of the tube is effectively the stagnation temperature within 1 %.2 ISO 2013 All rights reservedBS ISO 6358-1:2013ISO 6358-1:2013(E)3.3 Terms and definitions related to flow3.3.1choked flowflow whose velocity is equal
