This was a project under subject in graduation in Mechanical Engineering -DOMS- Material Handling System
Conveyor belts have been used for decades to transport bulk and unit loads. They have proved their worth everywhere because belt conveyor installations can be adapted to meet nearly all local conditions.
This project demonstrates how to design such Conveyor Belt for Coal Crushing in Thermal Power Plant application with mathematical and imperial ways
Introduction to IEEE STANDARDS and its different types.pptx
Design of material handling system belt conveyor system for crushed coal for power plant
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Project Report
on
“DESIGN OF MATERIAL HANDLING SYSTEM-BELT CONVEYOR
SYSTEM FOR CRUSHED COAL FOR POWER PLANT”
Submitted By
Suhas Bandal (S-38)
Aditya Deshpande (S-42)
Pushpal Gavali (W-02)
Apurva Khomane (S-46)
Final Year B. Tech
Under the Guidance of
Prof. M. Khodake
Department of Mechanical Engineering
Vishwakarma Institute of Technology, Pune
November 2016
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Bansilal Ramnath Agaewal Charitable Trust’s
VISHWAKARMA INSTITUTE OF TECHNOLOGY, PUNE
(An Autonomous institute Affiliated to Savitribai Phule Pune University)
Department of Mechanical Engineering
CERTIFICATE
This is to certify that the project entitled “DESIGN OF MATERIAL HANDLING
SYSTEM-BELT CONVEYOR SYSTEM FOR CRUSHED COAL FOR POWER
PLANT” has been satisfactorily completed in the academic year 2016-17, by
Suhas Bandal , Aditya Deshpande, Pushpak Gavali, Apurva Khomane in
the partial fulfillment of Bachelors Degree in Mechanical Engineering.
Prof. M. Khodake Dr. S. R. Bahulikar
(Guide) HOD
Mechanical engineering department
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ACKNOWLEGDEMENT
Design Project is a task, which lights on our perception and provides us with practical
exposure required for facing the industry. It is a fine blend of imagination, hardwork and
guidance.
We would like to take this opportunity to express our sincere gratitude towards our
H.O.D MECH. Dr. S. R. Bahulikar, and Our DOMS Project Guide Prof. M. Khodake
Without their considerate approach and insight, this report would ever have been possible.
No words would be good enough to express our deep gratitude to all department
staff members and our college library staff for their valuable support and concern, without
them, this seminar would have been distant reality.
We wish to thank our parents for their constant support and blessings. We also
appreciate the help rendered by all friends in completion of our seminar.
SUHAS R. BANDAL (S-38)
ADITYA DESHPANDE (S-42)
PUSHPAK GAVALI (W-02)
APURVA KHOMANE (S-46)
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INTRODUCTION
Conveyor belts have been used for decades to transport bulk and unit loads. They
have proved their worth everywhere because belt conveyor installations can be adapted to
meet nearly all local conditions. They are work-safe and economical.
The demand for ever increasing capacities and ever longer conveying lengths has
accelerated the development of the belt conveyor technique, new materials are being
developed, new conveying systems are being planned and tested especially those having
regard to the environmental.
The conveyor belt plays the major part in the whole system and has to overcome the
many and varied stresses. In addition to this every conveying problem is different and needs
careful planning and selection of the right elements in order to achieve the optimum
conveying capacity in an economical way.
There are a number of practical rules, values and experiences which can be useful
during the planning stage.
In future there will be more and more use of the computer for calculations and
dimensioning of belt conveyors. With this often the correlation of the valuation criteria will
no longer be recognizable.
PROJECT AND DESIGN CRITERIA FOR BELT CONVEYORS
Belt conveyor is constantly operating transporting equipment which is mainly used to
convey mass bulk material like mineral, coal, sand, etc in powder or block as well as
packed freight in metallurgy, mining, building heavy industries and transportation
industry.
Belt conveyor is the most perfect conveying equipment for coal-mining, because it
can work efficiently and continuously. Compared with other transporting equipments,
belt conveyor not only has the merits of long conveying distance, big capacity,
constant working operation, but also with the features of operational reliability, easy
to have automated and concentrated control.
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Belt conveyor has become the key equipment especially for high-output and high-
efficiency coal mine.
During the project design stage for the transport of raw materials or finished products,
the choice of the method must favor the most cost effective solution for the volume of
material moved; the plant and its maintenance; its flexibility for adaptation and its
ability to carry a variety of loads and even be overloaded at times.
