Optimize Fine Cone Crushing
Circuits Using Automation
2013 Management Workshop
Georgia Crushed Stone Association
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Presentation Summary
In today’s market the demand for fine aggregates has
risen. Many crushing plants have added or modified
crushing circuits to increase the production of minus
3/8” rock typically used in asphalt. Automation
packages ensure you maximize cone productivity
while protecting the machine from overload.
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The Challenge
• Receive a fine feed gradation
– Minus 1-1/2” or 2”
– Allow for varied feed gradations depending
on inventory balance
• Produce fine products
– ½” minus, 3/8” minus, MFG sand
• Maximize production while protecting
the crusher
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Cone Feed Video
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Cone Discharge Video
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Things We Need to Understand
• What happens in the crushing chamber
• Mechanical limits of fine crushing
• What data can be collected from
crusher systems
• What a good cone applications is
• How does fine crushing affect
performance
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Ideal - Evenly Graded Feed
Best Performance – reduction & TPH
– 90 to 100 percent passing the closed side feed opening.
– 40 to 60 percent passing the mid point of the crushing
chamber.
– 0 to 10 percent passing the crusher setting.
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Benefit of a well
graded feed.
Allows for effective
Inter-Particle Crushing
Need room for expansion
(voids)
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What We Have in Fine Crushing
Fine material fills the
voids between the coarser
stone.
The crushing stroke
compresses the material,
eliminating any voids and
packing material into a
solid mass.
(most sensitive at smaller settings)
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Crusher Overload in Fine Crushing
“Packing / Float”
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Liners
• Typically a “fine” chamber is used
• Temporary situation
– Make due with what’s in the crusher
– Live with issues
• CSS
• Short liner life
• Output gradation
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Match Profile to Feed
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Two Areas for Automation
• Cone Automation
– Collect sensor information
– Make decision to protect the machine and
continue operation
– Assume some human decisions
• Plant Automation
– Integrate multiple pieces of equipment to act in
unison and optimize production
– Reduce need for human interaction in the plant
operation
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Benefits of Cone Crusher Automation
Change crusher setting remotely
Automatic liner calibration
Protects from overload conditions
Tracks liner wear
Logs and trends data
Versatile
Minimizes installation costs
Highly effective troubleshooting tool
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Typical Components
Operator Interface Terminal (OIT)
The control panel enclosure is located
inside the operator control room.
ALL trending data is stored
on Compact Flash memory card
Optional USB Mouse
Optional USB Printer
Select list of printers
Ethernet Network
Crusher Panel
Ethernet Communication Hub
is located inside PLC enclosure.
Optional Modem
PLC (Programmable Logic Controller)
This is where the base program
resides and all the calculations
and decision are made.
Hardware connections are made to
motor starters that supply or receive
instructions from the PLC
PLC Panel
The PLC and the communication devices are
supplied in an enclosure for mounting
inside the Motor Control Room.
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DeviceNet Network
Located at the crusher lube tank, this unit centralizes
the communication from the many crusher sensors
and routes them to/from the PLC which is
located in the motor control room.
Crusher Protection
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Oil temp & flow
Hydraulic temp & pressure
Alarms and interlocks
Auto protect (open setting)
– Amp draw
– Bowl float
• Maintenance
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Troubleshooting
• Alarm history
• Trending reports
• Communicate with factory
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Liner Life & Calibration
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Trending
TRAC10
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Alarm History
TRAC10
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Today’s Cones in Fine Crushing
Video
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Today’s Cones - Settings
• Variables that affect settings
– Feed gradation
– Moisture in feed
– Screening efficiency
– Specification requirements of finished
product
– Depth of choke feed above head
• Goal is to utilize horsepower to the
fullest extent while protecting the
crusher
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Cone Automation = Optimum setting &
Optimum Production
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What is the “Optimum” CSS Worth?
