1、BSI Standards PublicationBS ISO 14085-4:2015Aerospace series Hydraulicfilter elements Test methodsPart 4: Verification of collapse/burstpressure ratingBS ISO 14085-4:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 14085-4:2015. The UK participation in its
2、preparation was entrusted to TechnicalCommittee ACE/69, Aerospace hydraulic systems, fluids and components.A list 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
3、are responsible for its correct application. The British Standards Institution 2015.Published by BSI Standards Limited 2015ISBN 978 0 580 80580 6ICS 49.080Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the S
4、tandards Policy and Strategy Committee on 31 March 2015.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 14085-4:2015 ISO 2015Aerospace series Hydraulic filter elements Test methods Part 4: Verification of collapse/burst pressure ratingSrie arospatiale Elments filtran
5、ts hydrauliques Mthode dessais Partie 4: Vrification de la rsistance lclatement/crasementINTERNATIONAL STANDARDISO14085-4First edition2015-03-01Reference numberISO 14085-4:2015(E)BS ISO 14085-4:2015ISO 14085-4:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015All rights rese
6、rved. 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 either IS
7、O 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 14085-4:2015ISO 14085-4:2015(E)Foreword ivIntroduction v1 Sc
8、ope . 12 Normative references 13 Terms and definitions . 14 Symbols and abbreviated terms . 25 Test circuit and equipment 26 Accuracy of measurements and variations of test conditions. 37 Test procedure 38 Reporting 49 Acceptance criteria 5Annex A (informative) Test data report form 6Annex B (inform
9、ative) Examples of abrupt decrease in the slope of the differential pressure versus contaminant mass added curve and increase in particle counts 7Bibliography 9 ISO 2015 All rights reserved iiiContents PageBS ISO 14085-4:2015ISO 14085-4:2015(E)ForewordISO (the International Organization for Standard
10、ization) 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 which a technical committee has been established has the right to
11、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 of electrotechnical standardization.The procedures used
12、to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of
13、the ISO/IEC Directives, Part 2 (see www.iso.org/directives).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 responsible for identifying any or all such patent rights. Details of any patent rights identified d
14、uring the development of 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 information given for the convenience of users and does not constitute an endorsement.For an explanation on the m
15、eaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 2
16、0, Aircraft and space vehicles, Subcommittee SC 10, Aerospace fluid systems and components.ISO 14085 consists of the following parts, under the general title Aerospace series Hydraulic filter elements Test methods : Part 1: Test sequence Part 2: Conditioning Part 3: Filtration efficiency and retenti
17、on capacity Part 4: Verification of collapse/burst pressure rating Part 5: Resistance to flow fatigue Part 6: Cleanliness leveliv ISO 2015 All rights reservedBS ISO 14085-4:2015ISO 14085-4:2015(E)IntroductionIn aerospace hydraulic fluid power systems, power is transmitted and controlled through a li
18、quid under pressure. The liquid is both a lubricant and power-transmitting medium. The presence of solid contaminant particles in the liquid interferes with the ability of the hydraulic fluid to lubricate, and causes wear and malfunction of the components. The extent of contamination in the fluid ha
19、s a direct bearing in the performance, reliability, and safety of the system, and needs to be controlled to levels that are considered appropriate for the system concerned.Filters are used to control the contamination level of the fluid by removing solid contaminant particles, typically consisting o
20、f a filter element enclosed in a filter housing. The filter element is the porous device that performs the actual process of filtration. The complete assembly is designated as a filter.As a filter element removes contaminant due to its efficiency, the filter element clogs and its differential pressu
21、re increases to values which can affect its structural integrity. The capability of the filter element to maintain a specified fluid cleanliness level depends on its performance and structural integrity, which can both be affected if the filter element differential pressure becomes too high.A collap
22、se/burst test quantifies the resistance of the filter element to high differential pressures that can occur both due to filter clogging, as well as that occurring in non-steady state operating conditions such as cold starts and decompression surges.This part of ISO 14085 provides a procedure to veri
23、fy that a filter element can withstand a designated high differential pressure without failure. ISO 2015 All rights reserved vBS ISO 14085-4:2015BS ISO 14085-4:2015Aerospace series Hydraulic filter elements Test methods Part 4: Verification of collapse/burst pressure rating1 ScopeThis part of ISO 14
24、085 describes a method for verifying the collapse/burst pressure rating of an aerospace hydraulic fluid power filter element. This represents the capability of a filter element to withstand a designated differential pressure in the normal (intended) direction of flow, created by flowing contaminated
25、 fluid through the filter element until either collapse/burst occurs or the maximum expected differential pressure is reached without element failure.The collapse/burst pressure test can be conducted in conjunction with an efficiency test performed according to the procedure defined in the ISO 14085
26、-3 by continuing the contaminant injection until the designated filter element differential pressure is reached.This part of ISO 14085 is not intended to qualify a filter element under replicate conditions of service; this can only be done by a specific test protocol developed for the purpose, inclu
27、ding actual conditions of use, for example the operating fluid or contamination.The tests data resulting from application of this part of ISO 14085 can be used to compare the performance of aerospace hydraulic filter elements.2 Normative referencesThe following documents, in whole or in part, are no
28、rmatively 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.ISO 1219-1, Fluid power systems and components Graphical sym