THE PARAMETERS FOR DESIGN OF BELT CONVEYOR
1. Belt speed
2. Belt width
3. Absorbed power
4. Gear box selection
5. Drive pulley shaft
For designing a conveyor belt, some basic information e.g. the material to be conveyed,
its lump size, tonnage per hour, distance over which it is to be carried, incline if any,
temperature and other environmental conditions is needed.
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DESIGN OF BELT CONVEYOR
The design of the belt conveyor must begin with an evaluation of the characteristics of the
conveyed material and in particular the angle of repose and the angle of surcharge. The angle
of repose of a material, also known as the “angle of natural friction” is the angle at which the
material, when heaped freely onto a horizontal surface takes up to the horizontal plane.
1. Belt speed
Very high speeds have meant a large increase in the volumes conveyed. Compared with the
load in total there is a reduction in the weight of conveyed material per linear meter of
conveyor and therefore there is a reduction in the costs of the structure in the troughing set
frames and in the belt itself. The physical characteristics of the conveyed material are the
determining factor in calculating the belt speed. With the increase of material lump size, or
its abrasiveness, or that of its specific weight, it is necessary to reduce the conveyor belt
speed.
Considering the factors that limit the maximum conveyor speed we may conclude: When one
considers the inclination of the belt leaving the load point; the greater the inclination, the
increase in the amount of turbulence as the material rotates on the belt. This phenomenon is a
limiting factor in calculating the maximum belt speed in that its effect is to prematurely wear
out the belt surface. The repeated action of abrasion on the belt material, given by numerous
loadings onto a particular section of the belt under the load hopper, is directly proportional to
the belt speed and inversely proportional to its length.
2. Belt width:
The optimum belt speed, the determination of the belt width is largely a function of the
quantity of conveyed material which is indicated by the design of conveyed belt. In practice
the choice and design of a troughing set is that which meets the required loaded volume,
using a belt of minimum width and therefore the most economic.
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Figure : components of belt conveyor
3. DRIVING DEVICE
Driving device is the power transmitting mechanism of a belt conveyor. It is made up
of an electromotor, coupling, reducer and driving pulley and so on. According to
different using conditions and working requirements, the drive mode of a belt
conveyor can be grouped to single-motor driving, multi-motor driving, single-pulley
driving, and double-pulley driving and multi-pulley driving.
Single motor and single pulley driving is adopted by a belt conveyor. The driving
device is installed at the discharge point which is located at the conveyor head. When
the power is big, a single motor and double-pulley driving is used, precisely, one
motor has 14 two driving pulleys, and the two pulleys are connected by a pair of
exposed gear which has the same number of teeth.
The pulleys can be classified into two types: driving pulleys and return pulleys. The
belt is driven by friction which is produced by pulley’s surface and belt’s surface
because of the function of driving pulley, and the movement direction of the belt is
changed at the same time.
Driving pulley is the main component of transmitting power. In order to transmitting
enough power, enough friction must be provided from the belt and pulley. According
to the theory of friction transmission, the methods of increasing friction between the
conveyor belt and the pulley and augmenting the wrap angle can be adopted to ensure
enough driving power when a driving device needs to be chosen. Usually, when a
single pulley is used, wrap angle can be 180o
-240o
; when double-pulley is used, the
wrap angle can reach 360o
-480o
. Double-pulley’s driving can enhance the conveyor’s
traction greatly, so it is often used especially when the transport distance is long.
Driving pulley’s surface has glossy-faced and rubber-faced types. Rubber-faced
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pulley 15 can be utilized to increase the friction coefficient between the driving pulley
and the belt, as well as to reduce the wear of the pulley. When the pulley is small, the
environment humidity is low, a glossy-faced pulley can be chosen. A rubber-faced
pulley can be used when the environment humidity is high, power is big, and slip is
easy.
Choosing a right pulley is important. When the belt of a fabric belt core is used, the
pulley is chosen on the basis of the belt’s thickness. The conveyor belt needs to move
around the pulley repeatedly during the working process, and bending occurs. When
the belt is bent, the external surface is stretched and while the internal surface is
compressed, the stress and strain of each layer vary. The rubber layers have
mechanical fatigue and are damaged due to the scaling when the repetitive bending
reaches a certain level. The smaller diameter of pulley, the bigger the deflection of
conveyor belt and the faster the scaling occurs.
Therefore, the diameter D of a driving pulley is decided by the allowable crook
degree of the belt, and D can be fixed by the following formula:
Vulcanized joint: Dı125Z;
Mechanical joint: Dı 100Z;
Mobile conveyor: Dı80Z.
Z- The layers of coated canvas of the belt.
4. RETURN PULLEY
A return pulley has three categories: 180o
, 90o
and 45o
. The return pulley’s diameter is
related to driving pulley’s diameter and the wrap angle that the belt has on the return
pulley.
