Source: https://www.scribd.com/doc/81849717/Belt-Conveyor-IS-11592
Timestamp: 2016-12-06 16:58:41
Document Index: 90395098

Matched Legal Cases: ['art 1', 'art 1', 'art 1', 'art 1', 'art 1', 'art 1', 'art 1', 'art.6', 'art 1', 'art 1', 'art 1', 'art 2', 'art 1', 'art 1', 'art 1', 'art 3', 'art 4', 'art. 9', 'art 7', 'art 8', 'art 2', 'art 1', 'art 1', 'art 1', 'art 2', 'art 3', 'art 4', 'art 5', 'art 6', 'art 1', 'art 1', 'art 2', 'art 3', 'art 4', 'art 5', 'art 1', 'art 3', 'art 4', 'art 1']

Belt Conveyor IS_11592
BrowseInterestsBiography & MemoirBusiness & LeadershipFiction & LiteraturePolitics & EconomyHealth & WellnessSociety & CultureHappiness & Self-HelpMystery, Thriller & CrimeHistoryYoung AdultBrowse byBooksAudiobooksArticlesSheet MusicBrowse allUploadSign inJoinIS 11592:2000(Reaffirmed 2005)
w’wfhm
Wmtwh-rmm? )-?r-d-wrm(
(m’7 p?w7)
Indian Standard AND DESIGN OF BELT CONVEYORS CODE OF PRACTICE ( First Revision)
ICS 53.040.10
@ BIS 2000
ZAFAR MARC
Price Group 15
Bulk Conveying, Elevating, Hoisting, Aerial Ropeways and Related Equipment Sectional Committee, ME 06
FOREWORD This Indian Standard (First Revision) was adopted by the Bureau of Indian Standards, after the draft finalized by the Bulk Conveying, Elevating, Hoisting, Aerial Ropeways and Related Equipment Sectional Committee had been approved by the Mechanical Engineering Divisional Council. Belt conveyors play an important role in the key sectors of the economy such as mines, steel plants, thermal power stations etc. Accordingly, the design of the belt conveyors has to take care of various parameters. This standard has been prepared to help the engineers and technocrats and industry for making use of uniform practice for selection and design of belt conveyors in India.
This standard was first published in 1985 and has been revised to bring it in line with 1S0 5048 which has since been revised. In addition, the reference of Indian standards referred in the standard is also being up-dated.
Further the errors noted during the implementation of the standards are also being corrected.
This standard has basically
covered the conveyor system using belts from 300 mm to 2000 mm belt widths conforming to IS 1891 (Part 1) : 1994 ‘Conveyor and elevator textile belting : Part 1 General purpose belting ~ourth revision)’. At present belts of width upto 3000 mm are also being used in Indian industries. This standard can be made applicable to belts of all widths subject to availability of technical data. In the preparation of this standard assistance has been derived from the following: 1S0 5048:1989 1S0 5049 (Part 1) :1994 1S0 5293:1981 ISO/TR 10357:1989 DIN 22101:1979 BS 2890:1973 BS 5934:1980 Continuous mechanical handling equipment — Belt conveyors with carrying idlers — Calculations of operating power and tensile forces Mobile equipment for continuous handling of bulk materials — Part 1: Rules for design of steel structures Conveyor belts — Formula for transition distance on three equal length idler rolls Conveyor belts — Formula for transition distance on three equal length idler rollers (new method) Continuous mechanical handling equipment; belt conveyors for bulk materials: bases for calculation and design Troughed belt conveyors Method for calculation of operating power and tensile forces in belt conveyors with carrying idlers on continuous mechanical handling equipment .
For the purpose of deciding whether a particular requirement of this standard is compiled with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS 2: 1960 ‘Rules for rounding off numerical values (revised)’. The number of significant places retained in the rounded off value should be same as that of the specified value in this standard.
IS 11592:2000
Indian Standard SELECTION AND DESIGN OF BELT CONVEYORS CODE OF PRACTICE ( First Revision)
1 SCOPE 1.1 This standard provides guidance for selection and design pt-actices to be adopted for belt conveyors.
1.6 This code covers the belt running on idler rollers only and not on slideslbeds.
1.2 This standard applies to stationary and shiftable and/or expendable conveyors handling loose bulk material and such material, which behave as solids+For guidance, classification and properties of such material are covered in IS 8730.
1.3 This standard covers the conveyors with belt widths ranging from 300 mm to 2000 mm as currently in vogue in conformity with relevant Indian Standards but excluding special purpose conveyors.
NOTES 1 Conveyors, not covered under this scope and special purpose conveyors, for example, feeders, package conveyors, etc. will be covered in a separate standard. 2 This standard also covers the conveyors using steel cord belting. 3 Special i-equiremen~ for conveyors for use in underground coat mines are also covered by this standard, 4 This standard does not include certain data on steel cord conveyors and conveyors for underground mines where relevant Indian Sr~ndards are available.
1.7 This standard applies for only smooth surfaced belt. 1.8 This standard excludes the installations using horizontal curves 2 REFERENCES 2.1 The Indian Standards listed in Annex A contain provisions which through reference in this text, constitute provision of this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are-encouraged to investigate the possibility of applying the most recent editions of the standards indicated in Annex A. 3 TERMINOLOGY, SYMBOLS AND UNITS
3.1 For the purpose of this standard, the terms and definitions given in IS 4240 shall apply.
1.4 Attention is drawn to the many varied factors which influence the driving force on,the drive pulley and which make it extremely difficult to redirect the power requirement exactly. This Indian Standard is intended to give a simple method of conveyor design calculation. Consequently it is limited in terms of precision but is sufficient in the majority of cases. Many factors are not taken into account in the fortnulae but details are provided on their nature and their effect. In simple cases, which are the most frequent, it is possible to progress easily from the calculation of power requirements to those of the necessary and the real tensions in the belt, which are critical in the selection of the belt and in the design of the mechanical equipment. However, certain conveyors present more complicated problems, for example those with multiple drives, or with an undulating profile in vertical elevation. For these calculations, which are not covered in this Indian Standard, it is advisable to consult a competent expert. 1.5 The recommendations given in this standard shall
3.2 Symbols and Units Symbols and their units used in this standard for calculations are summarized in Table 1. 4 TYPE OF CONVEYORS
4.1 The conveyors are troughed and flat, both hori-
zontal and/or inclined or declined with or without curvatures in vertical plane. 4.2 Troughed conveyor is that in which the belt forms a trough on the carrying side while restinglrunning over idler rolls which are either in set of 5-rolls/3-rolls or 2-rools. The troughing angle adopted shatl conform to IS 8598 and shall be selected from the following values: 15°, 20°, 25°, 30°, 35°, 40°, 45°.
NOTE—The troughed angle of 15° is applicable for 2-roll belt conveyors only.
4.2.1 For return idlers, the troughing angle of 0°, 10°, or 15°, shall preferably be adopted.
be applied both to individual conveyor, as well as systems consisting of more than one conveyor. Care shall however be taken to apply clauses pertaining to system requirements.
4.3 Flat belt conveyor is that in which the belt runs flat on the carrying side, over an idler or a set of idlers. 1
R.n Minimum
Tension at the curve when belt is partially
78. Rbc 47.12 77. No 32. 86.11.
15. R. 28. 17. T 68. h.718 Appr — 9:806 rdsz 79. T. 26. Tm 62. 36. 75. K. point and tangent point on curves Width ofmatenal on belt m m m 2.p. 9. 6.
10. m. (1) 1. i plane perpendicular to the longitudinal axis of the belt Dkances from point of separation to the points m situated on the tangent line from which ordinates are to be drawn Acceleration length at loading area Length of installation equipped with skirt plates excluding (see SI No. R= Wrap resistance between belt and pulley Inertial and frictional resistance at the loading point and in the acceleration area between the handled material and. b. 52.m. 65. s 54.. 40. Vw 71. 8. N 92. 20. m — N/m — — — — m m kg rev/rein revlmin N/m kW kW kW kW m’ls m N 82.eyrrrper metre kg/m k~m kg kgfm kglm m m m degree lnterskirt plate width Shafi diameter inside bearing Base for natural logarithm (a constant) Arititicial friction coefficient belt tension to limit belt sag belt tension under normal operating N N Unit (4) N N Description Unit No. I* 81. K 21. PA 33.ofthe pulley 44. la 83. (2) (3) Cross-sectional area of load on belt Area ofcontact between belt and belt cleaner Belt width Bearing life factor Conveyor capacity Coefficient depending upon trough angle Pulley diameter Belt modulus Belt specific modulus Force available for acceleration of the total equivalent mass 11. Special main resistances Special secondary resistances Maximum allowable belt sag — N and kNlm kN/m N/m N/m N/m N/m N/m N/m condition N/m Nlm N/m N/mm M/s Or/s both starting Safety factor Peripheral force on the drive pulleys Tension at the curvefor running condition Maximum recommended belt tension Average belt tension at the pulley Minimum Maximum conditions Maximum operating belt tension Maximum peripheral force slack side tension Belt tension in startirrghrrking loaded up to beginning of curve Maximum belt tension when belt is partially loaded up to beginning of curve Induced belt~dge stress in ~itions Belt speed Handled material conveying speed component in the direction of belt motian 70. m. x.. SF 55. T.
c C. N.p. (1) 49. 39. d 76. R. H. PM 35. T* 59. m. 12. hz Ordinates for trajectory of material Angle of tilt of the idler axis with respect to a 80. md 87. 56. Z 73.m 64.3.1 urrd8. K. T. P 90. 5. R~ 43. 31. Resistance due to friction between handled material and skirt plates Slope resistance N N 89. m.. Rv Height of material on belt at discharge pulley Slope factor Scraping factor Application factor for idler Lump factor Service factor Speed factor Conveyor length (distance between cerrtres) Length of installation equipped with tilted idler Total equivalent mass Rated motor speed Drive pulley speed Normal strength of belt Absorbed power Operating power requirement on drive pulley Motor output power (shaft) Installed motor output power Volumetric conveyor capacity Radius (minimum) of curve Pulley bearing resistance not to be calculated for drive pulley Resistance due to idler tilting Main resistances Resistance due to friction at discharge plough Secondary resistances Vectorial sum of the two belt tensions acting on the pulley and of the forces due to the mass of the revolving parts. n. 42.3. F. 4. m 29. T.
m — rih — m kNlm — N
Description (3) Special resistance Frictional resistance between handled material and the skirt plate in acceleration area 51. Frictional resistance due to the belt cleanersN N 91. N N N N N N N. 2.1. N N N N N 84. g
. F.2. PM. F Bracking force Force required for deceleration Additional force required for deceleration Equivalent force on each idler bearing Modified equivalent force on each idler bearing Total vertical. m. R 41. 22.1. 24. Tm 58. ~ 61.1 1. N: 30.IS 11592:2000 Table 1 Symbols and Units Table 1 (Con~inued)
S1 Symbols S lSymbols No. mB 85. R. 53.5.. R& 48.the belt 46. P“p 34. K. Tcm (4) m’
(C/auses 3. Fq -m
16. GLr2 (4wk2) 18. 23. v 69. Fd 14.3.8 . 7.. Tti 60. T. Y 72.2. R< 38. H
63. 88. 82) Mass ofbelt per metre Mass of revolving idler parts along the carrying side of the conveyor per metre Mass of material that can be safely discharged on the next chute or hopper Mass ofhandlcd material on conveyor per metre Equivalent mass for drive system per metre parts of pulleys per metre idler parts along the return kg/m length of conveyor Mass of revolving length of conveyor Mass ofrevolving Number of trippers Pressure between belt cleaner and belt side of the conv. L 27. Fd 13. K. T. e Load factor Coordinatesof curves Distance between working. R. Rw 45. F. 57. 25. b 74.8. R 50.force on central idler roll Moment of inertia of drive system Lift of conveyor between loading end and discharge end 19. Q 37. L. K.ms2 m 67. R. 3. R: (2)
A Al B B.
/m x y ff D 6 Length of the centre idler Maximum permissible slopping time or maximum permissible coasting time Transition distance Vertical distance the belt edge rises or lowers during transition Numerical coefficient. 101. flame proof motors. namely. 94. that is unusable width of the belt Total cross-sectional section section area of the material S. c) Whether future extensions are required or not. d) Material flow diagram and flow rates. 6. structures. = Lower
Table 2 lists the features of troughed and flat belt conveyors and shall help in selecting the type of belt conveyor. ploughs. points mentioned in 6. in addition to data covered in 6. Coefficient and bell P. transmission lines.+. 99. If so. Type of tripper/transfer feeder movement o (whether crawler mounted or rail mounted). points such as compact drive head.
Ill. fire retarding belting and safety precautions 3
Acceleration coetlcient Bulk density of material Angle of wrap Surcharge angle Belt width Surcharge angle Edge margin.
Table 2 Features of Belt Conveyors
Pc P. Declination undesirable
Coetlicient of friction between material and belt of friction between material and of friction between belt and belt
tlm] radian degree m degree m
6. Power transmission .q. 112. discharge/distribution point(s). and !3) Maximum allowable ground pressure.
(1) 93. and h) Specific requirement for tensioning arrangement. 121. (2) (3) Pitch of carrier idler or idler spacing on carrying side of the conveyor Pitch of return idler or idler spacing on return side of conveyor Ratiomf torque starting motor torque and full load pulley +0. rivers. /l* ~.IS 11592:2000 Table 1 (Concluded) S1 Symbols
No.025 m represents the approximate thickness 97. However. 113. b) Difference in levels between the head and tail ends. 116. existing and proposed roads. being a fimction ofconveyor length Factor for extra power for trippers Slope angle of the conveyor from horizontal line in the moving direction rf. e) Details of receiving point(s). 107. I 15. b) Over/under surface interferences.2. 124.
Troughed Belt Flat Belt Conveyors Lower capacity requirements Low speed requirements Relatively higher angle of repose of conveyed intermediate With or without vertical curvature Without Suitable for inclimtion or decliMaximum material. the following data is also required: a) Layout of working face.2 For layout of system of conveyors andlor individual conveyor in underground (mining) installations.
1/ f“.
Drive efficiency Angle from vertical leave the belt Troughing angle of return idlers Angle between side axis of the troughed canying idlers and horizontal troughing angle Coefficient and belt of friction between drive pulley of friction between carrying idlers at which material will
!.1 In case of shiftable conveyors. 98. !05. 106. P. 122. rails. 120.the proposed level of the head end or tail end to be altered.2. I 09. = Upper S. d) Type of shiftin~ e) Location of discharge conveyors in case of pivot operation. 114. 108.2 For system layout. 126. 117.1 For a single conveyor the centre-to-centre distance
. 104. buildings.025m (this (4) m m — m Description Unit
between head and tail pulley and lift of conveyors is fixed to suit feed and discharge requirements. 6. g) Climatic data and site condition.3 shall be considered here also to the extent applicable. 1. 95. 1 (6 1. 125. distributor plates vertical curvature inclination allowed is
Conveyors Higher capacity requirements High speed requirements Large lump size of material with or without intermediate discharge with trippers
110. Belt thickness Time taken to accelemte the load Deceleration time Reduced deceleration time Time required by motor to accelerate the conveyor 102 !03. 96. etc. 118. the following data is required to proceed further: a) Site plan with suitable contour drawings. & p @ qJ Coefficient skirt plates Coefficient cleaner
nation in accordance with IS 8730
6°. drains.6.
Radius of discharge of belt)
0. if any. discharge limited with Iumpssize of conveyed material. 119.efficiencies for positive and regenerative power respectively — degree — m m m s m s s s s
100. f) Material characteristics including size analysis.
t. 123.2. 6 LAYOUT . c) Grade deviations.
7. maintaining a minimum transfer point height and avoiding reversal of direction of flow of material unless absolutely necessary due to site constraints. 7. 7. 7.IS 11592:2000
against fire in all other equipment especially fluid coupling and other electrical items shall be duly taken care off.3.8 Consider the type of supporting idlers and their spacing [see 8.2 The known maximum lump size of the material can be found from Table 3 taking into account the classification of material as given in 7. 10andll. 7.7 Use the larger of the belt width as determined by 7.(!Q 900
of troughing angle.2)
All dimensions in millimetres. of Belt to ~ Uniform 75 75 75 100 125 125 180 180 200 260 1 050 1 350 1 500 280 360 380 380 410 410 460 500 NOTE — The exact determination also requires consideration Size Maximum Lump Size
missible limit (see IS 8730).2).
b) Keeping conveyor lengths (including allowance
for belt elongation) within reasonable limits so as not to exceed the likely RMBT (recommended maximum belt tension) for selected type of conveyor belting.1.
Table 3 Maximum Lumps Sizes in Relation -to Belt Width
perWidth
(Clause 7. 8.4 Ascertain speed factor as sum of lump size factor (see Table 4).
abrasiveness and other material
7. water ways and railways and maintaining minimum clearances in accordance with the statutory requirements. 90 percent by mass of all material less than two-third maximum lump size. Use of surge hopper shall be considered if coasting time cannot be corrected. taking following points into consideration:
a) Keeping allowable inclination within
b) Sized — Material not falling within the above grading.3. angle of inclinatiord declination and angle of surcharge for the material. it is unavoidable. determine belt width and troughing angle for the required capacity of the conveyor from Tables 7. c) Keeping minimum overhead clearances below the conveyors according to the site requirements while crossing road. belt speed or characteristics.6 and rework if the belt width requirement from 7.9.6 From the selected belt speed.6.1 Wherever multiple choices are specified. This shall not be cont%sedwith crusher setting or screen openings as these limit only one dimension. 7.3.* 7. the conveyor system is laid out.5 If the conveyor is inclined/declined. select a safe angle of inclination/declination for the particular material (also see IS 8730 and 8.2 and 7.1 Once the configuration and layout of a conveyor is finalized the following design steps are taken for sizing the conveyor.
. suitable means of coasting corrections at transfer point shall be considered. d) Keeping all transfer points in line with direction of flow. lAto lJ.2 Lump Size Lump size indicates the longest single dimension of larg.2 is lower than that required by 7.1 Material shall be classed as ‘sized’ and ‘unsized’ based on the material as follows:
1s 1891 (Pa’t 1. Determine the angle of surcharge according to the nature of the material (see IS 8730). air borne factor (see Table 4) and abrasiveness factor (see Table 5) and select belt speed (see Table6).4 Typical layouts of conveyors are shown in Fig. 7 CONVEYOR DESIGN PROCEDURE 7. the worst condition applicable shall be considered for the design of the conveyor system.1. 7.8 for selection and IS 4776 (Part 1) for spacing].3 Size of Material
7. (Standard Widths Underlined) X-N
Unsized (Maximum Dimensions) 100 100 125 150 200 230 300 330 380 430 460 530 660 680 750 800 900 1020 of maximum lump size
450 m 6(!!2 m 750 8. In case. 6. 75 percent by mass of all material less than one-half maximum lump size. est lump.1.3 Based on the above data. 6. 50 percent by mass of all material less than one-third maximum lump size. 4
Unsized — 30 percent by mass of all material less than one-sixth maximum lump size. and e) Coasting time of a conveyor shall be taken into consideration to avoid build-up of material.
The bend in carrying run can be made over an idler pulley.“
.er arrangements a. 1B Horizontal Conveyor — Discharges
at intermediate
points through fixed trippers or at end
ORIVE END
Fig. 1D Inclined or retarding conveyor for lowering material gently down slopes similar to those used in stvle in Fia. . Mav be combined with ot..IS 11592:2000 Skirt Boards on Intermediate Loading Hoppers Hinged to Clear Load from End Hopper
Fig...”. 1E Combination Inclined and Horizontal Conveyor — The horizontal run can be discharged at head end or at any intermediate point by means of fixed or movable trippers. 1A Horizontal or Inclined Conveyor — Loaded at one end and discharged at other end may also be loaded at intermediate points through fixed or movable spouts
. . 1C convevor.. in operation the drive acts as a brake
Fig.’”9-&q#J-
Fig. 1C Inclined Conveyor — will carry up varying slopes which depend upon the nature of material is loaded in usual way and discharges over head pulley
Fig.+
““:”””s...d whe..:. but the method shown is preferable 5
. /-+&Q y
~~-..~”’ .
RADIUS OF CURVE DEPENDING UPON TENSION OF BELT AT CURVE
Fig. 1F Simplest method for conveying horizontally and up an incline where belt tension is not excessive. The radius or curved section must be ample to prevent belt, loaded or empty, lifting from carriers, maximum inclines depend upon nature of material handled and method of loading
Fig. 1G This arrangement combining two conveyor units is often necessary where limited space and high belt tension make the sweeping curve impracticable
Fig. 1H For conveying on both upper and return belt often used with flat belt for packages
CARRYING T SA TRAINING IDLER 15 To 20 ~3To ~fi
h—’
+3104—4= TAIL END
30 ——————i RETURN SA TRAINING IOLER ORIVE END
Fig. lJ Idlers spacing for belt conveyor 6
7.9 Calculate the resistances (tensions) for all conditions including empty belt, loaded belt, liftidrop and other accessories.
