1、BRITISH STANDARD BS ISO 2942:2004 Hydraulic fluid power Filter elements Verification of fabrication integrity and determination of the first bubble point ICS 23.100.60 BS ISO 2942:2004 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 7 Decembe
2、r 2004 BSI 7 December 2004 ISBN 0 580 45000 7 National foreword This British Standard reproduces verbatim ISO 2942:2004 and implements it as the UK national standard. It supersedes BS ISO 2942:1994 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee MCE/1
3、8, Fluid power systems and components, to Subcommittee MCE/18/-/6, Contamination control, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international public
4、ations referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the nece
5、ssary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the inte
6、rpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii and v, a blank page, pages 1 to
7、7 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments Reference number ISO 2942:2004(E) OSI 4002INTERNATIONAL STANDARD ISO 2942 Fourth edition 2004-08-15 Hydraulic fluid power Fi
8、lter elements Verification of fabrication integrity and determination of the first bubble point Transmissions hydrauliques lments filtrants Vrification de la conformit de fabrication et dtermination du point de premire bulle BSISO2942:2004IS:2492 O4002(E) DPlcsid Fremia ihTs PDF file may ctnoian emd
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13、saCe tsopale 65 eneG 1121-HC 02 av leT. 4 + 10 947 22 1 11 xaF0 947 22 14 + 9 74 E-mail coirypthgiso.o gr We bwww.is.o gro Pulbisdehi n Switlrez dnaii ISO 4002 Allr ithgsr esedevrBSISO2942:2004IS:2492 O4002(E) I SO 4002 All irthgs ersedevr iiiContents Page Foreword iv Introduction v 1 Scope 1 2 Norm
14、ative references. 1 3 Terms and definitions. 1 4 Apparatus and materials 2 5 Test methods. 3 5.1 General procedure 3 5.2 Verification of fabrication integrity (absence of air bubbles). 4 5.3 Determination of the first bubble point. 4 6 Data presentation 5 7 Identification statement 5 Annex A (normat
15、ive) Test report for verification of filter element fabrication integrity and determination of first bubble point . 6 Bibliography . 7 BSISO2942:2004ISO 2942:2004(E) iv I SO 4002 All irthgs ersedevrForeword ISO (the International Organization for Standardization) is a worldwide federation of nationa
16、l 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 that committee. Internation
17、al 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 accordance with the rules
18、 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 requires approval by at le
19、ast 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 2942 was prepared by Technical Committee ISO/TC 131
20、, Fluid power systems, Subcommittee SC 6, Contamination control. This fourth edition cancels and replaces the third edition (ISO 2942:1994) which has been technically revised. BSISO2942:2004IS:2492 O4002(E) I SO 4002 All irthgs ersedevr vIntroduction In hydraulic fluid power systems, power is transm
21、itted and controlled through a liquid under pressure within an enclosed circuit. Filters maintain fluid cleanliness by removing insoluble contaminants. The ability of a filter to achieve and maintain the required level of performance depends, among other parameters, upon its filtration rating and st
22、ructural integrity. Any imperfections in the structure, either through poor manufacturing techniques or lack of strength, will allow bypassing of unfiltered fluid. The integrity of the element after manufacture can be evaluated using a non-destructive filter integrity test. This test determines whet
23、her flaws are present which would allow the fluid to bypass the filtering process and provides for quality control. The test is also used to evaluate whether damage has been sustained by the element during both service and laboratory tests. The first bubble point test is used for investigative produ
24、ct development and/or production process evaluation. The acceptability of filtration performance cannot be determined by the first bubble point test. BSISO2942:2004blankINTENRATIONAL TSANDADR IS:2492 O4002(E)I SO 4002 All irthgs ersedevr 1Hydraulic fluid power Filter elements Verification of fabrica
25、tion integrity and determination of the first bubble point 1 Scope This International Standard specifies a bubble-point test method applicable to filter elements used in hydraulic fluid power systems. It can be used either to verify the fabrication integrity of a filter element (by checking the abse
26、nce of bubbles) or to permit the localization of the largest pore of the filter element by determining the first bubble point. Verification of fabrication integrity defines the acceptability of the filter elements for further use or testing. The first bubble point is established through continuation
27、 of the fabrication integrity test. It is under no circumstances a functional characteristic of a filter element; in particular, it cannot be used for extrapolation to the concepts of filtration rating, efficiency or retention capacity and should be used for information only. 2 Normative references
28、The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 5598, Fluid power systems and components Voca
29、bulary ISO 6295, Petroleum products Mineral oils Determination of interfacial tension of oil against water Ring method. 3 Terms and definitions For the purposes of this International Standard, the definitions given in ISO 5598 and the following apply. 3.1 filter element porous device that performs t
30、he actual process of filtration NOTE This definition differs from that given in ISO 5598, which reads: “The component which ensures the retention of contaminant.” 3.2 fabrication integrity physical acceptability of a filter element to meet the specification designated by the filter manufacturer 3.3