• NO automation
– Run cone at .70” CSS
– This is “Safe” setting
– Never an issue
– Don’t need to watch too close
– Makes 155 TPH 3/8” x 0
• Automated cone
– Runs 90% of the time at .60” CSS (10% at .70”)
– This is “Optimum” setting
– Makes 165 TPH 3/8 x 0 when at .60” CSS
– 18,000 extra tons per year ($$$,$$$)
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CSS Optimization
• Manual set back
– Indicator notice or light
• Auto return on timer
– Periodic return to set point
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Try Different Levels in Cone
• What gives you the best output
gradation
– Lower depth of material & tighter setting
– More depth and larger setting
• Feed gradation changes
– As gradation changes voids in chamber
change
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Vary the Feed Gradation
• Coarser Feed
– More voids
– Tighter CSS
– Lower AMP draw
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• Finer Feed
– Less room for
expansion = packing
– Higher AMP draw
– May generate more
sand
Plant Automation
• Level sensor in cone
• Level sensor in bin
• Communicates with surge
feeders
•Cone overflow chutes with
presence detector
•Belt scales
•Zero speed switches
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Plant Automation – PID Controllers
• Proportional-integral-derivative Controllers
– PID controller calculates an "error" value as the difference
between a measured process variable and a desired set
point.
– The controller attempts to minimize the error by adjusting the
process control inputs.
– PID controller can be used to control any process which has
• a measurable output,
• a known ideal value for that output and
• an input to the process that will affect the relevant
measureable output
– Thinks for us so we don’t have to stare at cameras and spin
dials all day
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Plant Automation – PID Controllers
• Controllers communicate with
– Feeder VFD’s
– Level sensors
– Belt scales
– Crusher AMP outputs
• Logic is developed specific to your
crushing circuit
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Plant Automation
Sensing & Feedback Devices
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•
•
•
•
•
Laser
Radar
Ultrasonic
Tilt Switches
Presence detector
Zero speed switch
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Plant Automation
Sensing & Feedback Devices
• Variables that determine what level sensor is
used
–
–
–
–
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Distance from target
Range of measurement
Lump size of particles
Flow of material into bin or chamber
Dust
• Radar common in bins
• Laser common in crusher chamber
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Laser level sensor in cone
chamber
Track Plants
Laser
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Ultrasonic
Tilt Switch –
overflow protection
Radar Sensor
used for bin level.
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Don’t Forget Your Screening
• Account for heavier recirculation loads
– 35-40% vs 15-20%
– Consider one size larger than normal
– May use two decks to cut topsize
• Split loads, reduce bed depth
– Check speed & stroke on screen
• Weigh pros and cons of wet or dry
screening
• Specialty media
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Process Flow Software doesn’t Tell the
Whole Story
• Software takes the incoming TPH and
applies it to the manufacturers
published output gradation
• Using software you can feed sand to a
cone and make 89’s (may get a
warning)
• Experience is a big part of the equation
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Process Flow Software doesn’t Tell the
Whole Story in Fine Crushing
• The fine cone crusher:
– will find the setting it wants to run at not
the software
– setting will likely be greater than the
desired P-100 (100% passing)
– will likely reach the published TPH at the
operating CSS
– output gradation will not match the
published output gradation at the operating
CSS
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Estimating Net Finish Product
In a Fine Crush Application
• (A) Determine where crusher runs at based
on auto-protect control (consult manufacturer)
• (B) Determine average opening of screen
cloth determining top size of product
• Determine published capacity TPH midpoint
of crusher at the CSS
• Reduce published TPH midpoint 8% +/- per
1/16” differential between (A) & (B)
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Estimating Net Finish Product
Example
• (A) Crusher runs at .625” (per manufacturer)
• (B) Product is cut on .375” wire cloth
• Published midpoint capacity at 5/8” CSS is 257
TPH (225-290 range)
• Differential between A & B is
.250” or 4 / 16
• 4 x 8% = 32% is the differential between gross
and net finish product
• 257 TPH – 32% = 175 TPH net finished product
(3/8” x 0)
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Create & Understand Your Constant
• Benchmark existing equipment
– Individual machine performance
• Optimize existing circuit
– Change one thing at a time & re-measure
– Test circuit / test theory
• Study material specifications
– Talk to your customers
– Gradation specifications
– Cubicity requirements
• Automate the areas that require the highest
level of human process monitoring
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QUESTIONS?
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