Return pulley is a welded-steel plate construction with an antifriction bearing.
5. IDLER
Idler is the supporting device for belt and cargo of a belt conveyor. Idlers move as the
belt moves so as to reduce the running resistance of the conveyor. Idlers’ qualities
depend on the usage of the belt conveyor, particularly the life span of the belt.
However, the maintenance costs of idlers have become the major part of the
conveyor’s operating 17 costs. Hence, idlers need to have reasonable structure,
durability in use, small ratio of steering resistance, reliability, and dust or coal dust
cannot get in bearing, due to which the conveyor has a small running resistance, saves
energy and prolongs the service life.
The idler has steel idler and plastic idler types. The steel idler is manufactured of
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seamless steel tube. The diameter of the idler roller has something to do with the
belt’s width. In the design process of the belt conveyor, when the width B is equal to
or less than 800mm, the idler diameter should be ø89mm. When the width is 1000-
1400mm, then the roller diameter should be ø108mm.
In order to enhance productivity, trough idlers are usually used as upper idlers
to support the conveyor belt to transport bulk material. When the conveying
material is end product, a flat idler is used. In addition, in coal preparation
plants, flat idlers are chosen for both belts’ upper and below idlers.
In a trough idler, the angle between the inclined idler and the horizontal idler is called
a groove angle. Groove angle is a significant parameter related to the conveying
material. In the past time in China, the groove angle of the belt conveyor was 20o
. In
the designing of the belt conveyor, the groove angle is 30o
, 35o
, and 45o
. In the
condition of the same belt’s width, when the groove angle is increased from 20o
to
30o
, the section area of belt conveying bulk material could increase by 20%, the
conveying capacity can boost by 13%, and material spatter can be reduced.
6. FRAMEWORK
The framework of a fixed belt conveyor is a structure welded of angle iron and trough
iron. The framework can be grouped as drive frame, end frame, middle frame and
driving device frame.
Drive frame is used to install driving pulley and return pulley (Figure 12a), its side is
installed together with a driving frame. A tail drum is set up on the end frame (Figure
12b); the structure of end frame has something to do with the adopted tension device,
so the end frame should be chosen by the tension device. Middle frame is for the
installing of upper and down idlers; it is assembled by pieces of frame (Figure 12c).
Two ends of the middle frame are connected with a drive frame and end frame
respectively. The width of the middle frame is 300-500mm bigger than that of the
belt, and the height of the middle frame is approximately 550-650mm.
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7. TENSION DEVICE
The effect of belt conveyor’s tension device is as follows:
(1) To make the belt have enough initial tension, to ensure the friction between the belt and
the driving pulley and to have a certain friction reserved.
(2) To compensate the extension of traction members during the working process.
(3) To strict belt sagging between each supporting idlers so that the conveyor can run
regularly.
Tension device has three kinds of structure: a screw-type (Figure 13a), a car-like type (Figure
13b) and a vertical type (Figure 13c).
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PROJECT DESIGN SYSTEM SELECTION:
As we have to design conveyor for coal power plant, the lump size of coal matters. Also the
inclination angle is 150
, so we have selected trough conveyor for design of system. Above
figure shows this justification which is nothing but a guideline for selection of conveyor
according to lump size and inclination angle.
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PROJECT STATEMENT: Design of material handling system used for
conveying a coal in a thermal power station
DATA from system to be designed (Nashik Thermal Power Station):
1. Capacity of conveyor (c) = 300 mtph = 300*10^3 kg/hr
2. Density of coal = 800 kg/m^3
3. Belt speed (v) = 2.0 m/s …… (Assumed)
4. Material for belt = Polyamide …… (Selected from catalogue)
5. Surcharge factor for polyamide belt (C) = 0.0725
6. Number of plies for polyamide belt (Zp) = 3
7. Material factor for plies (K1) = 2.0
8. Belt tension and arc of contact factor for belt (K2) = 80
CALCULATIONS:
1. BELT WIDTH (B):
M=300*10^3kg/hr
Density=800kg/m^3
v=2m/s
C=0.0725
M = Density*Q
M=Density*C*(0.9B-.056)^2*v*3600,kg/hr
300*10^3=800*0.0725*(09*B-0.05)^2*2*3600
(0.9B-0.05)^2 = 0.7184
(0.9B-0.05)=0.84758
B=09973 m
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B=997.3 mm
Hence, standard belt width selected is,
B=1000 mm
2. DIAMETER OF DRIVE PULLEY:
Zp=3
K1=2.0
K2=80
The diameter of drive pulley is,
D=K1*K2*Zp
=2.0*80*3
D = 480 mm
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SIZING OF THE DRIVE PULLEY
The shaft of the drive pulley is subject to alternating flexing and torsion, causing fatigue
failure. To calculate correct shaft diameter it is necessary to determine the bending moment
Mf and the torsion moment Mt. The bending moment of the shaft is generated as a result of
the sum of the vector of tensions T1 and T2 and the weight of the pulley itself qT Fig.
