1、BS EN 16974:2016Conveyor belts Indentationrolling resistance related tobelt width Requirements,testingBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS EN 16974:2016 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN 16974:2016.The
2、 UK participation in its preparation was entrusted to Technical Committee PRI/67, Conveyor belts.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 are respon
3、sible for its correct application. The British Standards Institution 2016.Published by BSI Standards Limited 2016ISBN 978 0 580 92799 7 ICS 53.040.20 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standa
4、rds Policy and Strategy Committee on 30 September 2016.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS EN 16974:2016EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 16974 September 2016 ICS 53.040.20 English Version Conveyor belts - Indentation rolling resistance rel
5、ated to belt width - Requirements, testing Courroies transporteuses - Rsistance au roulement par suite denfoncement relative la largeur de courroie - Exigences, essais Frdergurte - Gurtbreitenbezogener Eindrckrollwiderstand - Anforderungen, Prfung This European Standard was approved by CEN on 13 Jul
6、y 2016. 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 such national standards may be obtai
7、ned 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 own language and notified to the CEN
8、-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, Germany, Greece, Hungary, Iceland, Ireland,
9、 Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre:
10、Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 16974:2016 EBS EN 16974:2016EN 16974:2016 (E) 2 Contents Page European foreword . 3 1 Scope 4 2 Normative references 4 3 General information . 4
11、 4 Symbols and units . 5 5 Test rig 6 6 Preparation of test samples 7 7 Procedure. 7 8 Calculation and expression of results 8 9 Test report . 8 Annex A (informative) Conversion of the measured width related indentation rolling resistance to a 3-part idler station 10 Bibliography . 12 BS EN 16974:20
12、16EN 16974:2016 (E) 3 European foreword This document (EN 16974:2016) has been prepared by 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
13、by endorsement, at the latest by March 2017, and conflicting national standards shall be withdrawn at the latest by March 2017. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any
14、or all such patent rights. 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 Republic, Denmark, Estonia, Finland, Former Yugoslav Republi
15、c 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. BS EN 16974:2016EN 16974:2016 (E) 4 1 Scope This European St
16、andard defines a method for the determination of the width related indentation rolling resistance of conveyor belts. The goal is that the method easily and quickly delivers values which are reproducible and relevant for the practical use. The test results enable a comparing evaluation and the design
17、 of belt conveyors with steelcord and fabric conveyor belts. This European Standard is not suitable or valid for light conveyor belts described in EN ISO 21183-1. 2 Normative references Not applicable. 3 General information The indentation rolling resistance is caused by the energy loss connected to
18、 the deformation of the conveyor belt due to its contact with the idler. Apart from the technological properties of the conveyor belt the magnitude of the indentation rolling resistance depends on the following factors: design of the conveyor belt, especially the pulley side cover plate thickness; v
19、ertical load; idler diameter; ambient temperature; belt speed. The width related indentation rolling resistance is measured in a test rig with an idler which exerts an evenly distributed vertical force on the belt. An indentation rolling resistance to be used for the design of belt conveyors for an
20、idler station with more than one idler can only be calculated considering the vertical forces and their distribution between belt and idler (refer to Annex A). BS EN 16974:2016EN 16974:2016 (E) 5 4 Symbols and units Table 1 shows the symbols and units used in this standard. Table 1 Symbols and units
21、 Symbol Meaning Unit B Belt width mm DR,MDiameter of measuring idler mm DR,GDiameter of the opposing idler mm DTrPulley diameter mm FE Indentation rolling resistance acting on one idler N FE,ges Total indentation rolling resistance acting on an idler station with three idlers N FEIndentation rolling
22、 resistance related to belt width N/mm FM,hHorizontal force acting on the measuring idler turning clockwise (FM,h,r) or anti-clockwise (FM,h,le) N FM,vThe vertical force on the measuring idler corresponding to the load N FM,vVertical force related to the belt width N/mm FnNormal force acting on an i
23、dler N FRIdler rolling resistance N L Distance axis-to-axis mm TUAmbient temperature C bKWidth of the rubber edge of the belt mm caFactor in the approximation equation for the width related indentation rolling resistance - cbExponent in the approximation equation for the width related indentation ro
24、lling resistance - bRLength of the contact line between belt and idler shell mm d Steelcord diameter mm q Length related load acting on the idler N/mm nsNumber of steelcords - s1Cover plate thickness, carrying side mm s2Cover plate thickness, pulley side mm t Cord pitch mm v Belt speed m/s z Coordin
25、ate of length mm BS EN 16974:2016EN 16974:2016 (E) 6 Table 2 described the used indices in this standard. Table 2 Indices Index Meaning m Middle idler s Side idler 5 Test rig The testing apparatus is a test rig with a rotating belt sample, constructed with a drive pulley and a tensioning pulley. Bot
26、h pulleys have a minimum diameter of 800 mm (Figure 1). The distance axis-to-axis has a minimum value of 3 500 mm. For high strength conveyor belts and large splice lengths differing pulley diameters and distances axis-to-axis shall be agreed upon with the operator of the test rig. The belt speed is
27、 adjustable and is constantly monitored with appropriate sensors. The complete test rig is placed in an isolated climate chamber, so that the ambient temperature can be adjusted with suitable heating and cooling devices. In the top run there is a special measuring arrangement with which an idler can
28、 be pressed down on to the belt with a defined force. As counter support an idler is installed. This idler has a minimum diameter DR,Gof 400 mm and the diameter shall be larger than the diameter of the measuring idler by a minimum factor of 1,5. R,G R,M1,5DD (1) The diameters DR,Gand DR,Mshall be ch
