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23/09/2014
Jenike & Johanson Pty Ltd 1
Transfer Chute Design for Increased Throughput – Practical Examples
Conveyors Conference Brisbane – 2014
Carrie Hartford Senior Engineer
Perth Western Australia chartford@Jenike.com
1 SCIENCE ⏐ENGINEERING ⏐DESIGN
WE ARE: A specialised engineering firm focusing on
providing clients solutions to material handling applications
2
SCIENCE ⏐ENGINEERING ⏐DESIGN
COMPANY PROFILE
� Incorporated in 1966 by Dr. Andrew Jenike � World’s largest firm specializing in materials flow � About 80 personnel world-wide � Offices in Australia, Brazil, Canada, Chile, USA � 7,500+ projects world-wide � Over 11,000 bulk materials tested � 650+ man-years experience
3 SCIENCE ⏐ENGINEERING ⏐DESIGN
OUR APPROACH
We use a scientific approach, based on the characteristics of the materials handled and
process requirements.
It is not a trial & error approach!
4
SCIENCE ⏐ENGINEERING ⏐DESIGN
OUTLINE
� Review common transfer chute designs � Discuss typical transfer chute problems � Evaluate how to predict wear in transfer chutes � Discuss wear liners � Evaluate increasing throughput with existing
infrastructure � What about different material handled through an
existing system?
5 SCIENCE ⏐ENGINEERING ⏐DESIGN
VARIOUS CHUTE DESIGNS
For free-flowing rocky material: � Rock box � Micro ledges
Minimise wear.
For fine, sticky material: � Hood and spoon � No ledges
Prevent plugging and minimise buildup.
What if the material is rocky and fine and sticky? � Prevent plugging and minimise wear
6
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SCIENCE ⏐ENGINEERING ⏐DESIGN
ROCK BOX CONFIGURATIONS
Use rock boxes only if material is free-flowing
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Hematite Iron Ore
SCIENCE ⏐ENGINEERING ⏐DESIGN
ROCK BOX CONFIGURATIONS
Rock box with sticky bauxite leads to frequent head box plugging
Heavy residual left in head box
8
SCIENCE ⏐ENGINEERING ⏐DESIGN
HOOD AND SPOON DESIGN
� Developed in early 1980’s by Jenike & Johanson (US Patent 4,646,910 - August 1985)
� Design reflects novel approach to controlling the material
� Minimises dust generation, centers the load on the receiving belt
� Minimises wear of the receiving belt by giving the load a velocity in the direction of the receiving belt
9 SCIENCE ⏐ENGINEERING ⏐DESIGN
HOOD AND SPOON DESIGN
Sticky fines on impact plate leading to frequent plugging
Proper stream capture with hood (low impact angle)
Proper stream control with spoon
US Patent 4,646,910
Rhino horn
10
SCIENCE ⏐ENGINEERING ⏐DESIGN
COMMON CHUTE FLOW PROBLEMS
� Plugging � Wear of chute surface � Spillage � Buildup � Dust generation � Excessive belt wear
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Plugging
SCIENCE ⏐ENGINEERING ⏐DESIGN
EXAMPLE CHUTE FLOW PROBLEMS
Wear of chute surface
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Jenike & Johanson Pty Ltd 3
SCIENCE ⏐ENGINEERING ⏐DESIGN
EXAMPLE CHUTE FLOW PROBLEMS
Spillage
Buildup 13 SCIENCE ⏐ENGINEERING ⏐DESIGN
IMPACT ANGLE & SLIDING FRICTION
V2 = Velocity along chute after impact
V1 = Impact velocity θ = Impact angle φ’ = Wall friction angle
θ
V1
V2
V2V1= cosθ − sinθ tan "φ
Impact angle and sliding friction is critical in chute design: If θ + φ’= 90°, no resultant velocity
14
SCIENCE ⏐ENGINEERING ⏐DESIGN
QUESTIONS ASKED TO MAXIMISE USAGE OF EXISTING PORT INFRASTRUCTURE
� Can we increase the throughput of the same material through the existing design? Consider: � Belt sizing and speed
� Loads on the belt � Support structure
� Material flow through the chutes
� Can we put a different material through the existing transfer chutes? � Example: handling magnetite concentrate in iron ore transfer chutes
� What are the implications? � Will material flow through the chutes?