Driving Pulley CATIA drawing
3. REDUCTION RATIO OF GEAR REDUCER (G)
n =1440 rpm
v = 2 m/s
v = (3.14*D*N)/60
N = 79.58 rpm
G = n/N
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= (1440)/(79.80)
G=18.096
4. Selection of gearbox: refer following tables
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Assumptions and Standards for design calculations:
1. Inclined belt conveyor at angle (α) =150
2. Length of load carrying run of belt (l3) = 200.5m
3. Mass of fabric ply belt per unit length (mb) = 12.5 kg/m
4. Centre dist. between two snub pulleys = 190.5 m
5. Horizontal distance between centre of tail pulley and centre of take up pulley = 15.25m
6. Diameter of snub pulley, bend pulleys and take up pulley = 250m
7. Mass of each carrying run idler (mci) = 30kg
8. Mass of each return run idler (mri) = 22kg
9. Pitch of carrying run idlers (tc) = 0.895 – 1.2 m
10. Pitch of return run idlers (tr) = 2.5m
11. Friction factor for idlers (fc) = 0.035
12. Snub factor for snub pulleys (ϵp1) = 0.02
13. Snub factor for bend pulley (ϵp2) = 0.04
14. Snub factor for driver pulley tail pulley and take up pulley (ϵp3) = 0.06
15. Material velocity component along belt length (Vi) = 0.75m/s
16. Frictional resistance due to belt cleaner near driver pulley = 100B
where, B = Belt width m
17. Angle of lap of drive pulley (ϴ) = 2000
18. Coefficient of friction between belt and drive pulley (µ) = 0.35
19. Driven efficiency (ɳ) = 0.91
20. Standard electric motor rating = 7.5, 10, 11, 12.5,
15,20,22,25,30,35,40,50,60,75,90,100,110,125.
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CALCULATION OF LENGTH:
1. dp2=0.25mm
2. dp3=0.25mm
3. dp4=0.25mm
4. dp3/2+dp4/2+l2+5=15.25
5. 0.25/2+0.25/2+l2+5=15.25
6. l2+5.25=15.25
7. l2=10m
Again,
1. l1+dp2/2+dp3+dp4/2+l2=190.5
2. l1+0.25/2+0.25+0.25/2+10=190.5
3. l1+10.5=190.5
4. l1=180m
No of carrying and return line idlers,
l1=180mm
l2=10m
l3=200.5m
tc=0.895m
tr=2.5m
No of return run idlers in length l1 (Zr1)
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tr=l1/(Zr1+1)
2.5=180/(Zr1+1)
Zr1+1=72
Zr1=71
No of returns run idlers in length l2 (Zr2)
Tr+l2/(Zr2+1)
2.5=10/(Zr2+1)
(Zr2+1)=4
Zr2=3
No of carrying run idlers (Zc)
Tc=l3/(Zc+1)
0.895=200.5/(Zc+1)
(Zc+1)=224.5
Zc=223.5
Zc =223
BELT TENSION ALONG CONVEYOR LENGTH:
1. At initial point (i): Fi=Fslack
2. At point 1:
Fc=100B
B=1000mm=1m
F1=Fi+Fc
=Fslack+100B
=Fslack+100*1
F1= Fslack+100
3. At point 2:
ϵp1=0.02
F2=F1+Fp1
=F1+ ϵp1*F1
=(1+ ϵp1)*F1
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=(1+0.02)(Fslack+100)
F2= [1.02 Fslack+102] N
4. At point 3:
Mb=12.5kg/m
Mri=22kg
Fc=0.035
Zr1=71
l1=180mm
F3=F2+Frr1
=F2+Fc(mb+Mr1*Zr1/l1)*g*l1
=(1.02*Fslack+102)+0.035*(12.5+22*71/180)*9.81*180
F3 = [1.02*Fslack+1410.85] N
5. At point 4:
ϵp2=0.04
F4=F3+Fp2
=F3+ ϵp2*F3
=(1+ ϵp2)*F3
=(1+0.04)*(1.02*Fslack+1410.85)
F4 = [1.0608*Fslack+1467.28] N
6. At point 5:
ϵp3=0.06
F5=F4+ ϵp3*F4
=(1+ ϵp3)*F4
=(1+0.06)(1.0608*Fslack+1467.28)
F5=1.1244Fslack+1555.31
7. At point 6:
ϵp4=0.04
F6=F5+ ϵp4*F5
=(1+ ϵp4)*F5
=(1+0.04)(101244*Fslack+1555.31)
F6=1.1694Fslack+1617.525
8. At point 7:
mb=12.5kg/m
mri=22kg
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Fc=0.035
Zr2=3
l2=10m
F7=F6+Frr2
=F6+Fc(mb+mri*Zr2/l2)*g*l2
=1.1694*Fslack+1617.52+0.035*(12.5+22*3/10)*9.81*10
F7 = [1.1694*Fslack+168309] N