7.10 From the tension requirement, sorbed power. sions. determine the ab-
Table 6 Maximum Recommended
BeltSpeeds
(Clauses 7.4,8 .1.3,8.2.2 and 8.3.3)
600 to 650 750 to 800 950 to 1050 1200 to 2000
7.11 Select type of drive and determine slack side ten7.12 Find out the minimum recommended belt tensions for limiting belt sag to 0.5 to 2 percent of the distance between adjacent idlers on the carrying side. This sag in no case shall exceed br$yond2 percent.
Table 4 Lump Size Factor
Speed Factor\
(Clause 7.4)
Material Lump Size Lump Size Factor Air Borne Factor 4
7.15 Compare slack side tension values obtained from 7.11 and 7.14 and use higher of the two values to calculate maximum operating tension. Also calcu-
Ftne Grain m Dust Granular Sized and Unsized
< 10mm <25 mm
late maximum starting tension. 7.16 Multiply maximum operating tension by the minimum safety factor with reference to type of belt, joints and take-up, etc. 7.17 Select a belt having breaking strength in excess of value obtained from 7.16. -Check this result with recommended maximum and minimum and maximum belt widthhtumbers of plies for troughing and supporting the load. 7.18 Tentatively decide belt specification including cover thickness grade and construction. 7.19 Check adequacy of belt for starting and breaking tension calculated in 7.15. 7.20 Finalise belt selection.
7.21 Determine drive power considering transmission
Quantity of largest lump is <20 percent of maximum permissible lump size (for the selected belt width)
Quantity of largest lump is <60 percent of maximum permissible lump size (for the selected belt width)
Largest lump does not maximum perexceed missible lump size (for the selected belt width) Largest lump does not permaximum exceed missible lump size (for the selected bett width)
Table 5 Abrasiveness
losses after selecting machinery between drive pulley and source of power. Consideration shall be given here to limiting requirements of starting tensions and corresponding minimum acceleration time requirements.
‘Abrasiveness Factor 1
Abrasiveness Non Abrasive Free flowing materials, such as cereal Type of Material
7.22 Determine the various pulley sizes namely, drive pulley, head pulley, tail Tttlley, snub pulley, take-up pulley, etc. Due considerations shall be given to recommendations made in IS 1891 (Part 1) while making the selection for pulley sizes.
7.22.1 Basis for selection of pulley sizes for PVC beh-
grains, wood, chips, wood pulp, fullers earth, flue dust, soda lime, char, loam sand, ground gravel. Materials, such as aggregate, run-of2
ing (see IS 3181) for underground use are as follows: PVC Belt Type Tensile Strength (Minimum)
Mildly Abrasive Abrasive Very Abrasive
bank sand and gravel, slate, coal, salt, sand stohe. Materials, such as slag, spar, limestone concentrates, pellets. Iron ores, minerals, taconite, jaspar, flint rock, glass heavy crdlet, 3 4
Minimum Pulley Diameters for Satisfactory Flexing Drive Pulley mm 450 500 650 800 900 Driven Low Pulley Tension mm Pulley mm 250 350 300 400 400 550 550 700 550 700
granite, traprock, pyrites, sinter, coke.
7.13 Calculate slope tension and return side friction tensions. upon conveyor configuration, that is inclination/decli nationregeneration, location of drive, compute the minimum required slack side tension. 7.14 Depending
3 4 5 6 8 7
Longi- Transtudinal verse (kN/m (kN/m Width) Width) 245 580 265 700 280 875 350 1140 350 1400
IS 11592:2000 Table 7 Maximum Section of the Handled Material in mz for Triple Roller Troguhed Belts According to Fig. 2 with Equal Length Carrying Idlers
(Clauses 7.6,8 .3.2,8.4.3,8.4.3.2
and 8.4.5)
I.J-l
SECTION B OF HANDLED
FOR TRIPLE ROLLER TROUGHED BELT
Surcharge Angle
20° 0° I0° 20” 30° o’ 10“ 20° 30° (r Io“ 20” 30° 0°
25” 0.0120 0.016 2 0.020 6 0.025 2 0.022 0.029 0.037 0.045 4 9 7 9
30° 0.0139 0.0180 0.0222 0.0266 0.0260 0.0332 0.0406 0.0484 0.0402 0.0518 0.0638 0.0763 0.0677 0.0857 0.104 0.134 0.0992 0.126 0.153 0.182 0.139
0.175 0.2)3 0.253 0.185 0.233 0.282 0.334 0.237 0.298 0.361 0.427 0.294 0.370 0.448 0.530
0.009 8 0.014 2 0.018 7 0.023 4 0.018 4 0.026 2 0.034 2 0.042 7 0.027 9 0.040 5 0.053 5 0.067 1 0.047 8 0.067 4 0.087 6 0.109 0.070 0 0.098 8 0.129 0.160 0.098 0
0.138 0.179 0.221 0.130 0.182 0.236 0.293 0.167 0.233 0.302 0.374 0.207 0.290 0.376 0.465
35° 0.0157 0.0196 0.0236 0.0278 0.0294 0.0362 0.0433 0.0507 0.0454 0.0564 0.0678 0.0798 0.0763 0.0933 0.111 0.129 0.112 0.137 0.163 0.190 0.1-57
0.191 0,220 0.264 0.208 0.253 0.300 0.349 0.266 0.324 0.384 0.446 0.331 0.403 0.476 0.554
40” 0.0173 0.0210 0.0247 0.0287 0.0322 0.0386 0.0453 0.0523 0.0500 0.0603 0.071 0.0822 0.0838 0.0998 0.116 0.134 0.123 0.146 0.171 0.196 0.171
0.204 0.237 0.272 0.228 0.270 0.314 0.360 0.292 0.346 0.401 0.460 0.362 0.429 0.490 0.571
45” 0.0186 0.0220 0.0256 0.0293 0.0347 0.0407 0.0469 0.0534 0.0540 0.0636 0.0736 0.0840 0.0898 0.105 0.120 0.136 0.132 0.154 0.176 0.200 0.184
0.214 0.245 0.277 0.244 0.283 0.324 0.366 0.313 0.363 0.414 0.468 0.388 0.450 0.514 0.581
0.0344 0.046 6 0.059 1 0.072 2 0.0582 0.077 I 0.096 6 0.117 0.085 3 0.113 0.142 0.172 0. I 20
0.158 0.197 0.238 0.159 0.209 0.261 0.3 I 5 0.203 0.268 0.334 0.403 0.253 0.332 0.4 I 5 0.501
20° 30” 1200 0° 10° 20° 30° 0°
10° 20° 30° I 600 0° 1o“ 20° 30° I 800 0° I 0° 20” 30° 2000 0° 10° 20” 30°
566 0.461 0.649 0.741 0.613 0.604 0.
35° 0.585 0. the angle of declination shall not exceed 12° in any case.1. For systems with ploughs and trippers.2 Care shall be taken for the inclination of an inclined/declined conveyor.510 0.
II Indicates sizes generally not available in the c&ntry
7.413 0. Inflammable.439 0.23 Finalized drive power considering transmission losses after selecting machinery between drive pulley and the source of power. 7.539 0.953
— 20”
0° 10“ 20° 30”
0.30 Calculate the braking force and torque required. 8 DESIGN ASPECTS 8.928
0° Io“ 20” 30° 0° 10° 20” 30°
2 800’)
0.777 0. and r) Sticky.859 0.774 0.528 0.552 0.737 0.950 1. .423 0.993 1.897 1.478 0.1 The proper design of a belt conveyor/conveyor system is greatly influenced by the characteristics of the material to be handled.311 0.803 0. d) Mildly abrasive.584 0. gear box.4~8 0.104
NOTE — Suitable
adjustment maybe made in case of other values of surcharge angle and troughing angle.697 0. belt/chain drive.0).10011
1o“ 20” 30°
2 600’J
2.or liable to react with rubber products.27 Consider location and type of take-up and find out the amount of take-up tension and the take-up movement.885 0. f) Very abrasive.573 0.710 0.914 0.806 0.677
0.4ngle
. Explosive or creating harmful dust.b) High temperature.505 0. Very dusty.827 0. as these are likely to slide down. Determine the type and location of hold bacldbrake.575 0.158
0. 8. .774 0. the material is classified as shown in IS 8730.677 0.982 0.801 0.748 0.428 0.24 Finalise the drive element’s specification like cou-
possible.549 0.656 0.508 0.484 0.894 1.3 Table 6 shows the maximum recommended belt speeds for different sizes of belts based on speed factor (speed factor -= lump size factor + abrasiveness factor).368 0. h) Easily degradable.257 0. lower speeds of belt shall be adopted.025 1.063
0.494 0.1 Characteristics Design of Material Affecting Conveyor
8.648 0.721 0. 8.749 0. carrying lumps of material.357 0.527 0.363 0.725 0. wherever 9
q) Hydroscopic.1. 7.
.586 0.1.694 0.628 0.455 0.IS 11592:2000 Table 7 — Concluded I Belt Surcharge
Width mm 2 2001) Angle I rougn . 7.25 Determine drive shaft diameter and other terminal shaftings.547 0. Highly corrosive. g) Sharp abrasive.482 0. j) k) m) n) p) Mildly corrosive.845 0. 7.629 0.640 0.
pling.672 0.569
0.663 0.408 0.660 0.26 Select proper bearings for the duty conditions and service life.822 0.863 0. c) Non-abrasive.1.729 0. In case of declination.
7.4 Physical Condition of Material Care shall be taken to analyse the physical condition of the material to be conveyed which are classified as follows: a) Oily . 7.653 0.695 0.716 0.446 0. Actual inclination of the conveyor shall not exceed the maximum allowable value (see IS 873.830 0. 7.360 0.303 0.28 Calculate coasting time of individual conveyors and correct the coasting times for the conveyor system..29 Consider if hold back and brake are required simultaneously or one will be sufficient.772 0.610 0. and meant for information only.999 0. e) Abrasive. 8.625 0.578 0.502 0. Generally.137
45° 0.885 0.
0656 0.0360 0. 3 and for Flat Belts According to Fig.6.0083 0.0140 0.0028 0.4.0092
0.0956 0.0115
0.0100 0.0138 0.0579 0.106 0.114 0.0380 0.0864 0.0212
0.0143 0.0102
0.3.2.0087 — 0.0342 0.0718 0.
.0690 0.0427 0.3.0044 — 0.
0.170 — — — — — — — —
0.4.0085
— — — .0179 0.0257
0.104 0.
SECTION B OF HANDLED MATERIAL
and 8. — —
0.0154 0.0057 0.0029 0.8.132 — 0.102 0.0406 — 0.0274 0.0265 0.0846 0.0059 0.0169 0.0653 — 0.0429 0.181 — — — — — — — —
Suitable adj ustments maybe made in case of other values of surcharge angle and troughing angle. 4 MAXIMUM SECTION B OF HANDLED MATERIAL FOR FLAT 13ELT
FOR Two EQUAL IDLER TROUGHED BELT
Two Idler Troughed Trough Angle
20” 30” 400 o“ 1o“ 20” 30° 0° 1o“ 20” 30° 0° 1o“ 20° 30° 0° 1o“ 20” 30° 0° 10° 20” 30° o“ Io“ 20” 30° 0° 1o“ 20” 30” 0° 10° 20° 30°
.140 0.0413 0.00.0473 0.0154 0.IS 11592:2000 Table 8 Maximum Section B of the Handled Material in mz for Two Equal Idler Troughed Belts According to Fig.0524 0.0112
— — — .0950 0.0145 0.0337 0.0273
0.0763 0.175
0.0170 0.0127 0.0130 0.0421 0.0536 0.0094 0.0399 0.0235
0.0129 0.123 0.3.085-1 0.0459 0.0192
0.8 .0765 0.14 “0.0425 0.0163 0.0647 0.0257 0.156 — — — — — . 4
(Clauses 7.112 0.153 0.0304 0.0486 0.0626 0.4.0594 0.116 0.0188
0.0449 0.0958 — 0.0560 0.0232 0.0047 0.0663 0.5)
--t —
FIG.0231 0.125 0. — —
0.0644 0.0259 — 0. .127 0.0210 0.8.030-8 0.0862 0.0277 0.
64 0. ‘shape.98 0.8 .6—
K AS A FUNCTION OF 8 FOR ASCENDING CONVEYOR
8. Higher belt speeds may be considered under special design conditions. e) Inclination of belt conveyor.9 0.2 Belt speed shall be selected from the recommendation given in Table 6.
a) Capacity required and belt ~idth. 5)
Conveyor Inclination. shapes.00 0.68 0.0
x E“ ~ ~
1.1 Selection of various components of the conveyor system shall be made taking the relevant physi-
8. angle of repose and angle of surcharge. Abrasion and Other Miscellaneous Characteristics of Materials “8.81 0.3.1 Based on size.8.1. Degrees 2 4 6 8 Lo 12 14 Slope Factor K Conveyor Inclination.IS 11592:2000 Table 9 Slope Factor K
(Clauses 7. Degrees 25 26 27 28 29 30 0.4. and f) Idler construction and diameter.85 0.1 Belt speed depends on the following factors:
cal conditions of material into account.4 and Fig.73 0. 8. flowability and other characteristics of the material conveyed.95 0.76 0.1.2. 8. the flowability of bulk materials is given in IS 8730.5.8
UJ L o d
0.89 0. d) Belt construction.5 Flowability. 8.66 0.61 0.56 Slope Factor K
1.71 slope Factor K Conveyor Inclination.97 0.2 Due consideration shall be given to abrasion and other miscellaneous characteristics of material in selection of belts.4.2.99 0. These properties of material are classified in IS 8730.59 0. b) Loading and unloading conditions.78-0.
~.6. 11
.93 0.91 16 18 20 21-22 23 24 0.1. 5
-2{
SLOPE ANGLE.5. c) Size.1.2 Belt Speed
8. Degreea 1.2.7
3.3.3 and 8.4. .
.0 t/m3 Belt speed
v= l.8 . p = 1.6.8.00
‘hiple
Equal Roll Roller ‘Ikoughed Belt.orn/s
K= 1.IS 11592:2000 Table 10 Maximum Cap-city of a Belt Conveyor in tonnedhour
(Clauses 7.lkmrgh Angle
0° 10° 20° So 0° 10° 20° 30° 0°
20° 35 51 67 84 56 94 123 153 100 145 192 241 172 242 315 392 252 355 464 576 352 497 644 795 468 655 849 1054 601 839 1087 1346 745 1044 1359 1674
25° 43 58 74 90 80 107 135 165 123 168 212 260 209 277 348 421 307 407 511 619 432 569 709 857 572 752 939 1 134 731 965 1202 1451 911 1195 1494 1803
30° 50 65 80 96 93 119 146 174 144 186 229 274 243 308 374 446 357 453 551 655 500 630 767 911 666 839 1015 1202 853 1073 1299 1537 1058 1332 1613 1908
35° 56 -70 85 100 106 130 156 182 163 203 244 287 274 336 399 464 403 493 587 684 565 687 792 950 749 911 1080 1256 957 I 166 1382 1605 1191 1451 1713 1994
40° 62 75 89 103 116 139 163 188 180 217 255 296 301 359 417 482 443 525 615 705 615 734 853 979 820 972 1130 1296 1051 1245 1443 1656 1303 1544 1793 2055
45” 67 79 92 105 125 146 169 192 194 229 265 302 323 378 432 489 475 554 633 720 662 770 882 997 878 1019 1166 1 317 1127 1307 1490 1685 1397 1620 1850 2091
10° 20° 30° 0°
10° 20° 30° 0° 10° 20° 30” o“
] 20(3
10° 20° 30” 0° 10° 20° 30° 0“ 10° 2W 30” 0°
1o“ 20° 30”
N(JKE— Suitable adjustments maybe made in case of other values of surcharge angle and troughing angle.5)
Capacity based on:
Bulk density of material.2.
2. . — — — — — — .0 .5)
p= 1.3
Bulk density of material.3. 17 34 52 -30 60 93 — 47 95 146 — 75 154 235 — 111 225 345 — 153 311 475 — 201 410 630
Suitable adjustments
may be made in case of other values of surcharge angle and troughing
.4.8 .Om/s
K= 1.5 15. — — .0t/m3
V= l.6.8 — 10.0 10.5 31 . 21 30 40 50 36 53 67 84 64 96 121 151 99 143 188 236 161 232 304 381 238 342 450 561 — — — — — — — —
20” — — — — 27 36 45 55 46 61 76 92 83 109 137 165 129 171 214 258 208 275 344 417 306 403 504 612 .IS 11592:2000 Table 11 Maximum Capacity of a Belt Conveyor in tonnes/hours
(Clauses 7. — — —
angle.3.
Surcharge Angle 15“
0° Io“ 20° 30” 0° I0° 20” 30° 0° 10° 20° 30° 0° 10“ 20” 30° o“ 10” 20” 30° 0° 10° 20” 30° 0° 1o“ 20° 30° 0° 10° 20” 30° 0° 10° 20° 30°
. — — — 33 41 49 58 55 69 83 98 98 123 148 175 I54 193 233 274 248 310 374 443 367 457 551 651 — — — .
25° .20. Belt speed Slope factor
and 8.8.
H. that is. tilled with material. (3)
speed. 1200.2 Tables 7.4.4 The standard width of belts in millimetres as specified in IS 1891 (Part 1) are as follows: 300. 5 gives values of K. 8.1 To take surges and unevenness in loading operations into account. (4)
=f.Pl+R.3.05 .+ R.5 Tables 10 and 11 give the belt conveyor capacities for horizontal conveyors.3 Higher belt speeds may be adopted after taking into consideration the resultant effect arising out ofi
a) creation of turbulence at loading points and acceleration in cover wear. the belt speed and the slope factor.4.4.0 based on the load cross-section as given in Tables 7 and 8 for a material of bulk density of 1. 8.1. For normally flowing material. 8.3.. dust generation and loss of tine powdery materials.4 Extreme care shall be exercised while selecting
8. surcharge angle of 20° shall generally be chosen as standard value.3 The width of belt for the capacity requirement can be read off from Tables 10 and 11.2. the corresponding value given in Table 10 and Table 11 shall be-multiplied by the actual bulk density of the material. To calculate the capacity of a specific conveyor. slope factor and carrying capacity respectively of belt conveyors. and the nature of the material being handled.5. the lump size of the material conveyed and the capacity requirements of the conveyor. its joining and safety devices for the conveyors.0 t/m. however attain surcharge angle of less than 20° and may drop down to OO. 1800 and 2000. 600.3.4.3 Widths of Belt
. 9.. This shall.1 The required peripheral force.5 shall be generally limited to 90 percent. TEon the driv-
ing pulley(s) ofa belt conveyor is obtained by adding up all the resistances.1 Peripheral Pulley(s).O. c) increase in product size degradation. + m. the slope factor.3.2. g.4. + R. K. for different inclinations of a conveyor. 1400. 8.1 The capacity of a belt conveyor is determined primarily by the following three factors:
a) Cross-section ofload on the belt — The crosssectional load on the belt will vary with the width of belt.2 General formula for calculation of the capacity of all types of belt conveyors shall be as follows: C=3600p A VK. 8.1 For belts of width greater then 2000 mm. also to check the adequacy of the type of belting..g+R.2. (1) 14
8.Pi+ R.IS 11592:2000 8.. The choice of right surcharge angle depends on the conveyed material and the distance it has to travel. 400. 8.. 1600. 1000. L. Easily flowing or almost fluid materials.2 Tables 7 and 8 indicate cross-sectional area from materials having surcharge angles of 0°..4. 800. 8.4.1 It is important 8. (5) = ixf. +(2m~+mG)cosi$J+ R. + (2m. and d) reduction in life of chutes and transfer devices. 500.
8.3. In case of conveyors with belt widths up to 600 mm. 8. The greater of the two values shall be adopted. Surcharge angle higher than 20° occur only for materials featuring a very high internal friction. 10°.0 mfs..4 The slope factor. TE= R + R.1 The width of belt is predominantly governed by two factors. b) Speed of belt. b) encouraging of low density material to become air borne. the capacity shall be reduced to 75 percent. [m.Pz+ Rs~ . the capacity of belt conveyor calculated according to 8. in equation [1) takes into account the decrease of the section of the handed-material on the belt when a gradient is involved.4 Capacity of Belt Conveyor
8.Pl+ R.Pl+ R~~ . 650. of width b (below 2000 mm): b = 0. the type of carrying idlers used which determines the amount of troughing given to the belt. + mG)cos 6] +mG. b= B.Pz . 20° and 30°.4. K= 1. [mC+m... 10 and 11 give cross-sectional area..5.4.3.g. and c) Slope factor..5. 8. Max .. A of the material is given in Tables 7 and 8 which are calculated on a belt width.25 . which determines the quantity af material that can be safely loaded on to a given cross-section. (2)
8. 8.5 Driving Force and Power Calculation 8.3. as lower speed will make the installation costly but on the other hand a higher speed is likely to create problems of spillage. Table 9 read with Fig.9 B -0.. Force Required on the Driving
8. L. and “belt speed of 1. however be checked for minimum belt width from Table 6 for given lump size factor.3 Figures 2 to 4 show -the most usual trough sections for which the cross-sectional area.
