DECANTER MACHINE, INC.

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DECANTER MACHINE, INC.
Screen bowl Operating and Maintenance Seminar
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Assembly Construction

• Manufactured from Carbon Steel
• Interior of Beach Bowl lined with ceramic tile
  for wear protection.
• Screen lined with Tungsten Carbide bars.
• Conveyor fitted with ceramic tile on the face
  ceramic compounds in high wear areas.
• All exposed steel is protected with coal tar
  epoxy.
• Centrifuge case protected in high wear areas with
  ceramic tile and coal tar epoxy.

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Assembly and Construction
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Installing Ceramic Tile in Bowl Section
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44 x 132 Screen lined with tungsten carbide
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Ceramic Lined Conveyor
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Rotation unit
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(No Transcript)
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Weirs

• Weir setting controls the depth of the slurry
  pool in the machine.
• Adjustable in ½ increments.
• Always place sealant behind weir plates when
  adjusting.

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Weir Adjustment

• Lower Weirs- Move towards the outside
• Raise Weirs- Move towards center of the machine

• Reduced moisture possibly increase torque
• Increase solids recovery and product moisture

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Discharge Headwall and Plows

• Plows are field replaceable.

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Variables

• Particle size of feed affects screenbowl
  performance
• Surface moisture of product is determined by the
  amount of minus 325 mesh material going to the
  centrifuge.
• This is because the surface area of the small
  coal particles is so great that more water is
  carried through with this fine material.
• This can be controlled somewhat with the weir
  settings

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(28 MESH 595 MICRONS)
(325 MESH 44 MICRONS)
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Principles of Operation

Solids Screen Effluent
Effluent
 
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Circuit Operation Control

• Key Instruments
• A digital torque monitor
• Measures the load on the planetary gear unit,
  therefore the amount of solids being conveyed by
  the centrifuge
• An amp readout
• Shows motor amps
• Function of amount of liquid being displaced by
  the centrifuge in normal operation.

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Circuit Operation Control Cont.

• Torque and amp readings are relatively steady
  when the centrifuge is operating under normal
  conditions
• If torque gets to preset amount - say 80, an
  alarm sounds. If torque continues to 90, feed
  valve closes, by pass opens, and flush water is
  introduced into the centrifuge until torque drops
  to approximately 40. This prevents the shear pin
  from shearing.
• On high amps, which may indicated a plugged
  hopper, the feed to the centrifuge should be shut
  off, and the centrifuge shut down until the cause
  for high amps is determined and corrected. Again
  an alarm should sound 5 before feed shutoff.

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Example of a Feed By-Pass System
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Example of a Feed By-Pass System(includes flush
water line)
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Spray Header and Solids Discharge Wash System
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Trouble ShootingDetecting Correcting Problems
SYMPTOM POSSIBLE REASONS REMEDY
Shearpin Failure Excessive fluctuations in feed rate Excessive fluctuations in feed concentrations Thrust Bearing Failure Tramp metal jams conveyor Check feed system Check feed system Replace thrust bearing Call DECANTER
Screen drain flow reduces or stops Screen blinding Shut down the machine back flush the screen (only effective at low bowl speed)
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SYMPTOM POSSIBLE REASONS REMEDY
Excessive Power Consumption Excessive feed rate Unsatisfactory cake discharge (solids rubbing on outside of rotor) Effluent pipe plugged Check feed system Check that solids discharge freely (chute modifications may be necessary) Check effluent discharge
Wet Cake Pool depth too high Screen blinding Bowl speed too low Excessive fines in feed Adjust Weirs Check as above Increase bowl speed Check feed
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SYMPTOM POSSIBLE REASONS REMEDY
Excessive Screen Drain Rate Screen damage Pool too deep Patch damaged section per DMI instructions Adjust Weir Plates
Excessive Solids in Screen Drain Broken Screen Segments Repair per DMI instructions
High solids concentration in main effluent Pool too shallow Bowl speed too low Solids Capacity exceeded Adjust Weir Plates Increase bowl speed Reduce feed rate or change gear ratio Exchange rotation unit
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SYMPTOM POSSIBLE REASONS REMEDY
Excessive Vibration Excessive conveyor wear Excessive headwall wear Machine blocked shearpin broken Exchange rotation unit Exchange rotation unit field repair headwall Replace Shearpin
Cake doesnt discharge Shearpin broken No solids in feed Gearbox spline broken Replace Shearpin Check feed system Replace gearbox
Main Bearing hot Check oil level/type Consult DMI, do not put water on pillowblock
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Plant Troubleshooting

