1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN ISO 284:2012Conveyor belts Electricalconductivity Specificationand test methodBS EN ISO 284:2012 BRITISH STANDARDNational forewordThis British Standard is the UK implementa
2、tion of EN ISO 284:2012. Itsupersedes BS EN ISO 284:2003 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee PRI/67, Conveyor belts.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not pu
3、rport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 77355 6ICS 53.040.10Compliance with a British Standard cannot confer immunity fromlegal obligatio
4、ns.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 December 2012.Amendments issued since publicationDate Text affectedEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 284 December 2012 ICS 53.040.10 Supersedes EN ISO 284:2003English
5、 Version Conveyor belts - Electrical conductivity - Specification and test method (ISO 284:2012) Courroies transporteuses - Conductibilit lectrique - Spcification et mthode dessai (ISO 284:2012) Frdergurte - Elektrische Leitfhigkeit - Spezifikation und Prfverfahren (ISO 284:2012) This European Stand
6、ard was approved by CEN on 30 November 2012. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning
7、 such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its
8、 own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, German
9、y, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR N
10、ORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 284:2012: EBS EN ISO 284:2012EN ISO 284:2012 (E) 3 Foreword This document (EN ISO 284:2012) has been prepared by T
11、echnical Committee ISO/TC 41 “Pulleys and belts (including veebelts)“ in collaboration with Technical Committee CEN/TC 188 “Conveyor belts” the secretariat of which is held by SNV. This European Standard shall be given the status of a national standard, either by publication of an identical text or
12、by endorsement, at the latest by June 2013, and conflicting national standards shall be withdrawn at the latest by June 2013. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for ide
13、ntifying any or all such patent rights. This document supersedes EN ISO 284:2003. According to the CEN/CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Repub
14、lic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endor
15、sement notice The text of ISO 284:2012 has been approved by CEN as a EN ISO 284:2012 without any modification. BS EN ISO 284:2012ISO 284:2012(E) ISO 2012 All rights reserved iiiContents PageForeword iv1 Scope 12 Normative references . 13 Specification . 14 Test method 14.1 Principle . 14.2 Materials
16、 and apparatus 14.3 Test pieces 24.4 Atmosphere for conditioning and testing . 34.5 Procedure 34.6 Expression of results . 44.7 Test report . 4Annex A (informative) Variation of electrical resistance with temperature and humidity . 5Bibliography . 6BS EN ISO 284:2012ISO 284:2012(E)ForewordISO (the I
17、nternational 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 body interested in a subject for which a technical committee
18、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 Electrotechnical Commission (IEC) on all matters of electrotechnica
19、l 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 the technical committees are circulated to the member bodie
20、s 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 rights. ISO shall not be held responsible for identifying any or
21、 all such patent rights.ISO 284 was prepared by Technical Committee ISO/TC 41, Pulleys and belts (including veebelts), Subcommittee SC 3, Conveyor belts.This fourth edition cancels and replaces the third edition (ISO 284:2003), of which it constitutes a minor revision.iv ISO 2012 All rights reserved
22、BS EN ISO 284:2012INTERNATIONAL STANDARD ISO 284:2012(E)Conveyor belts Electrical conductivity Specification and test method1 ScopeThis International Standard specifies the maximum electrical resistance of a conveyor belt and the corresponding test method.The test is intended to ensure that the belt
23、 is sufficiently conductive to avoid the accumulation of electrical static charge which can be developed during service use.This International Standard is not suitable or applicable to light conveyor belts as described in ISO 21183-11, the static electrical properties of which are measured by ISO 21
24、1782.2 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 any a
25、mendments) applies.ISO 18573, Conveyor belts Test atmospheres and conditioning periods3 SpecificationThe electrical resistance of the conveyor belt when tested in accordance with the method described in Clause 4 shall not exceed 3 108 (300 M). Lower values may be specified for special applications.4
26、 Test method4.1 PrincipleAn electric current of specified voltage is passed via electrodes through a suitably prepared test piece taken from the belt.4.2 Materials and apparatus4.2.1 Sheet of insulating material, a little larger than the test piece.4.2.2 Two cylindrical and coaxial brass electrodes,
27、 the base of one being circular and the other annular.The dimensions and masses are given in Figure 1. The bases of these electrodes shall be machined flat and polished. A flexible insulated wire shall be connected to each electrode.4.2.3 Ohmmeter (resistance-measuring instrument), with a range up t
28、o 1010 and accurate to 5 %.4.2.4 Source of direct current, adjustable to 1 000 V, and not permitting a current greater than 10 mA or causing an energy dissipation of more than 1 W in the test piece.The source of current may be either an accumulator or a rectified, stabilized AC-power supply. ISO 201
