Conveyor Systems at the Conveyor Systems at the Appl t S f tAppl t S f tAppleton Sugar factoryAppleton Sugar factory

To be presented at theTo be presented at the6868thth annual conference of the Jamaica Association of Sugar Technologists,annual conference of the Jamaica Association of Sugar Technologists,

November 11, 2005 November 11, 2005 at at

The Sunset Jamaica Grande ResortThe Sunset Jamaica Grande ResortThe Sunset Jamaica Grande Resort,The Sunset Jamaica Grande Resort,Ocho RiosOcho Rios

bybyKeith Richards & Trevor CameronKeith Richards & Trevor Cameron

IntroductionIntroduction

Factories were small and operated in a batchFactories were small and operated in a batch like form

Very time consuming and costlyVery time consuming and costly.

Presently, raw sugar factories operation are ntincontinuous

This operation could only be achieved with the aid of Conveyors

The intention of this paper is to:

(a) Describe different types of bulk solid conveyors

(b) Share some of the factors that are usually ( ) yconsidered during bulk solid conveyors selection and the general type of conveyors g yp ythat best suit these factors

(c) Describe the conveyors used in the(c) Describe the conveyors used in the different sections at Appleton sugar factory.factory.

SOME TYPES OF BULK SOLID CONVEYORSCONVEYORS

A. Belt ConveyorA. Belt Conveyor

B Screw ConveyorsB. Screw Conveyors

B k ElC. Bucket Elevators

D. Flight Conveyors

E. Vibrating or Oscillating Conveyors

Belt Conveyor

Most commonly usedMost commonly used

Orientation - Horizontal or inclined d p d th l f p f th liddepends on the angle of repose of the solid.

Usually made ofF b iFabric

Reinforced rubber

Segmented metal (lath)Segmented metal (lath)

Plastic

Belt Conveyor

The benefits of belt conveyors for cane andThe benefits of belt conveyors for cane and bagasse conveyors are ;

Reduction in energy

ticonsumption

E e of oper tionEase of operation

Reduction in maintenanceReduction in maintenance

Screw Conveyors

Called worm conveyorCalled worm conveyor

One of the oldest and most versatile conveyorconveyor

Used for free flowing materials

Consists of a helical screw rotating in a U-shaped trough

Orientation - horizontal or inclined with some loss of capacity..p y

Screw Conveyors

• Compared to belt Conveyors;Compared to belt Conveyors;Less efficient

Cheaper p

Easier to maintain

• Usually used;Over short distances

Elevation is required greater than the solid angle of repose

To deliver a metered flow of solidsTo deliver a metered flow of solids

Bucket Elevators

The simplest and most dependable units forThe simplest and most dependable units for making vertical lifts

Consist of buckets fitted to an endless chain b lor belt

Can handle a wide range of solids

Bucket Elevators

Four main types of bucket elevators.Four main types of bucket elevators.

(a) Spaced Bucket Centrifugal – discharge elevators(a) Spaced Bucket Cent fugal d scha ge elevato s

(b) Spaced Bucket Positive – discharge elevators

(c) Continuous – basket elevators and

(d) Super Capacity – bucket elevators

Flight Conveyors

Also called drag slats conveyorsAlso called drag slats conveyors

C b d b h h i l d i li dCan be used both horizontal and inclined

Used to transport lumps and fibrous type material

Flight Conveyors

Consists of;

Chain - Endless with laths/slats

Lugs - Attached to the chains at equal intervals

Runners - Metal strips to support the chain

Laths - Pulled over metal sheeting called bedding to support the conveyed solidsolid

Flight Conveyors

Can be arranged in parallel and with oneCan be arranged in parallel and with one main drive

Can be used to handle large tonnages at once.

Vibrating or Oscillating Conveyors

These are directional throw unitsThese are directional throw units Consists of ;

1. A spring

2 Supported horizontal pan2. Supported horizontal pan

3. Eccentric arm

4. Rotating eccentric weights g g

5. An electromagnet or a pneumatic or hydraulic cylinder

Vibrating or Oscillating Conveyors

Main disadvantageMain disadvantage Vibration that is usually transmitted to their supporting structures

CONVEYOR SELECTION

Factors to consider ;The throughput

Length of travel

Change in elevation

Material Characteristics

Process requirementq

Life expectancy of usage

Comparative costp

APPLETON’S CONVEYOR SYSTEMSYSTEM

Cane Washing Plant

Used to receive the cane from the fields

Slat conveyor with a bed angled at 45 0

Comprises ten (10) sets of drag chain

Angled slat conveyor was used to enable

washing

le eling andleveling and

handling high bulk volume

Auxiliary Cane Carrier

Segmented metal belt type conveyorSegmented metal belt type conveyor

SpecificationsThree (3) sets of roller ChainThree (3) sets of roller Chain

Interconnected with 520 metal slats

Total width is 1524mm (60")

Selection Ensure that all the cane comes in contact with the knife and shredder bladesand shredder blades

Offers strength and stability in the heavy – duty cane preparation process.

