1、BSI Standards Publication BS ISO 6358-1:2013 Pneumatic fluid power Determination of flow-rate characteristics of components using compressible fluids Part 1: General rules and test methods for steady-state flowBS ISO 6358-1:2013 National foreword This British Standard is the UK implementation of ISO
2、 6358-1:2013. 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with BS ISO 6358-2:2013 and BS ISO 6358-3, it supersedes BS 7294:1990 (dual numbered as ISO 6358:1989) which will be withdrawn on publication of Part 3.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 l
3、ist of 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 Standar
4、ds Limited 2013 ISBN 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 public
5、ation Date Text affected BRITISH STANDARDBS ISO 6358-1:2013 ISO 2013 Pneumatic fluid power Determination of flow-rate characteristics of components using compressible fluids Part 1: General rules and test methods for steady-state flow Transmissions pneumatiques Dtermination des caractristiques de db
6、it des composants traverss par un fluide compressible Partie 1: Rgles gnrales et mthodes dessai en rgime stationnaire INTERNATIONAL STANDARD ISO 6358-1 First edition 2013-05-15 Reference number ISO 6358-1:2013(E)BS ISO 6358-1:2013ISO 6358-1:2013(E)ii ISO 2013 All rights reserved COPYRIGHT PROTECTED
7、DOCUMENT ISO 2013 All rights 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. Permissio
8、n can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in SwitzerlandBS ISO 6358-1:2013ISO 6358-
9、1:2013(E) ISO 2013 All rights reserved iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member
10、 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 Elect
11、rotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopte
12、d by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
13、 rights. ISO shall not be held responsible 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, can
14、cels and replaces ISO 6358:1989, which 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 characteristic
15、s of components using compressible fluid:Part 1: General rules and test methods for steady-state flowPart 2: Alternative test methods The 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 I
16、SO 2013 All rights reserved Contents Page Introduction v 1 Scope . 1 2 Normative references 2 3 Terms and definitions . 2 3.1 Terms and definitions related to pressures . 2 3.2 Terms and definitions related to temperature 2 3.3 Terms and definitions related to flow . 3 3.4 Terms and definitions rela
17、ted to flow-rate characteristics 3 3.5 Miscellaneous terms and definitions . 4 4 Symbols and units . 4 5 Test installation . 5 5.1 Test circuit for constant upstream pressure test . 5 5.2 Test circuit for variable upstream pressure test 6 5.3 General requirements . 7 5.4 Pressure-measuring tubes (it
18、ems 6 and 10) . 7 5.5 Transition connectors (items 7 and 9) . 9 5.6 Special requirements 12 6 Test procedures 13 6.1 Test conditions .13 6.2 Measuring procedures .14 6.3 Calculation of characteristics 16 7 Presentation of test results 18 8 Identification statement (reference to this part of ISO 6358
19、) 19 Annex A (normative) Alternative test procedure .20 Annex B (informative) Flowmeter calibration 23 Annex C (informative) Evaluation of measurement uncertainty .25 Annex D (informative) Observations on error in test results 30 Annex E (informative) Equations and graphical representations of flow-
20、rate characteristics 41 Annex F (informative) Use of practical units .46 Annex G (informative) Results of testing performed on commercially available pneumatic components 47 Annex H (informative) Procedures for calculating critical back-pressure ratio, b, and subsonic index, m, by the least-square m
21、ethod using the Solver function in Microsoft Excel .57 Bibliography .61BS ISO 6358-1:2013ISO 6358-1:2013(E) Introduction In 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 resistiv
22、e to the flow of the gas and it is necessary, therefore, to define and determine 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 tw
23、o characteristic parameters: sonic conductance, C, and critical pressure ratio, 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 stagna
24、tion pressure instead, to take into account the influence of flow velocity on 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 t
25、he application of this method to additional components beyond pneumatic valves. However, this now requires the use of four parameters (C, b, m, and p c ) 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 characteristi
26、c parameters determined from test results. These parameters are described as follows 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 conditio
