SIST EN ISO 21178:2007
(Main)Light conveyor belts - Determination of electrical resistances (ISO 21178:2005)
Light conveyor belts - Determination of electrical resistances (ISO 21178:2005)
Will specify methods for determining the surface resistance, volume resistance perpendicular to the belt plane, and longitudinal and transverse volume resistance parallel to the belt plane of light conveyor belts. Will also specify two methods for determining the surface resistivity and the volume resistivity.
Leichte Födergurte - Bestimmung der elektrischen Widerstände (ISO 21178:2005)
Diese Europäische Norm legt Prüfverfahren zur Bestimmung der elektrischen Widerstände leichter Fördergurte fest, wie sie in ISO 21183-1 beschrieben sind. Die Widerstände sind der Oberflächenwiderstand, Durchgangswiderstand senkrecht zur Gurtoberfläche und Durchgangswiderstand in Längs- und Querrichtung parallel zur Gurtoberfläche. Des weiteren sind in dieser Norm zwei Verfahren zur Ermittlung des spezifischen Oberflächenwiderstandes und des spezifischen Durchgangswiderstandes enthalten.
Courroies transporteuses légeres - Détermination des résistances électriques (ISO 21178:2005)
L'ISO 21178:2005 spécifie des méthodes d'essai permettant de déterminer les résistances électriques des courroies transporteuses légères décrites dans l'ISO 21183-1. Ces résistances sont la résistance surfacique, la résistance volumique perpendiculaire au plan de la courroie et la résistance volumique dans les sens longitudinal et transversal, parallèlement au plan de la courroie. L'ISO 21178:2005 spécifie également deux méthodes d'essai pour déterminer la résistivité surfacique et la résistivité volumique.
Naprave za kontinuirni transport – Lahki trakovi tračnih transporterjev – Preskusna metoda za določanje električnih upornosti (ISO 21178:2005)
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Light conveyor belts - Determination of electrical resistances (ISO 21178:2005)Courroies transporteuses légeres - Détermination des résistances électriques (ISO 21178:2005)Leichte Födergurte - Bestimmung der elektrischen Widerstände (ISO 21178:2005)Ta slovenski standard je istoveten z:EN ISO 21178:2006SIST EN
ISO 21178:2007en53.040.20Deli za transporterjeComponents for conveyorsICS:SLOVENSKI
STANDARDSIST EN
ISO 21178:200701-april-2007
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN ISO 21178November 2006ICS 53.040.10Supersedes EN 1637:1999
English VersionLight conveyor belts - Determination of electrical resistances(ISO 21178:2005)Courroies transporteuses légères - Détermination desrésistances électriques (ISO 21178:2005)Leichte Födergurte - Bestimmung der elektrischenWiderstände (ISO 21178:2005)This European Standard was approved by CEN on 21 October 2006.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2006 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 21178:2006: E
EN ISO 21178:2006 (E) 2 Foreword The text of ISO 21178:2005 has been prepared by Technical Committee ISO/TC 41 "Pulleys and belts (including veebelts)” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 21178:2006 by Technical Committee CEN/TC 188 "Conveyor belts", the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2007, and conflicting national standards shall be withdrawn at the latest by May 2007. This document supersedes EN 1637:1999. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Endorsement notice The text of ISO 21178:2005 has been approved by CEN as EN ISO 21178:2006 without any modifications.
Reference numberISO 21178:2005(E)© ISO 2005
INTERNATIONAL STANDARD ISO21178First edition2005-11-01Light conveyor belts — Determination of electrical resistances Courroies transporteuses légères — Détermination des résistances électriques
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© ISO 2005 – All rights reserved
ISO 21178:2005(E) © ISO 2005 – All rights reserved
iiiContents Page Foreword.iv 1 Scope.1 2 Normative references.1 3 Symbols.1 4 Electrical surface resistances.2 4.1 Method A: measurement of surface resistance ROA omni-directionally.2 4.2 Method B: measurement of surface resistance ROB in longitudinal and transverse direction.5 5 Electrical surface resistivity ρs.7 5.1 General.7 5.2 Principle.7 5.3 Apparatus.7 5.4 Preparation and preservation of test pieces prior to testing.9 5.5 Procedure.9 5.6 Expression of results.9 5.7 Test report.10 6 Electrical volume resistances.10 6.1 Volume resistance RD perpendicular to plane of belt.10 6.2 Volume resistance RDi in longitudinal and transverse direction parallel to plane of belt.14 7 Electrical volume resistivity ρD.17 7.1 Procedure.17 7.2 Expression of results.17 7.3 Test report.17 Annex A (informative)
Comparative values for electrical resistances.18
ISO 21178:2005(E) iv
© ISO 2005 – All rights reserved Foreword ISO (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 body 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 Electrotechnical 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 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 rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 21178 was prepared by Technical Committee ISO/TC 41, Pulleys and belts (including veebelts), Subcommittee SC 3, Conveyor belts. This International Standard is based on EN 1637:1999, prepared by CEN/TC 188.
