Troubleshooting Conveyor Belt Mismatches: Diagnostics and Troubleshooting

1. Description of the Problem and Scope of Application

Conveyor belt mistracking is a critical fault characterized by deviation of the belt from the central axis of the conveyor, which leads to its contact with supporting elements of the frame or structures. This problem is one of the most common sources of downtime, equipment damage, and material loss in industrial plants.

This manual is intended to systematically diagnose and eliminate the root causes of tape misalignment, including those related to:

• Incorrect loading of material.
• Defects in tape connections (splices).
• Violation of alignment of rollers and drums.
• Improper tape tension.
• Accumulation of material and other external factors.

These procedures are applicable to a wide range of belt conveyors used in the mining, metallurgical, cement, food, chemical and other industries.

Classification of Malfunctions

• Critical: The belt is in constant contact with the frame, causing significant damage to the edges of the belt, a potential fire hazard due to friction, risk of damage to the conveyor structure or jamming of the system. Requires immediate stop and intervention.
• Serious: The tape periodically overlaps, resulting in significant material spillage, accelerated wear of rollers, tape edges, and other components. Requires emergency repair planning to prevent critical failures.
• Minor: A slight but constant deviation of the belt from the center, which does not cause immediate damage, but is an early sign of a potential problem. Requires monitoring and inclusion in scheduled maintenance.

2. Security measures

WARNING: Before performing any diagnostic or repair work on the conveyor system, all safety standards must be strictly followed, in particular DSTU EN 619:2018 (EN 619:2002, IDT), NPAOP 29.2-1.04-07 and the internal rules of the enterprise.

• LOCKING/MARKING (LOTO): It is necessary to de-energize all conveyor energy sources (electrical, hydraulic, pneumatic) and apply the blocking/marking procedure according to the DSTU EN 1037:2018 standard. Check for no voltage and residual energy.
• SAVED ENERGY: Conveyor belts can have significant tension (especially on large conveyors) or use counterweights. Ensure belt tension is released or counterweight system is locked before operation.
• PERSONAL PROTECTIVE EQUIPMENT (PPE): Always use appropriate PPE: safety glasses, safety gloves, safety shoes, safety helmet and tight work clothes.
• MOVING PARTS: Never work near moving parts of the conveyor without turning off the power and applying LOTO. The area under the conveyor, pinch points and roller rotation areas are extremely dangerous.
• DROPPING MATERIAL: Be careful of the possibility of material falling from the conveyor belt, especially when it is stopped or when working under the conveyor belt.

3. Necessary Diagnostic Tools

Accurate diagnosis of conveyor belt misalignment requires a set of specialized tools. Ensure that all equipment is certified and calibrated according to DSTU ISO 9001:2015 to ensure measurement accuracy.

4. Initial Assessment Checklist

Before starting a detailed diagnosis, it is important to collect as much information as possible about the operating conditions and history of the conveyor. This will help narrow down the potential causes.

5. Systematic Flow of Diagnostics

This flow allows you to sequentially identify the root cause of a tape match, moving from general symptoms to specific malfunctions.

1. **Observation of Tape Match:**
   1. **Symptom:** The tape matches evenly in one direction along its entire length.
      • **Check:** General pipeline alignment.
        • **If the result is:** All or a large part of the conveyor is not aligned.
        • **Probable cause:** Improper installation of the conveyor or subsidence of the foundation. Go to section 7.1.
   2. **Symptom:** The overlap of the tape is localized (on a certain area).
      • **Check:** Define a specific section (loading, unloading, along the route, return branch).
      • **If result:** Match in download area. Go to point 2.
      • **If result:** Match in unloading area/on drive or tension drum. Go to point 3.
      • **If the result:** A match on an empty (upper/lower) branch along the track. Go to point 4.
      • **If the result:** Coincidence of tape that changes the direction of movement (for example, in an "S" shape). Go to point 5.
2. **Diagnostics of the Loading Zone:**
   1. **Check:** Centrality of material loading.
      • **Measurement:** Visually assess or measure the material distribution on the belt.
      • **If the result:** The material is loaded off-center, displacing the tape.
      • **Probable Cause:** Loading tray misalignment or uneven material flow. Go to section 7.2.
   2. **Check:** Condition of footers and guides.
      • **Overview:** Check footer wear and correct angles.
      • **If result:** Worn or damaged footers creating one-way drag.
      • **Probable cause:** Mechanical wear, improper installation. Go to section 7.3.
3. **Diagnosis of Drive/Tension Drums:**
   1. **Check:** Alignment of drums.
      • **Measurement:** Use a laser leveler to check that the drum axes are parallel. Tolerance: ±1 mm per meter of drum length.
      • **If the result:** The drum is not parallel to the others or not perpendicular to the axis of the conveyor.
      • **Possible cause:** Subsidence of the foundation, deformation of the frame, improper installation, loosening of fasteners. Go to section 7.4.
   2. **Inspection:** Condition of drums (conicity, accumulation of material).
      • **Inspection:** Check for material build-up, lining wear, surface irregularities.
      • **If result:** Uneven wear or material build-up that changes the effective diameter of the drum.
      • **Probable cause:** Poor belt cleaning, liner wear. Go to section 7.5.
4. **Diagnosis of Rollers Along the Route:**
   1. **Check:** Alignment of support and turning rollers.
      • **Measurement:** Use a level/inclinometer. Make sure that all the rollers are perpendicular to the axis of the belt. Tolerance: angle deviation no more than 0.5°.
      • **If result:** Some rollers are installed at an angle or jammed.
      • **Probable cause:** Incorrect installation, deformation of brackets, wear of bearings, accumulation of material. Go to section 7.6.
   2. **Check:** Free rotation of the rollers.
      • **Inspection/Manual scrolling:** Make sure all reels spin freely.
      • **If Result:** One or more rollers are jammed or spin with high resistance.
      • **Probable cause:** Bearing wear, roller damage, material build-up. Go to section 7.7.
5. **Tape Tension and Splice Diagnostics:**
   1. **Check:** Tape tension.
      • **Measurement:** Use a strain gauge to check the tension. Compare with the manufacturer's recommendations (usually 1.5-2.5% of the breaking strength).
      • **If Result:** Excessive or insufficient belt tension.
      • **Probable cause:** Incorrect adjustment of the tension system, belt wear. Go to section 7.8.
   2. **Check:** Splice condition (tape connection).
      • **Inspection:** Visually inspect the splice for distortion, uneven wear, delamination, or displacement. Use a thickness gauge to check thickness uniformity across the width of the splice.
      • **If Result:** The splice is uneven, damaged, or has asymmetric wear.
      • **Possible cause:** Improper splicing, material aging, mechanical damage. Go to section 7.9.
6. **Diagnosis of Material Accumulation and Cleaning:**
   1. **Inspection:** Condition of belt cleaners and scrapers.
      • **Inspection:** Check the wear of the wiper blades, their correct fit to the tape.
      • **If Result:** Worn or misadjusted wipers causing material to build up on drums and rollers.
      • **Probable cause:** Lack of regular maintenance of cleaners, wrong choice of cleaner type. Go to section 7.10.
   2. **Check:** Accumulation of material on the conveyor frame, rollers, drums.
      • **Overview:** Visual control.
      • **If Result:** Material builds up, creating extra resistance on one side of the tape.
      • **Probable cause:** Inefficient cleaning system, poor design of trays, spillage of material. Go to section 7.11.