(7) = m=.o. when present over a part of the conveyor length. conditionssuch as fixed
and properly aligned
in idler bearings and seals. g) for flexible carcass belts and those with thick and flexible covers. 5 When the installation is running under no-load conditions.
sides of belt and the belt advancement resistance. is a basic value for normally aligned belt conveyors. dimensionless comprising of rolling resistance of the idlers along the carrying and return
m.020 reduced by 20 percent) and for unfavorable friction material.j may.
The basic value 0. and iv) the resistance due to wrapping of the belt on the pulleys. R = main resistances in N comprising of
i) rotational resistance of the carrying and return idlers due to the friction . the value of~ can be either lower or higher than under full-load operating conditions.020 ofJis only applicable to installations used at around 70 to 110 percent of their nominal capacity.
1 Underfavorable
installations with easily rolling idlers and low internal ffiction material j’may be as low as 0. belt speeda of about 5 mk. = secondary resistances in N comprising ofl i) the inertial and frictional resistances due to the acceleration of the material at the loading area. when these are present over the fill length of the-bel$ R. Downhill require to be braked by brake-motor.. increase above the value 0.the value
is unsure. Where the smaller
arepossible
for short high speed feed conveyors of large capacities. R. 0. b) for troughing angle of over 30°. f) fora decrease of the belt tension. and 0. and v) resistance due to tripers.Pz= special secondary resistance in N comprising ofi i) resistance due to friction with belt and pulley cleaners.
a’) = numerical coefficient. iii) pulley bearing ~esistance with the exception of the driving pulley bearings.5 m for the carrying side upper atrand of the belt and 3 m for the return
be calculated with a value lower by 40 percent than used for the calculation of driven belt conveyors. 0. 6.030 under certain adverse conditions and/or type installation as for example in case of underground mines. iv) resistance due to discharge ploughs. d) for carrying idler diameters lower than the above mentiond. and ii) resistance due to friction against chute flaps or skirt plates. ii) resistance due to the friction on the side walls of the skirt board at the loading area.020. R. w-a safety measure. depending on the mass of the moving parts and on the conveyor belt tension. k) for idler spacing of markedly side (lower strand]of the”belt. .020 range up to materials with a high internal friction 0.030 in the following cases: a) for handled coetlicienta. being a function of conveyor length L (see Fig. and ii) belt advancement resistance. that is. 2 The basic value.j’may majority of cases. ii) resistance due to friction with the chute flaps or skirt plates.012. j) when operating conditions are dusty and wet and/or sticky. more than 1.H. surrounding temperatures of about 20”C and 108 to 159 mm diameter carrying idlers with labyrinth grease seals. conveying products with an average internal friction coefficient. 4 The artificial friction coefflcient. = special main resistances in N comprising drag resistance due to forward tilt of the idler in the direction of movement of the belt. is a basic value for down hill conveyors requiring a brake-motor.020 increased by 50 percent). RS~ = slope resistance in N. the recurrent flexing of the belt and of the material. conditions such as poorly aligned belt conveyors with badly rolling idlers andhigh internal be as high as 0:030 (basic value of 0.~ may decrease under the basic value of O.016 (basic value of 0. 6 Value of~may increase above the value of O. the resistance due to lifting or lowering the material on inclined conveyors.012. iii) resistance due to inverting the return strand to the belt.5 m for the carrying aide of the belt and of around 3 m for the return side of the belt.g
NOTE — H is taken as positive for descending for ascending installation and negative J = installation. as indicated by the batched area of Fig. equipped with three-roll carrying idlers for the upper side of the belt.
.IS 11592:2000
where T~ = driving force on the driving pulleys in N. and . e) for surrounding temperatures of less than 20”C. resulting from the impression of the idlers in the belt. h) for poorly aligned installations. a 30° side troughing angle.020
c) for belt speeds of over 5 nr/s. together with idler spacing of 1 to 1..020 if the conditions stated in Note 3 are reversed. 6) Total resistance without slope resistance and without special resistance Main resistance
1) For conveyom with centre distances less than 80 secondary resistances and the greater values
artificial coefficient of ftiction. The result of this is a basic value off= 0. 3 The value. conveyors which shall.
where R.0
1. (for symbols.
1.6 u.5. =AVK.. (12) R&.5
64.Iift of the tripper also.(V-VJ ..lOOO.(9) where Q =volumetric conveyor capacity inm3/s..— .0 5 q g 3.1000p. = intertial and frictional resistance at the loading point and in the acceleration area between the handled material and the belt in N .1. of handled material in kglm = 1000 rQ/V .2 Equation (6) is generally use for determining the driving force Tw If the conveyor slope is less than 18°.0
2.Q2. the factor cos 8 in equations (5) and (6) shall be omitted. b o U 3.. 8. R. Q..5
2. = frictional resistance between handled material and the skirt plates in the acceleration area in N
= p2.1.05 1.. see Table 1)
R~~ .
6 VALUES OF COEFFICIENTCXAS FUNCTIONOF CONVEYOR LENGTH L
8.g.IS 11592:2000
5.(13)
CONVEYOR LENGTH (DISTANCE
FIG. In case a belt tripper is used H shall include . and .(10) H = lift of the conveyor between the discharge area in m. However equation (6) can be used for approximate calculations for conveyors length more than 80 m.3 Calculation for secondary resistance..1 1.0 10
CENTRES). Equation (5) is applicable for all conveyor lengths.. (8) R m= = mass per metre. p...
frictional resistance due to belt cleaners..IS 11592:2000
RW = wrap resistance between belt and pulley..3.(17)
coefficient of friction between material and belt 0.4 coefficient of friction between material and skirt plates 0..1 The highest peripheral force on the driving pulley.7 between belt and belt cleaner Pressure between belt cleaner and belt = 3 (10)4 to 105N/mz K.k = resistance due to friction between handled material and skirt plates in N g. .5 to 0.. c. + R. (21) in case of return idlers equipped with two rollers...ma + nl~) cos 5 sin i .005~
.1OOOp.2. c) loaded on some sections of the conveyor with a rising.Pland RSP1 R. (25)
.5..3 to 0. Min .(19)
RI = resistance due to idler tilting = g. shall
be calculated in accordance with formula (23).4 Calculation for special main and secondary resistances.7 coefficient of friction between material and skirt plates 0..5 to 0. R. For belt conveyors running over rough ground with slope changes or only sloping in the down hill direction.=+ R>
8. ..5 to 0. whether positive or negative. wz.. for example: a) empty conveyor.v. p.l +-R~P2) — (Ri + R. in N (not to be calculated for drive pulleys) . = g ... Rb.(24) 0.. — V2b~ .v= special resistances in N — (R$..(16)
length at loading area m
resistance due to friction at the discharge plough in N B.3.(18) .2 The formulae given in 8. for which partial loading of the belt is frequently the case.p.5.5... level or slightly dropping run where each section requires positive force to move it.
8.. b) fully loaded throughout.. and d) loaded on regenerative sections and empty on
sections with a rising.1. the computing of the peripheral force shall be carried out for different operating conditions.6 to 0.1 for the calculation of the peripheral force at the driving pulley tire suitable only for uniformly and continuously loaded installations.1.~ . = scraping factor in N/m = normally 1500 N/m
v? ..7 8. KOL.5 trough factor above 30° and up to 45° trough coefficient of friction between carrying idlers and belts 0.7 0. a value between 360 and 530 N/m length of each scraper may be
.K= . following table gives the values of wrap resistance
Locaticul of
?’Ldley
Degrze of Wrap of Belt
150° to 240° 150° to 240° —
Wrap Resistance N
230 175 140
Tigb[ side
Slack side All other pulleys
pulley bearing resistance (not to bc! calculated for driving pulleys) in N
0. (22) 17
8. R.5. (20) ( in case of carrying idlers equipped with three equal length rollers..1 The power required at the driving pulley(s) of a belt conveyor shall be: PDP= ~ kw 1000 .4 trough factor up to 30° trough 0. ‘&PI . For guidance.(14)
for steel cord belt
NOTE calculated in accordance
‘B[’40+001”a+ ‘2B[200+00’”a:
NOTE — The
R~C= frictional resistance due to belt cleaners in N = A. and empty on the remaining sections which would be regenerative if loaded.3 Belt Conveyor Operating Power Requirements 8... level or slightly
. descending run. found in this manner shall be used for the design of the driving system.(15)
—The values of wrap resistance Rw shall generally be with formulae (14) and (15).
guidance. P#i (fn~) cos ~ cos 6 sin i .Q2.5.
’numbers of trippers shall be 7’~( + @)N and further 1 calculations shall be based on this force only. nd R.....
l~sg—
1 ep~. 3 rJ. 8. the peripheral forces applied to all the driving pulleys are transmitted to the belt by friction without slipping and the belt sag between the supporting idlers does not exceed a safe limit. stopped either at no load or completely or partially loaded. d) The peripheral force required on the driving pulleys for a belt conveyor with ‘n.4. the actual eftlciency
may be taken into account..5. b) Table 13 gives the values of factor~for a tripper which is either fixed or separately driven and Table 14 is for belt propelled trippers and is restricted to those lengths and slopes where these are applicable. 8.otoo... Table12
referred.5. the coefficient of friction between the driving pulley and the belt and -can be determined from Table 16. being different at different point on belt of the conveyor. (26)
[Clause 8.
. depend upon: a) the path of the conveyor. consideration shall be given to the actual likely condition of usage of installation. (31)
where T=max E Maximum peripheral force.: ‘v ‘w . often occurs when starting up or when braking the completely loaded conveyor.Forguidance.5.3. b) the number and arrangement of the driving pulleys.4 Belt Forces 8. at any rating.IS 11592:2000 Table 12 Efficiency for Various ‘Ikansmission Units
PA=—
+ (Rwd
‘Rbd)v
~. braking.. However
where necessary. number of trippers-the power requirement shall be: Pa=~(l+ntp)+ where ~-= factor for extra power for each tripper and shall be taken from Table 13 or Table 14 as the case may be.3. nominal rating.= 1.2 The motor output power (shaft) shall be: (27) for conveyors requiring Tositive power = PAqz for regenerative conveyors . 2 Multiply together appropriate percentage for each reduction from prime mover to head pulley transmission...3.2 (Note 1)] ~pe
of Drive Percentage Etllciency Enclosed gear units — Single reduction heticatlstraight cut Double reduction helical/straight cut Up to 98 Up to 96
after taking drive pulleys loss into acount
where RWd Wrap resistance between belt and pulley = for drive pulley and is to be calculated as a given for RW. to obtain overall efficiency of
ofq. with ratio of TEand TEmmmay be taken from Table 15 depending upon the characteristics of selected drive.. in N. For guidance.5.5. 2 While deciding on the motor power to be adopted. (28)
NOTES 1 Efficiency of various transmission elements shall be taken into accounl while adopting the values may be
helicaf/straight cut
Spiral bevel/helical/worm gear Double reduction Triple reduction Chain drives — Totally enclosed V-Belt drives Tooth belt drives
Fluid drives NOTES
and oil lubricated
up to 94 Use manufacturers’ rating up to 96 up to 94 Up to 98 95
95-98 Use manufacturer’s rating
1 The percentage given for gear units are based upon well ventilated boxes tilled with the manufacturer’s recommended lubricants.95.3 Additional power required due to tripper a) If a belt conveyor has n.. 18 ‘R”.. 8.3 Transmission of the peripheral force at the drivirrg pulley(s) For the transmission of a peripheral force for TE from a driving pulley to the belt the minimum tensile force Tz~inon the return belt shall be calculated from the formula: (30)
.1 The tensiIe forces on the belt. c) The lift of the tripper shall be included in the conveyor lift (H).. (29)
d) the type.4.5..2 The tensile forces exerted on the belt shall be such that. c) the characteristics of the driving and braking systems. location and arrangement of the belt tensioning devices.
. = Pulley bearing resistance for drive pulley and is to be calculated as given for R~.
8.4.5.1 . and e) the load case of the installation: starting. 8.
08 0.07 0.07 0.07 0.09 — — — — —
— — — — — .09 0.08 16°-20° 0.07 0.07 0.24 0.07 0.5.07 0.27 0.07 0.52 0.27 0.07 007 0.21 0.21 0.12 0.07 0.29 0.07
0.10 0.25 0.10 —
0.07 0.07 0.08 0.07 0.5.46 0.11 0.11 0.17 0.08 0.44 0.5.11 0.36 0.07 0.17 0.08 6“ -10° — 0.10 .19 0.11 0.08 0.18 0.08 0.3 (a) und 8.08 0:08 0.10
0.19 0.07 0.08 0.07 — —
0.17 0.3.07
0.15 0.12 0.07 0.54 0.11 0.10
1“-5”
0.07 0.13 0.10
0.07 0.30 0.3.11 0.10 0.15 0.40 0.23 0.20 0.08 0.10 0.12
Table 14 Factor ~ for Extra Power Required for Belt Propelled ‘IYippers [Clauses 8.13 0.07 0. 0.14 0.10 0.14 0.3.35 0.10 0.— — — — —
.— — —
019 0.08 0.17 0.30 0.07 0.32 0.15 Slope 11”-15° “0.13 0.07 0.08 0.11 0.50 — — .08 0.07 0.5.-IS 11592:2000 Table 13 Factor /3 for Extra Power Required for Separately Driven ‘Mpper
[Clauses 8.07 0.12 0.23 0.3 (b)]
m 5 10 15 20 30 45 60 75 90 120 I 50 180 210 250
Slope 11°-150 16°-20° 0.07 0.3 (a) and 8.19 0.08 0.14 0.19 0.11 0.3.08 0.3 (b)] —
Conveyor Length m 5 10 Is 20 30 45 60 Tripper 0° — — — — — — —19.14 0.08 0.15 0.06
75 90 120 i 50 180 210 250 300 6(X3 1000
— 0.08 0.09 0.
where = maximum allowable belt sag = 0.d~].005 and 0.
1. as normally it is not reasonable and not practicable to produce different take-up forces with different load cases.02.2
for return side
. that the maximum tensile force applied to the belt can be calculated. It is only in the simple cases. Type of Drive Drive Coefficient
~~(m~+mG)g 8S > ~m~. The minimum necessary tensile force is fixed either by the ability of transmitting the peripheral force at a driving pulley or by the limitation of belt sag. that is. exerted on the belt which has to be used for the choice and the dimensioning of the belt can not be indicated s
Three phase squirrel cage motor with special fluidcouplingwithdelayedchamber
fitting Three phase squirrel cage motor with
1. (32)
O Three phase squirrel cage motor with pin bush coupling and. 7 TENSILE FORCES EXERTED ON“BELT
. 8S ‘
for carrying side .2 and 2.2tol. the arrangement and characteristics of the driving and braking devices. occur relatively often. This highest value of the necessary tensile force for a given load case is generally maintained with all the other load cases even if they do not require it. in the case of horizontal conveying or with a small gradient. by using formula (34) (see Fig. by suitably adding to or subtracting from the minimum forces exerted on the belt the motion resistances.5tol. In case of textile
T. The maximum allowable belt sag [(S = hla).6
1.4 Minimum tensile force to limit the belt sag The minimum tensile force Tn.4.4.
@ ANGLE OF WRAP
FIG. however.6.IS 11592:2000 8.. is generally fixed at between 0.5.4. and ifthere is a single driving pulley. the forces due to the weight of the belt and the conveyed products.5. to 2.5 Variation of the tensile forces and maximum terrsileforce on the belt The necessary tensile force and its alteration along the conveying length shall he determined for each load case as a function of the number.005 to 0.ifl which shall be exerted on the belt to limit the amount of belt sag between the
two sets of idlers shall be: Table 15 Values of Drive Coefficient&
(Clause 8. The maximum tensile force T~m.. The carcass is the reinforcing member and may be of either textile reinforcements or steel cords and supplies the tensile strength and the body to the belt to hold the shape. 7):
.1 A conveyor belt consists of two elements. which. and the peripheral forces applied to oil the driving pulleys.. slip-ring motor with slip gear startinrz control 1.8. and according to the type and location of the tensioning devices.3) sl
No.. and if low braking forces for stopping the plant are required. According is between to the
should be higher the coefficient
plant up then when at its nominal drive characteristics.2
special fluid coupling with delayed chamber with panel and scoop control v) Three phase squirrel cage motor with flexible coupling and start/delta start.6 Belt Specification
8. the carcass and the cover..(34)
The coefficient force takes into account the fact that when starting the rating.direct on line start ii) iii) Three phase squirrel cage motor with fluid coupling and direct on the line start 1. Values lower than these never be reached at any point on the installation.2
by a formula which is universally valid.02 8.g — —. approximately..
4 to 0.3
Pulyurethane Laggingwith .35 to 0. e) temperature of the material to be handled.3.1 Tensile forces calculated in accordance with formula (34) (see 8. 8. c) lump size of the material.5 in case of textile belts and 7 to 10 in case of steel cord belts depending upon the application.-Thismay be checked h-n manufacturers’ recommendatory tables pro-vialing maximum number of plies for adequate troughmg or minimum width for adequate troughing for various types/constructions.6. moisture absorption and in some conditions to oils. This may be checked from manufacturers’ recommendatory tables providing either mini-
. The steel cord beking is used to meet the condition of small elongation and good troughbility in conjunction with higher operating tensile forces. gauging.00. 8.5.0 mm for textile rubber belts and 0. troughing and training the belt will be very difilcult. the frequency with which the belt receives the load. If the belt is too tough.0 to 3. aging.3 The back cover thickness of a belt is generally 1.6.6.15
reinforcement.5. tearing. o chemical activity of the material. h) fire resistant cover needed or not.4 to 0.05
0.2.3.2 Selection of Belt Carcass 8. However.9). b) Adequate flexibility to trough on the specified angle of idlers. chemical and heat. g) contamination of the material with oils.15 to 0. abrasion. The factor of safety may vary from 9 to 12.IS 11592:2000 Table 16 Friction Coefficient Between Driving Pulley and Rubber Belting
(Clause 8. the most important of which are: a) abrasive qualities of the material being handled.45 0.35 to 0.1 The properties needed for the cover of belt include resistance to cutting.4 0.2.6.4 The selected belting carcass shall be subsequently cross-checked for compatibility with the vertical curves occurring on the conveyor (see 8.2. type oftakb-up device and type of starting for convertors.8 to 1.6. In case of steel cord belts.6.0 mm and range up to fill thickness of face cover.45 0.3)
Pulley Leg
Operating Conditions \ Dry condition operation Clean wet condition (water) operation Operation under wet and dirty (clay or loam conditions) Operation under very wei and dirty condition [ 0.35.4.5) is then used in selection of belt carcass based on full thickness tensile strength (FTTS) (belt type). the strength of carcass has a practical limit.23
o. PVC belting is generally selected for underground mining applications where fire hazard exists. The full thickness tensile strength of belt tixes the ‘Type’ of belt to be selected.2
0.5 to 0. For general guidance a factor of safety of 10 is normally used for textile belts with vulcanized joints and on a conveyor with gravity take-up and 7 for steel cord belting.2 Full thickness tensile strength (FTTS) method The value of tensile forces (see 8.6.6.35 0. 8.6. Thereftrre.3 After the selection. back cover thickness is minimum 4.25
0.4 Care shall be taken for the determination of back cover thickness for belts on tandem drives and other 21
8.25 to 0. The strength of fabric and the number of plies in the carcass of the belt maybe varied together to suit the strength requirements.35 0.the belt with lesser number of plies with stronger fabric is generally preferred because it is more flexible both in troughing and going round the terminal pulleys.3.2.4 Smooth Bare Rim Steel Pulley
RubberLagging with Herringbone PatternedGrooves
0.1) multiplied by factor of safety gives the required value of full thickness tensile strength of the required belt.2 mm for PVC belts.4.30 Less than 0. b) loading cycle.3
0. the selected carcass shall he checked for the following two constraints: a) Adequate ‘body’ to support the load of the material carried for the specific width of the belt. 8.3 Selection of Cover 8.I I
0. 8.3. the carcass is normally buildup of plies of textile fabric. that is. type of belt joint.2 The grade and thickness of top cover of belt depend upon a number of conditions.2
Caramic Lagging withHerringbone Patterned rooves G
PVC Belt Type
0.Herringbone PatternedGrooves
mum number of plies for adequate load support or maximum width for adequate load support for various types/constructions as also impact loading. 8.6.6. d) loading and unloading conditions. 8.4 0.