29、bols and circuit diagrams Part 1: Graphical symbols for conventional use and data-processing applicationsISO 2942, Hydraulic fluid power Filter elements Verification of fabrication integrity and determination of the first bubble pointISO 5598, Fluid power systems and components VocabularyISO 11943,
30、Hydraulic fluid power On-line automatic particle-counting systems for liquids Methods of calibration and validation3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 5598 and the following apply.3.1free-flow dummy elementduplicate test filter element wit
31、h its media layers removed to replicate the flow pattern in the housing generated by the test filter elementINTERNATIONAL STANDARD ISO 14085-4:2015(E) ISO 2015 All rights reserved 1BS ISO 14085-4:2015ISO 14085-4:2015(E)4 Symbols and abbreviated termsGraphic symbols used are in accordance with ISO 12
32、19-1.5 Test circuit and equipment5.1 Test stand: Use a test stand and components similar to that depicted in Figure 1 to perform the collapse/burst test. Critical components of the test system are described below.KeyA contaminant injection system 7 shut-off valveB filter test system 8 clean-up filte
33、r1 reservoir 9 check valve2 pump 10 flow meter3 relief valve 11 temperature controller4 temperature gauge 12 diffuser5 test filter 13 flow control valve6 differential pressure (p) transducer 14 alternate contaminant injection pointFigure 1 Typical circuit diagram for collapse/burst test5.2 Test filt
34、er housing: Use a suitable test filter housing modified as necessary to ensure that fluid cannot by-pass the filter element.5.3 Test system pump: Use a pump and motor capable of maintaining the flow of the fluid in the test circuit at a pressure greater than the differential pressure required. The p
35、ump and motor drive system shall maintain a constant uniform flow rate within a tolerance of 5 % throughout the entire test.NOTE Positive and/or negative fluctuations in flow rate causing excessive pressure ripple can lead to inaccurate results.5.4 Reservoir: Use a reservoir of sufficient size to co
36、ntain the fluid in the test circuit, designed to keep the contamination in suspension; dead legs and quiescent areas shall be avoided. A cylindrical reservoir with a conical bottom that has an included angle of not more than 90 has been shown to satisfy this requirement. The return line to the reser
37、voir shall terminate with a diffuser that shall be below the fluid level to prevent aeration of the fluid.5.5 Valves and connectors: Connectors and valves are necessary to control the flow of fluid through the filter. A pressure relief valve is optional.2 ISO 2015 All rights reservedBS ISO 14085-4:2
38、015ISO 14085-4:2015(E)5.6 Pressure gauge: Use a differential pressure transducer capable of recording the expected differential pressure, and an electronic strip chart-recording device with a response rate of 40 Hz to 100 Hz, or an equivalent recording device.5.7 Test fluid: Unless otherwise agreed
39、between parties involved, the test fluid shall be the fluid defined in ISO 14085-3, Annex A.5.8 Test contaminant: The test contaminant shall be ISO 12103-1, A2 (ISO Fine Test Dust).5.9 Online automatic particle counter: Optionally, an online automatic particle counter, calibrated in accordance with
40、ISO 11943, can be installed in the system, downstream from the filter under test, and particle counts recorded throughout the test.6 Accuracy of measurements and variations of test conditions6.1 Utilize and maintain instrument accuracy and test conditions variations within the limits in Table 1.6.2
41、Maintain specific test parameters within the limits in Table 1.Table 1 Instruments accuracy and test conditions variationsTest parameter SI UnitInstrument accuracy () of readingAllowed test condition variation ()Differential pressure Pa, kPa or bar 5 % Flow Injection flow ml/min 2 % 5 %Test flow l/m
42、in 2 % 5 %Kinematic viscosity (2) mm2/s a2 % 1 mm2/sMass g 0,1 mg Temperature C 1 C 2 CTime s 1 s Injection system volume l 2 % Filter test system volume l 2 % 5 %a1 mm2/s = 1 cSt (centistoke).7 Test procedure7.1 If the burst/collapse pressure test is to be performed after an efficiency test per ISO
43、 14085-3, continue injecting test contaminant until the designated collapse/burst pressure is reached or until failure occurs.7.2 If the collapse/burst pressure test is to be performed alone, subject the filter element to a fabrication integrity test per ISO 2942.7.3 Disqualify from further testing
44、any element that does not meet or exceed the manufacturers specified minimum first bubble pressure. If the element meets or exceeds the manufacturers rated minimum first bubble pressure, allow the fluid used in the fabrication integrity test to evaporate from the element, or rinse the element with t
45、he fluid to be used in the collapse/burst test procedure. ISO 2015 All rights reserved 3BS ISO 14085-4:2015ISO 14085-4:2015(E)7.4 Install the filter housing and a free-flow dummy element in the collapse/burst test circuit at the location shown in Figure 1.7.5 Determine the differential pressure acro
46、ss the filter housing with the free-flow dummy element installed at either the manufacturers rated nominal flow rate or at a value between 50 % and 100 % of the nominal flow rate, and at either a selected test temperature between 15 C and 40 C or at a specified test temperature, and record.7.6 Insta
47、ll the test filter element in the test filter housing.7.7 Subject the element to the flow rate and temperature determined in 7.5. Maintain a uniform flow rate throughout the entire test. Record the viscosity of the fluid at test temperature and the overall differential pressure. The pressure relief
48、valve cracking pressure, if one is installed in the system, should be set at not less than 150 % of the specified final collapse/burst pressure of the element being tested.7.8 Inject the test contaminant into the system either continuously or intermittently (sometimes known as “batch loading”). For
49、intermittent loading, a controlled amount of the test contaminant is introduced at a rate that is not greater than 5 % of the elements estimated contaminant capacity, at intervals of at least 2 min, while maintaining the specified test flow rate and test temperature. Record the lot number of contaminant used. The contaminant shall be injected in a uniform manner and at low enough concentration so that the pressure measurement equipment can detect any structural failure.NOTE To reduce t