9. At point 8:
ϵp5=0.02
F8=F7+Fp5
=F7+ ϵp5*F7
=(1+ ϵp5)*F7
=(1+0.02)(1.1694*Fslack+1683.09)
F8 = [1.1928*Fslack+1716.76] N
10. At point 9:
ϵp6=0.06
F9=F8+Fp6
=F8+ϵp6*F8
= (1+ϵp6)F8
= (1+0.06)(1.1928Fslack+1716.76)
F9 = 1.2642Fslack+1819.76 N
11.At point 10:
Vi = 0.75 m/s
M = 300*10^3/3600 kg/s=833.33kg/s
F10 = F9 +Fl
= F9+ m*(v-vi)
=1.2642Fslack +1819.76+83.33(2-0.75)
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F10 = 1.2642Fslack+1923.92N
12. At point 11:
Mm=m/v= 83..33/2=41.665kg/m
Mb=12.5kg/s
Mci=30kg
Zc=223
l3=200.5m
Fc=0.035
h=81.894m
Height through which material is raised (h)=150
α =15
l3=200.5
sin15=h/l3
sin 15 = h/200.5
h=51.894m
F11=F10+fcr+Fm
=F10+Fc(Mm+Mb+(Mci*Zc)/l3)*9*l3+Mmgh
=(1.2642Fslack+1923.92)0.035*(41.665+12.5+30*223/200.5)*9.81*200.5+41.665*9.81*51.89
4
F11 = (1.2642Fslack+29160.56)N
13. At final point F:
ϵp7=0.06
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Ptight =F11+Fp7
=F11+ϵp7*F11= (1+ϵp7)F11
=(1+0.06)*(1.2642Fslack+29160.56)
Ftight = 1.34F slack +30910.19N
14. Ratio of effective belt tensions on drive pulley:
u=0.35, ϴ=200*
Ftight /Fslack = e^µϴ
Ftight/Fslack=3.393
Ftight = 3.393Fslack
15. Effective belt tension on drive pulley:
3.393Fslack =1.34Fslack +30910.19
2.052Fslack =15063.44N
Ftight = 51110.27N
16. Power required on drive pulley (Po):
Po= (Ftight- Fslack)*V/1000 , KW
=( 51110.27-15063.44)*2/1000
Po= 72.09 KW
17.Input power to belt conveyor (Pi):
ƞ=0.91
Pi= Po/ƞ =72.09/0.91
Pi=79.22KW
Power rating of standard electric motor selection = 90 KW
Refer the table for specifications of motor.
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Here we have considered 3 phase AC induction motors of Kirloskar Brothers Limited, India.
Motor selected is KL280M sqireel cage induction 4 pole with 1500rpm synchronous speed.
This is selected as per our power and speed requirement.
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Driving motor CATIA Drawing
18.Counter weight for take up:
W= F4+F5
=(1.0608Fslack+1467.28)+1.1244Fslack +1555.31)
=2.1852Fslack+3022.59
W=35939.21N
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19. Idler Spacing or Troughing set pitch:
Here, we use above formula to find idler spacing.
Where,
Mi mass of belt and live load kilograms per metre
T tension at the point investigated KN
sag a percentage of a idler spacing expressed as decimal and usaully 0.02 (2%)
Live Load C/3.6S Kg/m
S Belt Speed m/s
C Capacity t/h
So idler spacing comes to be 1.15147042 m. here, we have considered 439.6616 Kg/m of
mass of belt and live load as per our design requirement.
The trough set pitch ao most commonly used for the upper strand of a belt conveyor is 1
metre, whilst for the return strand the sets are pitched normally at 3 metres (au). The
deflection of the belt between 2 consecutive carrying troughing sets should not be more than
28. DOMS- Material Handling System
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2 % of the pitch itself. A greater deflection causes the discharge of the material during the
loading and promotes excessive frictional forces during the belt movement due to the
manipulation of the material being conveyed. This not only the increases the horse power and
work, but also increases forces on the rollers, and overall a premature belt surface wear
occurs. Refer table 6.