8. special consideration shall be made in selection of pulley diameters and lagging. wherever necessary. 4) consisting of a single horizontal idler roll positioned between brackets which attach directly to the conveyor frame. 3) In an offset troughing idler. 3) Horizontal carrying idler for supporting flat loaded belts (see Fig. The softer rubber tends to resist the build up and allowing of solid objects to get embedded in the rubber rather than damage the belt.4 In case of steel cord belting and PVC belting. the three equal length roll troughing idler forms the belt into the best troughed shape to carry a maximum load cross-section.8. for instance where conveyor’s load must be spread for manual inspection.4 Standardization of Belt Constructions are being selected for a number of conveyors in a plant it is worthwhile to consider . 8. material and application.1.3 The lagging thickness shall vary between 6 to 12 mm and the durometer hardness on head pulley shall be 55 to 65 Shore A scale.8 Idlers 8. are given in
8.7.1. which are inclined upward and a ‘horizontal central roll. are used at loading points where the-lump size and the weight of the handled
. 2) Troughing idler arrangement having a relatively long horizontal roll and two short upward inclined rolls does not form a given belt into a trough for maximum load crosssection but is useful under certain conditions. where there is considerable wear and tear in the back side of the belt. .8. 4) Catenary type — Troughing idler consists of a flexible catenary member on which integral small diameter rolls or multiple roll assembly is mounted. The recommended
values of rubber cover grade selection IS 1891 (Part 1). whilst on the snub and bend pulley shall be 35 to 45 Shore A scale. 5) Garland type — This type of idlers are suspended from stringers by suitable suspension methods.5 The cover grade is determined by characteristics of the material handled.1 General Types of Idlers 8.7. which rotates as an assembly in fixed bearings at the ends of the catenary member or in the individual rolls which may rotate on bearings supported by the flexible catenary member.7.1s 115Y2
: 2(NMJ
special applications.7 Pulleys
8. 2) consisting of four/two outer rolls.7.8.2 Carrying idlers
a) General configurations — Carrying idlers can
have three types of general configurations: 1) Five/three roll throughing idlers for 22
troughed belts (see Fig. the inclined rolls (two numbers on both the sides) and the horizontal roll are located in two different vertical planes. to increase the coefficient of friction between the belt and the drive pulley.1 Based on percentage tensile force (ratio between
the working tensile force and maximum allowable tensile force of the selected belt). picking up or sorting. thickness. The inclined end rolls turn up the belt edges to prevent or greatly minimize spillage. This type of idlers consist of rolls connected in between with flexible links and can be used for both on carrying and return side.
8. 8. 8. 3) consisting of two identical idler rolls. its type. Where belting specifications
8.3. and b) Return idlers which support empty return run of the conveyor belt.2 The drive pulleys may be lagged. It may be noted here that the adequacy of belting constructions with respect to actual service conditions that exist on each individual installation should be ensured whilst standardizing. inclined upward 10 facilitate the belt to from a trough. This is to be looked into . 6) Impact cushioned idlers — Impact type idlers having rolls made of resilient material. In such cases the back cover thickness may be increased to 3 mm and above as maybe necessary. roll inclination and surcharge angle of the material.1 There are two basic type of belt conveyor idlers: a) Carrying idlers which support the loaded run of the conveyor belt.6. The rolls can be moulded either in the flexible member. For a given width of belt.6. diameters of pulleys shall be selected from the recommended values given in IS 1891 (Part 1) and shall conform to IS 8531.standardization of carcass and covers for a particular width of belting. 8. b) Type of carrying idlers 1) The most commonly used type to carrying idlers consists of three in line idler rolls of equal length.in terms of expected life and inventory. 2) Two roll throughing idlers for troughed belts (see Fig.
l. with the pivot axis approximately vertical. to suit the troughed belt contour between the last regular troughing idler end the adjacent pulley.. design and mounting hold spacing shall allow for adequate transverse belt movement without permitting the belt edges to come in contact with any stationary part of the conveyor w its frame. or double covered helically shaped self-cleaning return idlers are used. Troughing angle of transition idlers shall be kept as 10°. For moderate impact absorption. are pivotally mounted. 8. The impact resistance Ihat a belt can withstand without any damage can be obtained from the belt manufacturer. shall be used as impact idlers. are mounted so that when the belt dikplaces a little. both troughing idlers and flat carrying idlers can -be so arranged that they automatically move the belt to its central position on the idlers. The transition idlers are designed with concentrator (end) rolls and long centre rolls. ii) Rotary discs are provided at the outer ends of the inclined rolls. c) Self-cleaning return idlers — The idlers are used to clean the belt carrying sticky material which adhere to the belt. low stretch belts. idler rolls are covered with a thick layer of tough rubber. The sticky material can be abrasive thereby causing high wear rate or the material may buildup and adhere to the return idlers causing misalignment of the belt.
.8. The most frequently used type of impact idlers consists of a three roll assembly. iii) Fixed guide idler rollers.2 Idler Specification The carrying and return run idlers shall conform to IS -8598. 8.2(b)(8). Where garland type carrying idlers are used.1. Where garland idlers are used there is no necessity to use the training idlers. For very sticky material metalcage. Similar impact idlers are made to support flat loaded belts also. supported on 20° or above troughing idlers. so that when the under surface of the slightly
displaced belt engages the discs. Idler roll length. impact idlers shall invariably be used. as insurance against possible damage to the belt. In case of transverse belt displacement. bracket. In case the impact at the feed and exceed-s 50 Nm.3 Return idlers Return idlers are of three general types to perform various functions: a) Normal return idlers — These idlers are used to support the flat return belt and consists of a long single roll. the idler assembly will pivot. Several types of self cleaning return idler rolls are available. if the belt was rigidly supported. 15°. The three general methods of pivotally mounting the idlers are as follows: i) Small approximately vertical rolls. 20°. as units.IS 11592:2000
material may seriously damage the belt. rubber disc.8. consisting of a roll on a vertical or nearly vertical axis. such fixed idlers shall be used with great care for unusual circumstances.high tension. 25°. Disc rolls. fitted at each end with a mounted bracket. helical and metal-cage idlers present only very narrow surfaces for adhesion and thus reduce the tendency to build up. In case of adjustable transition idlers. each roll being made of spaced resilient discs. and 30°. For this purpose the troughing or flat belt carrying idlers. garland impact idlers. With these idlers the loaded belt is properly supported near the head and tail pulleys without excessive stretch of the belt edges. from appreciable transverse displacements because continuous contact with fixed guide rollers of the belt edge greatly accelerates the belt edge wear and may ruin or appreciably reduce the normal life of a costly belt. 8) Trahing idlers — Training idlers are used to train or align the belt to a central position since conveyor belts tend to displace transversely. 7) Transition idlers — Transition type troughing idlers are used adjacent to the head and tail pulleys on wide. the end rolls are adjustable. contact of these rolls w[th the belt will cause the idler to pivot. b) Training return idlers — These idlers are used to train and align the return run of the belt and can be mounted to train or align the return belt in a manner similar to the tra:ning idlers specified in 8. connected in between with flexible links.8. sometimes are used to restrain a conveyor belt from transverse displacement. on either end of the carrying idler.
In case of steel cord belting.4.4. for all practical cases. The transition distance shall be calculated from the following formula:
o. which means different idler spacings are required to limit the belt sag to a fixed value. the first might be one-tenth of the conveyor length (independent of loading section) with a carrying idler spacing of 100 percent of the average.3. therefore. 2) The load shall not change its cross-section between idlers that is the edges of the belt shall not flatten down. To minimize this stretch. However.is known as transition distance. the distance of self-aligning idlers on carrying run may be reduced to 10 m.1 Carrying idler spacing The following points shall be considered carefully while determining the idler spacing for carrying idlers of a belt conveyor: a) Increased idler spacing increases the belt sag and hence the power loss due to friction is greater. This spacing shall not be short so that the edges of the belt are stretched too much as the belt loses its tmughed shape and flatterns down the rim of the pulley.5 to 2. b) Very low belt sag means higher belt tensions and therefore. 8.4. 8. 8. The maximum spacing shall be so selected as to ensure that the belt do-esnot loose its troughed shape. the belt sag shall be limited to 0.for graduated idler spacings by deciding a safe maximum allowable belt sag (S).8.8. very considerably along the length of the conveyor.8.707y 2 AT
.8.. 3) The load on each idler shall not exceed the load rating value. In normal circumstances. shall be such as to limit the edge tension to a maximum of 130 percent of maximum rated belt tension and prevent buckling of centre portion of belt. For example. c) The practical upper limit of belt sag is 2 percent of the idler spacing after which the force required to pull the load increases steeply. 8. To determine the idler spacing towards or at the head. the following factors other than the limiting belt sag shall be considered: 1) There shall be no side spill of the material as the belt flattens out in going from the last troughing idlers on to the head pulley.in the direction of belt run for the unidirectional conveyors and it shall be ‘zero’ degree for reversible belt conveyor.8.8. there can be three sections.4 Calculation of transition distance The distance between the terminal pulley and the adjacent fully troughed idler set at either at the head or tail end of a conveyor. the idler spacing shall be arranged to suit the belt tensions at various points. The idler spacings in the carrying side (PC)and in the return side (P. In case or short convertors. Alternately the rim of terminal pulley may be set at a line located at one-third of the depth of troughed section . in a long centre conveyor. 8. the secbnd section of three-tenth of conveyor length at 85 percent of average spacing. usually the pin of the terminal pulley is set in line with the tops of the horizontal rolls of the troughing idlers. 8.8.4.2 The spacings of carrying as well as return idlers for belt widths of 1200 or more as given in Table 17 shall be checked for the idler load capacities.) of the belt can be determined from the equations (32) and (33).3. d) The belt tensions. If the slope of the conveyor varies. In addition.3 Angle of tilt on side rollers of idlers shall be assmall aspossible (generally 2°)andinanycase.of the conveyor.8. The transition distance.3 Tilting ofldler
8.2-The angle of tilt on side rollers of idlers shall be . cost of the belt is high.4 Idler Spacing 8.. at least one set of self-aligning idlers shall be provided at the carrying and return run.3 A set of self aligning idler shall be provided at drive end and return end of conveyor and at an interval of 15 m on the carrying run wherever feasible and 30 m at the return run. occurrence of zero or negative tensions in the centre of the belts also shall be avoided when the belt tension is low such as occurring at tail end of some conveyors. conveyors arranged with the pitch as indicated in Table 17 may be found to be suitable.IS 11592:2000 8. Proper care shall be taken to determine the idler spacings for such conveyors.8.1 Angle of tilt shall be provided on the side rollers if specified by the purchaser. 24
Idlers at the feed point of the conveyor shall-be closely spaced to avoid higher belt sag due to impact of load.3. (35)
. . and finding other terms of the equations. it shall not be more than 3°. especially for a long centre conveyor. with uniform slope.0 percent of the idler spacing. and the remaining three-fifth of conveyor length at 125 percent of average spacing.
. when fed by mobile plough feeder or by mobile reclaimer provision
.40 to 1..4. The rim of the tail pulley shall be in accordance with 8. Provision of impact shall be considered.4.4.80
Recommended Spacings
300 400 500 650 800 1000 1200 I 400 1600 1800 2000
B sinA — when pulley is in line with ..8. 8.8.4.4. the idlers just ahead of the loading point shall be set closer than the average spacing so that the belt takes the load of the material away from the skirt boards without abrupt change of load crosssection. When idler spacing is graduated. for example. An alternative method of
calculating AT is given in Annex F. In case of a long conveyor having a continuous loading zone for almost entire length of the conveyor.8.8.6 Special considerations for spacing the idlers at loading point The following points shall be considered while deciding the idler spacing at the loading point: a) The distance between tail pulley and the first 25 @ f)
fully troughed idler shall be in accordance with 8.5 by one-third of the trough depth above the line of the centre idler roller E= the elastic modulus measured at the maximum rated belt tension (RMBT) in N/inn and is provided by the manufacturer AT = the induced belt edge stress in the transition in N/mm and is selected from
Table 18 in relation to the ratio of belt tension at the transition to maximum rated belt tension..l(g) and 8. The spacing of first few idlers under the skirt board shall be made closer.20 to 2.8.8.4.IS 11592:2000 Table 17 Recommended Idler Spacing
[Clauses 8.20
1.(36) 3 top centre idler roller
B sinA — when pulley is elevated .4 so as to aviod the belt getting damaged due to liftrng and rubbing against the loading chute or skirt boards.
Carrying Idler Sets for Materials of Bulk Density (t/m3)
Ftat Belt
Return Idler Sets
Trotrghed and Flat Belt
in Alldimensions rnillimetres.33 to 0. nor any darnage is done to the belt where it is backed up by the idler. 8. Rubber covered idlers or alternatively mounting the idler stand on rubber ‘filler blocks shall be considered if the impact of the material is severe at the feed point.75 of normal idler spacing to prevent the belt from sagging away from the boards or the rubber guard strip. generally 0. The first fully troughed idler is generally set about 150 mm behind the end of the loading chute or wherever the material first strikes the belt so that neither the idler is hurt by the impact of the material.4.5 Special consideration for spacing the idlers ut head end The distance from the head pulley to the nearest troughing idler shall not be more than the spacing of the idler which is considered proper for the load on the belt and tension on the belt.(37) 4.
values of specific modulus. spacing shall .3 Concave Curves
8. shall be considered in design to ensure that the path of the belt follows a satisfactory radius: a) Overstress of belt edges B.0 0.13.45Tm 0.7 Idler spacing on curves (convex or concave) Following points shall be taken into consideration: a) The spacing of the idlers on concave curves shailbenormal spacing. namely. For calculation.
Table 18 Induced Belt Edge Stress
tension act downwards or against the belt supports..9 Curves in Belt Conveyors
.1 There are two kinds of curves in belt conveyors:
8.3.9. 8. E. the belt speed.7. 8..8.2 The minimum radius of the curves shall not be less than 12 times the width of belt for practical purposes where troughing idlers of 30° troughing angle or less are used.(39)
0.6 to 0.05
1 TCwill be checkedfor all load conditions. However.Esin A Minimum radius.3 on discharge trajectories).2..
..8.8. where components . the spacing on that part of the length of conveyor. even if the beh speed is not high.2.1 It is extremely important to select proper idlers as they considerably influence the performance of a belt conveyor. 8. two factors. C and D for guidance.4 Idler with 8.55Tm AT
4. m . etc.(38)
(Clause 8.(40)
8. as follows.5.1 0. 2 Racths to be checked forallload conditions
to be adopted.3 Annex E gives the method for calculation of idler bearing load.9.. the freeIy sagging belt forms a curve that composes part of a catenary. 8.. ‘c =
o.30Tm 0.9.5
[dler Selection
The transition of the belt from inclined to horizontal or less inclined maybe done with help of a turning pulley or a group (minimum three sets) of troughed idlers.of belt tension act upward tending to lift the beh off its supports.2 Convex Curves
8.2 Typical methods for selection of idler based on a particular service conditions of a belt conveyor are given in Annexes B. E = Es x Rated Tensile Strength 8.4.4)
Ratio of Belt Tension at lkansition to Maximum Rated Belt Tension (TJ 1.20T= O.8.lOT~
9(L – 4. it shall be 40 to 50 percent of the normal spacing of the idlers or if the spacing is variable. where the components of belt 26
8. the later method shall generally be adopted.9.3. 8.2.8 0. However... 8.1 When the belt curves upwards from horizontal to an incline section or from an inclined section of the belt to a more inclined section.8.8. loading.9.5.9.3 Belt modulus ‘E’ required by formulae (38) and (39) is a product of specific modulus for the material of belt carcass and rated tensile strength.. can be taken from Annex G.2 0.
a) Convex curves.4.Esin A m Minimum radius. and b) Concave curves.40T~ 0. Any method of selection of idler may be used for arriving at suitable idler sizes. surrounding conditions.9 0.7 0.3 .IS 11592:2000
of impact table in the feeding machine is recommended in place of providing continuously closed spaced cushioned idlers for the entire length of the travel. andfor convex curves.8. the characteristics of the material handled. The belt shall not be bent with the aid of a turning pulley where the belt speed is high enough to cause the load to leave the belt by an appreciable distance (see 8.2.9.
and maximum radius
8.9. The receiving conveyorshallhave normally spaced troughing idlers without any skirt. The selection of idler is governed by many factors.2 The minimum radius shall be such that the belt will not lift off the carrying or return idlers even under worst condition when the belt is fully Ioaded up to the start of the curve and empty thereafter.60Tm 0.35Tm 0.5.5(Tm– ~)
b) Luck of tension at belt centre B.3. the type of service. b) The number of idler spacings shall not be less than three for any type of curves.9.
the ratio of maximum tensile force. 8..10.5) metres .2 Types and Selection of Drives 8...1. 8 gives typical values for ordinates with 8 = 20°. and the minimum tensile force.7 Table 19 read with Fig.= c 9..
8.mJX=.mmB. . RC= TC.10..3.9.2... 8.. short centre conveyors handling 27
. (44) R.B.that is the slackside tensile force in the belt.9.3.3 For the selection of type of drive.b) Overstress at centre of belt 13... + R.[Rs + R..5 Belt modulus ‘E’ required for formulae (45) and (46) can be calculated with the help of equation (40) and Annex G. (46)
belt tension but inversely proportional to the mass of belt per metre.3..10.3.X shall be worked out from equations (33) and (5) considering the belt is only partially loaded.10. cos ~ . Rc=T.3 The radius of the curve is proportional to the
c) Lack of tension at belt edge B. (43)
drive is given by equation (30) -in 8. bare/lagged pulley drive
8.. minimum number of pulleys and least flexing of the belt consistent with the lowest practical belt tension is preferred. + m.% RADIUS OF CURVATUREFOR CONVACE
8.T2 minimum and T~ for different arcs of contact on driving pulley(s).8 mB Minimum radius for loaded belt..4 The minimum radius.2 Table 20 gives the value of ratios of forces 7’1.~AX T ‘&’ [m.P21 [R.5 (~ -4. should be as high as possible. T2.
FIG. unsnubbed.. T.l000 9. T .8 m~
.1 Basis of Selection 8. This can be used for low capacity.EsinA Minimum radius Rc = 4.l 000 metres R..IS 11592:2000
All dimensions in mil]imetres. 8..B. having belt wrapped around it on an arc of 180°.4. 8.3.of the curve is recommended as 45 metres for practical purposes.10 Drive Selection 8.6 The empty belt may be held from rising too far by the use of one or more hold-down pulleys set high enough to clear load when the belt is on the carriers.. RC.9. T.1000 9. (42) .3.10. + . For most efficient drive.1 Single.9. However following three factors shall be considered in design to ensure that the path of the belt follows a satisfactory radius: a) Lift off Minimum radius for empty belt.1.] shall be caluclated for distance in which belt is empty and shall exclude the length of cruve.1 The fundamental equation for a belt conveyor
Minimum radius for partially loaded belt (loaded up to beginning of curve).5. + R.10. (41)
8.1. sinA E Minimum radius
‘C =
9 (Tm-~)
‘etres
““” ’45)
The simplest drive arrangement consists of one steel pulley connected to the source of power.9..8 (m~ + m~ ) meme~ .. 8.
the belt tension during the start will tend to be as much as the drive capable of exerting and in cases of repeated over-ioading. 8. When selecting hydraulic couplings it shall be remembered that the slip characteristics can be modified by adjusting the volume of oil in the working circuit.