15 SCIENCE ⏐ENGINEERING ⏐DESIGN
CASE STUDY
� Iron ore export terminal in South Africa � Belt width: 1650 mm wide � Belt speed: 5.5 m/s � Flow rate: 10,000 tph � Right angle transfer chute
� Rock box used to minimise wear
� Client needed to increase throughput.
16
SCIENCE ⏐ENGINEERING ⏐DESIGN
Increase in fines, mc, & flow rate
Buildup in the chute (eventual plugging)
Changed the flow
path through the
chute
Changed the way material
exited the chute
Spillage, dusting, & premature belt wear
PROGRESSION OF PROBLEMS
Iron Ore
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TO ANALYSE AND DESIGN CHUTES
• Bulk density • Coefficient of sliding friction • Particle size • Particle density • Chute tests
• Angle of repose • Drawdown angle • Wear tests • Angle of internal friction • Belt surcharge angle
Flow properties tests needed:
Angle of repose Drawdown angle
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SCIENCE ⏐ENGINEERING ⏐DESIGN
FLOWABILITY COMPARISON
Test results are for example only
SCIENCE ⏐ENGINEERING ⏐DESIGN
BELT SURCHARGE ANGLE TEST
Before test After test
SCIENCE ⏐ENGINEERING ⏐DESIGN
Wear results vary and are dependent on material characteristics such as particle size, shape, and abrasiveness of particles
WEAR TESTS
AR 500
Test results are for example only
Alumina Ceramic
Arcoplate
Wear ratio (wear/
distance moved)
Pressure
Adjustable force
Bulk material In hopper
Collecting Drum
Screw Feeder
Wear coupon mounted in rotating head
Proprietary J&J wear testing apparatus
21 SCIENCE ⏐ENGINEERING ⏐DESIGN
WEAR LINERS
22
Arcoplate Hand Polish
Alloy Steel
Arcoplate Machined Polish
Alloy Steel
Bisplate 360/400 Di Candilo Steel
Compacted Bed
Duaplate (under flux)
Machined Ground Bradken
Duaplate Flapper Wheel
Polish Bradken
Hardox 450
SSAB
NiHard Bradken
P90 Ceramic
Imatech
Silicon Carbide Ceramic
Concord Engineering
Sure Alloy SA 1750
Standard SAS Global
Tivar 88-2 UHMWPE
Eplas Perth
Surface finish does matter! Installation direction does matter!
SCIENCE ⏐ENGINEERING ⏐DESIGN
WEAR PREDICTION
THROUGH DEM
23
Corrugated wear pattern predicted with DEM matched field experience
SCIENCE ⏐ENGINEERING ⏐DESIGN 24
DEM ANALYSIS OF STICKY IRON ORE
Estimated wear
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SCIENCE ⏐ENGINEERING ⏐DESIGN 25
DEM ANALYSIS OF STICKY IRON ORE Estimated wear
SCIENCE ⏐ENGINEERING ⏐DESIGN
HOOD AND SPOON DESIGN
Proper belt loading with spoon
Proper stream capture with hood
26
SCIENCE ⏐ENGINEERING ⏐DESIGN
HOOD AND SPOON DESIGN
Other benefits: � Minimal downtown – chute went 2.5
years before changing out the head chute, still not much wear in the spoon.
� Eliminated belt tracking problems � No spillage � Reduced dusting significantly � Obtained desired throughput
27 SCIENCE ⏐ENGINEERING ⏐DESIGN
OTHER ISSUES FROM INCREASED FLOWRATE
� Example: Material flies over the head chute
28
Head chute height was set based on cross sectional area of material on
belt and material
trajectory.
Belt speed and cross-sectional area of material
on the belt increased to
increase throughput.
Caused some material to fly over the head chute. Chute was also fuller than designed
for.
Resulted in increased
spillage and higher plugging
potential.
SCIENCE ⏐ENGINEERING ⏐DESIGN
CHANGING MATERIAL � Example: Using magnetite in hematite handling
systems with rock boxes � Cycle times of fine, sticky material versus lump
ore needs to be evaluated
29 SCIENCE ⏐ENGINEERING ⏐DESIGN
CONCLUSION
� Increasing throughput and/or handling different material through existing infrastructure can have significant financial benefits.
� Material testing and DEM are good predictive tools to analyse the feasibility of a usage change.
� DEM can also be used to predict high wear areas of the transfer chute.
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QUESTIONS?
31
Carrie Hartford Senior Engineer
Perth Western Australia chartford@Jenike.com
www.jenike.com
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