So our both values from calculation and standard matches. So we have taken spacing as 1.2 m
i.e. 1200 mm.
FINDING AVAILABLE FACTOR OF SAFETY
Here, it is important to find factor of safety for conveyor system.
Here, maximum tension in the conveyor belt is given by,
Ftmax= Ftight + Fc
So, Ftmax= Ftight + mbv^2
Where, Fc= centrifugal tension in the belt, N
Mb=mass of belt per meter length, Kg/m
Required breaking strength of conveyor belt is given by,
Fbs= Nf x Ftmax
And, Fbs= Sut x B x Zp
So,
Ftmax= 51110.27 + 15.5 x 2^2
= 51172.27 N
Now,
Fbs for polymide belt is taken from standard value as 300N/mm
So,
Fbs= 300 x 1000 x 3
= 900000 N
Now,
Available factor of safety is,
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FOS x 511172.27= 900000
So,
Factor of safety is 17.58
So we can say that the overall factor of safety is within permissible range.
DRIVING PULLEY SELECTION:
According to the position that they occupy in a belt conveyor, the pulleys must withstand the
forces imposed by both belt tension and conveyed load. To be as efficient as possible both for
replacement and for new installation, proper selection of pulleys requires the following data
that allows the determination of the construction characteristics and dimensions.
The principal data necessary to design a pulley comprises the following:
1. Belt width
2. Diameter of drum in relation to the belt
3. Type and characteristics of locking arrangement of the shaft to the pulley (locking
ring, key, welding)
4. Position of pulley (drive, return, snub etc...)
5. Wrap angle of belt on pulley "α";
6. Belt tensions t1, t2 or t3 ;
7. Distance between the supports and
8. Flange of the pulley "ag" ;
9. Type of lagging as required..
Shaft importance
Excessive deflection of the pulley shaft constitutes the major reason for failure of the drum
structure. The correct sizing of the shaft is therefore of the greatest importance and must take
into account an extra high safety factor.
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After having sized the diameter of the shaft for various pulleys, the next selection check is to
verify that the deflection of the shaft does not exceed allowable values. In particular the
deflection "ft" and the angle of inclination " αt " must respect the relationship:
Where:
ag = expressed in mm
E = modulus of elasticity of steel (MPa)
J = moment of inertia of shaft section (mm^4)
Cpr = load on shaft (N)
TROUGH DESIGN:
As per lump size and type, 3 troughed set is preferred. The trough is so selected of channel
section as given below. The same channel section is used for trough and base structure. The
rollers are decided as per weight and length. We also performed analysis of troughing set on
ANSYS Workbench 16.0. Following figures shows trough design. The stress and
deformation are 198 MPa and 3.18 mm respectively. These are within limits.
The load applied on the trough contains self-weight of assembly, belt load per unit length and
live load of coal to be handled. So each trough roller contains 2500N load. The bottom of the
assembly is fixed as fixed support.
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BEARING OF DRIVING PULLEY
Here as per standards and radial load, T4CB100 i.e. single row taper roller bearing is
selected. This would be for shaft diameter 100 mm and expected life of 80000 hours as per
SKF bearing catalogue.
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STRUCTURE DESIGN
SELECTION OF SECTION
Data:
Total Maximum Load on Section=W = 3.5 KN/m------total live load and dead load
Live load= weight of lumb belt per m
Dead load= idler and all its trough setting
Span of Beam=2m
Cross section Using Channel Section
E= 2*105
Calculations:
Maximum Bending Moment= M= (WL2
/8) = 1.75 KN-m
Cross-section:
Zp Required = (M*C/fy)
Where,
Zp = Shape Factor
C = Constant For Section (1.11 to 1.15 for Channel Section)
Fy = Yield Strength = 250
Now,
Zp required = (1.75*103
*22
/250) = 28 cm2
Select From Steel Table ISJC 125
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Above figure shows ISJC 125 channel section. This is referred by Indian Standard Junior
Channel (steel construction) on the basis of sectional area.