. Two basic forms are available. tandem drives are used. The rate at which this slack belt is accumulated and.10.3. 28
abrasive materials.4 Drive pulleys with twin drive For belt conveyors. the rate at which the take-up unit has to be designed to operate is directly proportional to the rate to acceleration.5 To avoid these undesirable aspects it is necessary to limit the torque developed during startup. . 8. The tandem drive with arc of contact from 300° to 440° or more can function with one or two motors. It shall be ensured that the drive system including drive motor. ac motor to be employed. The tandem pulleys are both driven and share the load resulting in a lower effective tension for a given power transmitted. In the other type the filling may be adjusted during operation so that both the rate of filling and the final quantity can be varied.1 At the start of the belt. bardlagged pulley drive The ratio of maximum belt tension to effective belt tension for the drive is decreased by snubbing. use of twin drive pulleys can be considered as given in Annex H. and this is achieved by acceleration control. and that the speed differential between the drive pulleys is within the slip characteristics of motors and couplings.. to ensure that on multi-motor dual drives that all electric motors and hydraulic couplings have the same torque and speed characteristics respectively. gear box. any more tensile force than the recommended transient capacity of the belt. The pulley may be lagged to increase the coefficient of friction and avoid pulley wear for abrasive materials. The first type is very widely adopted for conveyor drives up to approximately 110 kW but it is obvious that the latter type gives a wider range of adjustment and is amenable to external control.3. coupling. clutch) by use of devices for speed and acceleration control.3 Belt manufacturers commonly rate conveyor
belts so that they are able to withstand the frequent extra loads that occur in starting. centrifugal hydraulic slip.10.4 The above applies to normal duty conveyors with single or dual drive provided with controlled start of motor (that is fluid coupling. the desired acceleration control.10. In majority of normal medium to large capacity belt conveyors. does not exert even at the starting condition. In one type the -oil filling can only be adjusted with the unit stationary and remains constant thereafter.10.3. but the motor and associated switchgear are both large and expensive. and extend the acceleration period as reasonably long as possible. A most effective means of control is to interpose a hydraulic coupling or torque converter between the electric motor and input shaft of the drive unit’s reduction gear. high speed. 8. pulley and chain drive.IS 11592:2000
non-abrasive material. however.10.3.10. eddy current. Also drive factors.3 Drive motors 8. The acceleration control can be provided by using a dc motor as the prime mover. (47)
8.B sF=— TSB
. handling mild abrasive to fairly
1 eP$ – 1 or T2/T~allow for some extra tension before
slipping would occur between pulley and belt. the tension is normal tension plus additional tension to overcome the inertia of the load. 8.10. A correctly designed drive will allow maximum allowable tension force of the belt until the belt has been brought to its running speed. the belt may fail due to fatigue.3 Tandem drive Where the belt tensile fo~ces are very high and it js necessary to increase the angle of arc of contact.10.3. 8.. The arc
of contact is increased from 180° to 210° and can further be increased to 260° by providing snub/drive pulley.10. It is commonly selected in multi-motor installations where individual powers of 75 kW and larger are used. The location of such drive is usually determined by the physical requirements of the plant and its accessibility. 8. This increased starting tension is detrimental to the belt specially for long conveyors and it is necessary to design the drive system to suit the strength of the selected belt.2. This allows the compact.the belt at head pulley which may be bare or lagged. etc. It is important. so the longer and more controlled the acceleration the smoother and lower the rate of take-up.2. Except in short and low speed conveyor. 8. whilst providing.2 Snubbed. 210° snub pulley drive with head pulley lagged with hard rubber is adopted.2. therefore.2 Safety factor condition at starting and braking
Safety factor for the belts when calculated in accordance with the following formula shall not fall below six in case of textile fabric belt and below five in case of steel cord belt when the conveyors are starting up or braking: N~.
005 0.5 30 31.133 0.628
0.5 15 16.5 45 46.036 2.334 0.400 0.5 24 25.541 4.059 1.217 1.155 0.555 5.352 ().844 0.040
0.285 2.411 1.00370.366 4.022 0.150 0.416 0.069 ().703 0.589 1.860 0.092 0.048 0.337 0.050 0.545 2.864 4.167 0.731 0.827 0.076 2.085 0.085 1.008 0.056 0.515 1.300 4.419 3.5 9 105 1~ 13.817 0.504 0.255 0.5 66 67.656 1.576 0.245 0.201 0.5 63 64.626 0.02
0.093 0.494 2.106 0.00460 0.626 0.061 0.577 0.954 3.206 1.156 1.5 3 4.292 5.5 33 34.379 0.412 0.170 0.434 0.289 0.016 0.352 2.436 0.957 1.030 0.480 2.942 2.700 4.5 39 40.104 0.213 2.081 0.144 0.024 2.969 2.015 0.296 ().658 1.137 2.192 0.668 0.270 2.225 0.5 0.5 42 43.170 3.5 4x 49.553 1.5 54 55.300 0.825 6.5 60 61.111 4.375 3.037 0.815 2.653
L)is-
Radius of Curve (RJ in metres 50 65 80 95 110 125 140 165 180 210 240 270 300 330 — 360
kmce t’I’OM
‘r~ngent hint in metres 1.072 2.567 4.527 3.964 4.616 2.982 2.5 57 58.523 1.341 1.153 0.009 0.843 2.00340.777 3.757 0.904 1.325
.509 3.167 2.540 0.266 0.006 0.630 3.343 0.189 0.042 0.816 0.427 0.443 1.018 0.754 1.100 0.656 0.958 2.939 1.361 0.050
0.082 3.276 0.882 2.675 0.742 1.292 3.057 1.118 .500 0.013 1.506 1.634 0.776
2.831 3.879 3.232 1.9.823 3.5 36 .101 6.153 2.902 1.312 2.986 1.156 0.041 2.464 0.582 ().990 2.804 1.358 1.229 0.441 0.183 0.671 1.279 2.2.394 3.961 1.528 0.093 1.565 0.5 27 28.380 1.434 0.530
0.960 5.454 0.767 0.034 4.066 0.129 1.208 1.117 0:168 0.035 5.012 0.720
0.054 0.625 3.341 2.178 5.126 0.683 0.090 0.202 4.014 0.609 2.056 0.629 4.252 1.224 2.054 3.831 1.341 0.163 0.5 21 22.214 3.907 1.853 3.903 1.848 4.450 0.508 1.698 1.011
0.364 1.366 1.075 0.047 0.541 1.312 0.363 0.441 3.800 0.515 0.506 0.240 0.052 1.112 0.394 0.060 0.819 2.793 0.410 2.277 0.017 0.106 1.448 4.135 0.503 1.033 0.637 2.984 1.5 lx 19.204 0.203 1.027 1.378 0.253 0.356 1.715 2.735 0.772 0.078 0.092 0.305 1.760 0.5 6 7.256
.229 1.733 3.375 2.502 0.073 4.068 1.013 0.600 0.191 1.303 0.947 3.010 0.202 0.905 1.607 1.567 0.652 0.418
0.375 0.023
0.085 0.784 5.027 0.226 5.900 5.032 0.37.117 0.873 0.324 0.458 2.683 2.820 1.492 2.147 1.303 4.703 3.353 1.028 0.255 0.692 0.805 0.776 4.613 0.286 3.122 0.853 1.491 0.5 51 52.469 0.507 0.336 0.705 0.00410.375 1.IS 11592:2000 Table 19 Value of Ordinates for Convace Curve
(Clause 8.200 0.161 1.808 1.746 2.109 0.189 3.920 1.036 0.218 0.517 2.975 4.306 0.244 1.025 0.262 0.108 3.742 2.006 0.964 1.225 0.015 3.649 0.750
0.128 0.3.553 0.003 0.384
0.654 1.482 1.
11.42 0..03
400 420 440 460 480 500 600
5.11 1.39 3. shall be at least equal to or greater than that of the preceding one. this aspect takes special importance as otherwise belt is liable to be damaged by burning.46 0.11. +2mB+mG+mp)L.30 0.2 Hold-back and 13rake. but it shall be equipped with an automatic brake capable of bringing the fully loaded conveyor to rest within a reasonable time.72 6.67 1.11.00 3.5.07 1.25
Ratio T1/TE
Bare pulley Lagged pulley
Arc of Con&act on Driving
Pulley degree 180
Bare p[llley 2.055 1. In general.50
1.85 1. when power is off.26
1.51 13.23
0.1 Coasting Time
be provided on conveyors which tend to reverse the direction of run when power is off or under very heavy overload. If Lhephysical properties of conveyor are such that it would coast for a longer time than the one on to which it feeds there will be pile up of material at the transfer point. have to be interconnected electrically so that if one conveyor is stopped for any reason.29 1. the length of the deceleration cycle of any successive conveyor calculated in accordance with 8.26 0..00 15.19 0.19 3.17 0.11.10.02 10. (mc+m.54 1.58 1.2.08
1.67 0.1 Hold-back
. T~–~ where T~ = 1. (49)
important to note that the drives of a conveyor system which consists of more than one belt conveyor in which at least one belt feeds on to another.063 1.06
0. 8.1
For conveyors with belts conforming to IS 1891 (Part 2) carrying hot material.50 0.54 0.19
0.050 0.3 Acceleration Time 8.08 0.32 0.86 13.46
I 90 200 210 220 230 240 360 380
2.29 2.83 4.4. 8..90 7. the one feeding on to it must stop.IS 11592:2000 Table 20 Arc of Contact and Ratio of Tensions
(Based on ~ = 0.58 0.08
Plain Snubbed do do Snubbed do do Tandem do do do Tandem do
--i -i
do Tandem do I
8.13 4.80 5.13 1.13
0.063 0.2.055 0.2 Any conveyor requiring greater power to lift the load than the power required to move the belt and the load horizontally.25 6.3 A regenerative downhill conveyor does not need a hold-back.11 0.11.08 1.39 2.13 0.42
1.5 T~ for steel cord belts.35 for lagged-pulley) (Clause 8.11.85 4.33 9.73 2.35 1.67 8.1.11.14 0.~ 8. .07 0.78 0.38 1.09 1.21 21.11.13
1.05 1. 8.15 8.72 0.1 Acceleration time for the load of a conveyor The time taken to accelerate the load on any conveyor is given by (for symbols see Table 1).2.1.V.15 0.11..85 0.62 1.14 1.3.09 0.72 1.50 2. 8.19 1.15 1.6 T~ for tensile fabric belts.21 1.78
1.21 39.90 19.62 0.11 Coasting 8.61 2. in any conveyor system with more than one conveyors. and and/or brake shall 30 = 1.30 1.030
1.11. shall be provided with hold-back or brake arrangement.23 1.32 1.38 0.25
for bare pulley and 0.17 1.61 3.19 Lagged pulley Bare pulley
Ratio TJz’E
.35 0.21 0.
and gravity material load forces.L.JLkg + (GD)2 2nN 2 “(160V
Time taken by the motor to accelerate the
the drive motor needs to accelerate
The time which the
proportional to the deceleration braking force.me~—
t~ –t: newtons .11.IS 11592:2000 8. +m. The frictional resistance forces and gravity forces.. + 2m. while starting the conveyor fully loaded that it tm2 ta.required is:
~ = PA. if needed. dampness.3)
— The GLY value in the above equation shall be
(qp\x PM.2 The braking force is given:
cumulative value of all the equivalent GD2 of motor.1 Functions
energy of a conveyor to the power absorbed.
8.. inclined or declined.the effective driving force. drive pulley.5 Braking or Deceleration Forces 8.11. b) permanently ensuring adequate belt tension at the loading point and at any other point of the conveyor to keep the troughed belt in shape and limit belt sag between carrying idlers. coupling and drive pulley in
Nm all referred to the motor
shaft axis..11. (52)
v“td”
.11.looo
ate the drive and drive pulley and is not transmitted to the belt..11.11. (55)
8.5.. Coupting)
(For Gear Box)
a) In case of horizontal. = P..l OOO td–tj meq –mi. (56)
8.4.11.S.4. the time..4...11.1 The braking force required for any conveyor is the algebraic sum of inertia force. 8.3 If the deceleration time.4 If the brake is connected to the drive pulley
F.. is to be reduced since the total retarding force is inversely to “t’d”
.1 By
b) In case of regenerative decline belt conveyors by v Fb = m~ — + T~ newtons . t~in seconds to bring Lheconveyor to ~est from its running speed of V m/s with usual notations is given by:
equating the kinetic td = meq
Main functions of take-up are: a) ensuring adequate tension of the belt leaving the drive pulley so as to aviod any slipping of the belt.11.
. c) compensating for operating belt length variation due to physical factors (instantaneous tensions. frictional r~sistance force.11..(51) .12 Take-Up 8.. and d) making available.PA).11. td.2 The resisting frictional retarding force is:
<I ‘YE
..L newtons
m= ..
(For S. 8. an adequate extra 31
1 OOOPA
. temperature of conveyed material. permanent elongation.12.4.q
(mC m.5. 8.5 The difference in the values of 8.3.5.. reducer.
. inclined or declined and non-regenerative belt conveyors. are equal to T~.
t max 8.3. the drive pulley is required to transmit to the belt a braking force equal to: PA.4. + mti+ m.4.11. etc).4 is the braking force required to deceler-
time.. (57)
V“t.S.11. outside temperature.4. . if any. (60) .3 The allowable time taken for the motor to
accelerate the loaded belt has to be greater than or equal to the minimum acceleration time to stay within the maximum allowable belt tension.(53) v = ralio of average starting motor torque and full load motor torque depending upon type of coupling to and starting of motor (see also 8. (58)
‘eq
‘Z-w+w$a=]+
(For Motor) (for H. (50)
JH.4 Deceleration Time
8. Fad. by v F~ = me~—
– T~ newtons
..4. Coupling) (For
Drive Pulley)
8..3 and 8. additional
conveyor assuming the components treated as hollow cylinders is given by (for symbols see Table 1):
tm =..
12.up pulley remains fixed between successive periodic adjustments. 8. For this reason. for example. Take-ups of this type generally used are.. Automatic take-up has following features: a) It is self-adjusting and automatic. 8. the take. provision of loop at drive end maybe made to cater for take-up and small extension of belt conveyor lengths. This generally leads to excessive tension of belt (when tension is insufficient.1 Two types of take-up generally used are:
up devices shall include a system for adjusting belt tension. 8. A tension indicator may be included between winch and pulley.3 Automatic take-up In this system. sheave. The most frequently used type is gravity weight operated take-up device. 8.IS 11592:2000
length of belt to enable rejoining without having to add an extra piece of belt. the belt tension at this location. and
that are adjusted
b) automatic take-up devices (constant load type). Hydraulic. However. 8. This excessive tension is unavoidable and shall be taken into account when determining the size of the belt. In this system.2 Types
8. But acceleration and braking of conveyors have certain effects on the takeup.or vertical installation. c) It is suitable for horizontal . it may be used for long conveyors and under heavy duty conditions provided that these conveyors are equipped with belts having very low elongation coefficient under the effect of load and over a long period. These have to be taken into account while deciding the location of take-up. 32 = belt take-up take-up .5.12. electronic sensing devices etc) is provided to signal for the winch motor to run in one direction or reverse for specific number of turns or to stop as governed by predetermined values of belt tensions for any particular installation.12.12.12. the applied tension is not fully determinable.. the take-up weight can be calculated as follows: Take-up weight mechanical advantage tension at point of take-up – weight of pulley and its frame + friction force of carriage rope. these devices are used only in case of short conveyors of up to 60 m lengths and under light duty cycle condition. 8. 9 to 12. The heavy tension is gravity type-up arrangements continues to exist in the belt even when it is not running. This is “highlyrecommended for long centres high capacity belt conveyors since it fetches-lessspace (horizontalhertic~) and also do not unnecessarily put the belt always in heavy tension as imparted by the constant counter weights necessary for operation at maximum design load in a gravity take-up. take-up pulley is mounted on slides or on a trolley and travels freely while a constant tension is automatically maintained to ensure normal conveyor operation in all cases.12.12.3 Selection of Take-Up The choice of take-up and their location has to be decided depending on the configuration and length of the conveyor and available space.3.2. pneumatic or electrical take-up devices of various types are also used.2.12. For guidance effect of acceleration and braking on counterweight take-up is given in Table 21.4 Winch take-up (automatic) Winch take-up device can also be used as automatic take-up arrangement when automatic tension regulation (ATR.2. etc 8. d) It is prefemed for long centre conveyors. b) Wnck take-up — In this system.12. b) Greater take-up movement is possible. This system also requires careful checking of tension and leads to excessive belt tension in order to aviod too frequent take-ups.2 Fixed take-up devicc. e) It can be located at drive end (preferred for low tensions). a) Screw take-up — In this system the adjustment is manually effected by means of two screws acting upon the pulley bearings and which are tightened simultaneously or successively.. and b) Allowance for contingenciesand factor of safety.1 It consists of two parts: a) Allowance for belt elongation. thetension is adjusted by means of a mechanical motorized device which does not automatically compensate for belt length variations. All types of automatic take-
. The screw is normally of non-expendable type and sliding surfaces are suitably protected against ingress of dirt. steel cord belts which are used almost exclusively.12.s In this type of take-up devices. f) In case of underground mines.(61)
a) fixed take-up devices periodically. belt slips and quickly deteriorates).4 Take-Up Weight After having decided the location of take-up. designing the mechanical components and calculating the adjustments.1 Typical take-ups are shown in Fig. by employing load cells. 8.5 Take-Up Movement 8.2.
Conveyor Geometry
Horizontal head drive
Preferred Take-Up Location
Following drive on return side of belt None
to Iitl counterweight. or head
I)Such take-up problems ~an be handled by a very heavy single counterweight.12. e) Starting up system and magnitude of resulting dynamic force on the belt. of its being brought back to its former position by cutting and rejoining the belt. and decline. . b) Check the operating tensions at critical points through the circuit. 8. (63) t) Allowance for contingency and safety =0.!3 Possibility. the values of take-up shall be not less than the values specified in Table 1of IS 4776 (Part 1). tail drive
At or neti head
Critical — iitls countemveight and feeds slack to foot of
inclinel) Combination of
incline.12. d) Ratio of operating tension to the maximum allowed tension.w. (64)
g) Belt reserve for splicing. ~~.3(b) – Value at 8. tail drive
Tends to Iitl counterweight if declination is low
Decline then horizontal portion.1 For a successful belt conveyor installation. h) Weather conditions in which the installation is operated (wide temperature deviations between day and night). In any ease. Calculate average belt tension throughout the circuit with belt starting when fully loaded.. 8. 33
absolutely necessary that the conveyor belt be loaded properly and discharged properly. head drive Following head or low point in return run Little or none Critical when stopping with decline loaded — Lifts counterweight and slack runs to foot of decline’) Critical — Iitts counterweight Little or none
Combination of incline and decline.3(c)
x LF -
Belt rating Total length of belt . c) The average tension with conveyor empty and stopped. Little or none
[ncline.5.3 Take-up movement may be worked out as follows:
d) Determine the load facto~ ~ _ Value at 8.IS 11592:2000 Table 21 Effect of Acceleration or Braking-on Counter Weight Take-Up [Ql..13 Conveyor Loading and Discharge 8. when take-up device has reached the end of its adjustment length. it is
a) Delermine the belt elongation according to manufacturers recommendations.4 Where take-up movement worked out is very large.300 m+ 0.5 percent of belt length in mm .12. large
Brakes not usually enough to cause trotible.13.These values are applicable to underground installations also using belts conformingtoIS318 1[seeIS 4776 (F&t 2)]. and J Influence on some types of belts of the physical characteristics of conveyed materials (heat or excessive moisture content) especially if covers are not carefully checked and maintained periodically. Besides contributing to a good performance of the conveyor without spillage. (62) e) Actual belt = v~~x Belt elongation at elongation reference lead . a double counterweight...oo Q 19 ‘l\ Iubuwoc Q.
b) Belt jointing system.5. head drive
Following drive on return side of belt At or near head
Decline. tail drive
Following head or point in return run
feeds slack to foot of decline
and by tail-end bmkes. and tail driving. The requirements of loading and discharge are so important that they need very careful consideration while planning the layout and detailing of the loacling/unloading facilities.. f) Position of take-up device.5.
.12. it maybe necessary to reduce the take-up movement or make use of combination of gravity and winch take-up or use more than one gravity take-up. c) Belt carcass determining the elastic and permanent stretch values which shall be provided by the manufacturer..5. It shall be equal to allowance for one minimum splice length. a properly designed loading and discharge system would add considerably to the belt conveyor life.
OPERATING SCREW @PEcTIoN PLATFORM
FIG.—-.ADJUSTMENT 9ELT TRAVEL BEND P’uLLEY PULLEY
FIG. +&_.-.
10 TYPKAL
11 TYPICAL
SCREW OPERATED
GRAVITY WEIGHT OPERATED
TAKE-UP AT TAIL END OF CONVEYOR
TAKE-UP AT INTERMEDIATEPOINT OF CONVEYOR
.+!~ -l.IS 11592:2000
CARRYING S1OE
TAKE UP BY HY‘Di?AULIC ELECTRIC GRAVITY WEIGHT OR MECHANICAL MET HOD . ~. AS SHOWN
BELT FROM DRIVING PULLEY TAKE-UP .
II T ._. ‘FIG.
