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11592:2000
Indian AND DESIGN
Standard OF BELT CONVEYORS
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.
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
Continuous mechanical handling equipment — Belt conveyors with carrying idlers — Calculations of operating power and tensile forces
1S0 5049 (Part 1) :1994
Mobile equipment for continuous handling of bulk materials — Part 1: Rules for design of steel structures
1S0 5293:1981
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)
DIN 22101:1979
Continuous mechanical handling equipment; belt conveyors for bulk materials:
bases for calculation and design
BS 2890:1973
BS 5934:1980
Method for calculation of operating power and tensile forces in belt conveyors with carrying idlers on continuous mechanical handling equipment
1.1 This standard provides guidance for selection and
design pt-actices to be adopted for belt conveyors.
1.2 This standard applies to stationary and shiftable and/or expendable conveyors handling loose bulk ma- terial and such material, which behave as solids+For guidance, classification and properties of such mate- rial 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.
1 Conveyors,
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.
under this scope and special purpose
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 re- quirement 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 pro- vided 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 ex- ample those with multiple drives, or with an undulat- ing 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
be applied both to individual conveyor, as well as
conveyor. Care shall however be taken to apply clauses
pertaining to system requirements.
1.6 This code covers the belt running on idler rollers
only and not on slideslbeds.
This standard applies for only smooth surfaced
2.1 The Indian Standards listed in Annex A contain
provisions which through reference in this text, con- stitute provision of this standard. At the time of pub- lication, the editions indicated were valid. All stan- dards 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,
3.1 For the purpose of this standard, the terms and
definitions given in IS 4240 shall apply.
Symbols and their units used in this standard for cal- culations are summarized in Table 1.
4.1 The conveyors
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 con- form to IS 8598 and shall be selected from the follow- ing values: 15°, 20°, 25°, 30°, 35°, 40°, 45°.
and flat, both hori-
are troughed
conveyors only.
troughed angle of 15° is applicable
for 2-roll
4.3 Flat belt conveyor
flat on the carrying
is that in which the belt runs
(C/auses 3.2,8 .5.1.3,8.11.3.1
urrd8.1 1.3.2.)
S lSymbols
Cross-sectional area of load on belt
Area ofcontact between belt and belt cleaner
5. Conveyor capacity
6. Coefficient depending upon trough angle
Belt specific modulus
Force available for acceleration of the total equi-
valent mass
11. 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
16. Total vertical.force on central idler roll
17. Moment of inertia of drive system
N.ms2
(4wk2)
18. Lift of conveyor between loading end and dis-
Height of material on belt
at discharge pulley
Scraping factor
22. factor for idler
23. K,
Lump factor
24. K,
Conveyor length (distance between cerrtres)
Length of installation equipped with tilted idler
Total equivalent mass
rev/rein
Drive pulley speed
Normal strength of belt
Operating power requirement on drive pulley
Motor output power (shaft)
Installed motor output power
m’ls
Pulley bearing resistance not to be calculated for
Resistance due to friction at discharge plough
sum of the two belt tensions acting on
the pulley and of the forces due to the mass of
the revolving parts.ofthe pulley
Wrap resistance between belt and pulley
Inertial and frictional resistance at the loading N
point and in the acceleration
handled material and.the belt
Frictional resistance due to the belt cleanersN
Resistance due to friction between handled N
material and skirt plates
1 (Con~inued)
S1 Symbols
Frictional resistance between handled material
and the skirt plate in acceleration area
Special main resistances
Special secondary resistances
Peripheral force on the drive pulleys
Tension at the curvefor both starting and
Maximum recommended belt tension
Average belt tension at the pulley
belt tension to limit belt sag
belt tension under normal operating
