Belt ConveyorsBelt Conveyors

Presentation by Group 1Presentation by Group 1

What is Belt Conveyor?What is Belt Conveyor?

Belt Conveyor is a Material Handling Belt Conveyor is a Material Handling Equipment.Equipment.

Belt Conveyor consist of a belt running Belt Conveyor consist of a belt running over drums or pulleys provided at the over drums or pulleys provided at the end and are supported at intervals by a end and are supported at intervals by a series of rollers known as Idlers.series of rollers known as Idlers.

Types of Belt Conveyors:Types of Belt Conveyors:

Flat Belt ConveyorsFlat Belt Conveyors

Troughed Belt ConveyorsTroughed Belt Conveyors

Portable Belt ConveyorsPortable Belt Conveyors

Belt Conveyor Components :Belt Conveyor Components :

Following are the main components of Following are the main components of a Belt Conveyor system :a Belt Conveyor system :

BeltBelt Pulleys and IdlersPulleys and Idlers DrivesDrives Motor and ControlsMotor and Controls Conveyor Belt Take-upsConveyor Belt Take-ups Hold BacksHold Backs FeedersFeeders

Belt :Belt :

Conveyor Belt consist of a carcass Conveyor Belt consist of a carcass embedded in rubber.embedded in rubber.

The carcass is made up of Plies or Layers of The carcass is made up of Plies or Layers of Fabric (Cotton or Synthetic ) bonded Fabric (Cotton or Synthetic ) bonded together carries tension and absorbs impact.together carries tension and absorbs impact.

The rubber compound may be natural, The rubber compound may be natural, synthetic or a blend. Steel-wire standard synthetic or a blend. Steel-wire standard cable may also be used in place of fabric.cable may also be used in place of fabric.

Belt (Continued) :Belt (Continued) :

Vulcanizing or Mechanical Vulcanizing or Mechanical Fasteners are used to make the Fasteners are used to make the Conveyor Belts endless at the job Conveyor Belts endless at the job site.site.

Pulleys and Idlers :Pulleys and Idlers :

Pulleys are generally located at the Pulleys are generally located at the terminals of a belt conveyors, where they terminals of a belt conveyors, where they support the belt and transmit driving support the belt and transmit driving power.power.

The Conveyor Belts are supported on idlers The Conveyor Belts are supported on idlers between the terminals.between the terminals.

The idlers are generally of three-roll type , The idlers are generally of three-roll type , with the central roll horizontal and two with the central roll horizontal and two side rolls inclined to form a trough.side rolls inclined to form a trough.

Pulleys and Idlers (Continued):Pulleys and Idlers (Continued):

This angle of inclination is generally This angle of inclination is generally kept at 20˚.kept at 20˚.

The idler rolls are made up of steel The idler rolls are made up of steel tubing , with welded end discs which tubing , with welded end discs which has antifriction bearings.has antifriction bearings.

The idler supporting the loaded strand The idler supporting the loaded strand of the belt is known as upper idler.of the belt is known as upper idler.

Pulleys and Idlers (Continued):Pulleys and Idlers (Continued):

The idler supporting the return The idler supporting the return belt is called as lower idler.belt is called as lower idler.

The upper idler may be 3-roller The upper idler may be 3-roller type or single-roller type.type or single-roller type.

But lower idler always have a But lower idler always have a single roller. single roller.

Drives :Drives :

Nearly all belt conveyors are driven Nearly all belt conveyors are driven by electric motors.by electric motors.

Speed reduction may be achieved by Speed reduction may be achieved by chain and sprockets, V-belt or chain and sprockets, V-belt or gearing.gearing.

The drives are located at the The drives are located at the discharge end of inclined conveyors. discharge end of inclined conveyors.

Motors and Controls :Motors and Controls :

Squirrel-cage and wound-rotor type Squirrel-cage and wound-rotor type motors are commonly used in motors are commonly used in conveyors.conveyors.

The motor for a conveyor belt drive The motor for a conveyor belt drive must have sufficient torque to must have sufficient torque to overcome the starting friction of the overcome the starting friction of the system.system.

Conveyor Belt Take-ups :Conveyor Belt Take-ups :

Take-ups are provided to adjust Take-ups are provided to adjust increase in length of the belt due to increase in length of the belt due to its elongation after it is put into its elongation after it is put into operation. Take-ups are of 2 types ,operation. Take-ups are of 2 types ,

1.1. Screw take-upsScrew take-ups

2.2. Counter weight take-upsCounter weight take-ups

1.1. Screw take-ups :Screw take-ups :

These are used to increase the These are used to increase the length of the conveyor by moving the length of the conveyor by moving the head or tail pulley.head or tail pulley.

This system is used for short belts.This system is used for short belts.

2. Weight take-ups :2. Weight take-ups :

In this system weighted pulleys are In this system weighted pulleys are provided to create uniform tension in provided to create uniform tension in the returning belt.the returning belt.