29、2 All rights reserved 1BS EN ISO 284:2012ISO 284:2012(E)4.2.5 Contact agent (to ensure good contact between electrodes and test piece), having an electrical surface resistivity no higher than 104.A jelly of suitable composition is given in Table 1.Table 1 Suitable composition of contact agentCompone
30、nt Proportionmass fractionAnhydrous polyethylene glycol (molecular mass: 600) 800 mg/gWater 200 mg/gPotassium chloride 10 mg/gSoft soap (pharmaceutical quality) 1 mg/gDimensions in millimetresKey1 electrode of minimum mass of 115 g2 electrode of minimum mass of 900 gFigure 1 Electrodes4.3 Test piece
31、s4.3.1 DimensionsThe test piece shall be square and shall be cut from the full thickness of the belt. The length of a side shall be 300 mm minimum.4.3.2 NumberOne test piece shall be taken. If the specification requires that two or more test pieces are to be taken but does not specify how they shall
32、 be selected, reference may be made to ISO 2823.2 ISO 2012 All rights reservedBS EN ISO 284:2012ISO 284:2012(E)4.3.3 Cleaning of test surfacesIf suitable, clean both surfaces of the test piece by rubbing with Fullers earth, (i.e. hydrated magnesium-aluminium silicate), for example, using a clean clo
33、th. After cleaning away all traces of the powder, wipe the surface with a clean cloth moistened with distilled water, then dry with a clean cloth.4.4 Atmosphere for conditioning and testingBefore testing, expose the test piece for at least 2 h to one of the standard laboratory atmospheres specified
34、in ISO 18573. Conduct the test in this atmosphere (see Annex A). An atmosphere of 23 C 2 C and 50 % 5 % relative humidity is preferred.4.5 Procedure4.5.1 Check test room atmosphere.4.5.2 Paint on one of the surfaces of the test piece the contact agent (4.2.5) in the two areas illustrated in Figure 2
35、. Great care shall be taken to ensure the accuracy of the dimensions of the areas, but the symmetry of the centre is not critical. If the test piece surface is flat, this jelly may be painted on the bottom surface of the cleaned electrodes. In the case of textured surfaces, the two areas shown in Fi
36、gure 2 shall be painted on the test piece. The test shall be carried out immediately after painting.NOTE In the case of covers with surface undulations, contact between the electrodes and the test piece can be improved by thin sheets of metal foil of the same dimensions as the brass electrodes, plac
37、ed on the liquid contact agent and made to follow the form of the surface by rubbing lightly with the finger. The brass electrodes are then placed on the foil.4.5.3 Place the test piece on the sheet of insulating material, with the test surface upwards.4.5.4 Clean the lower faces of the brass electr
38、odes and place them on the liquid contact agent pattern on the test piece.4.5.5 Take care not to breathe on the test surface, as any condensation of moisture may falsify the result.4.5.6 Connect the outer electrode to the earth or low-voltage terminal of the measuring instrument.4.5.7 Connect the in
39、ner electrode to the high-voltage terminal of the measuring instrument.4.5.8 Measure the resistance after applying the voltage for at least 1 min.4.5.9 Repeat the test on the other surface of the test piece. ISO 2012 All rights reserved 3BS EN ISO 284:2012ISO 284:2012(E)Dimensions in millimetresKey1
40、 contact agent (4.2.5)Figure 2 Design to be painted on the test piece4.6 Expression of resultsFor each surface of the belt subjected to test, record the electrical resistance, in ohms.4.7 Test reportThe test report shall include the following information: complete designation of the conveyor belt ma
41、terial and the manufacturing date; reference to this International Standard, i.e. ISO 284:2012; test room temperature and relative humidity; conditioning period; contact agent applied; voltage applied to the electrodes; results of the tests; date of test; any deviations from the standard test.4 ISO
42、2012 All rights reservedBS EN ISO 284:2012ISO 284:2012(E)Annex A (informative) Variation of electrical resistance with temperature and humidityA.1 GeneralThe materials used for the covers of conveyor belts are, in terms of electrical resistance, sensitive to their temperature-history and their strai
43、n-history. This phenomenon arises because of the structural configuration of the conductive particles (e.g. carbon) in the polymer and the degree of their orientation, which can change, between the manufacturing stage and installation due to the strain-history of the belt.The antistatic properties o
44、f the covers of conveyor belts are also influenced by their electrostatic charging characteristics, which are related to their relative permittivity, a full discussion of which can be found in IEC 602504.A.2 ConformityThe surface electrical resistance of a conveyor belt cover as measured by this met
45、hod may vary if the temperature in the test laboratory varies during the test and will fall dramatically if the relative humidity rises above 50 %. If a test result does not prove conformity with the requirements of this specification, it is advisable for the test to be repeated at the higher limit
46、of temperature and humidity required by the product specification. ISO 2012 All rights reserved 5BS EN ISO 284:2012ISO 284:2012(E)Bibliography1 ISO 21183-1, Light conveyor belts Part 1: Principal characteristics and applications2 ISO 21178, Light conveyor belts Determination of electrical resistance
47、s3 ISO 282, Conveyor belts Sampling4 IEC 60250, Recommended methods for the determination of the permittivity and dielectric dissipation factor of electrical insulating materials at power, audio and radio frequencies including metre wavelengths6 ISO 2012 All rights reservedBS EN ISO 284:2012This pag
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