INTERNATIONAL STANDARD ISO 21178:2005(E) © ISO 2005 – All rights reserved
1Light conveyor belts — Determination of electrical resistances 1 Scope This International Standard specifies test methods for determining the electrical resistances of light conveyor belts according to ISO 21183-1. The resistances are surface resistance, volume resistance perpendicular to the belt plane, and longitudinal and transverse volume resistance parallel to the belt plane. This International Standard also specifies two test methods for determining the surface resistivity and the volume resistivity. 2 Normative references 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 18573:2003, Conveyor belts — Test atmospheres and conditioning periods ISO 21183-1, Light conveyor belts — Part 1: Principal characteristics and applications 3 Symbols Symbol Quantity Unit ROA Electrical surface resistance, method A Ω ROB Electrical surface resistance, method B Ω ROG Electrical surface resistance for the determination of ρs Ω RD Electrical volume resistance perpendicular to the plane of the belt Ω RDi Electrical volume resistance in longitudinal and transverse direction parallel
to the plane of the belt Ω ρs1) Electrical surface resistivity Ω ρD Electrical volume resistivity Ω⋅cm d1/2/3 Diameter of electrode cm dm Middle of the gap diameter cm g Width of the gap cm A Surface of the electrode cm2 h Thickness of test piece cm
1) The SI unit of surface resistivity is the ohm (Ω). In practice this is sometimes referred to as “ohm/square” or “Ω/sq” or “Ω/†”. The size of the square is immaterial.
ISO 21178:2005(E) 2
© ISO 2005 – All rights reserved 4 Electrical surface resistances 4.1 Method A: measurement of surface resistance ROA omni-directionally 4.1.1 Applicability This method is applicable to belts which are electrically two-dimensionally isotropic in the plane of the belt. 4.1.2 Principle An electric current of specified voltage is passed via electrodes through a suitably prepared test piece taken from the belt. 4.1.3 Apparatus 4.1.3.1 Sheet of insulating material, a little larger than the test piece. 4.1.3.2 Two cylindrical and coaxial brass electrodes, the base of one being circular and that of the other annular. The dimensions and masses are given in Figure 2. The bases of these electrodes shall be machined flat and polished. 4.1.3.3 Flexible insulated wire, connected to each electrode. 4.1.3.4 Ohmmeter, having a measuring range up to 1010 Ω and accurate to within ± 5 %. 4.1.3.5 Source of direct current, adjustable up to 500 V, and not permitting a current greater than 10 mA. NOTE The source of current can be either an accumulator or a rectified, stabilized a.c. power supply. 4.1.4 Test piece 4.1.4.1 Material Test piece material shall be new, unused (“virgin”), but shall not be tested sooner than five days after manufacture. It shall be free from contamination and superficial damage. 4.1.4.2 Dimensions The test pieces shall be square, 300 mm × 300 mm minimum, and shall be cut from the full thickness of the belt. 4.1.4.3 Number Three test pieces shall be taken. One test piece shall be taken from the middle of the belt, the other two test pieces shall be taken 100 mm from each of the belt edges. 4.1.4.4 Cleaning If necessary, clean both surfaces of the test pieces by rubbing with fuller's earth (hydrated magnesium-aluminium silicate), for example, using a clean cloth. After cleaning away all traces of the powder, wipe the surface with a clean cloth moistened with distilled water and then dry with a clean cloth.
ISO 21178:2005(E) © ISO 2005 – All rights reserved
34.1.4.5 Conditioning Before testing, condition the test pieces in accordance with ISO 18573:2003, Atmosphere B, for 24 h, except that, if the light conveyor belt consists of materials with a high absorption of moisture, e.g. cotton or polyamide, condition the test piece for 48 h. 4.1.4.6 Preparation Prepare the test pieces in the following manner after conditioning according to 4.1.4.5. To ensure good contact between electrodes and test piece a contact agent shall be used. The electrical surface resistivity of the contact agent shall not be higher than 104 Ω. For checking this value, use the same electrode arrangement as described in Clause 5. NOTE A jelly having the following composition is suitable: anhydrous polyethylene glycol of molecular mass 600 800 parts by mass; water 200 parts by mass; potassium chloride 10 parts by mass; soft soap (pharmaceutical quality) 1 part by mass. If the surface of the test piece is flat, paint the contact agent onto the bottom surface of the cleaned electrodes. If the surface of the test piece is textured, paint two areas of the test piece as shown in Figure 1. Take care to ensure the accuracy of the dimensions of the painted areas, although the symmetry of the centre is not critical. Carry out the test immediately after painting. If silver lacquer is used as the contact agent, carry out the test after evaporating the solvent. 4.1.5 Procedure Measure the temperature and relative humidity in the test room. Place the test piece on the sheet of insulating material, with the test surface upwards. Paint the test piece or bottom surface of the cleaned electrodes with contact agent and let the solvent evaporate, if necessary. If necessary, clean the electrodes and place them on the test piece. Apply the test voltage to the electrodes, starting with a low voltage to protect very fine antistatic layers against damage. Read the value of the electrical resistance 1 min after applying the test voltage.
ISO 21178:2005(E) 4
© ISO 2005 – All rights reserved Dimensions in millimetres
Key 1 contact agent Figure 1 — Design to be painted on the test piece Dimensions in millimetres
Key 1 min. mass 115 g 2 min. mass 900 g Figure 2 — Electrodes
ISO 21178:2005(E) © ISO 2005 – All rights reserved
54.1.6 Expression of results For each surface of the belt subjected to test, record the electrical resistance, in ohms, measured for eac
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