1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 6772:2012Aerospace Fluid systems Impulse testing of hydraulichose, tubing and fittingassembliesBS ISO 6772:2012 BRITISH STANDARDNational forewordThis British Standard is t
2、he UK implementation of ISO 6772:2012. It supersedes BS 2M52:1989 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee ACE/69, Aerospace hydraulic systems, fluids and components.A list of organizations represented on this committee can be obtained on reques
3、t 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 2012. Published by BSI Standards Limited 2012ISBN 978 0 580 67897 4 ICS 49.080; 83.140.40 Compliance with a
4、 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 2012.Amendments issued since publicationDate Text affectedBS ISO 6772:2012 ISO 2012Aerospace Fluid systems Impulse tes
5、ting of hydraulic hose, tubing and fitting assembliesAronautique et espace Systmes de fluides Essai dimpulsion des tuyauteries flexibles, tubes et raccordsINTERNATIONAL STANDARDISO6772Third edition2012-10-01Reference numberISO 6772:2012(E)BS ISO 6772:2012ISO 6772:2012(E)ii ISO 2012 All rights reserv
6、edCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address
7、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 6772:2012ISO 6772:2012(E) ISO 2012 All rights reserved iiiContents PageForewo
8、rd ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Requirements 14.1 Shape of impulse trace . 14.2 Calculation of pressure rise . 24.3 Preparation of specimens 24.4 Test fluid . 35 Principle of test 36 Test method . 37 Intended use 47.1 Standard 47.2 Reference . 4Bibl
9、iography 6BS ISO 6772:2012ISO 6772:2012(E)ForewordISO (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 b
10、ody 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 Electro
11、technical 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 adopted by
12、 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 righ
13、ts. ISO shall not be held responsible for identifying any or all such patent rights.ISO 6772 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee SC 10, Aerospace fluid systems and components.This third edition cancels and replaces the second edition (ISO 6772:198
14、8), which has been technically revised. The main changes are as follows: 3.2: definition has been modified; Clause 5: new paragraph has been added; Tables 1, 2 and 3 have been modified to cover additional classes J and K.iv ISO 2012 All rights reservedBS ISO 6772:2012ISO 6772:2012(E)IntroductionIn h
15、ydraulic systems, power is transmitted through the hydraulic fluid under pressure with a network of tubing and hoses, and their attendant fitting assemblies. In order to demonstrate that these transmission elements are fit for purpose in terms of the prevention of premature failures due to fatigue,
16、it is necessary to conduct appropriate impulse pressure testing.This document provides the overall requirements for pressure impulse testing of hydraulic system distribution elements. ISO 2012 All rights reserved vBS ISO 6772:2012BS ISO 6772:2012Aerospace Fluid systems Impulse testing of hydraulic h
17、ose, tubing and fitting assemblies1 ScopeThis International Standard specifies the requirements and the procedures for impulse testing of hose, tubing, and fitting assemblies for use in aerospace hydraulic systems. Requirements may apply, when appropriate, to components used in other aerospace fluid
18、 systems.2 Normative referencesThe 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 a
19、ny amendments) applies.ISO 6771, Aerospace Fluid systems and components Pressure and temperature classificationsISO 8575, Aerospace Fluid systems Hydraulic system tubing3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1rate of pressure riseslope o
20、f the pressure/time curve in the straight portion of the pressure increase portionNOTE For the purpose of this definition, the rate of rise is determined between 10 % of the total rise above back-pressure and 10 % of the total rise below peak pressure.3.2peak pressuremaximum value for an operating p
21、ressure of short durationISO 8625-1:1993, 1.254 Requirements4.1 Shape of impulse traceWhen observed on an oscilloscope, the impulse traces show as approximate pressure/time cycles. It is mandatory that these pressure/time curves be confined to the shaded area indicated in Figure 1. The dynamic impul
22、se trace produced by the test machine shall be in conformity with the trace illustrated in Figure 1.INTERNATIONAL STANDARD ISO 6772:2012(E) ISO 2012 All rights reserved 1BS ISO 6772:2012ISO 6772:2012(E)KeyX Percent of one cycleY Percentage of nominal pressure 5 %1 The slope of this portion of curve,
23、 between 10 % and 90 % of peak pressure, gives the rate of rise (see 4.2)2 Peak pressure (see Table 1 or 2). Only one pressure peak is allowed above 110 % of operating pressure and it must be within the first 15 % of cycle3 Back pressure in pressure classes B, D, E: (345 170) kPa / (50 25) psiBack p
24、ressure in pressure classes J, K: (700 350) kPa / (100 50) psiFigure 1 Impulse trace4.2 Calculation of pressure riseThe rate of pressure rise shall be calculated using the following formula:Rate of pressure riseat at=09 0109 01,pptptpwherep is the peak pressure, in kilopascals;t at 0,9 p is the time