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ANALYTICAL SOLUTION FOR DEFLECTION IN BEAM
Data:
Type of Beam= simply supported Beam- Uniform distributed load
E = 2*105
N/mm2
Izz = 270 cm4
= 270*104
mm4
...... From Steel Table
W = 3.5 KN/m = 3.5 N/mm
Deflection at Any point x for simply supported uniformly loaded Beam is,
Deflection at x = δx = {[wx(2lx2
-x3
-l3
)]/24EI}
Now,
Δmax at x=l/2 = 5wl4
/384EI
Δmax at x=l/2 = (5*3.5*20004
)/(384*2*105
*270*104
)
Δmax at x=l/2 = 1.3503086mm
Δlimit = Span/360
Δlimit = 2000/360
Δlimit = 5.55556mm
As, Δmax < Δlimit
Hence Design is safe.
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ASSEMBLY DRAWING
DRIVING PULLEY
DRIVEN PULLEY
TENSION TAKE UP
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Assembly drawing of trough structure in CATIA
MACHINING OF THE SHAFT
The machining of the shaft can be done in four steps.
(1) Cutting of the shaft. If the length of the shaft is used as an axial criterion when assembling
an idler, then the length L is very important. If there is a big error, the bearing cannot be
located. The best machining method is to use a circular saw to cut, which can control cutting
length automatically.
(2) Milling grooves. This should be done on a special milling machine.
(3) Processing center hole. If the centre bore is as the concentricity criterion of assembling, it
should be machined on a good lathe, not just a common drilling machine. As for a short shaft,
a baby lathe can be the best choice, which has little equipment investment but high
efficiency.
(4) Machining retaining circlip slot and chamfering of shaft ends. Providing that the shaft has
accurate cutting length, the machine of retaining circlip slot which is based on the two ends
of the shaft could be easy, a long shaft can be processed on the lathe while a short one on the
baby lathe.
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MACHINING OF IDLER TUBE
The processing of idler tube has cutting, boring holes on the two ends and chamfering both
inside and outside working steps. Currently, the cutting has three methods:
(1) Hobbing
Advantages: high efficiency, accurate linear dimension.
Disadvantage: big cutting deformation.
(2) Saw cutting.
A saw machine can cut steel tube with dimensional accuracy after being transformed
by electronic control and measure, but has low efficiency compared with hobbing.
(3) Cutting on lathe.
It is an easy manufacturing method without special purpose machines. Low
efficiency, rotating speed should be controlled while cutting to avoid bending
deflection in lengthwise for long steel tube in the machining process.
MANUFACTURING IDLERS IN LARGE SCALE
Idler is the main part of a belt conveyor and it’s easily broken, the market demand is very
great. At present, there are nearly a thousand roller manufacturers in China. The quality of
technical equipments and products vary, only twenty or thirty companies can have quality
and scale advantages. According to the data, high-quality and service life idlers account for
less than 20% in market share, which means that as an important link of conveyor chain it has
a huge development space.
The line should include bearing punch line, bearing seat automatic processing machines, axis
machining center, pipe cutting line, assembly and test production line, spray drying
production line. The idler production process is shown in Figure 18.
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1. Bearing seat punching line
The production line is mainly composed of uncoiler, straightener/feeder, manipulator, punch
and unloader and so on. Cold-strip steel passes uncoiler, straightener to uncoil and feed
automatically followed by the punching process in six steps in turn to finish stamping of
bearing seat. The change of tooling die can be achieved through mold changing systems,
which is convenient and reliable. In control, gang control is carried out in punching
equipment and manipulator, with the function of setting parameters, optimizing and editing,
saving, fault diagnosing and alarming.
2. Automatic bearing seat processing machines (including press bearing)
Stamped bearing seat on the spinning staging is transferred to special lathe by a manipulator,
and the lathe machining bearing seat’s ex-circle and chamfer automatically, the bearing seat
is transferred to bearing press by the conveyor to press bearing automatically, and finally sent
to unloading platform.
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3. Axis machining center
Multi-station CNC machining center can be divided into four parts in accordance with the
machining process:
(1) The length of about 6m, diameters of ø20, ø25, ø30, ø35,ø40mm of cold drawn round
steel can be by blanked by dimensions , cutting length of 330 ~ 2548mm, length error in
0.2mm.
(2) The work pieces which are used to chamfer shaft and drill the center hole are fed into the
lathe automatically by a manipulator, to complete the processing of chamfer at both ends of
the shaft and drill the center hole after being located and clamped.
(3) Processing two circlip grooves in the shaft at both ends.
(4) Through slot (or solid slot) are milled at both ends of the shaft at the same time, slot error
should be controlled to 0.1mm or less. The processing center can achieve automatic feeding
and discharging, scaling-off, debugging, easy to change clamp, equipment has reliable
operation, as well as with the function of setting parameters, optimizing, modifying, saving,
fault diagnosing, alarming, etc.
