1、BS ISO 2941:2009ICS 23.100.60NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDHydraulic fluid power Filter elements Verification ofcollapse/burst pressureratingThis British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 3
2、1 July 2009 BSI 2009ISBN 978 0 580 58468 8Amendments/corrigenda issued since publicationDate CommentsBS ISO 2941:2009National forewordThis British Standard is the UK implementation of ISO 2941:2009. Itsupersedes BS ISO 2941:1974 which is withdrawn.The UK participation in its preparation was entruste
3、d to TechnicalCommittee MCE/18/-/6, Contamination control.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Complia
4、nce with a British Standard cannot confer immunityfrom legal obligations.BS ISO 2941:2009Reference numberISO 2941:2009(E)ISO 2009INTERNATIONAL STANDARD ISO2941Second edition2009-04-01Hydraulic fluid power Filter elements Verification of collapse/burst pressure rating Transmissions hydrauliques lment
5、s filtrants Vrification de la pression dcrasement/clatement BS ISO 2941:2009ISO 2941:2009(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are
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8、ting to it is found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2009 All 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 pho
9、tocopying and microfilm, without permission in writing 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 Sw
10、itzerland ii ISO 2009 All rights reservedBS ISO 2941:2009ISO 2941:2009(E) ISO 2009 All rights reserved iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Graphic symbols. 1 5 Test circuit and equipment 1 6 Test procedure 3 7 Acceptance cri
11、teria. 4 8 Reporting . 5 9 Identification statement (reference to this International Standard) . 5 Annex A (informative) Recommendations for electronic strip chart-recording device used in the ISO 2941 collapse/burst test procedure and typical curves generated by these devices 6 Annex B (informative
12、) Test data report form. 7 Annex C (informative) Examples of abrupt decrease in the slope of the differential pressure versus contaminant mass added curve .8 BS ISO 2941:2009ISO 2941:2009(E) iv ISO 2009 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwi
13、de 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 be represented on tha
14、t 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. International Standards are drafted in a
15、ccordance 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 circulated to the member bodies for voting. Publication as an International Standard re
16、quires 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 responsible for identifying any or all such patent rights. ISO 2941 was prepared by Techni
17、cal Committee ISO/TC 131, Fluid power systems, Subcommittee SC 6, Contamination control. This second edition cancels and replaces the first edition (ISO 2941:1974), of which Clauses 5 and 6 have been technically revised and to which informative Annexes A, B and C have been added. BS ISO 2941:2009ISO
18、 2941:2009(E) ISO 2009 All rights reserved vIntroduction In hydraulic fluid power systems, power is transmitted and controlled through a liquid under pressure within an enclosed circuit. Filters maintain the cleanliness of fluid in a fluid power system by removing insoluble contaminants. A filter el
19、ement is the porous device that performs the actual process of filtration. The capability of the filter element to maintain a specified fluid cleanliness level depends on its performance and structural integrity and its ability to withstand non-steady-state conditions (e.g. cold starts and decompres
20、sion surges). The filter elements resistance to collapse or burst is a measure of its ability to withstand such effects. BS ISO 2941:2009BS ISO 2941:2009INTERNATIONAL STANDARD ISO 2941:2009(E) ISO 2009 All rights reserved 1Hydraulic fluid power Filter elements Verification of collapse/burst pressure
21、 rating 1 Scope This International Standard specifies a method for verifying the collapse/burst pressure rating of a hydraulic fluid power filter element, i.e. the capability of a filter element to withstand a designated differential pressure at the normal (i.e., intended direction of) flow, by mean
22、s of pumping contaminated fluid through the filter element until either collapse/burst occurs or the maximum expected differential pressure is reached without element failure. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated
23、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 Graphic symbols and circuit diagrams Part 1: Graphic symbols for conventional use and data-processing a
24、pplications ISO 2942, Hydraulic fluid power Filter elements Verification of fabrication integrity and determination of the first bubble point ISO 2943, Hydraulic fluid power Filter elements Verification of material compatibility with fluids ISO 5598, Fluid power systems and components Vocabulary ISO
25、 12103-1, Road vehicles Test dust for filter evaluation Part 1: Arizona test dust 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 5598 apply. 4 Graphic symbols Graphic symbols used in this International Standard are in accordance with ISO 1219-1. 5 T
26、est circuit and equipment 5.1 Test circuit Figure 1 shows the arrangement of a typical circuit for the collapse/burst test described in Clause 6. BS ISO 2941:2009ISO 2941:2009(E) 2 ISO 2009 All rights reservedKey 1 contamination injection site 2 system pump 3 alternate contamination injection site 4
27、 pressure relief valve 5 differential pressure gauge 6 filter under test 7 flowmeter Figure 1 Typical circuit for collapse/burst test 5.2 Apparatus The following test equipment shall be used: 5.2.1 Test filter housing (recommended by the filter manufacturer), modified as necessary to ensure that flu
28、id cannot bypass the filter element. 5.2.2 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 pump and motor drive system shall maintain a constant uniform flow rate within a tolerance of 5 % throughout