9 TYPCIAL
TAKE-UP ENT u
PULLEY — /ADJUSTMENT .
b -–
TAKE-UP /RXLEY
12 TYPICAL GRAvlTY WEIGHT OPERATED TAKE-UP TAIL END OF CONVEYOR
. . fj
Keeping in conformity with the static angle of repose of the material. 8. c) Material velocity being in the direction of belt travel and as close to the velocity of the belt as possible. m) Providing the back or bottom plates of the chutes in a manner so that the material preferable is guided from the back of the chute to the belt. if provided. 8. cl) Loading of the lumps near the centre and riding a cushion of fines.3 Conveyor Discharge 8. the fixed trippers may be provided.13. it should preferably be about 20° to 30° higher than the static angle of repose of
~) Providing a suitable skirt plate extending along
are necessary. 8.2 Conveyor Loading 8. j) Inclining the loading chute both forwards and outwards.3 If several specific points of discharge are required.0 m for every 0. stickiness.3.13.13. 8. The slope shall be fixed based on the properties of the material such as moisture contents. Moveable trippers.3.4 A carefully designed discharge chute is necessary for successful operation as besides meeting the operational requirements of discharging or apportioning the-material in to the various directions. It can also eliminate collection of the material adhering 35
lumpy material so that the impact is absorbed by the stone boxes where the blow of the abrasive material is taken on the retained material at that point.13. either on one or both sides. q) providing minimum angle of slope. h) Feeding the sloping conveyors where the size of lump or absence of fines would indicate danger of lumps rolling specially for downhill conveyors.2. These skirt boards are usually an extension of the sides of the loading chute.13.
f) Avoiding horizontal greater than 90° angularity of transfer
the material. abrasive and
8.1 The material can be discharged-from the belt conveyor in different ways to achieve the various desired results.
n) Provision of stone boxes for heavy.
the sides of the belt serving to confine the load while it is in a state of agitation before it settles down into a quite moving stream.IS 11592:2000
need very careful consideration while planning the layout and detailing of the loadingh-mloading facilities.3. The skirt board preferably should terminate above an idler rather than between the idlers. The length of skirt board is generally between 0. At times.3. 8.1 Some of the main considerations for proper loading of the material and transfer of the material on to the belt conveyor are as follows: Placing of material centrally on the belt. Sometimes. inside width being 2. a properly designed loading and discharge system would add considerably to the belt conveyor life. The flexibility of dischrage arrangement of belt conveyor facilities its use in the maximum fill of long bins and the erection of large and various shaped storage piles. can discharge intermittently either on one or both sides of the belt conveyor. r) Avoiding direct impact of the material on to the roller and the bottom most back portion of the chute being minimum 150 mm away from the idler.2 Skirt board To retain the material
loading boards chute on the belt after h leaves the and until it reaches belt speed.6 m to 1. a) 1 b) Avoiding too frequent surging of loads. Besides contributing to a good performance of the conveyor without spillage. the skirt boards are provided with rubber screen. rubber flapper to minimize the dusting due to air turbulence.6 m in length. A fork in the discharge chute with a gate or flapper can permit the material to flow either in one or in both directions as desired. The skirt boards are normally covered with rubber strips of adjustable type both at the back and at the sides being provided with suitable shape for centralizing the material on the belt.2. e) Keeping the loading in case of transverse transfer as near to 90° as possible. flowability etc. In case of fines and lumps. that is.5 mk speed of belt depending on the loading conditions but in any case not less than 1. The discharge can be accomplished either at the end of the conveyor or at a definite point or points in between which can extend along side the belt conveyor.13.2 The simplest arrangement of discharge from a conveyor belt is by material passing over an end pulley and falling on to a pile or onto the other conveyor through a suitable loading chute. it may be necessary to provide a grizzly so that the screened fines may receive the lumps over them. at a point or for a considerable distance.13. ploughs can also be used for discharging the material either on one or both sides at intermediate locations. P) Keeping the transfer heights to the minimum.5 to 3 times the largest dimensions of uniformly sized lumps.13. k) Keeping the width of the chutes generally not greater than two-thirds the width of the receiving belt.
The following are some cfthe main features for designing a good discharge chute:
a) The upper end of the discharge chute shall enclose the cleaning device and catch material cleaned from the belt if necessary by employing a separate dribble chute.4. 3 The trajectory obtained as discussed here locates the bottom of the stream of material.4. 8.3. The toe guard shall have a minimum depth of 65 mm and a thickness of minimum 6 mm. b) Calculate the trajectory of the material and ensure that material falling from the end of the dischaEge pulley falls on the back plate of the loading chute. 4) The section for hand railing shall be of galvanized pipe of 32 mm nominal bore unless specifically required by purchaser. 5) The hand rail post shall be 32 NB (A) galvanized piW or minimum ISA 65 x 65 x 6 galvanized unless specified otherwise. if required by purchaser. In case of double conveyors. side walkways (see Fig.1 The path or the trajectory of the material after it leaves the belt is a parabola when the material is discharged over the head pulley.13. Actual slope is often greater than that is assumed for the following reasons: a) The rim of the head pulley is sometimes set above the line along the rims of the carriers centml rolls. care shall be taken
for the actual slope of the centre portion of the belt.5
of dusty or dry powdary
and fine material. 13) shall be provided. This is the point at which the centrifugal force on the material acting radially outward is balanced by [he gravitational force or its component in the radial direction as the case may be. 1. is not taken into account in determining the trajectory. besides taking care of the surge loading.14 Structura}s 8. due attention shall be given to the provisions laid down in IS 7155 (-in eight parts). 9 Providing cross-sectional area of 4 times. lumpy and heavy material. the load cross-section and minimum three lumps. one at top and other at half way height from floor. d) Toe guard — Toe guard shall be provided around all openings on floor and also on sides of conveyor gallery walkway as a safety measure. For conveyor standlpost havrng more than 3 m spacing.13.2 Practical determination of the trajectory is explained in Annex J. f-) Provision of rock boxes in the discharge chute.13. e) Avoiding abrupt changes of direction in the chute to eliminate material build up and plugging. Gallery walkway supporting angle shall be considered-as toe guard provided dimension limitation as shown in Fig. b) A maintenance walkway of:800 mm minimum width along the run of the conveyor in a gallery shall be provided. and additional walkway on the other side may also be provided. and is determined by two considerations: a) Thepoint where the material leaves the belt. d) Providing sliding surface at an angle of about 20° to 30° higher than the static angle of repose. 2 The effect of air resistance being negligible in most of the ca$es. avoidance
8. that is. double handrails. 12 is satisfied.IS 11592:2000
the belt. It shall also be provided on one side of walkway in conveyor gallery having slope more than 7°.13.
While designing the structural.14. e) Hand rail — Hand rails shall fu”lfil the following requirements: 1) Hand rails shall be provided around all openings. 8.4 Trajectory of Material 8.5 Typical arrangements of loading and discharge chutes are shown in Fig. c) Provision of removable of liners in case of abrasive material. shall also take into account the likely loads coming on account of any spillages due to failure of protective/ coasting devices.13. 3) The hand railing shall be supported either from conveyor stand/post or from independent support. b) There is always some sag in the belt which causes an increase in actual slope. for abrasive.
controlling 8. the railing shall have independent supports. the following main points shall also be taken into consideration: a) The design of the structural members. In addition. f) The walkway along the inclined conveyor shall 36
1 In drawing the belt running into the pulley.
. 2) The hand rails. 12) may be provided on two sides cf conveyors in addition to the central walkway. b) The direcriorr in which the material moves at the instant it leaves the belt. However in case of belt height more than 1 m from floor level. either single or double (as indicated in Fig. shall “beprovided. c) Walkwary runner — Size of the selection shall be adequate to satisfy strength and deflection. where necessary. If specified by the purchaser.
k) Wherever conveyor has to run in an underground tunnel. In case of conveyor installations with more than 10° inclination. Suitable precautions shall be taken to protect the roller guides/slotted holes/guides etc. a clear walkway space of 1000 mm shall be provided along the length of conveyor on either side. this clear space shall be 37
not less than 1 m along the length of conveyor on either side from any structure of the conveyor. it is desirable that such connections be made so that the gallery frames are free to move in the longitudinal direction. Wherever provision has to be left in the transfer tower for keeping a heavy equipment forming a part of the conveyor such as pulley.4 of IS 6521 (Part 1) in the design of structural components. at head or tail end a clear walkway space of not less than 1 m on either side shall be provided. In case of double conveyors. 13 ARRANGEMENT JN DOUBLE CONVEYORS AND THEIR DESIGN APPROACH
be provided with anti-skid surface and shall be designed for a single moving load of 300 daN or a live load of 250 dapa whichever is larger.14.2 to 3. For conveyors used in underground mines.4 of IS 800 and 6. n) Transfer homes shall be so designed so as to provide sufficient head room for removal of heaviest parts and lifting of the belt to enable changing of the conveyor belting.2 Structural Design 8.1 Whenever designing the structure for conveyors.14.
h) Supporting of gallery frames on the trestles
using roller supports shall be prefer~d. m) The drive end structure shall be made sufficiently rigid to prevent any vibration and shall be provided with sufficient maintenance space all around. IS 7155 (in eight parts). due consideration shall be given to 3. Use of gratings or chequered plates or precast conci-ete slabs with their top surface left unfinished may be considered for providing anti-skid surface. from accumulation of dust or material carried through the conveyor.14. stepped walkways without any intermediate landings shall be provided.IS 11592:2000
WALKWAY RUNNER
/ SIOE WALKWAY (OPTIONAL) IF TO BE PROVIDED
SPECIFIEO BY PURCHASER
FiG. etc taking into account the various environmental conditions including earthquake and wind forces. motor gearbox. IS 875 (in five parts).8. Where -i)
conveyor gallery connected to junction frames have to be
houses or other buildings. Such installations shall be regularly inspected for their proper operation. provision of gallery seal plates shall be considered in structural design. In addition. which shall not be less than 800 mm to the nearest obstacle.8. the structural shall be designed to take care of the concentrated load in addition to the distributed load of 350 dapa.8.2. P) All structural design shall conform to related Indian Standards such as IS 800. a central walkway of minimum 1000 mm width shall be provided ensuring that at least 800 mm is available at drive or head pulley end. the total of following three load _groups shall
. However in case of gratings. g) For corrosive and open atmospheric conditions of working.3 and 6. The design of structure shall be in accordance with 8. 8.
For the design of gallery walkway. under 8. platform.2 The main loads comprise of all the permanent loads which occur when the equipment is used under normal operating conditions as specified by the purchaser. the downward units may have the same output as the upward units. 2) Live loads to be considered for gallery frame work design shall be in accordance with 8.l(f).
Additional loads. the load on the conveyor will be assumed to be that which results from the output thus limited. a load of 10 percent of the theoretical effective load calculated according to 8. #atforms and ~oof— Loads on these structures shall be considered as given below: 1) Live loads.2.14. The main components of main loads are:
— These are load forces of all fixed and movable construction parts.5.2. they are to be taken as minimum values. shall be considered as acting locally. These can be neglected for appliances working outdoors if the acceleration or deceleration is less than or equal to 0.14. shall be taken into account. the cross-sectional area shall be determined assuming a surcharge angLeof 20°.2. member. the rotating parts of machinery .14. g) Loads on gang ways.etc.2 rn/s2. Figures 2 to 4 show the maximum sections of product conveyed as a function of surcharge angle and for the trough angle for different conveyor design. the worst combination shall be considered as indicated in 8. the factor shall be 1. the sizing of the member shall be done accordingly.
8. of moving structural parts. 5) When higher loads are to be supported temporarily. Inclination of the conveyor—The effect of f) inclination of conveyors shall be taken into account for design of structures.2. e) Permanent dynamic effects — Following points shall be considered under this head: 1) In general the dynamic effect of the falling masses at the transfer points. For guidance. For trippers and other movable equipments. For
.2 (g)(4) above.l(f).14.2 (b) (1) or 8. 4) The stairs shall be designed for a single moving load of 1000 N and the railings and the guards shall be able to withstand a horizontal load of 300 N.1. could be applied to the conveyor.2 (b) (2) on upward units is lower than that of downward units. 3) Where the design output resulting from 8. c) Incrustation — The degree of incrustation (dirt accumulation) depends on the specific material and the operating conditions prevailing ineach given case.2(b) shall be taken into account as the load on the conveyor devices due to dirt accumulation. etc. 2) The inertia force due to acceleration and braking.2.2.14. purlins shall be according to IS 875 (in five partsj. 3) The platform members shall be suitably designed for live load of 2500 Pa (uniformly divided load) or 3000 N whichever is worst. The following points are considered while deciding the
storage yard appliances. always present in operation of mechanical and electrical plants as well as of the support structure. h) While designing the trestles supporting the conveyor gantry. and c) Special loads. like tripper and shuttle conveyor. the load as calculated above together with weight of belt shall be multiplied by factor 1.14. Unless otherwise specified in the agreement. 4) Dynamic loadfactor — In order to take into account the dynamic loads which.14. only for the design of cladding roof truss. The inclinations shall be according to appropriate conveyor layout. 2) Where there is no output limiter. the design output is that resulting from the maximum cross-sectional area of material conveyed on the conveyor multiplied by the conveying speed.2(g)(l) to 8.14. 38
a) Dead loads
designed output:
1) Where the belt load is limited by automatic devices. d) Forces at conveying elements for the useful load — Belt tensions shall be ‘taken into consideration for the calculation as far as they have an affect on the structure. The actual values can deviate to either higher or lower values. 80 percent of live load considered for walkway under (g) shall be taken. b) Useful loads — The effective load carried on the conveyor is considered which is determined from designed output in m3/h.Is 11592:2000
be taken into account: a) Main loads. the values are generally lower while for reclaimers.
Temperature effects need in special cases.14.
. c) Spillage load — During the operation of belt conveyor or at the time of repair/replacement of belts. If the main forces are such that they have to be taken into account. f) Foundation for conveyors structures shall be suitably designed and constructed so that it does not settle. require a continuous hood over the conveyor.14. e) Conveyor installations transporting ~ne materials like sulphur. The resulting loads on the structure shall be calculated in terms of the retardation imparted to the machinery by the buffer in use.7 VT. the wind effects shall be disregarded. if any. The lattice girders supporting the conveyor shall be suitably braced at top and botton chord levels to transmit the wind load to the end portals connected to the trestles. plant cleaning or fire fighting etc. fine chemicals.4 Special loads These comprise the loads which shall not occur during and outside the operation of the equipment but the occurrence of which is not to be excluded.
Temperature load —
8. The actual bulk weight must be taken for calculation.2. if settlement can not be avoided. Those loads either replace certain main loads or are loaded to the main loads. paddle feeders etc. occurring less than 2 x 104 times during the life time of the appliances shall be checked as additional load. reference may be made to IS 1893. c) Bujfer eflects-For equipment like tripper. In case. This shall also take care of all longitudinal forces foreseen in the given block. for example. This hood is also required where protection from mois ure contamination is required and where J ust control equipment are provided as essential requirement. paddle feeders etc.7 m/s. The structure shall. the material on the belt is spilled on to the conveyor structure. when using materials with very different expansion coefficients within the same component. with due reference to the slope angle. when buffering is not made impossible by special devices. b) Loads due to earthquakes—As far as the delivery contract contains data concerning the effects due to earthquakes. account must be taken of the reaction on the structure by collision with buffer. Due consideration shall given to the action of deformation in structures due to settlement of foundation. and coal with high percentage of fines. d) Wind load—Wind loads on the structure of the conveyor installation shall be calculated taking into consideration the recommendation made in IS 875 (in five parts). these loads have to 39
be considered in the calculation as special loads. temperature expansion joints shall be introduced at intervals of approximately 180 m to divide galleries in to blocks. It shall be assumed that the buffers are capable of absorbing the kinetic energy of the machine with operating load upto a certain fraction of the rated traveling speed VT— this fraction is fixed at minimum 0. The main components of special loads are: a) Clogging of chutes—The weight of the
clogging is to be calculated using a load which
is equivalent to the capacity of the chute in question. Alternatively. the temperature effects may be taken care of by providing suitable connection details to permit movements due to thermal effects such as slotted holes etc. As additional loads.7 m. no account shall be taken of-buffer effects. the customer does not prescribe load values due to particular climatic conditions. The main components of additional loads are: a) Snow and ice load — The loads due to snow and ice shall be considered as in case of incrustation load [see 8. g) In case of galleries. While calculating load.2 (c)]. The material normally within the chute may be deducted. ores. d) Non-permanent dynamic effect — The main forces due to the “acceleration and braking of moving parts such as traveling tripper. they may be disregarded if their effect is less than that of the wind forces during the operation. For speeds in excess of 0. In each block.k.
h) Other loads. A load of 1 kPa may be considered. snow and ice
load need not be included. therefore.2. for the provision of following: 1) Water pipe line for dust suppression. take into account loading due to this effect. Due consideration shall be given to these loads in design of structures for conveyors. having speeds belowO.3
These are loads that may occur intermittently during operation or the equipment or when the equipment is not working. one four-legged rigid support guaranteeing stability of structure in longitudinal direction shall be provided.
end hinged and other end fixed etc. 8. 17) shall be provided to reduce the effect of vibration. 8. from
maintenance platform supported from frame. The load to be considered for the design of stand or postshall include weight of stand unit and weight of cabled in addition to the loads specified in 8.4. in case of shiftable conveyor is shown in Fig. 14. walkway not exceeding
used in open-cast and underground mines.4. 9 ACCESSORIES 9.14.14. and/or drive unit if
8.2(b) and 8.2(a). 17 for supporting stools between conveyor galleries bottom and top of stool. The following loads shall be considered for the design of stringer:
a) A concentrated
~ 325 8.2.14. 8.8 Design of Head and Tail Frame 8. b) Trippers both belt driven and motorised.2
In addition. In order to take into account the dynamic effect. preferably.7 Cladding for Galleries/Tower Structure In view of the economy in structural members/ foundations. 250 m in length.14. weight of belt and weight of carrying idler unit. namely. both ends hinged or one
shown in Fig.4.4 Design Considerations for Stringer and Stand Supporting Intermediate Portion of Conveyor 8. (as
Maximum belt tension. screens and vibrating feeders shall be in accordance with IS 2974 (Part 1) or IS 2974 (Part 3) or IS 2974 (Part 4). be designed as braced portal frame. 8.2 Design of stringer The design of stringer shall be carried out considering the stringer as either a simply supported beam or a continuous beam as the case may be. the above loads as calculated in 8.14. 15.14. both live and dead load.1 Head and tail frames shall. Provision of translucent sheets at intervals shall also-be considered for natural lighting inside galleries during daytime. fixed and moving.2(c).l(a) and 8.4.
crossovers sha!l be provided from ground to ground with cat ladder or from side walkway to otherside at a spacing S.14. easy availability and ease in working.l(b) shall be multiplied by 1. then the amplitude of vibration of the foundation shall not exceed the values specified in Fig.5 Limiting Deflection Deflection for various structural members supporting conveyor structure shall not exceed the following limits: a) Conveyor gantrylbridge b) Trestle supporting grmtry/tower in the transverse direction c) Stringer supporting conveyor structural member directly supporting in the tripper d) Member supporting the tripper ~ 325 Height 1000 m 900
and cable racks. 8.8. the material shall be either of “G I sheets or aluminium sheets. Dead load of head or tail pulley together with the belt being supported by head or tail pulley.14. The design of foundations and structures supporting heavy machineries such as crushers. Additional loads.14. Following loads shall be considered for the design:
load consisting of material conveyed considering normal capacity of conveyor.4. 8.
8. belt top cover.4 Supporting stools Typical arrangement is shown in Fig.14.5 Skid walkway andlor central 180 m.4. like motors.
8.14.8 . 40
flexible and fluid couplings.25. b) A uniformity distributed load consisting of weight of decking plate. gear boxes.8.4.3 De$gn of stand or post Stand/Post shall be designed considering end conditions provided. It shall be either zero or positive to neutralize the deflection due to dead load only. clutches and brakes.
.1 General The various accessories required for a conveyor could be briefly stated as follows: a) Drive elements
and chain drives.6 Camber shall be provided for span greater than 20 m.14. easy repairs.IS 11592:2000 2) Dust extraction/ventillation
3) Electric j) cables In case of conveyors exceeding ducting.14.8.3 Vibration It’no resonance is to occur in adjoining structures and buildings.14. Self weight.14.14. faster speed.1 Figure 16 gives the general layout of intermediate portion of conveyor for the purpose of identification of loads. belt side cover and weight of stringer itselfi and c) A concentrated load consisting of weight of belt and weight of return idler rinit.14.
FIG.30 mm. 14
IN OPEN-CAST
2. it is possible to state that if no resonance is to occur in adjoining buildings and structures.050
0. then the amplitudes of vibrations of a foundation shall not exceed 0.25
F-eHtNw?’A
100 200 500 1000 2000 5000 10000 FREQUENCY (f) IN CPM
NOTES 1 Resonance in the neighboring
structures will be negligible if the amptitude of vibration is less than 0. 2 For foundations of rotary type of machines of low frequency (O to 300 c/rein).20 mm. 15 LIMITING AMPT]TUDE FOR VERTICAL VIBRATION
0.1S 11592:2000
STRINGER GARLANO~YPE IDLERS
ll\ /A\
RAILFOR SHIFTING THE CONVEYOR
HOLLOWSLEEPER/
\ RETURNROLLEi
. belt slip. and j) k) Skirt plates. Decking plates. over load devices. binlowering rock ladders and telescopic chutes. emergency stop switches and cable. g) Control gears. take-up movement. frequency and combined voltage and frequency variation. pull-out torque.1. overload switches. etc. type of coupling used and following electrical parameters effecting motor design: a) Rated voltage and frequency. d) Special lowering chute for example. for example. type of mounting. speed/torque characteristics of load. belt sway overspeed tripping. starting current (for selection of cables considering voltage drop during starting conveyor drive). e) Belt cleaners both internal and external. b) Variation in voltage. e) Ambient temperature. spiral.!0 Type or enclosure and degree of prtection. 8 Hold-backs. 9.2. 16
FOR INTERMED1ATE-PORTIONOF CONVEYOR STRUCTURE
c) Ploughs. d) Class of insulation. h) Protective.
