This guide offers practical solutions for common conveyor belt problems, aiming to enhance efficiency and reduce downtime.
It’s important to also prioritize safety in conveyor operation, adhering to OSHA and other safety standards, including ANSI B20.1.
Proper installation, maintenance, and use of safety guards and practices are essential for a safe and functional conveyor system.
1. Alignment and Tracking Issues
Belt runs off tail pulley
The problem of a conveyor belt running off the tail pulley is typically caused by issues such as an inadequately weighted counterweight, misaligned idlers/pulleys, frozen idlers, spillage at the loading point, or material build-up, with solutions including recalibration, realignment, maintenance improvements, flow control, and cleaning.
| Problem | Solution |
|---|---|
| Counterweight too light | Recalculate weight and adjust counterweight or take-up accordingly. |
| Idlers/pulleys not square | Realign, install limit switches or safety. |
| Frozen idlers | Free idlers, lubricate, and improve maintenance. |
| Spillage at loading point | Control flow with chutes, feeders, center load. |
| Material build-up | Remove accumulation. Install belt cleaners. |
Entire belt runs off at all points of the line
When the entire conveyor belt runs off at all points of the line, common causes include side loading, spillage at the loading point, misaligned idlers/pulleys, material build-up, uneven belt strain, and improperly placed idlers, with solutions involving load adjustment, flow control, realignment, cleaning, belt repair, and idler repositioning.
| Problem | Solution |
|---|---|
| Side loading | Load in center and direction of travel. |
| Spillage at loading point | Control flow with chutes, feeders, center load. |
| Idlers/pulleys not square | Re-align, install limit switches or safety. |
| Material build-up | Remove accumulation. Install belt cleaners. |
| Belt strained on one side | Remove strained section and splice in new piece. |
| Idlers improperly placed | Relocate or insert additional idlers for support. |
One belt section runs off at all points of the line
When one section of the conveyor belt runs off at all points of the line, it’s typically due to faulty fasteners or splice, worn or broken edges, or a bowed belt, with recommended solutions including using correct fasteners, repairing the belt edge, and avoiding the storage of belt rolls in damp locations.
| Problem | Solution |
|---|---|
| Bad fasteners or splice | Use correct fasteners; resplice belt. |
| Edge worn or broken | Repair belt edge. |
| Bowed belt | Avoid telescoping belt rolls or storing in damp locations. |
Belt runs off at head
When a conveyor belt runs off at the head, it is often caused by misaligned idlers/pulleys, worn pulley lagging, material build-up, or improperly placed idlers, and can be solved by realigning the components, replacing worn parts, removing debris, and adjusting idler placement for better support.
| Problem | Solution |
|---|---|
| Idlers/pulleys not square | Realign, install limit switches or safety. |
| Pulley lagging worn | Replace worn lagging. |
| Material build-up | Remove accumulation. Install belt cleaners. |
| Idlers improperly placed | Relocate or insert additional idlers for support |
Belt runs to one side throughout entire length at specific idlers
The issue of a conveyor belt running to one side along its entire length at specific idlers is generally due to misaligned idlers/pulleys, improperly placed idlers, or material build-up, and can be solved by realigning and repositioning idlers and removing accumulated material.
| Problem | Solution |
|---|---|
| Idlers/pulleys not square | Realign, install limit switches or safety. |
| Idlers improperly placed | Relocate or insert additional idlers for support. |
| Material build-up | Remove accumulation. Install belt cleaners |
2. Traction and Slippage Problems
Belt slip
Belt slip occurs due to insufficient traction, light counterweights, material build-up, frozen idlers, or worn pulley lagging, and can be solved by increasing traction, adjusting counterweights, cleaning, lubricating, and replacing parts as needed.
| Problem | Solution |
|---|---|
| Insufficient traction between belt and pulley | Increase wrap with snub pulleys, lag drive pulley, install belt cleaners. |
| Counterweight too light | Recalculate weight and adjust counterweight or take-up accordingly. |
| Material build-up | Remove accumulation. Install belt cleaners. |
| Frozen idlers | Free idlers, lubricate, and improve maintenance. |
| Pulley lagging worn | Replace worn lagging. |
Belt slip on starting
Belt slip on starting shares similar causes and solutions, with the additional factor of being underbelted, requiring tension recalibration and belt selection.
| Problem | Solution |
|---|---|
| Insufficient traction between belt and pulley | Increase wrap with snub pulleys, lag drive pulleys, install belt cleaners. |
| Counterweight too light | Recalculate weight and adjust counterweight or take-up accordingly. |
| Pulley lagging worn | Replace worn lagging. |
| Drive underbelted | Recalculate maximum belt tensions and select correct belt. |
3. Belt Tension and Structural Integrity
Excessive belt stretch
Excessive belt stretch is often caused by factors like over-tensioning, underbelted drives, material build-up, overly heavy counterweights, incorrect speed differentials, or damage from harsh conditions, with solutions including tension recalibration, belt selection, cleaning, weight adjustment, speed adjustment, and using belts designed for specific environmental conditions.