29、the entire test. Positive and/or negative fluctuations in flow rate lead to inaccurate results. 5.2.3 Reservoir, of sufficient size to contain 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
30、 a conical bottom has been shown to satisfy this requirement. The return line to the reservoir shall be below the fluid level to prevent aeration of the fluid. 5.2.4 Connectors and valves, as necessary to control the flow of fluid through the filter. A pressure relief valve is optional. 5.2.5 Differ
31、ential pressure transducer, capable of registering the expected differential pressure. BS ISO 2941:2009ISO 2941:2009(E) ISO 2009 All rights reserved 35.2.6 Electronic strip chart-recording device, with a response rate of 40 Hz to 100 Hz, or an equivalent recording device (see Annex A for recommendat
32、ions for the electronic strip chart-recording device). NOTE Optionally, an online automatic particle counter or contamination level indicator can be installed in the system, downstream from the filter under test. 5.3 Fluid A fluid compatible with the filter element material, as determined in accorda
33、nce with ISO 2943, shall be used. 5.4 Contaminant The test contaminant shall be ISO 12103-1 A2 (ISO Fine Test Dust) or A3 (ISO Medium Test Dust) or another inert particulate contaminant. The contaminant shall not add to the strength of the element under test. 5.5 Instrument accuracy and test conditi
34、ons Instrument accuracy and test conditions shall be maintained within the limits given in Table 1. Table 1 Instrument accuracy and test condition variation Test parameter Unit Instrument accuracy of reading Allowed test condition variation Differential pressure Pa or kPa (bar) 5 % Injection flow ra
35、te mL/min 2 % 5 % Test flow rate L/min 2 % 5 % Kinematic viscosityamm2/s 2 % Mass g 0,1 mg Temperature C 1 C 2 C Time s 1 s Injection system volume L 2 % Filter test system volume L 2 % 5 % a1 mm2/s = 1 cSt (centistoke). 6 Test procedure 6.1 Subject the filter element to a fabrication integrity test
36、 in accordance with ISO 2942. 6.2 Disqualify from further testing 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 integri
37、ty test to evaporate from the element, or rinse the element with the fluid being used in the collapse/burst test procedure. 6.3 Install the filter housing in the collapse/burst test circuit at the location shown in Figure 1. 6.4 Determine the differential pressure across the empty filter housing at
38、either the manufacturers rated nominal flow rate or at a value between 50 % and 80 % 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. 6.5 Install the element in the test filter housing. BS ISO 2941:2009ISO 2941:
39、2009(E) 4 ISO 2009 All rights reserved6.6 Subject the element to the flow rate and temperature determined in 6.4. Maintain a uniform flow rate throughout the entire test. Maintain the test temperature within a tolerance of 2 C. Record the viscosity of the fluid at the test temperature and the overal
40、l differential pressure. The pressure relief valve, 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. 6.7 Inject into the system, either continuously or intermittently (sometimes known as “batch loading
41、”), a controlled amount of the test contaminant 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 type of contaminant used. The contaminant used shall
42、be injected in a uniform manner and at a concentration low enough so that the pressure measurement equipment can detect any structural failure. To reduce testing time, a preload of contaminant equal to 50 % of the elements estimated contaminant capacity may be added, if agreed by the manufacturer. 6
43、.8 Record the flow rate and differential pressure across the filter as a function of contaminant mass added, expressed in grams or units of time, until the differential pressure, expressed in kilopascals, across the element (filter assembly differential pressure minus housing differential pressure)
44、meets or exceeds the specified collapse/burst pressure rating or until failure. If contaminant is added intermittently, wait 2 min after the addition of contaminant before recording the flow rate and differential pressure. 6.9 Subject the filter element to a fabrication integrity test in accordance
45、with ISO 2942, using the same fluid as in 6.1, if physical collapse has not occurred. 6.10 Record the following data: a) test flow rate; b) maximum filter-element differential pressure achieved; c) fluid temperature; d) type and viscosity at the test temperature of the fluid used in the test circuit
46、; e) type of contaminant introduced; f) direction of flow through the element; g) type of pump. 6.11 If the contaminant fills the filter housing before collapse/burst is achieved, the test shall not be valid. 6.12 Calculate the contaminant mass injection rate, expressed in grams per minute, and mult
47、iply the test time, expressed in minutes, by this factor to give the mass of contaminant added. 6.13 Plot the relationship of differential pressure versus contaminant mass added in linear co-ordinate format. 7 Acceptance criteria The filter element collapse/burst pressure rating shall be verified if
48、 a) there is no visual evidence of failure in the elements structure, filter medium and seals, when tested in accordance with ISO 2942, and b) there is no abrupt decrease in the slope of the differential pressure versus contaminant mass added curve plotted in 6.13 prior to the specified collapse/bur
49、st pressure rating (see Annex C for examples of BS ISO 2941:2009ISO 2941:2009(E) ISO 2009 All rights reserved 5abrupt decreases in slope). Transients in differential pressure should not be included when evaluating the curve for an abrupt decrease in slope. 8 Reporting 8.1 The test information recorded in the documentation for a filter element tested in accordance with this International Standard shall show a) the test flow rate; b) the maximum filter el