FtG. chute plugging. c) Construction.1 General 9. o Speed. h) Direction of rotation.2.1 The motor for belt conveyor drive shall be
selected considering various factors such as starting torque. .2 Motor Selection
9.devices for example.IS 11592:2000
BELT Q /WilONAL SIDE COVER I PITCH FOR IN METRES IDLERS 1A
~TURN IDLER UNIT
DECKING PLAT-E (OpTIONAL) r
OR POST MATERIAL
F’T r
ROLLER CABLES
[OPTIONAL)
NOTE — Belt top cover and belt side cover maybe replaced by semi-circular type belt cover in one piece.
and q) Type of earthing and number of earthing terminals. suitable protection like locked rotor relay and speed monitoring device shall be provided to the drive.2 Motor shall have continuous ratio at least equal
multiplied by the drive efficiency of the motor.
9. p) Vibration limit. The starting time of the conveyor shall not ~ exceed locked motor withstand time of the motor.IS 11592:2000
FIG. 9. In case of low starting torque requirements.2.1.5 Motor acceleration time. k) Short circuit load of terminal box. The motor shall be capable of giving higher torque than required at steady-state of operating condition under worst permissible conditions of voltage and frequency vatiation.2. most economical and minimum maintenance drive units for conveyors coupled with fluid couplings. t~. n) Type of starting.3 For downhill regenerative conveyors. the motor
rating shall be at least equal to the power required
9.1. shall be within
to the power required by the conveyor divided by the efficiency of the drive unit. where acceleration time is more than thermal withstand time.1.
17 TYPICAL DETAILS OF HEAD AND TAIL FRAMES
j) Location of terminal box looking from drive end shaft. squirrel cage three-phase alternating current induction motors are the simplest. rn) Number of cables and size of cables for cable terminal box.4 In general. 9.2.
1 Selection of the type of speed reducers can be
9.3. 9.3.3 or traction type fluid coupling.2 For medium length conveyor of medium cupacit y up to drive power of 150 kW to ensure torque
control of drive.3. for stabilizing the desired value of load torque of driving motor. shall be done trddng into consideration various aspects such as layout. not only during starting but also during normal operation of the conveyor. pin-bush coupling. 9.3 The choice between an allowable slip type coupling.2.3. or c) Squirrel cage motor with scoop controlled fluid coupling or traction type fluid coupling. 9.25 1. worm and helical.2. for example. flexible coupling maybe used. Method of starting shall be determined by the system parameters.Is 11592:2000 the thermal
motor period. 9. 9. 9. 9. Duration of Service 2 hours per day 8 hours per day 12 hours per day 24 hours per day Service Factor 0.3) and drive requirements.3 to 9.6 The geatbox shall be selected to suit the drive system (see 9.3 Speed Reducers
9.3.4. and c) Reduction in oversizing of cables for motors to compensate terminal voltage drop duTin.1 The rating of the gearbox shall not be less than the rating of the installed motor. helical gear box shall be preferred. the following type of drives be
a) Slip-ring induction motor with resistance starting. . or b) Squirrel cage motor with controlled eddycurrent coupling.7 The selection of gear type.2.2.2. spur. 9.2.6.1 Ladders and spiral chutes are used to lower loads
. 9. the for that
9. worm reducers may also be considered. designed. shall always be considered for any conveyor requiring higher motor power than 30 kW. in accordance with IS 7403.3.2.2.1 1.
determined by preference cost.
For long conveyors of heavy capacity. power limitations.
9. 9.2. space limitations and drive location.3. squirrel cage induction motor with direct on line start-shall be used. elfeciency. economics.g starting. for example.2.2. that is. Fluid coupling provide following advantages: Smooth acceleration of belt thereby reducing T. 9.5 For drive motor of above 30 kW. and a solid coupling.2.2 The gearbox shall be enclosed type running in an oil bath to give quietness of operation and saving of power.4 For drive motor of power requirements up to 30 kW.5) and the requirements of 9.3.2. 9.5. Emiix 9 b) Quicker acceleration of motor reducing its heating during its starting. or c) uc motors with static power amplifiers.3.4 Couplings
9.3 Stepless or in-xtage reduction may be accomplished satisfactorily by means of a V-belt drive in portable and very small capacity installations so that additional advantage of changing the speed ratio to meet different capacity requirements of the conveyors are obtained. the rating for motor is not the criteria for type of starting. fluid coupling.9 1. 44
9.6 The gear box shall be rated with the following minimum service factor for electric drives.2.2. the following electric drives are recommended: a) Squirrel cage motors with controlled electromagnetic (eddy-current) couplings.5 For selection of motor and its starting methods.5
9. consideration shall be given to the type of coupling selected (see 9.2 shall characteristics withstand the of the motor.2. Motorised head pulley up to 10 kW can be used. For slipring induction motors requiring power up to 630 kW.1 The use of flexible couplings shall be preferred
up to 30 kW and may also be considered for small conveyors requiring less than 50 kW.or d) Slip-ring motor with resistance start. 9.1 For conveyors of small capacities up to drive power of 40 kW.5 Ladders and Spiral Chutes
9.2.2.2 Fluid couplings shall preferably be used when conveyor power requirement exceeds 30kW.4. the starting motor shall that is.4 When high voltage motors are used. etc.4. or d) Squirrel cage motor with scoop controlled fluid
coupling 9.2. or b) -Squirrel cage motors with thyristor frequency converters with sufficient overload capacity. torque.
Trippers shall have dimensions as given in IS 14386.4 Movable trippers can be moved by a cable and winch by the belt itself. The layer of material covering the shelves protects”them against rapid wear. for instance).
9.6. the conveyor belt being flattended by means of movable platform of timber. The consequent build up of material cm these idlers causes a reduction in the belt life ‘and the return idler life. steel plate or rollers.8 Belt ‘llmner The cleaning of a belt handling wet. the only contact being with the snubbing pulley causing a reverse bend in the belt.6. 9. Fixed trippers are better in performance than ploughs. or by an electric motor mounted on the tripper.6. A spiral chute is a trough which
9. When not in use the blades can be raised to clear the material on the belt.2 Ploughs are used in places where it is inconvenient or impossible to install a tripper.6 Ploughs 9.IS 11592:2000
vertically by gravity.6. the blade can be arranged in ‘V’ form. 45
. one above and forward of the other. This damage can be greatly reduced by the use of turn-over conveyor belt system.5. This is especially the case when handling materials which are likely to pack on the belt.
9. The chute can be arranged to catch and divert the discharged material in any desired dkection (see Fig. More ‘than one stationary tripper may be used on a belt conveyor. 9. 9. The material being lowered is held up by failing from shelf to she\f. Ploughs are cheaper than trippers and takes-up less head room. 9. 9. 9. They retard the rate at which the load descends and prevent its landing with an impact. By this construction material is discharged to a chute as the belt wraps around the upper pulley. Plough can be used on belt troughed with idler rolls inclined at 20°.3 All trippers absorb a certain amount of power from conveyor belt drive. 18). The spiral chutes have the property of automatically keeping the speed of the load within definite limits.3 The plough m:iy be fixed or traveling. sometimes mounted within a vertical pipe of large diameter. A flat steel plate or closed pitched one piece idler roller of a span more than the belt width may be used under the troughed belt where it flattens to discharge/directldivide the material flow. The movable plough can be operated manually or by ropeh~iulagesystem. coal briquettes) has to be lowered from a great height (within a hopper. The belt at both ends of the return strand is turned.5 The blades can be constructed of timber or steel plate. from belt conveyors.6.5.7.1 It is necessary to clean the belt when snub pulleys or bend pulleys or tandem drive pulleys make contact with the dirty side of the belt on the return run. 9. 9. the inside of which holds alternately spaced shelves.7.7 IMppers
9. sticky. with rubber diaphragms or spiral chutes may be used to arrest the material degradation.4 A bulk or unit load lowered along a spiral chute SIides down the spiral surface and reaches the lower
level without impact.2 Trippers can be stationary (fixed) or movable.6. Stationary trippers are used where the discharge of material is to occur at a specific location. a chute or guard shall be provided at each discharge point to prevent scattered material from collecting under the upper run and fouling the idlers or else falling on the return belt.7. The conveyor belt passes over and around the upper pulley and around and under the bwer pulley. 9. 9. 9. corrosive or freezing materials is always difficult and very rarely is all the material removed before the carrying surface comes in contact with the return idlers. special devices like partitions. each being in the same direction giving a 360° twist.9.2 Ladder chute for bulk material is a vertical square pipe. the angle being determined by the speed of the belt.5. Essentially.4 Several ploughs can be incorporated along one belt conveyor and can be arranged to discharge material to either or both sides of the belt simultaneously. This results in the carrying surface of the belt never being in contact with any of the carrying. The
single discharge type shall be arranged at an angle to the belt when discharging at one side and when it is
desired to discharge the material to both sides simultaneously. This is because belt flexes over the tripper pulleys and also the material is to be raised to sufficient height to allow for necessary chute head room.9 Belt Cleaner
9.6 With any construction.or return idlers. coal.3 When a fragile load (such as coke. trippers consist of a frame supporting two idling pulleys. 9.1 Ploughs are used to discharge/divert free flowing ond non-abrasive materials which can be carried with a little or no troughing.1 Trippers are devices used to discharge bulk
around a vertical column or suspended rod. rounded or oblique-angled cross-section depending on the shape generated. The belt usually inclines to the upper pulley and may run horizontal or it may then incline again from the lower pulley. The chute may have a
IOIIL)WS a helix secured
materials from a belt conveyor at points upstream from the head pulley.7. such as sticky and wet
Three-way chute with flap vah. 18 TRIPPERS
#. R
-.e for discharge to both alternatively forward
Three-way chute with two flap valves for dkcharge to either sides alternatively.
TYPICALTRAVELLINGTRIPPER The discharge chutes may be as below and are shown in direction arrow ‘B’
One-way chute for one side discherge (left hand)
Orw-way
chute for cme side discharge (right hand)
Two-wav chute for discharge to both sides eimultaneou..6
“R-qv./’
Two-way chute with flap valve for discharge to one side (left side) or alternatively forward
Two-way chute with flap valve for discharge to one side right hand or alternatively forward
-./’
Two-way chuta with flap valws for discharge to either side alternatively or to both sides simultaneously
-.-/’
FIG. both sides simultanaousiy or alternatively forward.
The most effective as well as mast economic type of belt cleaning apparatus is the spring-loaded type belt wiper. two cleaners may be provided so that one can be removed at any time for servicing.2 There are three main types of external automatic belt cleaners:
a) a rotary brush. In any case. or those that are likely to have damp. The speed of the tip of the bristles for brushes 200 to 300 mm in diameter shall generally be:
Damp materials Wet and sticky materials
2. 9.9. Any additional safety requirements to the extent specified by the purchaser shall also be taken into account.0 mls 5.
When particularly gummy materials with tendency to cling to the belt and solidfy.5 rnls 6. internal belt cleaners of V-type
encountered.0 to 7.1 The brush shall be mounted so that it can be
adjusted toward the belt to compensate for wear on the tips of bristles and in such a way that the drive to the bmsh is not affected. arrange pulleys at the discharge end to allow ample room for cleaning equipment including dribble chute of flume. Their use is recommended even on short conveyor lengths and where ful I length decking is provided from the feed to the discharge end as a safety measure. as this will tend to keep the material from adhering. brushes are short-lived.4.3 The ~otary brush is fitted with a drive pulley
centre roller chain
and is rotated in opposite direction from it by a short drive. Tripper pulleys and deflector pulleys that engage the carrying side of belt.
9.1 In addition. 9.
The conveyor shall conform to all the statutory requirements. Dry or very wet materials are easiest to remove.4.5 lnh
9. Usually a small amount of water will suffice.5 It is sometimes necessary to use steel scrappers on the rims of snub pulleys. whilst at the same time. greasy which eventually rot the belt.IS 11592:2000
or oily patches
m~terials.2.0 to 3. A cantilevered weighted arm is attached to the brush for facing it to the belt. in order to prevent accumulation of material.9. and c) the spring-loaded wiper.9.4 Because of high speed.9. It is also beneficial to have a very fine spray directed against the belt just before it passes under the loading point.3.
9. preventing jamming and unnecessary wear on the bristles.9. never on a ptdley. b) thecou’nterweighted wiper. 9. As the cleaner is specially effective in removing water. One cleaner shall generally have at least 300 mm of straight belt.0 to 7.4. The blade shall be located so that the scrapings can be disposed of. two cleaners not less than 750 mm. are
The complete conveyor system and the conveyor shall be provided with suitable painting both primary and finished to suit the environmental conditions in accordance with requirements of the purchaser.
10 SAFETY AND STATUTORY REQUIREMENTS
shall be used neartai lpu]leytoprevent material from getting between the pulle_yand belt as it wraps round the tail pulley.3 The blades of the spring type cleaner shall engage the belt only where it is straight. it is recommended to use water spray directed against the -return belt about 500 mm ahead of the cleaner. the conveyor shall also take into account all the statutory requirements as mentioned in IS 7155 (in eight parts).
. 9.9.
9.9. In addition.2 Where cleaning is of primary importance. may hurt the surface of the belt or cause it to run out of line. These can also be made of adjustable counterweighted type. there is little danger of objectionable dribble.9. These V-type_plough cleaners shall be adjusted to float on the return belt without exerting undue load on belt surface.9.
training and supervision of operators (first revision) (Part 7): 1990 Inspection and maintenance (first revision) (Part 8): 1994 Flight conveyor (scraper conveyor) (first revision) Code of practice for selection of 7403:1974 standard worm and helical gear boxes Specification for pulleys for belt 8531:1986 conveyors (/irst revision) Specification for idlers and idler sets 8598:1987 for belt conveyors @st revision) Classification and codification of 8730:1997 bulk materials for continuous material handling equipment (firs/ revision) Belt conveyor — Traveling tripper 14386:1996 — Motorised — For belt widths 650 mm to 1600 mm —Dimensions
(Clause 2) LIST OF REFERRED INDIAN STANDARDS 1SNo.(/irst revision) (Part 2): 1977 Troughed belt conveyors for underground installation 6521 (Part 1) : Code of practice for design of tower cranes: Part 1 Static and rail 1972 mounted Code of recommended practice for 7155 conveyor safety: (Part 1): 1986 General information (first revision) (Part 2): 1986 General safety requirements (first revision) (Part 3): 1986 -Belt conveyor and feeders (first revision) (Part 4): 1990 Vibrating convey orlfeeder (first revision) (Part 5): 1990 Apron conveyorlapron feeder (first revision) (Part 6): 1990 Selection.
7’Me
(Part 1) :1987
(Part (Part (Part (Part
:1987 :1987 :1987 :1987
1891 (Part 1) :1994 (Part 2) :1993 (Part 3) :1988 (Part 4) :1978 (Part 5) :1993 1893:1975 2974 (Part 1) :1982 (Part 3) :1992
(Part 4) :1979
3181:1992
4240:1984
truction in steel (second revision) Code of practice for design loads (other than earthquake) for buildings and structures: Dead loads—Unit weights of building material and stored materials (second revision) Imposed loads (second revision) Wind loads (second revision) Snow loads (second revision) Special loads and load combinations (second revision) Conveyor and elevator textile belting: General purpose belting (fourth revision) Heat resistant belting (thiti revision) Oil resistant belting (second revision) Hygenic belting (first revision) Fire resistant belting for surface application Criteria for earthquake resistant design of structures (fourrh revision) Code of practice for design and construction of machine foundations: Foundation for reciprocating type machines (second revision) Foundatio-ns for rotary type machines (medium and high frequency) (second revision) Foundations for rotary type machines of law frequency (first revision) Conveyor belt — Fire resistant conveyor belting for underground and such other hazardous applications ~ourth revision) Glossary of conveyor terms and definitions @t tzwision)
Specification for troughed conveyors: 4776 (Part 1): 1977 Troughed”belt conveyors for surface installation . 800:1984 875 Title
Code of practice for general cons-
0 4. c) System accepting occasional stc3ppage as normal.0
Large size lumps.. small sized lumps. From this point move vertically up or down
to join the lines representing conveyor speed desired. abrasive.
abrasive.5 to 101.710219.
.I 400
4. 19) and move
horizontally to meet the lines representing required belt width.0 ds speed. 19). large lumps.1
168. highly duty. Join point A and B. B-2. m/s 2.7
Unsizes medium lumps. moderately abrasive. d) Conveying trap rock with 1790 kg/m3 density.IS 11592:2000
(Clause 8. and o Moving at 1.suitable idler far following duty: a) 16 hlday continuous duty. then move horizontally representating maintenance condition From this point move vertically again
to meet line applicable. The segment of the selection bar through which line AB passes. to meet the
curves signifying effect of stoppage on the system. continuous duty.6to
139.3 t0219.0
Unsized. mixed with tine sized small lumps. intermittent duty.2 Select density of material to be “handled along the axis Yq of square 11 (see Fig.
4. This will represent reference point B.3 From this point of intersection proceed horizontally to meet axis YJ.5. B-2.2)
FIRST METHOD FOR IDLER SELECTION
B-1 IDLER CLASSIFICATION The idlers are classified
given in Table B-2 22.8.1 Select required
of square I
(see Fig.6
88. axis
33-2.0
63. e) On belt width 6$0 mm.
139.l
Ball/roller/taper roller Ball/roller/taper roller
5. into six numbers series as
IDLER SEL-ECTIOiV
duty along Y.
lumps-Non-
Fine material.7
Ilall/roller/taper roller
500. This will represent reference point A.
127 to 139.0
Large capacity conveyor with lumps. b) Used under normal conditions and normal maintenance.
B-2. will indicate the series of idler conveyor most suitable for use. continuous duty.
Table 22 Idler Classification
(Clause B-1)
Maximum Belt Speed.9 to 139. mixed with small sized medium lumps moderately abrasive contimrous duty.5 4.4 The dotted line drawn on the chart as an example illustrates the selection of.
300-800 400-1000 500-1200
Fine material with small abrasive. From this point move horizontally to meet Yzaxis.
{--TRAP
ET WE. 3
move horizontally to meet Y1 axis..
1 Select required duty along Y. will indicate the series of
idler conveyor most suitable for use... The segment of the selection bar through lineAB passes. From this point
representing conveyor speed desired. axis of square I..RETi CONC IRON ORES
32WII
Cl BORINGS
2 Select density of material to be handled along the axis Y. . Join point A and B. From this point move vertically up or
down to joint the lines
From this point of intersection proceett horizontally
to meet axis Y..
of square II and move Irorizmstallyto meet the lines representing required bolt width. This will represent reference point A. This will represent reference point B.
L7 SALT 720 WHEAT GRAINS D COAL 0 SULPHUR 100 SLAG 1250 PHOSPHATE ROCKS LIME STONE ) =OIJ??3ARY SAND O EARTH.
FIG. then move horizontally to meet line representing maintenance condition applicable from this point move vertically again to meet the curves signifying effect of
stoppage on the system. g
NORMAL OCCASIONAL STOPPAGE ACCEPTABLE UNS HEOULEO STOPS ACCEPTABLE PROCESS NOT UPSET
OF NOC0NSE12UENCE
STOPPA6E
HIGHEST RELIABILITY STOPPAGE CATASTROPHIC BAO ~l? CONDITIONS MAtNTEt4At4CX
SAW WWO DUST CHIPS
CHARCOAL DRY ASHES
. 19 SELECTION OF IDLERS
108.5. 133. 20 and 21 respectively.2)
SECOND C-1 IDLER CLASSIFICATION
Idlers are Table 23.9. fine
Roller/taper
roller/ball
101.88.
. 127. high and for heavier capacities weight. abrasive materials where the size of lump is limited by belt width.5.76. or for when continuous operation handling materials. 114. 139. 114.8.6.
101.6. 127.7.7
500~ I 600
continuous operation.1. 120. highest
capacities and for the heaviest and coarsest materials.I 200
For intermittent operation.6
B-elt Width
intermittent tively low
operation. )52.3.1
For continuous operation. 120. classified in four series as given in
OF IDLER SELECTION c-2 I-DLER SELECTION
Idler spacing for troughed belts and flat belts are
in Fig.IS 11592:2000
(Clause 8. semi-abrasive materials containing lumps larger and heavier than those handled by light duty series idlers. 101.9.4 to 219.
Roller/taper rollerlball
23 Idler
(Clause C-1)
Series Bearing Type
Shaft Dia at Bearing
RoB Dia (mm) 63. 108. 152.
Deep groove ball b&dring
88. light weight.3. medium capacities and for moderate weight. capacities
light weight materials limited lump size. 133.