• High Torque

• Too many solids
• Check deslime screen for holes or worn panels
• Check deslime sieve bend for holes or wear
• Rotation assembly wearing out

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Plant Troubleshooting

• Shear Pin Failure

• Feed Flucuations
• Check sieve bends for proper discharge
• Check flotation level control (possible flooding
  of the machine)
• By-pass valve not working properly

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Plant Troubleshooting

• High motor amps

• High flows to machine
• Check flotation cell level
• Reduce push water if used
• Sieves flooding
• Discharge chutes plugged
• Check for flow

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Decanter Screenbowl Operating Tips

• Monitor torque and AMPS on shift report.
• If torque increases, this is an indication of
  more solids going into the centrifuge. if AMPS
  increase, either more feed slurry is going to the
  centrifuge, or an effluent (main, screendrain)
  hopper or product hopper is being blinded.

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Decanter Screen bowl Operating Tips

• Monitor screen drain during operation to verify
  drain hopper is not plugged.
• For maximum recovery Decanters should be run at a
  deep pool 3-3.5 inches for 36" x 72". For maximum
  cake dryness, Decanters should be run at a low
  pool 2 inches or less on all units.
•  

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Decanter Screen bowl Operating Tips

• To help prevent shearing the new pin on startup,
  rotate the shearpin clamp block clockwise at
  least 50 revolutions before installing the new
  pin. This will help discharge solids left in the
  machine when the pin broke. A large crescent
  wrench or strap wrench will be necessary to
  rotate the clamp block. Make sure total rotation
  unit does not turn while turning shear pin block.
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Decanter Screen bowl Operating Tips

• Clean out machine at the end of each shift.
  After machine has been shut off allow to coast
  down for about 5 minutes then manually turn spray
  header water line on to wash the screen and
  discharge chute.
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Plant Testing

• Samples should be taken periodically of
• Feed size analysis and percent solids
• Main effluent size analysis and percent solids
  (If percent solids increase machine may be
  flooded or hopper plugged)
• Screen drain size analysis and percent solids (If
  percent solids or size increase, screen section
  may be damaged, or machine flooded)
• Product size analysis and percent solids (If
  moisture increases, feed size may have decreased,
  or machine may be flooded.)

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Preventative Maintenance
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Preventative Maintenance
ITEM OF POINTS LUBRICANT APPLICATION LUBRICANT APPLICATION FREQUENCY
Main Bearings (2) AFMA 4EP Bearing sump Check level weekly Change every 3 months
Conveyor Bearings (8) GRADE 2EP Grease Gun Weekly when shutdown
Thrust Bearings (2) GRADE 2EP Grease Gun Weekly when shutdown
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ITEM OF POINTS LUBRICANT APPLICATION LUBRICANT APPLICATION FREQUENCY
Main Drive Motor (2) Per Motor Data Tag Grease Gun Manufacture Instructions
Gearbox SA-56/SA-70 (1) EP150 AGMA 4EP Oil Filled 1000 oclock position Check level weekly Change oil every 3 months
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Greasing Thrust Bearings2 spots
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Greasing Conveyor Bearings8 Spots (4 each end)
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SA-70 Gearbox

• Notice oil plugs at top of gearbox. Rotate to ten
  oclock to check oil level.

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SA-56 Gearbox

• Notice oil level plugs at the top of the gearbox.
  Rotate to ten oclock to check level.

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Decanter Screen bowl Maintenance Tips

• Decanters should be greased weekly.
• Plows should be inspected monthly along with
  screen section.

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Screen tile repair

• Fill entire window with Alumi-plate (being sure
  not to push material into conveyor.
• Weld a patch over the entire window with the
  trailing edge having a complete weld.

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Machine Photos

• The following photos show wear related damage to
  the rotation assembly.

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Damage from solids build-up in screen discharge
hopper

• Material cut screen section in two pieces

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Discharge Headwall and Plows

• Plows are field replaceable.

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Headwall Damage

• Notice bolts holding headwall to screen frame are
  showing

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Stock Exchange Units and Spare Parts