29、osen corresponding to the parameters of the belt conveyor and to be agreed upon with the operator of the test rig. The test rig shall be constructed in a way that it is possible to install the test belt as an endless belt. Figure 1 shows a schematic picture of the test rig. Key 1 temperature isolati
30、ng chamber Figure 1 Schematic picture of the test rig BS EN 16974:2016EN 16974:2016 (E) 7 For the measurement of the indentation rolling resistance idlers with varying diameters and shell lengths are used. These are installed in an adjustable frame. The shell length of the idler shall be at least 10
31、 % longer than the width of the test belt. The frame shall be in a statically simply fixed position. It shall be avoided that the position is over-determined and that resulting forces are created. These could distort the measurement results. All suspension points shall be equipped with suitable forc
32、e sensors in order to determine all suspending forces unambiguously. The perpendicular alignment of the measuring idler to the belt can be checked with the help of a force sensor which records the forces that act in axial direction upon the idler, if the alignment is not correct. In order to determi
33、ne the width related indentation rolling resistance the forces are measured which act upon the left and the right side of the idler and therefore upon the frame with suitable force sensors. To calculate the indentation rolling resistance from these values, the part of the horizontal force cause by t
34、he idler rolling resistance shall be known and shall be subtracted from the measured horizontal force FM,h. The idler rolling resistance can either be measured simultaneously with suitable sensors, or it can be measured separately. In this case the test parameters of the measurement of indentation r
35、olling resistance need to be taken into consideration. 6 Preparation of test samples The endless length of the test belts depends on the distance axis-to-axis of the test rig L and the pulley diameter DTrand deviations from the values stated in clause 5 shall be agreed with the operator of the test
36、rig. The width of the test belt shall be a minimum of 350 mm. For steel cord belts the width of the rubber belt edge shall be chosen as follows: =k1()2b td (2) In fabric belts rubber edges shall be avoided, so that the belt width is equal to the width of the tension carrier. The test belts shall be
37、joined with a splice of minimized length, which can differ from the standard splice layout. The horizontal force measured in the splice area can differ from the force measured in the belt. Therefore it is not taken into consideration for the calculation of the indentation rolling resistance. 7 Proce
38、dure The cover plate to be measured shall be in contact with the measuring idler. Prior to each measurement the test rig shall be operated in constant test conditions long enough, so that the idler running resistance and the measured horizontal forces reach a steady-state. The complete test rig shal
39、l be brought to the desired temperature over a sufficiently long time, so that in the complete cross section of the test belt the temperature equals the surrounding temperature in the climate chamber of the test rig. In order to cancel the influence of zero drift errors when measuring the horizontal
40、 forces acting on the measuring idler, the belt running direction shall be alternated several times during the measurement. The value of the difference between the measured horizontal force of the belt running to the left FM,h,land the belt running to the right FM,h,ris taken into account for the ca
41、lculation of the indentation rolling resistance. The measurements shall be performed with a test idler of which the diameter DR,Mequals the diameter of the idlers in the conveyor. The vertical forces used in the measurements shall be chosen according to the normal forces between belt and idler stati
42、on in the real life conveyor. The different temperatures TUset in the climate chamber of the test rig shall be chosen corresponding to the temperatures to be expected at the real life conveyor. BS EN 16974:2016EN 16974:2016 (E) 8 In order to gain accurate results it is important to achieve an introd
43、uction free from superpositions of the vertical force FM,v which is a magnitude larger than the measured horizontal forces. A possible influence on the horizontal force from the vertical force shall be taken into consideration. 8 Calculation and expression of results The width related indentation ro
44、lling resistance FEis calculated from the absolute value of the difference between the horizontal force measured for the belt running to the left FM,h,land running to the right FM,h,r, considering their different algebraic signs. Furthermore the rolling resistance FRof the used measuring idler shall
45、 be subtracted. =M,h,l M,h,r RE| |22FF FFB(3) When showing the width related indentation rolling resistance as variation of the vertical force FM,vit is recommended to also relate the vertical force to the belt width. =M,vM,vFFB(4) Figure 2 shows an example for the relation between the width related
46、 indentation rolling resistance FEand the width related vertical force FM,v, considering the ambient temperature TUas parameter. Figure 2 Example for the variation of the width related indentation rolling resistance FEdepending on the width related vertical force FM,vunder consideration of the ambie
47、nt temperature TU9 Test report The test report shall contain the following information: a) belt manufacturer; b) for steelcord conveyor belts: 1) belt type; 2) width related nominal breaking force of the belt in N/mm; 3) belt width B in mm; BS EN 16974:2016EN 16974:2016 (E) 9 4) number of breakers;
48、5) steelcord diameter d in mm; 6) cord pitch t in mm; 7) thickness of the cover plate including protective layers and transverse reinforcements (carrying side s1and pulley side s2in mm); 8) type and position of protective layers and transverse reinforcements; 9) additional notes (e.g. according to D
49、IN 22129-2 or EN ISO 15236-3); c) for fabric conveyor belts: 1) belt type; 2) width related nominal breaking force of the belt in N/mm; 3) belt width B in mm; 4) number of plies; 5) thickness of the cover plate including protective layers and transverse reinforcements (carrying side s1and pulley side s2in mm); 6) type and position of protective layers and transverse reinforcements; 7) additional notes (e.g. according to DIN 22102-1 or DIN 22109-5); d) test conditions: 1) type and diameter of the measuring idler DR,Mrespectively th