This system is used for long belts This system is used for long belts

Hold Backs :Hold Backs :

Hold backs are mechanical devices which Hold backs are mechanical devices which allow the driving pulley to rotate only in allow the driving pulley to rotate only in normal direction and prevent to rotate in normal direction and prevent to rotate in opposite directionopposite direction

Hold backs are provided on the driving Hold backs are provided on the driving pulley to prevent the load from causing pulley to prevent the load from causing the belt to run backward in the event of the belt to run backward in the event of power failure ,if the belt is operating on an power failure ,if the belt is operating on an incline.incline.

Feeders :Feeders :

These are used to deliver the These are used to deliver the material to a belt at a uniform rate.material to a belt at a uniform rate.

It may deliver the material on the It may deliver the material on the belt either directly or through a chute belt either directly or through a chute in order to reduce the impact of in order to reduce the impact of falling material.falling material.

Power Required to Drive a Belt Power Required to Drive a Belt Conveyor :Conveyor :

Belt Conveyor system requires external Belt Conveyor system requires external power for following purposes: power for following purposes:

To move the empty belt over the To move the empty belt over the idlersidlers

To move the load To move the load I.I. HorizontallyHorizontally II.II. VerticallyVertically To rotate all pulleysTo rotate all pulleys To compensate for friction and other To compensate for friction and other

losseslosses

Power Required to Drive a Belt Power Required to Drive a Belt Conveyor : (continued)Conveyor : (continued)

Power required to move the empty Power required to move the empty belt :belt :

Horse Power required to move an empty Horse Power required to move an empty belt is given by the equation :belt is given by the equation :

LSCWLSCW

PP = =

45004500

Power Required to Drive a Belt Power Required to Drive a Belt Conveyor : (continued)Conveyor : (continued)

Where ,Where ,

L = Length of conveyor , mL = Length of conveyor , m

S = Speed of the belt , m/minS = Speed of the belt , m/min

C = Idler-friction factorC = Idler-friction factor

W= Weight of the moving parts/m of W= Weight of the moving parts/m of conveyorconveyor

Power Required to Drive a Belt Power Required to Drive a Belt Conveyor : (continued)Conveyor : (continued)

Power required to move a load Power required to move a load horizontally :horizontally :

Horse power required to move a load Horse power required to move a load horizontally may be expressed by ,horizontally may be expressed by ,

LCTLCT P P ==

36003600

Power Required to Drive a Belt Power Required to Drive a Belt Conveyor : (continued)Conveyor : (continued)

Where ,Where ,

L = Length of conveyor , mL = Length of conveyor , m

C = Idler-friction factorC = Idler-friction factor

T = Tons material moved per hourT = Tons material moved per hour

Power Required to Drive a Belt Power Required to Drive a Belt Conveyor : (continued)Conveyor : (continued)

Power required to move a load up an Power required to move a load up an inclined :inclined :

Two components may be calculated from Two components may be calculated from following relationfollowing relation

i- To move the load horizontallyi- To move the load horizontally

LCTLCT P P ==

36003600

Power Required to Drive a Belt Power Required to Drive a Belt Conveyor : (continued)Conveyor : (continued)

ii- Lift the load through the net change in ii- Lift the load through the net change in elevationelevation

THTH P P ==

36003600Where , T = Material moved in tons/hrWhere , T = Material moved in tons/hr

H = Net change in elevation ,mH = Net change in elevation ,m

Belt Capacity :Belt Capacity :

Carrying capacity of a belt (tons/hr) =Carrying capacity of a belt (tons/hr) =

cross sectional area of material on cross sectional area of material on the belt (mthe belt (m22) ) x x Speed of the belt Speed of the belt (m/hr) (m/hr) x x Unit weight of the material Unit weight of the material (tons/m(tons/m33))

Selection and Design Selection and Design Criteria :Criteria :

A belt should have following qualities :A belt should have following qualities : WidthWidth StrengthStrength Thickness and GradeThickness and Grade Lateral FlexibilityLateral Flexibility Impact ResistanceImpact Resistance Lateral StiffnessLateral Stiffness Longitudinal FlexibilityLongitudinal Flexibility

Advantages of Belt Conveyor:Advantages of Belt Conveyor:

It is capable of handling light or heavy ,fine or It is capable of handling light or heavy ,fine or coarse ,wet or dry material.coarse ,wet or dry material.

It can handle ,thousands of tons of material per It can handle ,thousands of tons of material per hour for several kilometers.hour for several kilometers.

It can handle hot materials up to 160˚C or so.It can handle hot materials up to 160˚C or so. It is lighter in weight and consumes less power.It is lighter in weight and consumes less power. It operates without noise.It operates without noise. It gives a continuous discharge and quantity of It gives a continuous discharge and quantity of

which can be varied by varying the speed of belt.which can be varied by varying the speed of belt. It can carry material horizontally or in an inclinationIt can carry material horizontally or in an inclination