4. Pipe cutting lines
Roller tubes with the diameters of ø89, ø1o8, ø133, ø159, ø194mm and with a wall thickness
of 3.2 ~ 5.0mm can be achieved to complete automatic feeding, cutting off, automatic
processing of both ends of the surface and the internal hole.
5. Assembling and inspecting line
This production line consists of 5 parts:
(1) Cleaning device on the pipe tube surface which is mainly used for removing rust of the
tube surface.
(2) Pipe receiving platform is used for receiving, storaging the pipes transferred from the
pipe machining lathe, and transporting to a welding device. In the process of conveying
pipes, compressed air is used to purge the inside of the pipes.
(3) The welding device includes shaft inserting, bearing seat pressing and fitting, and bearing
seat welding.
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40
(4) Storage platform for cooling the idlers being welded and conveying idlers to the
assembly and inspecting lines.
(5)The roller assembly and inspecting includes grease injection, pressuring seals,installing
circlip, and inspecting circular run-out. Lithium lubricating grease is used as a lubricant,
which is suitable in the environment of high temperature. (More than 170oC)
The process of pipes accepting, welding and assembling and inspecting, etc a series of
procedures rely on robots, manipulators to be completed. Special injection equipment is used
to grease seal; the qualified pieces are distinguished from the failed ones when circular run-
out is tested.
6. Spraying and drying production line
Idlers are transferred to the drying room by a chain drive after electrostatic spraying in the
spraying room. Idlers are dried because of the circulating air in the drying room. The output
of the finished products is achieved in the final stage.
BELT CLEANER:
The problem of conveyed material adhering to the conveyor belt, occurs frequently with wet
or sticky material, resulting in frequent downtime for maintenance, and clean up, with
consequent loss of production. The problems of belt cleaning have increased in parallel with
the development of conveyors of ever increasing lengths, speed and belts widths, necessary to
satisfy the need to maximise load capacities.
Therefore, the use of cleaning equipment has become an indispensable requirement to assure
general plant efficiency and to reduce the periods of service needed for maintenance. There
has been a notable development of this equipment in recent time for differing reasons :
prolonging the life of the conveyor; limiting the deterioration of the belt, improving the
energy efficiency of the installation, reducing loss of material thereby increasing the load
capacity, eliminating a major cause of wear on the return rollers.
Selection criteria
The choice of a belt cleaner depends on the efficiency that is desired to obtain from the
conveyor; the material itself; and the environmental conditions prevailing. However the
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adoption of a cleaning system should be considered early in the conveyor project design
phase. It may prove to be very difficult to achieve an average degree of efficiency by
retrofitting cleaning system into an existing plant; moreover, this operation may necessitate
expensive modification to the plant structure. Where high standard of cleaning is requested,
and for particularly difficult applications, it is advisable to employ more than one cleaning
system combining them in a way that increases the overall system efficiency. It is however
good practice that the user scrupulously observes the function and maintenance of the
cleaners in use, to assure their maximum and continuous efficiency
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FINAL BILL OF MATERIAL OF COMPONENTS
SR.NO COMPONENT NAME QUANTITY
COST PER
PART
TOTAL
COST
1 Motor 1 60000 60000
2
Worm and Worm wheel
Gearbox 1 25000 25000
3 Troughed Idler 210 X 3 =630 500 315000
4 Troughed Idler frame 210 1500 315000
5
Straight Return Run
Idler 100 1760 176000
6 Brush type of cleaner 1 5000 5000
7 Hooper 1 2500 2500
8 Drive Pulley 1 12000 12000
9 Tail pulley 1 10000 10000
10 Snub Pulley 5 5000 25000
11 Take up device 1 15000 15000
12
Structural Steel
CHANNEL 800 METER 380000 380000
13 Conveyor belt 250METER
1500 PER
METER 375000
TOTAL APPROX. COSTING 1715500
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CONCLUSION
From this project of material handling system design of belt conveyor, we learned many
things. Starting from material selection and selection of trough set to the finding factor of
safety, whole process is well understood and learned.
Selection of standard components, base structure design and making of manual for use
purposes gave us an insight of designing of system for actual industrial world.
This project helped us for gaining through knowledge of conveyor belt selection and
construction of system for transporting of coal in coal handling plant in thermal power plant.
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REFERENCES
1. RULLI RULMECA S.p.A. Company’s manual for Rollers and components for bulk
handling
2. Design of Mechanical System by R.B. Patil, Techmax Publication
3. Indian Standard Selection And Design of Belt Conveyors — Code of Practice, IS
11592 : 2000 (Reaffirmed 2010)
4. Indian Standard Structural beam selection IS 800:2007, ICS 77.140.01