2. m w 0.500
0.250 1.750
1.500 d z 3 { x
300 $ 2 0’ s A z y ~ : w
150 135 120 105 90 75 60 L5
1.IS 11592:2000
1500 1350 1200 1050 E ~ nd s
w A ~
450 \ 300 150
0. 21 FLAT BELT IDLER 52
.500 1.375
0.000 0.000 1.750
FIG.750 ~ g w z ~= .750 1.150
FIG. 20 TROUGHED BELT IDLER
1500 1350 1200 1050 900 750 600 b50
)ELT WIDTH AND IDLER SERIES
several decades of life may be expected. In temporary installation such as dam construction or quarrying.4.8.3.3 Type of Material Handled The weight of material on belt effects the load and spacing of idlers and therefore has a direct bearing on idler selection.4. This includes the hours of operation per day and overall life expected from the installation. It determines the rotational speed of idler based upon the diameter of the roll.
24 Classification-Idler Series Number (clause D-1)
Ail dimensions in md]imetres. life may be a few years while for permanent installations.
Table 25 Service Factor ‘A’
152. The product of service factors ‘A’ and ‘B’ ( ‘A’ and ‘C’ for return idlers) gives application factor used in the selection of idler series number.5
lt)l. 133. Table 26 and “Table 27 give the service factors ‘B’ and ‘C’ applicable for troughing and return idlers respectively. and c) Belt speed.5.1 Table 25 gives the service factor ‘A’representing
Maximum Belt Width 650
1200 1600 1600 2000
Idler Series Number I II
Shaft Dia at Bearing 17 20
20 or 22 250130 25. only weight carried by idlers is that of belt itself. limited by belt widths only Two shift operation—(10 Return idlers Troughing idlers — Classified material up to to 16 hours per day) to 9 hours per day)
The severity of conditions under which the idlers will be used.2)
THIRD METHOD FOR IDLER SELECTION
D-1 CLASSIFICATION
OF IDLERS
D-2.1
D-2 BASIS FOR SELECTION
Return idlers Troughing idlers —
(Clause D-3. 159
the type of service of.2 ~pe
Intermittent operation-(less
Portable or temporary installations
Seasonat operation for stockpiling Conveying materials with bulk density over 1920 kg/m3 One shift operation—(6 Return idlers Troughing idlers — Classified material up to 1280 kg/m3 Classified materiat up to 1920 kg/m3 Classified material over 1920 kg/m3 Unclassified material.159
168.6to
127. representing the effect of material handled. limited by belt width only Continuous operation<over All materials 16 hours per day) 15
than 6 hours per day)
D-2. 139.7 139. 152. is the prime consideration for the selection of idlers. 219. ‘D-2. b) Characteristics of material to be handled.
Classified material over 1600 kg/m3 Unclassified materiat.conveyor installation.IS 11592:2000
(Clause 8.
D-3 METHOD SERIES FOR SELECTION OF IDLER
The idlers are classified into five series numbers as given in Table 24 based upon roll diameters and hewing sizes. The material lump size modifies the direct effect of weight by introduction of an impact factor. D-2. In case of return idlers.7.1 This selection of idler series depends on three
Factor ‘A’
conditions: a) Type of service. The bearings may be either deep grooved ball or taper roller bearings with shaft diameter as
shown in Table 24. Belt speed also has a direct bearing on wear life of idler roll surface.4 Belt Speed Belt speed is an important factor in idler serJice life and therefore governs its selection.30 or 40
63. particularly for the return idlers.
1 18.75 m/s 800 mm
From Table 25 From Table 27 Application factor for return idlers
Factor A = 9 Factor C = 8 Ax C=9 X8=72
D-3.1)
Bulk Density of Material.3
Above 2000 2.
D-3.75 m/s and an application factor of 72.9 3.75 m/s and an application factor of 576 a series II idler is selected. a series II idler is indicated.5 4.4.1) when plotted. troughing idler application factor
Factor A = 12 Factor B =48 Ax B= 12x48=576
D-3.7
112 140 168 196 224 252 280
128 160 192 224 256 288 320
’200 250 300 350 400 450
80 96 112 12/? 144 260
120 144 168 192 216 240
D-3.8 24.2 Figures 22 and 23 depict the relationshfi between app~ication factor and belt speed for troughing and return idlers.7 21. 22 and Fig.4. 23 for a belt speed of 1.2 13. D-3.2. These curves are used for selection of idler series number for troughing and return idlers respectively.2 8.IS 11592:2000 Table 26 Service Factor ‘B’ Table 27 Service Factor ‘C’
(Clause D-3.1 From Fig.6 16. 23 gives the best suited idler series number for troughing and return idlers respectively of the particular installation.4.1. D-3.4 Example
D-3.1 From Fig. 1600 kg/m3 100 mm 1.6 25. 1)
Size mm 100
(Clause D-3. kg/m3 800 1200 1600 2000 2400 2800 3200
Bulk Density of Material.6 4.6 20. 20. tigainst the selected belt speed for installation in Fig.19 14. kg/m3
up to I 200 300 2.0 10.3 The application factor (see D-3.5 6.0 20. for a belt speed of 1.6 6.4.
.3 2.5 4.6 10.8 3.8 9.1 For Troughing Idler Selection
From Table 25 From Table 26 Therefore.8 3.2 For Return Idler Selection
Type of service Type of material Maximum lump size Belt speed Belt width selected
8 h/day one shift Crushed stone.2 13.2 17.0 16.3 400 500 630 800 1000 1200 1400 1600 1800
1 200to2000 2.6 6.0 22.
0 w 03 1.0 4.5
3.0 E a : 2. \ —
‘r.IS 11592:2000
5.5 s 3.0 3.
-t-h--m.
SELECTJON
FOR TROUGHING IDLER (FOR BELT WIDTH UP TO
FIG.0 \ 0.5
& m ~ 2.5 ~
o 500 1000 1500 2000 APPLICATION FACTOR (FOR TROUGHING IDLE-RS)
lr1 .5
.5 \’ \
au-l ~ 2.. 23
IDLER (FOR BELT WIDTH
.5. E-3 The modified equivalent force on each bearing considering the life of bearing is given by: Feqm =~fjKiBf .7 0.7
Factor K.3 2.6 2.3
150 to 200 200 to 250 250 to 300
1. K.0
Lump factor (K..3
250 to 300 300 to 350 350 to 400 400 to 450 450 to 500 500 to 550 550 to 600
Classified material Oto 100
2.9 1.0 2.0 3..7
2.IS 11592:2000
(Clause 8.0 4.3
3.0 to 2. (67)
‘=[:’’1G:”p.7
Maximum lump dimension in mm
Unclassified material
100to 150 150 to 20U
1. (66)
where B~is the bearing life factor.Up 1.0 3.7
10to 16 16t024 Service fwtor (Kv) Belt
SpCd.0 to 5.) Hours of operation
LrP to 6
Service/Speed/Lump 0.0 to
1.3 1.8. I1tiS
. The value B[ based on 60000 working hours at the required belt speed may be obtained from bearing manufacturers.0
CALCULATIONS FOR EQUIVALENT LOAD ON IDLER BEARINGS THREE EQUAL ROLL TROUGHED IDLER SET E-1 The load on central idler-roll is the summation of FOR
loads due to weight of material and weight of belt and is given by (for symbols see Table 1)
where Ki is the application factor for the idlers as given in Table 28..3 1.
NOTE — The above is typical method of calculation and there can be orher methods as w~lL
Table 28 Application
Factor Ki
(Clause E-2)
Service fhctor (Ks.0 1.0
1..= K. &Ki 2 ..
K..7 3.+[+mBg”pc)newt
E-2 The equivalent force on each bearing of the idler
is given by: Feq=~.
0.6 0.7 1 T~ Tm T. Tm
0..85 Tm t. 0.
F-3 Value of AT given in Table 29 will ensure that: a) edge tension does not exceed either in steady operating conditions or in the temporary nonsteady conditions from the maximum recommended tension of the belt or belt joint in the steady condition by the ratio selected.8Tm
180% AT
2Tm 200%
2..4T.5 Tm 1...3
0..6 0..5 Tm 1.
No belt centre
0.. AT
F-1 ]nduced belt edge tension is the ratio of maximum belt edge tension and the maximum rated belt tension.45 Tm 0.
1.6 0.45 Tn.8.15 T~
0.75 Tm 0.. 130%
1.45T~ 145%
1.75 T..
0. T.7 times the maximum rated belt tension in case of steel cord belts for belt edge tension in short time non-steady operating condition.05 Tm
1. I T.95 Tm
2..6 0.5 T~
1. 0..6Tm 160%
1. the maximum belt edge tension under steady operating condition is selected.2 T...6 0..3Tm 230%
2..6T).1 Tm
0..2 T.15 T~
0. T. 0..95 Tm
2.3T. If agreed by the manufacturer.l T..9 T~ T~ 0.IS 11592:2000
(Clause 8.8
2.2 Tm 1.
Tm T~ T~
Tm T~ T.5 Tm 1.5 Tm 1.n
Tm T~ T.
Tm T~ T. 0.l..15 T.3
0.25 Tm
1.35 Tm
Maximum belt edge tensioo F percent T~
T. 0.4 0..l T..9 T~ 1.. I .4) ALTERNATIVE METHOD OF CALCULATION OF INDUCED BELT EDGE TENSION. T..35 T~ 1.n 1.65 Tm
1.4.2 Tm
Tm T~ T. if agreed by the belt manufacturer. F-4 A hgiher value of AT may be fixed.4
0..4 Tm 2.9T.5 T.5 Tm
1.15 Tn
. 0. 0.. .05 Tm
1.6 0...3T.8
2. 0.. 0.2 Tm
1.2 Tm
0.8 Tm 1.3 Tm
1. b) tension in the belt centre remains adequate and always positive to prevent belt buckling.45 Tm 0..7Tm 270% Criterion
‘rension F Ratio of Average Belt Tension at Transition to T 1. 1.6 0.55 Tm 0..9 0..9
1..8 Tm 1.25 Tm
1.5 Tm 1.4 T.1 2. The value of AT is Laken from Table 29 (interpolating if necessary) against the ratio of average belt tension at transition 10 maximum rated belt tension with the assumption that the gap (or overlap) between the rollers (idlers) conforms to IS 8598. 0..9 T~ T.2 Tm
1:35 Tm
1.. T.6 0.2T.OT.3 0...6 0.05 Tm 1..8 Tm 1.2 Tm
0.5 Tm
1.75 Tm
0.9 T.5 Tm 1. 0.8 Tm 1.’
of the manuIacturer..1
1..2 T.15 T~
— — .15 Tm 1.05 T.9
— ..3r.35 Tm 1..15 T.2 Tm
0. 1.2 Tm
0.. the value of maximum belt edge tension may be taken as twice the’ maximum rated belt tension in case of textile belts and 2.15 Tn
0.l 0.65 Tm 1...1
2..05T~
2.8 Tm
1. l....95 Tm
0. t)...9
1.7 Tm 2. 1.8 T..6 0. 0.The induced belt edge tension may be more than lnaximum rated belt tension during peak belt loadings in short time non-steady operating condition during stw-ting and stopping the conveyor belt..75 Tm 1.15 T~
0.. T.9
t Tm .7 T.3 0..
F-2 Based on the recommendation
Table 29 Values of AT
(Clauses F-2 and F-3)
hlaximwn Belt Edge
1. for the maximum transition distance.25Tm 0.9
1. 0.65 Tm 1.5Tn.
Polyamide Polyester Nylon/Nylon
5-7 10-20 6-8
(Clause 8. Also the greater flexibility of layout of dual drives normally makes it possible to reeve the belt in such a way that.
H-4 With this type of drive. when these are fitted.2.2. The scope of having a greater length of belt between the two drive pulleys. the two drives will not share equally.5)
SPECIFIC MODULUS FOR BELT MATERIALS
types of material of belts
G-1 For the calculation of belt modulus. the values for specific modulus for different are given below:
Curcass Construction (Longitudinal Direction)
7-1o
Typical Value 9 7 16 6.9.
H-2 The driving motors shall be of the same type and have the same torque/speed characteristics.3 and 8. The difference in speed will be a function of the belt tensions related to the stretch characteristics of the belt and is normally well within the slip characteristics of either the electric motors or fluid couplings (when these are fitted). there being a small difference in power due to the contraction of the belt in drive head causing the secondary pulley to revolve at a lower speed than the primary pulley.
. so that both drive pulleys drive on the clear side of belt.IS 11592:2000
(Clauses 8. makes for greater flexibility in absorbing the effect of belt contraction or creep. In dual. as also shall be of the case with fluid couplings.10.9. H-3 In practice. drive units should be arranged. thus eliminating the liklihood of difficulty due to material built-up on the face of the pulleys. the distance between the two drive pulleys is not fixed as in the case of geared tandem drive and the extent of separation is not critical. although practical considerations such as
mounting and housing usually make it convenient to have the two drive units reasonably close together.3. than is possible with geared tandem drive.4)
SELECTION OF DRIVE PULLEYS WITH TWIN DRIVE
H-1 Drive pulleys with twin drive consists of two pulleys of identical overall diameters each being independently driven.the noncarrying or clean side of the belt is in contact with both drive pulleys.
PULLEYDIAMETER— METRES
FIG. from point at equal intervals placed on tangent line drawn at the point of separation are calculated from the following formula:
‘“’’l-t+
1.6 1... 24. J-2 DETERMINATION SEPARATION OF POINT OF
J-2.0 0..8 1.2)
DETERMINATION OF TRAJECTORY OF MATERIAL LEAVIN..13. Trajectory of material is fixed by the angle of separation of material from the belt and the vertical ordinates from the tangent line drawn at the point of separation on head pulley. J-3 DETERMINATION OF ORDINATES
J-2... a graphical representation for determination of angle of separation is given in Fig.IS 11592:2000
(Clause 8.2 ANGLE ~ 1... .4.1 The length of vertical ordinates h..8 0. (68)
leaving lhe head pulley in a conveyor system. that is.50”
J-3.2 For guidance.1 The angle of separation.00 1. h2..4 1.G THE BELT
J-1 For design of discharge openings and receiving
chutes. it is necessary to know the trajectory of material
V* cOse=—
-g”rP
24 ANGLE OF SEPARATIONFORBELTS
3. the angle from vertical at which malerial will leave the belt as it travels over discharge pulley is calculated from the followin~ formula:
the tangent line shall be drawn in the direction of belt travel (see Fig. of the conveyor belt then the tangent line is drawn at the point of separation (see Fig.110
J-4.(3 2 1 and is less than or equal to angle of inclination. ..IS 11592:2000
. 6.196
0.012 116
0. 25)...2 and J-4.441 h II
0.226 hlj 2.600 h 12
0.0 m/s of belt speed are given below:
h. 25).2 For guidance the value of ordinates.483
0.993 h“ 14 2. 25).. 25). h2 113 h4 h5
pulley.784 h 13 2.. hz.3 For Descending Belts
If cos Et<1 and angle of separation is more than angle of inclination. in the manner laid down
J-4. (69)
J-3.757 OF
J-4 GRAPHICAL REPRESENTATION TRAJECTORY OF MATERIAL
J-4.. of conveyor belt.765
0. If cos 0 = 1...1 The graphical representation of trajectory of material indicates the actual path which will be followed by the material after it leaves the discharge
J-5 For drawing the trajectory of top of the stream of material of height HI. in metres with 1 = 0.3.2 For Ascending and Horizontal Belts If cos 61<1 (see J-2.
0.. If cos .. the tangent line shall be drawn in the
direction of belt travel (see Fig... The trajectory of the material depends upon of the belt conveyor and is the configuration
graphically represented in J-2. the radius rPin formula (68) is replaced by (rP+ Hi ) and velocity V by : v(rP+H1)
..1) then the tangent line shall be drawn at the point of separation (see Fig. 5.50 m per 1.049
ASCENDING BELT
k-’
CASE 2 HORIZONTAL BELT
CASE 4 ASCENDING BELT
~. -..1S 11592:2000
CASE 1 HORIZONTAL BELT
CASE 5 Cose<l ande>6 t)~sc EN131NG BELT
CASE Cose>l
e<6
Fi~..
2350216. T. This Indian Standard has been developed from Doc : No. JAIPUR. a standard along with amendments is reaffirmed when such review indicates that no changes are needed. New Delhi 110002 “Telephones :3230131. No part of these publications may be reproduced in any form without the prior permission in writing of BIS. 1. GHAZIABAD. New Delhi-2
BUREAW OF INDIAN STANDARDS Headquarters: Manak -Bhavan.2350442 2351519. it is taken up for revision. FARIDABAD. such as symbols and sizes. ME 06 (0331). BIS. Scheme VU M. Users of Indian Standards should ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of ‘BIS Handbook’ and ‘Standards: Monthly Additions’. Sector 34-A. of neeessary details. Campus. LUCKNO W. type or grade designations. IV Cross Road. I. P. in the course of implementing the standard. V.2352315
8329295. Kankurgachi CALCUTTA 700054 Telegrams : Manaksanstha (Common to all offices) Telephone 3237617 3233841
3378499. E9 MiDC.3378561 3378626. ‘ilk does not preelude the free use. NAGPUR. THIRUVANANTHAPURAM.Bureau of Indian Standards
BIS is a statutory institution established under the Bureau of Indian Stan&rds Act.
Amendments are issued to standards as the need arises on the basis of comments. 3239402 Regional Offices : Central : Manak Bhavan. Road.
Rinted at : Prabhat Offset Press.3379120 { 603843 602025
Northern : SCO 335-336. BHOPAL.8327858 { 8327891.
Amend No. Marol. marking and quality certification of goods and attending to connected matters in the country. RAJKOT. 3233375. 8327892
Branches : AHMADABAD. PATNA. CHANDIGARH 160022 { Southern : C. KANPU~. HYDERABAD.T. BANGALORE. Enquiries relating to copyright be -addressed to the Director (Publications). if the review indicates that changes are needed. COIMBATORE. BHUBANESH WAR. GUWAHATI. 9 Bahadur Shah Zafar Marg NEW DELHI 110002 : 1/14 C. Standards are also reviewed periodically.CHENNAI 600113 { Western : Manakalaya. 1986 to promote
harmonious development of the activities of standardization. PUNE. 9 Bahadur Shah Zafar Marg. Copyright
BIS has the copyright of all “itspublications. .
More From This User11592Construction Personnel ManagementConstruction Finance Management Ncp 29NCP 21
Belt Conveyor IS_11592 by Kavvindra Mehra46 viewsEmbedDownloadRead on Scribd mobile: iPhone, iPad and Android.Copyright: Attribution Non-Commercial (BY-NC)List price: $0.00Download as PDF, TXT or read online from ScribdFlag for inappropriate contentMore informationShow less
RelatedYokohama Conveyor Beltsby U Thaung MyintGoodyear Conveyor Handbookby sasha_seferovic1874Belt Conveyor Design - Apex Fennerby dhangkaConveyor Belt Design Manual Contitech - Engby canito73Belt Conveyor Design-Dunlopby adi_ganteng12Conveyor Belt Design Manual - Bridgestone-1by adi_ganteng12conveyor belt designby Mark Jun TrinidadTroughed Belt Conveyorsby jyoti ranjan nayakBelt Conveyorby spvimalANALYSIS AND DESIGN OF TT - 22-5-08by api-19884175BANDO Eng. Catalogby atm_oApex Belting Conveyor Handbookby sasha_seferovic1874Conveyor Designby Al HisadinPROJECT REPORT ON DESIGN OF BELT CONVEYORby adnankhan890000001743-Calculation Report Conveyor Structure T-1022by Shada MohammedDIN 22101by Ravikanth AluriConveyor Belt Projectby UnniKrishnan NeithilathL3271.F3by Jorge Rolando Alvarez Mendozabelt_conveyor_manualby anthonyfoeIS 11592by Ravikanth AluriConveyor+Calculationby deyvishwarupconveyor selectionby Dr_M_SolimanDesign Guidelines Conveyorsby anujsharma2807Belt Conveyor Pulley Designby thakur_raghabConveyor Componentsby wmacaddBelt Conveyorby Purev-Ochir TogtohbaatarConveyor Design-Draft.xlsby mkchy12Belt_Conveyor_Pulleysby Pok Jak SallehSimilar to Belt ConveyorYokohama Conveyor BeltsGoodyear Conveyor HandbookBelt Conveyor Design - Apex FennerConveyor Belt Design Manual Contitech - EngBelt Conveyor Design-DunlopConveyor Belt Design Manual - Bridgestone-1conveyor belt designTroughed Belt ConveyorsBelt ConveyorANALYSIS AND DESIGN OF TT - 22-5-08BANDO Eng. CatalogApex Belting Conveyor HandbookConveyor DesignPROJECT REPORT ON DESIGN OF BELT CONVEYOR0000001743-Calculation Report Conveyor Structure T-1022DIN 22101Conveyor Belt ProjectL3271.F3belt_conveyor_manualIS 11592Conveyor+Calculationconveyor selectionDesign Guidelines ConveyorsBelt Conveyor Pulley DesignConveyor ComponentsBelt ConveyorConveyor Design-Draft.xlsBelt_Conveyor_PulleysAs 1755-1986 Conveyors - Design & FabricationConveyor Belt Hand BookBelt Conveyor