Drag Conveyor

Flight conveyorFlight conveyor

Used to retrieve cane droppings from the washing plantwashing plant

Horizontal at its loading point but l i l l l f 500ultimately travels at an angle of 500

Specifications38 lathes measuring 34 “

pitch of 24 “

total chain length per side of 76 ‘total chain length per side of 76

Knifed cane belt conveyor

Rubber belt conveyorRubber belt conveyor

Inclined trough

S l i f hi b l i b d h f hSelection of this belt is based on the fact that the belt passes two tramp iron magnets

Specifications

1800mm in width

0 – 2.5 m/s (variable speed )

Shredded cane droppings conveyor

Transports droppings from the tail end ofTransports droppings from the tail end of the knifed cane belt conveyor

Comprises two (2) screw conveyors @ 900 toComprises two (2) screw conveyors @ 900 to each other.

S ifi iSpecifications

The first conveyor is 20 inches in diameter

Second - 12 inches

Combined length of 25 feetCombined length of 25 feet

Mill Inter-carriers

Slat conveyorsSlat conveyors

Feeds vertical Donnelly chutes located ten feet (10 ‘) above the next millfeet (10 ‘) above the next mill.

Specifications

Inclined at 600

22 l h22 lathes

30 inches pitch

Bagasse Elevator

The first bagasse carrier in closed loopThe first bagasse carrier in closed loop system

SpecificationsSpecificationsInclination - 300

Slats - 60

Width 41 “Width - 41

Pitch - 2 feet

Main Bagasse Conveyor

Flight carrierFlight carrier

Fitted with G tGates

Screens for sieving bagasse for use as bagacillo

The bagasse goes to storage THEN toThe bagasse goes to storage THEN to boilers

B f d b il l lBagasse feed to boilers completely independent of the milling operation

Main Bagasse ConveyorMain Bagasse Conveyor

SpecificationsSpecifications

O i i H i lOrientation - Horizontal

Length - 350’

Lathe - 120

Bagacillo screw conveyors

Directly below the Main bagasse carrierDirectly below the Main bagasse carrier

Transports bagacillo to the mud mixer

Two enclosed screw conveyors in series

Significantly reduces dust g y

Specifications

Length - 48 ‘

Screw diameter - 12”

#2 Conveyor

A rubber belt carrierA rubber belt carrier

C i h b di l b biCarries the bagasse directly to bagasse bin

Reclaimers

Carry out the task of both stacking andCarry out the task of both stacking and retrieving the bagasse for use at the boilers.

Bagasse is sent to a rubber belt during the i iretrieving process.

They are automated

#3 Conveyor

•Rubber belt conveyor

•Fed from bagasse bin

H i t l t it l di i t•Horizontal at its loading point

•Ultimately travels at an angle of 400

•Discharges at upper section ofDischarges at upper section of boiler

#4 Conveyor

AA slat conveyorA A slat conveyor

Selected becausefeeds bagasse to Boiler gates had to befeeds bagasse to Boiler - gates had to be

installed in conveyor bedding

Gates feed four twenty feet (20’) verticalGates feed four twenty feet (20 ) vertical chutes

# 5 Conveyor

•Rubber belt

•Returns excess bagasse from #4 conveyor to the main carrier

•Shortest carrier in the closed loop

Sugar ConveyorsSugar Conveyors

Pre-drying sugar screw conveyors

Three Screw conveyors in seriesThree Screw conveyors in series

T i h diTransports moist sugar to the cascading sugar dryer from centrifuges

Fully enclosed for hygienic purposes y yg p p

Cascading sugar dryer

Rotates about slightly inclined horizontal axis

Hot air moving counter –currently to sugar

S it i t ith f tSugar exits into either of two inclined screw conveyors

Sugar lumps to be re-melted g p

Export grade sugar sent to sugar belt.

Post drying sugar screw conveyors

2 off

Located 1800 to each other

Sugar Belt

Th fi l i hThe final conveyor in the sugar process Loading point is horizontal Changes to an angle of 700

Transport sugar to large 500 ton sugar bin

CONVEYOR CONTROL SYSTEMCONVEYOR CONTROL SYSTEM

Used to reduce the possibility of damage toUsed to reduce the possibility of damage to self and equipment

To manage the loading of materials

Common devices and methods used at Appleton are as follows

Load cellsControl Washing plant

Magnetic Pick Ups (MPU’s) All belt carriers

Electrical probes Control knifed cane belt speedControl knifed cane belt speed

InterlocksPrevent chokes

Visual monitoring stationsCameras for monitoring boiler conveyors

Conveyor start up sequence

CONCLUSION

The use of conveyors has contributed to k bl i i h fremarkable improvement in the factory

operations.

Continuous operations possible by using bulk solid conveyors

Control systems put in place to improve the safety of personnel and equipment y p q p

To optimize efficiency, conveyor selection is of utmost importance to any factoryof utmost importance to any factory

The EndThe End