Quality Problems Caused & Corrections

qpc

The direction of the cause and solution for common conveyor belt problems

What’s the problem?Why does it happen?The solution
1. Belt edge wear and broken excessively 1) Off-center loadingAdjust the chute to place load on the center of the belt and discharge material in direction of the belt moving.
2) Material Spillage and cumulationImprove loading and conveying conditions, install cleaning devices, and improve maintenance.
3) Bowed beltFor a new belt, this condition should disappear soon, otherwise, the belt must be straightened or replaced. In the meanwhile, should check the storage and handling situation.
4) Belt-hitting structureInstall training idlers on carrying and return sides.
5) Belt too rigid for adequate troughingInstall a more flexible belt.
2. Stripping of cover1) Impact of materials on beltReduce impact by improving chute design, and installing impact idlers or impact beds.
2) Skirt board improperly adjusted or of the wrong martialAdjust Skirt Board support to a minimum of 25 mm between the metal and belt with a gap increasing in direction of belt travel. Kindly note: use a skirt board rubber (not an old belt).
3. Severe pulley cover wear1) Material trapped between belt and pulleyInstall scraper on return run ahead of tail pulley.
2) Spillage on the drive pulleyIncrease tension, lag drive pulley, and increase the arc of contact.
3) Sticking Idlers.Free idlers and improve maintenance.
4. Cover harden or crack1) Heat or chemical use conditionUse a belt designed for the specific condition.
2) Improper storage or handlingRefer to proper storage and handling instructions.
5. Cover softening or swells in spots1) Contamination by spilled grease, over-lubrication of idlersImprove housekeeping, reduce the quantity of grease used, and check grease seals.
6. Cover bubbles1) Cover cuts or very small punctures Make spot repair with a vulcanizer or self-curing repair material.
7. Short breaks in carcass parallel to belt edge, start the break in carcass1) Impact of material on the belt.Reduce impact by improving chute design, and installing impact idlers or impact beds.
2) Material trapped between belt and pulleyInstall scraper on return run ahead of tail pulley.
8. Transverse breaks1) Belt edges folding up on the structureReadjust idlers in the affected area, and install limit switches to provide more clearance.
2) Improper transition between the troughed belt and terminal pulleyAdjust transition as recommended.
3) Severe convex, vertical curve.Decrease idler spacing in the curve, increase curve radius
9. Lengthways carcass break with covers intact.1) Belt running off center and folding overUse limit switches and determine the reasons for the belt running out.
10. Belt breaks at or behind fasteners, fasteners pullout1) Wrong type of fastener, fasteners too tight or too looseUse proper fasteners, and set up a schedule for regular fastener inspection.
2)Fastener plates too long for pulley sizeReplace with smaller fasteners, and increase pulley size.
3) Tension too highIncrease speed, reduce friction decrease tension by increasing the arc of contact. 
11. Ply separation1) Pulley too smallUse larger diameter pulleys.
2) Heat or chemical use conditionUse a belt designed for the specific condition.
3) Too many reverse bendsUse a more flexible belt.
4) Mildew or dust penetration into the carcassPrevent cuts, and arrange for immediate repairs.
12. Particular section of the belt runs to one side at all points on the conveyor1) Belt not joined squarelyRemove the affected splice and re-splice.