Maximum operating belt tension
Maximum peripheral force
T,m,n
Belt tension in startirrghrrking condition
Tension at the curve when belt
loaded up to beginning of curve
Maximum belt tension when belt is partially
Induced belt~dge stress in ~itions
Handled material conveying speed component
in the direction of belt motian
Coordinatesof curves
Distance between working, point and tangent
point on curves
Width ofmatenal on belt
lnterskirt plate width
Shafi diameter inside bearing
Arititicial friction coefficient
Ordinates for trajectory of material
Angle of tilt of the idler axis with respect to a
plane perpendicular to the longitudinal axis of
81.1,,12
Dkances from point of separation to the points
situated on the tangent line from which ordi-
nates are to be drawn
82. Acceleration length at loading area
83. Length of installation equipped with skirt plates
excluding (see SI No. 82)
84. Mass ofbelt per metre
85. Mass of revolving idler parts along the carrying
side of the conveyor per metre
86. Mass of material that can be safely discharged
on the next chute or hopper
87. Mass ofhandlcd material on conveyor per metre
88. Equivalent mass for drive system per metre
89. Mass of revolving parts of pulleys per metre
90. Mass ofrevolving idler parts along the return
side of the conv.eyrrrper metre
91. Number of trippers
92. Pressure between belt cleaner and belt
1 (Concluded)
Pitch of carrier idler or idler spacing on carrying
94. Pitch of return idler or idler spacing on return side of conveyor
95. Ratiomf starting motor torque and full load torque
96. t,
Radius of discharge pulley +0.025m (this
m represents the approximate
of belt)
Time taken to accelemte
100. Reduced deceleration time
101. Time required by motor to accelerate veyor
Length of the centre idler
!03.
Maximum permissible slopping time or maxi-
mum permissible coasting time
distance the belt edge rises or lowers
Numerical coefficient, being a fimction ofcon- veyor length
Factor for extra power for trippers
Slope angle of the conveyor from horizontal line in the moving direction
between head and tail pulley and lift of conveyors is fixed to suit feed and discharge requirements. How- ever, points mentioned in 6.3 shall be considered here also to the extent applicable.
m 6.2 For system layout, the following data is required to proceed further:
a) Site plan with suitable contour drawings;
b) Over/under surface interferences, namely, exist-
m ing and proposed roads, drains, rails, rivers, transmission lines, buildings, structures, etc;
c) Grade deviations;
d) Material flow diagram and flow rates;
e) Details of receiving point(s), discharge/distri-
s bution point(s);
f) Material characteristics including size analysis;
g) Climatic data and site condition; and
h) Specific requirement for tensioning arrangement,
m if any.
degree Troughed
rf,q, Power
Higher capacity requirements Lower capacity requirements
and regenerative power respectively Drive efficiency
Angle from vertical at which material will leave the belt
Troughing angle of return idlers
Angle between side axis of the troughed canying idlers and horizontal troughing angle
Coefficient of friction between drive pulley and belt
!.+,
Coefficient of friction between carrying idlers and bell
of friction between material and belt
Coefficient of friction between material and
skirt plates Coefficient of friction between belt and belt cleaner
Acceleration coetlcient
Edge margin, that is unusable width of the belt
Total cross-sectional area of the material
S, = Upper
S, = Lower
— High speed requirements Low speed requirements
Large lump size of material with
degree or without intermediate discharge
with trippers Iumpssize of conveyed
Relatively higher angle of repose
of conveyed material, limited
intermediate discharge with ploughs, distributor plates
Maximum inclination allowed is
With or without vertical curvature Without vertical curvature
Suitable for inclimtion
nation in accordance with IS 8730 6°. Declination undesirable
or decli-
— 6.2.1 In case of shiftable conveyors, in addition to data
covered in 6.2, the following data is also required:
Layout of working face;
Difference in levels between the head and tail ends;
Whether future extensions are required or not.
If so,the proposed level of the head end or tail
end to be altered;
Type of shiftin~
Location of discharge conveyors in case of pivot operation;
of tripper/transfer
or rail mounted);
Maximum allowable ground pressure.