| Problem | Solution |
|---|---|
| Excessive tension | Recalculate and adjust tension. |
| Drive underbelted | Recalculate maximum belt tensions and select correct belt. |
| Material build-up | Remove accumulation. Install belt cleaner. |
| Counterweight too heavy | Recalculate weight and adjust, reduce take-up tension to slip point, and then tighten slightly. |
| Wrong differential speed | Make required adjustment. |
| Damage by abrasives, acid, chemicals, heat, oil, etc. | Use belt designed for specific conditions, make spot repairs, install rubber disc idlers, do not over lubricate idlers. |
Belt breaks at or behind fasteners; fasteners tear loose
This issue is often caused by incorrect fasteners or splice, small pulleys, excessive tension, worn pulley lagging, material trapped between the belt and pulley, or an underbelted drive, and can be solved by using suitable fasteners, upsizing pulleys, adjusting tension, replacing lagging, clearing material, and recalibrating belt tension.
| Problem | Solution |
|---|---|
| Bad fasteners or splice | Use correct fasteners; resplice belt. |
| Pulleys too small | Use large diameter pulleys. |
| Excessive tension | Recalculate and adjust tension. |
| Pulley lagging worn | Replace worn lagging. |
| Material between belt/pulley | Use skirtboards, remove accumulation, improve maintenance. |
| Drive underbelted | Recalculate maximum belt tensions and select correct belt. |
Vulcanized splice separation
This problem typically arises from excessive tension, small pulleys, underbelted drives, material accumulation between the belt and pulley, incorrect fasteners or splice, or wrong differential speed, and solutions include tension adjustment, using larger pulleys, selecting the correct belt, clearing material, resplicing, and speed adjustment.
| Problem | Solution |
|---|---|
| Excessive tension | Recalculate and adjust tension. |
| Pulleys too small | Use larger diameter pulleys. |
| Drive underbelted | Recalculate maximum belt tensions and select correct belt. |
| Material between belt/pulley | Use skirtboards, remove accumulation, improve maintenance. |
| Bad fasteners or splice | Use correct fasteners; resplice belt. |
| Wrong differential speed | Make required adjustment. |
Ply separation
Ply separation in conveyor belts can be due to excessive tension, small pulleys, damaged belt edges, exposure to harsh conditions, or too high belt speed, and can be solved by recalibrating tension, using larger pulleys, repairing the belt, using belts suitable for specific conditions, and reducing belt speed.
| Problem | Solution |
|---|---|
| Excessive tensions | Recalculate and adjust tension. |
| Pulleys too small | Use larger diameter pulleys. |
| Edge worn or broken | Repair belt edge. |
| Damage by abrasives, acid, chemicals, heat, oil, etc. | Use belt designed for specific conditions, make spot repairs, install rubber disc idlers, do not over lubricate. |
| Belt speed too fast | Reduce belt speed. |
4. Wear and Tear
Excess bottom cover wear
This issue commonly results from material build-up, frozen idlers, missing breaker strips, insufficient traction, material trapped between the belt and pulley, or worn pulley lagging. Solutions include removing accumulation, freeing and lubricating idlers, installing new breaker strips, increasing traction with snub pulleys, using skirtboards for material management, and replacing lagging.
| Problem | Solution |
|---|---|
| Material build-up | Remove accumulation, install belt cleaner. |
| Frozen idlers | Free idlers, lubricate, and improve maintenance. |
| Breaker strip missing | When service is lost, install new breaker strip. |
| Insufficient traction between belt and pulley | Increase wrap with snub pulleys, lag drive pulley, install belt cleaners. |
| Material between belt/pulley | Use skirtboards, remove accumulation, improve maintenance. |
| Pulley lagging worn | Replace worn lagging. |
Excessive edge wear, broken edges
Causes include side loading, uneven belt strain, spillage at the loading point, exposure to harsh substances, a bowed belt, and material build-up. Solutions involve centering the load, removing strained sections for splicing, controlling flow at loading points, using belts suitable for specific conditions, avoiding improper storage of belt rolls, and cleaning accumulated material.
| Problem | Solution |
|---|---|
| Side loading | Load in center and in the direction of travel. |
| Belt strained on one side | Remove strained section and splice in new piece. |
| Spillage at loading point | Control flow with chutes, feeders, center load. |
| Damage by abrasives, acid, chemicals, heat, oil, etc. | Use belt designed for specific conditions, make spot repairs, install rubber disc idlers, do not over lubricate idlers. |
| Bowed belt | Avoid telescoping belt rolls or storing in damp locations. |
| Material build-up | Remove accumulation and/or install belt cleaners. |
Excessive wear, including rips, gouges, ruptures and tears
This severe wear can be due to extreme material impact, inappropriate loading velocity, spillage at loading points, material build-up, exposure to damaging substances, or missing breaker strips. Solutions include using well-designed chutes, adjusting loading speed, controlling flow, removing build-up, using condition-specific belts, and installing new breaker strips as needed.