31、first bubble point pressure at which the first bubble stream appears when a filter element is tested using the method specified in this International Standard NOTE In the absence of manufacturing defects, this value is indicative of the largest pore of the filtering medium. BSISO2942:2004IS:2492 O40
32、02(E) 2 I SO 4002 All irthgs ersedevr4 Apparatus and materials 4.1 Bubble-point testing apparatus, as shown in Figure 1, is comprised of the elements 4.1.1 to 4.1.5: 4.1.1 Compressed-air supply, with filter(s) and pressure regulator(s), adjustable up to 10 kPa (100 mbar). 4.1.2 Pressure-measuring de
33、vice, with an accuracy of 5 % of the reading. 4.1.3 Temperature-measuring device, with an accuracy of 0,5 C. 4.1.4 Test container, for submerging the filter element under test. 4.1.5 Device, for restraining the filter element during immersion to the required depth and allowing rotation about the ele
34、ments major axis either manually or with an automatic mechanism. 4.2 Test liquid The test liquid shall be clean propan-2-ol (isopropyl alcohol or IPA) or an alternative liquid designated by the filter element manufacturer. Its cleanliness shall be consistent with subsequent test requirements. Its su
35、rface tension shall be regularly checked in accordance with the requirements of ISO 6295. It is advisable to renew the liquid when its surface tension varies by 15 % from the original value. If the test element has been exposed to other hydraulic fluids prior to being subjected to the fabrication in
36、tegrity test, then it is permissible to use the same type of hydraulic fluid as the fabrication integrity test liquid, provided that the requirements of 4.2 are met. If this is not possible, all residual previous liquid shall be removed by appropriate means before testing. This is to ensure correct
37、and consistent wetting of the elements media. Test data can be compared only between tests that have used the same type of test liquid at equal testing conditions. BSISO2942:2004IS:2492 O4002(E) I SO 4002 All irthgs ersedevr 3Dimensions in millimetres Key 1 compressed air supply 2 compressed air fil
38、ter 3 pressure regulator 4 test container 5 test liquid 6 thermometer 7 filter element under test 8 pressure-measuring device Figure 1 Typical bubble-point testing apparatus 5 Test methods WARNING Exercise care when using solvents with low flash points, as there could be a risk of fire or explosion.
39、 Appropriate precautions should be taken to avoid inhalation of fumes from these solvents. Always use suitable protective equipment. Attention is drawn to local health and safety procedures. 5.1 General procedure 5.1.1 Check that the manufacturers identification number or part number of the filter e
40、lement to be tested complies with the manufacturers specification. 5.1.2 Install the clean filter element in the bubble-point testing apparatus (see 4.1), with the major axis of the filter element parallel to the surface of the test liquid (see 4.2). BSISO2942:2004ISO 2942:2004(E) 4 I SO 4002 All ir
41、thgs ersedevr5.1.3 Submerge the filter element in the test liquid, which shall be at a temperature of (22 5) C. 5.1.4 Allow the filter element to remain submerged in the test liquid for 5 min before proceeding, to ensure that the filter element media fibres are wetted. The filter element may be soak
42、ed in the test container (4.1.4) prior to its being secured in the restraining device (4.1.5). If soaking is carried out while the filter element is secured in the restraining device, ensure that no pressure is applied to the filter during the soaking period. 5.1.5 Ensure that the lines connecting t
43、he pressure-measuring device (4.1.2) to the rest of the apparatus are void of liquid. 5.2 Verification of fabrication integrity (absence of air bubbles) 5.2.1 Apply just enough air pressure to the inside of the filter element to clear any lines of test liquid and to pressurize the element. If necess
44、ary, readjust the depth of the test liquid covering the element to (12 3) mm above the top of the filter media. 5.2.2 After the pressure stabilizes, rotate the element around its major axis and gradually increase the pressure in a minimum of four suitable increments for example, 100 Pa (1 mbar). All
45、ow the element at least one rotation of 360 at each increment while checking for evidence of bubbles. Continue increasing the pressure until the value designated by the filter manufacturer is reached. NOTE Air bubbles might be trapped on or within the outer structure of the filter element, resulting
46、 in a few spurious bubbles. These bubbles can be ignored. A steady stream of bubbles from the filter element at or below the manufacturers designated pressure is the only consideration. Adequate lighting is required for reliable observation. Increase air pressure slowly to allow equilibrium to be es
47、tablished and to prevent overshooting of pressure. Avoid mechanical vibration or jarring of the test element to prevent upsetting bubble equilibrium, which will give an erroneous and an unrepresentative first bubble-point value. The speed at which the filter element is rotated should be controlled s
48、o as not to disturb or release air from the element. Adjust the depth of the test liquid covering the filter element to (12 3) mm above the top of the filter media throughout the test. 5.2.3 Record the temperature of the test liquid. 5.2.4 The acceptance criterion is that there shall be no evidence
49、of a single continuous stream of bubbles at or below the pressure specified by the manufacturer. Record the acceptance or failure of the filter element in accordance with the requirements of Annex A. 5.3 Determination of the first bubble point 5.3.1 Gradually apply air pressure progressively to the inside of the filter element in accordance with 5.2.1, while rotating it about its axis in accordance with 5.2.2. Incr