6.2.2 For layout of system of conveyors andlor indi- vidual conveyor in underground (mining) installations, points such as compact drive head, flame proof motors, fire retarding belting and safety precautions
tlm]
Table 2 lists the features of troughed and flat belt con- veyors and shall help in selecting the type of belt con- veyor.
.6.1 For a single conveyor the centre-to-centre distance
against fire in all other equipment especially fluid cou-
pling and other electrical care off.
items shall be duly taken
6.3 Based
data, the conveyor system is
laid out, taking following points into consideration:
b) Keeping conveyor lengths (including allowance for belt elongation) within reasonable limits so as not to exceed the likely RMBT (recommen- ded maximum belt tension) for selected type of conveyor belting;
c) Keeping minimum overhead clearances below the conveyors according to the site require- ments while crossing road, water ways and railways and maintaining minimum clearances in accordance with the statutory requirements;
d) Keeping all transfer points in line with direction of flow, maintaining a minimum transfer point height and avoiding reversal of direction of flow of material unless absolutely necessary due to site constraints; and
e) Coasting time of a conveyor shall be taken into consideration to avoid build-up of material. In case, it is unavoidable, suitable means of coasting corrections at transfer point shall be considered. Use of surge hopper shall be considered if coasting time cannot be corrected.
Typical layouts of conveyors are shown in Fig. lJ.
7 CONVEYOR DESIGN PROCEDURE
7.1 Once the configuration
is finalized the following design steps are taken for
sizing the conveyor.
7.1.1 Wherever multiple choices are specified, the worst condition applicable shall be considered for the design of the conveyor system.
7.2 The known maximum lump size of the material
can be found from Table 3 taking into account the classification of material as given in 7.3.1.*
and layout of a conveyor
7.3.1 Material shall be classed as ‘sized’ and ‘unsized’
a) Unsized — 30 percent by mass of all material less than one-sixth maximum lump size.
50 percent by mass of all material less than
one-third maximum lump size.
75 percent by mass of all material less than
one-half maximum lump size.
90 percent by mass of all material
two-third maximum lump size.
b) Sized — Material not falling within the above grading.
-to Belt Width
(Pa’t
6(!!2
8.(!Q
of troughing
belt speed or
7.3.2 Lump Size
Lump size indicates the longest single dimension of larg. est lump. This shall not be cont%sedwith crusher setting or screen openings as these limit only one dimension.
7.4 Ascertain speed factor as sum of lump size factor
(see Table 4), air borne factor (see Table 4) and abrasiveness factor (see Table 5) and select belt speed (see Table6).
7.5 If the conveyor is inclined/declined, select a safe
angle of inclination/declination for the particular material (also see IS 8730 and 8.1.2). Determine the angle of surcharge according to the nature of the material (see IS 8730).
7.6 From the selected belt speed, angle of inclinatiord
declination and angle of surcharge for the material, determine belt width and troughing angle for the required capacity of the conveyor from Tables 7, 8,9,
10andll,
7.7 Use the larger of the belt width as determined
by 7.2 and 7.6 and rework if the belt width require- ment from 7.2 is lower than that required by 7.6.
7.8 Consider the type of supporting idlers and their
spacing [see 8.8 for selection and IS 4776 (Part 1) for
spacing].
Load from End Hopper
Fig. 1A Horizontal
— Loaded
,., ,,,:. +
/-+&Q y
~~-.”.~”’
Fig. 1B Horizontal
Conveyor — Discharges
““:”””s;’”-9-&q#J-
Fig. 1C Inclined Conveyor
up varying
Fig. 1D Inclined or retarding conveyor for lowering
which depend
— will carry the nature
material gently down slopes similar to those used
way and discharges
in stvle in Fia. 1C convevor.