| Problem | Solution |
|---|---|
| Extreme material impact | Use correctly designed chutes or baffles, install impact idlers, adjust skirting, load fines first. |
| Relative loading velocity too high or low | Adjust chutes or speed. |
| Spillage at loading point | Control flow with chutes, feeders, center load. |
| Material build-up | Remove accumulation and/or install belt cleaners. |
| Damage by abrasives, acid, chemicals, heat, oil, etc. | Use belt designed for specific conditions, make spot repairs, install rubber disc idlers, do not over lubricate idlers. |
| Breaker strip missing | When service is lost, install new breaker strip. |
5. Material Degradation
Cover swells in spots or streaks
This issue is typically caused by damage from abrasives, acid, chemicals, heat, or oil. The solution involves using belts designed for specific conditions, making spot repairs, and installing rubber disc idlers without over-lubricating.
| Problem | Solution |
|---|---|
| Damage by abrasives, acid, chemicals, heat, oil, etc. | Use belt designed for specific conditions, make spot repairs, install rubber disc idlers, do not over lubricate idlers. |
Belt hardens or cracks
Hardening or cracking of the belt often results from exposure to harsh conditions, small pulleys, worn pulley lagging, or improper storage/handling. Solutions include using condition-specific belts, using larger pulleys, replacing lagging, and following proper storage methods.
| Problem | Solution |
|---|---|
| Damage by abrasives, acid, chemicals, heat, oil, etc. | Use belt designed for specific conditions, make spot repairs, install rubber disc idlers, do not over lubricate idlers. |
| Pulleys too small | Use larger diameter pulleys. |
| Pulley lagging worn | Replace worn lagging. |
| Improper storage/handling | Refer to your local representative for methods. |
Covers become checked or brittle
This problem is usually due to damage from harsh substances or improper storage/handling. The solutions involve using belts suitable for specific environmental conditions and consulting a PPI representative for proper handling and storage methods.
| Problem | Solution |
|---|---|
| Damage by abrasives, acid, chemicals, heat, oil, etc. | Use belt designed for specific conditions, make spot repairs, install rubber disc idlers, do not over lubricate idlers. |
| Improper storage/handling | Refer to your local representative for methods. |
Longitudinal grooving or cracking of top cover
Causes include skirting rubbing against the belt, frozen idlers, material build-up, and extreme material impact. Solutions encompass correctly installing skirting, freeing and lubricating idlers, removing material build-up, and using appropriate chutes or baffles.
| Problem | Solution |
|---|---|
| Skirting rubbing belt | Install skirting correctly. |
| Frozen idlers | Free idlers, lubricate, improve maintenance. |
| Material build-up | Remove accumulation and/or install belt cleaners. |
| Extreme material impact | Use correctly designed chutes or baffles, install impact idlers, adjust skirting, load fines first. |
Longitudinal grooving or cracking of bottom cover
This is typically caused by frozen idlers, material build-up, or worn pulley lagging. Remedies include freeing and lubricating idlers, cleaning accumulated material, and replacing lagging.
| Problem | Solution |
|---|---|
| Frozen idlers | Free idlers, lubricate, improve maintenance. |
| Material build-up | Remove accumulation and/or install belt cleaners. |
| Pulley lagging worn | Replace worn lagging. |
Fabric decay, carcass cracks, ruptures, gouges, soft spots
Factors contributing to this issue include extreme material impact, material trapped between belt/pulley, missing breaker strip, underbelted drives, damage from harsh substances, and small radius of convex curves. Solutions involve using designed chutes or baffles, clearing trapped material, installing new breaker strips, recalculating belt tensions, using condition-specific belts, and realigning idlers to prevent tension issues.
| Problem | Solution |
|---|---|
| Extreme material impact | Use correctly designed chutes or baffles, install impact idlers, adjust skirting, load fines first. |
| Material between belt/pulley | Use skirtboards, remove accumulation, improve maintenance. |
| Breaker strip missing | Install new breaker strip when service is lost. |
| Driver underbelted | Recalculate maximum belt tensions and select correct belt. |
| Damage by abrasives, acid, chemicals, heat, oil, etc. | Use belt designed for specific conditions, make spot repairs, install rubber disc idlers, do not over lubricate. |
| Radius of convex vertical curve too small | Increase radius by vertical realignment of idler to prevent excessive edge tension. |
Sources:
- “B20.1 Safety Standard for Conveyors and Related Equipment | ASME – ASME.” Asme.org, 2018, www.asme.org/codes-standards/find-codes-standards/b20-1-safety-standard-conveyors-related-equipment.
- “ASME B20.1-2021 – Safety Standard for Conveyors and Related Equipment.” Webstore.ansi.org, webstore.ansi.org/standards/asme/asmeb202021. Accessed 16 Jan. 2024.