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Parts and Functions of a Conveyor System

• 2012 Dr. B. C. Paul
• Note- These slides include figures and tables
  taken from the Conveyor Equipment Manufactures
  Association. Credit is given for these figures
  and tables. These slides also include material
  from the authors own earlier work.

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Major Components of Conveyor

• Long Continuous belt
• Carried on rolls - rollers held by frame
• Belt wrapped around pulleys at ends
• Pulleys coupled to gears and motors
• Peripheral Devices to drop on belt, direct around
  corner, clean, discharge etc.

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Conveyor Parts
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Conveyor Parts
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How Conveyors Function

• Material Falls on moving belt that carries it
  along
• A continuous haulage system that is not limited
  by cycles of batch movement
• Requires a continuous frame and structure before
  can transport material over route

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Significant Variations

• Belt may ride on a frame with air holes - a
  compressor blows air under belt. Belt rides on a
  cushion of air.
• Rollers wrap belt entirely around material - used
  to allow vertical conveying of material

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Conveyor Belting Parts

• Carcass - woven fabric or material for tensile
  strength
• Skims - rubber layers between carcass plys
• Braker - fabric coat above carcass to break
  impact of load
• Top Cover - A rubber that resists cutting
  abrasion and sometimes chemical action

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Conveyor Belting Types

• Multi-Ply - multi-ply carcass separated by skims
  - traditional - trade-off between stiffness and
  strength
• Reduced Ply - complex interwoven carcass not
  dependent on separate plys thinner less stiff for
  same strength
• Steel - carcass lengthwise steel belts - high
  tensile strength - heavy ores long runs
• Solid Woven - Carcass impregnated with elastomer

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Conveyor Belting Elastomers

• Most Elastomer Covers in Mining for bump and
  abrasion resistance - good natural or synthetic
  rubber
• Oiled Stoker Coals may need chemical resistance -
  neoprene rubber
• Hot process Ores may need heat resistance - check
  the carcass too - usually limit to 75 of rated

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Elastomer Covers
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Conveyor Belting Splices

• Mechanical
• Fast
• Done by Hand
• Easily done and undone (even when dont want it
  undone)
• collects dirt looses strength
• Vulcanized
• Needs big machine and time
• Once done hard to undo
• Provides Superior Strength

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Idlers

• Supports Belt and Material Load
• Built with
• Shaft surrounded by bearings
• Then roll of steel or rubber
• Two main types
• Carrying for material and belt
• return supports belt on return trip

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Idler Size and Duty

• Rated by Diameter
• ranges 4 to 7 inches
• smaller is less costly but higher wear and
  frictional losses
• 5 inches common for mining
• Rated by Weight Carriage
• ranges A to E for increasing duty
• A and B light C and D heavy duty E extra
• B and C common for mining

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Carrying Idlers

• Usually troughed with 3 equal size rollers on a
  frame in mining applications
• Some suspended catenary systems have 5 rollers
• Troughs usually 20 , 35, 45 degrees
• Deeper trough more volume
• Requires thinner belt to lay in trough which
  limits strength
• 35 common choice for mining

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Carrying Idlers
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Return Idlers

• Usually Flat and one piece
• Sometimes two piece V for belt training
• Spiral roll to self and belt clean

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Specialty Idlers

• Impact Idlers for taking material dropping onto
  belt
• Belt Training (Training means keeping in line in
  trough)
• Can put idler off center to pull to side
• Can put wheels on edge but wear belt
• Can put v return to pull one way or other.

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Pulley

• Like Roller only belt wraps around
• Head Pulley - turns belt back around to return -
  may be coupled to drive
• Tail Pulley - turns empty belt around for loading
  - occasionally coupled to drive
• Drive Pulley - Coupled to motor pulls belt -
  usually special grip surface

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Pulleys

• Snub Pulley - usually used to change direction of
  belt and increase the contact angle with the
  drive pully (more surface area to transfer power)
• Take Up Pulley - Used to maintain tension on a
  belt left loose enough for some flexibility

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Pulleys
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Drive Pulley Considerations

• Pulley should be large enough to avoid to hard
  bend at point of tension application
• Pulley should have grab - risk of slippage is
  function of grab and tension - more grab - less
  tension - could mean a cheaper belt
• Place Drive in practical location to minimize the
  highest tension in the belt - a head pulley
  location often good on a belt up a slope

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Loading a Conveyor Belt

• Need to get even load on belt and get material
  traveling in same direction to minimize belt
  strain
• Chute - may use scalping bars so fines fall on
  first and provide cushion
• Transfer Conveyor - wear on short replaceable
  belt get things up to speed
• Vibratory feeder

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Methods of Loading a Belt
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Methods of Loading a Belt
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Loading a Conveyor Belt

• Skirt board along edge for about 8 to 10 feet to
  keep material on belt and line it up
• Loading points or transfer points are common
  spill locations
• Production rate is not really constant
• Simulation programs can aid in determining speed
  and belt size for network.

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Unloading a Belt

• Over the end of belt
• Flatten to fast and stretch the belt
• Flatten to slow material will spread and spill
  over sides
• for 35 degree trough need about 1.5 times belt
  width to flatten
• Often have brushes to belt after material
  discharge

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Methods of Cleaning Belt After Discharge
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Unloading a Belt

• Plow - V on belt pushes off to sides.
• Limited speed about 200 fpm
• Need flat belt
• Tripper - moving plow to one side
• can trip from one conveyor to another
• good for loading multiple silos

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Plow for Discharging Material from Belt
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Tripper for Belt Discharge