Mav be combined
ot;er
drive acts
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. The bend in carrying run can be
over an idler pulley, but the method
Fig. 1F Simplest
up an incline where
belt, loaded
lifting from carriers,
Fig. 1G This arrangement
two conveyor
units is often
Fig. 1H For conveying
+3104—4=
on both upper
belt often used
with flat belt for packages
15 To 20 ~3To
30 ——————i
Fig. lJ
7.9 Calculate the resistances (tensions) for all condi- tions including empty belt, loaded belt, liftidrop and other accessories.
7.10 From the tension
7.11 Select type of drive and determine slack side ten-
7.12 Find out the minimum recommended belt ten-
sions 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.
Ftne Grain
m Dust
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
selected belt width)
selected bett width)
5 Abrasiveness
‘Abrasi-
Free flowing materials, such as cereal
grains, wood, chips, wood pulp, fullers earth, flue dust, soda lime, char, loam
sand, ground gravel.
Materials, such as aggregate, run-of-
bank sand and gravel, sand stohe.
slate, coal, salt,
such as slag, spar, limestone
concentrates, pellets.
Iron ores, taconite,
crdlet,
7.13 Calculate slope tension and return side friction tensions.
7.14 Depending upon conveyor configuration, that is inclination/decli nationregeneration, location of drive, compute the minimum required slack side tension.
Table 6 Maximum
(Clauses 7.4,8 .1.3,8.2.2
and 8.3.3)
7.15 Compare
from 7.11 and 7.14 and use higher of the two values
to calculate maximum operating tension. Also calcu-
late maximum starting tension. 7.16 Multiply maximum operating tension by the mini- mum 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 sup-
porting the load.
7.18 Tentatively
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.
losses after selecting machinery between drive pulley and source of power. Consideration shall be given here to limiting requirements of starting tensions and cor- responding minimum acceleration time requirements.
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.
ing (see IS 3181) for underground use are as follows:
decide belt specification
Diameters for
Satisfactory Flexing
of the Handled
in mz for Triple
Troguhed
to Fig. 2 with
FIG. 2 MAXIMUM
0. I 20
0.1-57
0.2)3
1o“
0.3 I 5
Table 7 — Concluded
I rougn .4ngle
600’J
800’)
I NOTE — Suitable adjustment
made in case of other values of surcharge angle and troughing angle.
II Indicates sizes generally
in the c&ntry
and meant for information
7.23 Finalized drive power considering transmission
losses after selecting machinery between drive pulley
and the source of power.
like cou-
7.24 Finalise
the drive element’s
pling, belt/chain drive, gear box.
7.25 Determine drive shaft diameter and other termi-
nal shaftings.
7.26 Select proper bearings
7.27 Consider location and type of take-up and find
out the amount of take-up movement.
7.28 Calculate coasting time of individual conveyors
tension and the take-up
for the duty conditions
times for the conveyor system.
if hold back and brake are required
simultaneously or one will be sufficient. Determine the type and location of hold bacldbrake.
7.30 Calculate the braking force and torque required.
7.29 Consider
8 DESIGN ASPECTS
Affecting Conveyor
8.1.1 The proper design of a belt conveyor/conveyor system is greatly influenced by the characteristics of the material to be handled. Generally, the material is classified as shown in IS 8730.
8.1.2 Care shall be taken for the inclination of an inclined/declined conveyor, carrying lumps of material, as these are likely to slide down, wherever
possible. Actual inclination of the conveyor shall not exceed the maximum allowable value (see IS 873.0). In case of declination, the angle of declination shall not exceed 12° in any case.
8,1.3 Table 6 shows the maximum recommended belt speeds for different sizes of belts based on speed fac- tor (speed factor -= lump size factor + abrasiveness factor). For systems with ploughs and trippers, lower speeds of belt shall be adopted.
8.1.4 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 .or liable to react with rubber products,
.b) High temperature,
Mildly abrasive,
Very abrasive,
Sharp abrasive,
Easily degradable,
Mildly corrosive,
Highly corrosive,
Explosive or creating harmful dust,