25、, in seconds, at 0,9 p;t at 0,1 p is the time, in seconds, at 0,1 p.4.3 Preparation of specimensThe preparation of test specimens shall be defined in the detail design specification of the component. Specimens shall be subjected to the relevant treatments and production test requirements of the comp
26、onent specification.2 ISO 2012 All rights reservedBS ISO 6772:2012ISO 6772:2012(E)4.4 Test fluidThe test fluid shall be the specified aircraft system fluid or another hydraulic fluid which is compatible with the item being tested.5 Principle of testThis method of testing is intended to determine the
27、 ability of flexible hose assemblies, tubing and fitting assemblies to withstand hydraulic impulse for qualification testing under simulated conditions.6 Test methodFor testing of hose, tubing and fitting assemblies, including boss or port fittings, the cycle rate shall be (70 5) cycles/min. Unless
28、otherwise specified, the peak pressure and the rate of pressure rise shall be as specified in Tables 1 and 2. Unless otherwise specified, the assembly shall be tested in the sequence shown in Table 3.The sweep rate on the oscilloscope or recorder shall be adjusted so that the slope of the pressure r
29、ise shall take advantage of the full size of the screen. The trace and photographs of the impulse cycle shall be an accurate record of the impulse cycle and show a grid or other means to permit accurate checking. The end-to-end accuracy and sampling rate of the data acquisition system and sensors sh
30、ould ensure that the impulse measurement uncertainty is within the pressure waveform specifications of this document. The accuracy of the measurements shall be traceable to international standards.Unless otherwise specified in the detail or procurement specification, the total number of cycles shall
31、 be 200 000.After the temperature has stabilized at the maximum or minimum, as specified in Table 3, a minimum soak time of 1 h is required before that portion of the test sequence is begun. If temperature control is required by the procurement specification, the fluid temperature shall be measured
32、at the test manifold and the ambient temperature shall be measured approximately 150 mm from the test specimens. The peak pressure shall be measured at the test manifold.Table 1 Peak pressure and rate of pressure riseSI-metric units of measureHoses, tubing and fitting assemblies Peak pressure Minimu
33、m rate of pressure riseMaximum rate of pressure risePressure class aNominal outside diameter bkPa % kPa/s kPa/sB 10 500DN14 and smaller125 126 000700 000DN16 to DN25 (incl.) 520 000DN32 340 000DN40 and over 280 000D 21 000All diameters150315 0002 100 000E 28 000420 000J 35 000525 000K 55 000135 525
34、000 4 590 000aPressure classes in accordance with ISO 6771.bNominal outside diameters in accordance with ISO 8575. DN = nominal outside diameter in mm, example: DN16 = nominal outside diameter of 16 mm. ISO 2012 All rights reserved 3BS ISO 6772:2012ISO 6772:2012(E)Table 2 Peak pressure and rate of p
35、ressure riseImperial units of measureHoses, tubing and fitting assemblies Peak pressure Minimum rate of pressure riseMaximum rate of pressure risePressure class aNominal outside diameter bpsi % psi/s psi/sB 1 50008 and smaller125 18 000100 00010 through 12 75 00020 50 00024 and over 40 000D 3 000All
36、 diameters15045 000300 000E 4 00060 000J 5 00075 000K 8 000135 75 000 650 000aPressure classes in accordance with ISO 6771.bNominal outside diameters in accordance with ISO 8575. Dash size is the equivalent of the diameter in 1/16 inch, example: - 06 = 6/16 inch diameter.Table 3 Sequence and duratio
37、n of impulse testing at temperature aSequence No.Number of cycles as a percentage of the total number of cyclesTemperature (ambient and fluid)1 50 Maximum2 24 From 15 C to 35 C/60 F to 95 F3 1 Minimum4 5 Maximum5 20Ambient and fluid: any of the above. These cycles may be added to any one sequence or
38、 divided among them.aUnless otherwise specified in the detail or procurement specification.7 Intended use7.1 StandardThis test is intended to promote standardization of impulse test requirements, procedures and equipment for the standard qualification and evaluation impulse testing of hydraulic hose
39、 assemblies, tubing and fittings.7.2 ReferenceIf reference is made to this International Standard in a specification as part of the requirements, the following additional requirements shall be specified:a) nominal pressure;4 ISO 2012 All rights reservedBS ISO 6772:2012ISO 6772:2012(E)b) operating te
40、mperature limits;c) design of specimens. ISO 2012 All rights reserved 5BS ISO 6772:2012ISO 6772:2012(E)Bibliography1 ISO 8625-1:1993, Aerospace Fluid systems Vocabulary Part 1: General terms and definitions related to pressure2 SAE AIR 1228, Standard Impulse Machine Equipment and Operation6 ISO 2012
41、 All rights reservedBS ISO 6772:2012BS ISO 6772:2012ISO 6772:2012(E) ISO 2012 All rights reservedICS 49.080, 83.140.40Price based on 6 pagesThis page deliberately left blankBSI is the independent national body responsible for preparing British Standards and other standards-related publications, info
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