Conveyor Problems And Causes

July 9, 2011

The following technical bulletin presents a list of typical conveyor problems and causes. Blair Rubber’s technical staff is available to provide further assistance with Blair’s belt splicing products and questions/answers that are not addressed in the following troubleshooting guide.

Conveyor Problems And Causes

1. All Portions Of The Conveyor Belt Run To One Side At A Given Point On The Structure.

Cause

  • One Or More Idlers Immediately Preceding Trouble Not At Right Angles To The Direction Of Belt Travel.
  • Conveyor Frame Or Structure Crooked.
  • One Or More Idler Stands Not Centered Under Belt.
  • Sticking Idlers.
  • Belt Runs Off Terminal Pulley.
  • Buildup Of Material On Idlers.
  • Structure Not Level And Belt Tends To Shift To Low Side.

 

2. A Particular Section Of The Conveyor Belt Runs To One Side At All Points On The Conveyor.

Cause

  • Belt Not Joined Squarely.
  • Bowed Belt
  • Worn Edge

 

3. The Conveyor Belt Runs To One Side For Long Distance Along The Bed.

Cause

  • Load Being Placed On Belt Off Center.
  • Conveyor Frame Or Structure Crooked.

 

4. The Belt Tracks Erratically And Does Not Follow A Pattern.

Cause

  • Belt Is Too Stiff To Train.
  • Combination Of Causes Listed Under 1 & 2.

 

5. Severe Wear On The Pulley Side Of The Conveyor Belt.

Cause

  • Slippage On Drive Pulley
  • Material Spills Between Belt And Pulley.
  • Material Build Up At Loading Point Until Belt Is Dragging
  • Sticking Idlers
  • Excessive Tilt To Troughin Idlers
  • Bolt Heads Protuding Above Lagging
  • Bottom Cover Too Thin.

 

6. Excessive Stretch In The Conveyor Belt

Cause

  • Tension Too High.

 

7. Lengthwise Gouging Or Stripping Of The Top Cover

Cause

  • Skirt Board Seals Too Stiff And Pressed Against Belt
  • Excessive Space Between Belt And Skirt Seals
  • Metal Sides Of Chute Or Skirts Too Close To Belt And Gap Not Increasing In Direction Of Belt Travel.
  • Belt Is Spanked Down Under Impact At Loading Point Allowing Material To Be Trapped Under Skirts.
  • Material Hanging Under Back Panel Of Chute.
  • Jamming Of Material In Chute.

 

8. Breaks In The Carcass Parallel To The Belt Edge

Cause

  • Impact Of Lumps Falling On Belt

 

9. Transverse Breaks In The Center Of The Carcass

Cause

  • Material Trapped Between Belt And Pulley
  • Impact Or Lumps Falling On Belt

 

10. Transverse Breaks At The Belt Edge

Cause

  • Belt Edges Folding Up On Structure Where It Rounds A Pulley Due To Wandering Or Pressing To Hard Against Side Guide Rollers
  • Final Idler Before Head Pulley Located To Close Or Too
  • High In Respect To Head Pulley.
  • Inadequate Convex Curve Radius.

 

11. Excessive Top Cover Wear Uniformly Around The Belt.

Cause

  • Dirty, Stuck Or Misaligned Return Rolls.
  • Cover Quality Low.
  • Pile Up Of Spilled Material At Tail Pulley
  • Side Loading Or Poor Loading.I.E.,Delivery Of Material Too Slow.
  • Excessive Sag Between Idlers Causing Load To Work And Shuffle On Belt As It Passes Over Idlers.
  • Belt Wear Due To Dragging Accumulated Material Out Of Loading Chute.

 

12. Cover Or Sand Blisters

Cause

  • Cover Cuts Or Very Small Cover Punctures Allow Fine Particles Of “Sand” To Work Under Cover And Cut Cover Away From Carcass.
  • Oil Either In Material Or From Outside Source.

 

13. Belt Rises Off Troughing Idlers, Bowing Towards Its Load.

Cause

  • Oil Either In Material Or From Outside Source.

 

14. Cover Swells In Spots Or Lines Of Swelling On The Pulley Side Coincident With The Junction Of The Troughing Idler Rolls

Cause

  • Over-Lubrication Of Top Run Idlers
  • Spilled Oil Or Grease

 

15. Fasteners Pull Out

Cause

  • Wrong Type Of Fastener Or Fasteners Not Tight
  • Tension To High
  • Heat
  • Tandem Drive Poorly Compensated
  • Inadequate Convex Curve Radius

 

16. Transverse Breaks In The Belt Immediately Behind The Fasteners.

Cause

  • Fastener Plates Are Too Long For Pulley Sizes.

 

17. Belt Moves Sideways, After Making A Complete Revalution, And Generally Moves A Constant Distance Off Of Center.

Cause

  • Belt Was Not Squared When Spliced.

 

18. Drive Pulley Spins

Cause

  • Tighten The Belt.
  • Lag Drive Pulley.

 

19. Belt Stretches More Than 2% Tends To Be More Narrow

Cause

  • Undersized Belt
  • Counterweight To Heavy
  • Belt Tightened To Much Too Reduce Slippage.

 

20. Conveyor Belt Breaks

Cause

  • Belt Overloaded
  • Splice Failure
  • Belt Wear From Age

 

21. Vulcanized Splice Peels Apart

Cause

  • Improper Cure
  • Incompatible Materials
  • Moisture In Splice
  • Cement Drying Time
  • Pulley Diameter To Small

 

22. Wearing Or Fraying Of Belt Edge

Cause

  • Improper Tracking Or Training
  • Material Build-Up
  • Side Loading

 

23. Cover Becomes Soft And Tacky

Cause

  • Improper Compound For Service

 

24. Cover Is Cracking

Cause

  • Excessive Heat
  • Age Or Weather Cracking
  • Undersized Pulleys
  • Ozone Attack

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