27、ns.The critical back-pressure ratio, b, representing the boundary between choked 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 n
28、ecessary to represent more accurately the subsonic flow behaviour. For components 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 de
29、termine C, b, and m.The parameter p cis the cracking pressure. This parameter is 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 viol
30、ations of the theory of compressible fluid flow. This includes expanded inlet pressure-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
31、 of downstream stagnation pressure to better accommodate the different component models. 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
32、consumption, it is desirable to apply the methods specified in ISO 6358-2, which covers 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 pipin
33、g, using the characteristics of each component and piping determined in accordance with 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
34、All rights reserved vBS ISO 6358-1:2013BS ISO 6358-1:2013Pneumatic fluid power Determination of flow-rate characteristics of components using compressible fluids Part 1: General rules and test methods for steady-state flow 1 Scope This part of ISO 6358 specifies a steady-state method for testing pne
35、umatic fluid power components that use compressible fluids, i.e. gases, and that have internal 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
36、use, i.e. components that exhibit remarkable hysteretic behaviour (because they can contain 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
37、measurement, e.g. cylinders, accumulators, etc. Table 1 provides a summary of which parts of ISO 6358 can be applied to various components. Table 1 Application of ISO 6358 test methods to components Components Constant upstream pressure test Variable upstream pressure test ISO 6358-1 constant upstre
38、am pressure test ISO 6358-2 charge test ISO 6358-1 variable upstream pres- sure test ISO 6358-2 dis- charge test Group 1 Directional control valves yes yes yes yes Flow control valves yes yes yes yes Connectors yes yes yes yes Valve manifolds yes yes yes yes Group of components yes yes yes yes Group
39、 2 Filters and lubricators yes no no no Non-return (check) valves yes no no no Tubes and hoses yes no no no Group 3 Silencers and exhaust oil mist separators no no yes yes Blow nozzles no no yes yes Quick-exhaust valves no no yes yes Cylinder end heads no no yes yes This part of ISO 6358 specifies r
40、equirements for the test installation, the test procedure, and the presentation of results for the steady-state 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. Evaluati
41、on of measurement uncertainties is described in Annex C. Observations of the error in the test results are described 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
42、in Annex F. Test results INTERNATIONAL ST ANDARD ISO 6358-1:2013(E) ISO 2013 All rights reserved 1BS ISO 6358-1:2013ISO 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 refere
43、nces The following documents, in whole or in part, are normatively referenced in this document and are indispensable 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. IS
44、O 228-1, Pipe threads where pressure-tight joints are not made on the threads Part 1: Dimensions, tolerances and designation ISO 1219-1, Fluid power systems and components Graphical symbols and circuit diagrams Part 1: Graphical symbols for conventional use and data-processing applications ISO 5598,
45、 Fluid power systems and components Vocabulary ISO 8778, Pneumatic fluid power Standard reference atmosphere ISO 14743:2004, Pneumatic fluid power Push-in connectors for thermoplastic tubes ISO 16030, Pneumatic fluid power Connections Ports and stud ends 3 Terms and definitions For the purposes of t
46、his document, the terms and definitions given in ISO 5598 and the following apply. The terms and definitions given in 3.1 through 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
47、and definitions related to pressures 3.1.1 static pressure pressure measured perpendicularly to the flow direction without influence of disturbances Note 1 to entry: Static pressure can be measured by connecting a pressure-measuring device to a pressure- tapping mounting in a wall. 3.1.2 stagnation
48、pressure pressure that would exist in a f lowing gas stream if the stream were brought to rest by an isentropic process Note 1 to entry: 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
49、 related to temperature 3.2.1 static temperature temperature that would be measured by a device that moves with the flowing gas at its velocity 3.2.2 stagnation temperature temperature that would exist in a flowing gas stream if the stream were brought to rest by an isentropic process Note 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