6. Malfunction-Cause matrix

This matrix systematizes the relationships between observed tape mismatch symptoms, probable causes, diagnostic tests, and expected outcomes.

7. Analysis of the Root Causes of Each Malfunction

Understanding the root cause is critical to effectively resolving the conflict and preventing it from happening again. Each of the following sections details the causes, methods of confirmation, and potential consequences.

7.1. General Misalignment of the Conveyor or Subsidence of the Foundation

• **Why this happens:** Initial incorrect installation of the conveyor system, deformation of the supporting structures over time, uneven settlement of the foundation, the influence of external dynamic loads.
• **How ​​to confirm:**
  • Use a laser theodolite or optical level to check the horizontality and linearity of the entire conveyor route.
  • Measure diagonals and parallelism on several sections of the conveyor.
  • Check the verticality of the support posts with an inclinometer.
• **Causes, if not eliminated:** Continuous belt overlap, accelerated wear of belt edges, broken rollers and their brackets, deformation of the conveyor frame, increased energy consumption of the drive mechanism.

7.2. Decentralized Material Download

• **Why this happens:** Improper design or location of the loading tray, misalignment of the tray, misalignment of the loading center due to uneven material flow, or misalignment of the belt itself under the tray.
• **How ​​to confirm:**
  • Visually observe the process of loading the material on the go.
  • Measure the distance from the center of the tape to the edges of the material.
  • Check that the loading tray is correctly installed relative to the belt axis.
• **Causes, if not eliminated:** One-sided pressure on the belt causing it to shift, increased wear on one side of the belt and rollers, material shedding, contamination.

7.3. Uneven Wear or Shifting of the Loading Tray Footers

• **Why this happens:** Mechanical wear of footers due to friction with the material, incorrect choice of lining material, loosening of footer fasteners, shock loads.
• **How ​​to confirm:**
  • Inspect the loading tray liners for visible wear, chips, cracks.
  • Measure the gaps between the edges of the tape and the footers on both sides.
• **Causes, if not corrected:** One-way resistance to belt movement, forcing it to run in the opposite direction, damage to belt edges, increased friction and heat.

7.4. Improper Alignment of Drive/Tension Drums

• **Why this happens:** Improper installation, subsidence of the supports, deformation of the frame, loosening or damage to the fixings of the bearing assemblies of the drums.
• **How ​​to confirm:**
  • Use a laser shaft aligner to check that the drum axis is parallel to the conveyor axis. Allowable deviation: ±1 mm per meter of drum length.
  • Measure the distance from the edges of the drum to the nearest frame elements on both sides.
• **Which causes, if not corrected:** The tape is constantly moving towards the shorter distance, causing edge wear, increased stress on the drum bearings, damage to the drum lining.

7.5. Accumulation of Material or Uneven Wear of the Surface of the Drums

• **Why this happens:** Inefficient operation of belt cleaners, wet or sticky material sticking to the surface of the drum, wear of the drum lining due to friction or abrasive effect of the material.
• **How ​​to confirm:**
  • Inspect the surface of the drums for material sticking or visible uneven wear of the lining.
  • Check the performance of the belt cleaners.
• **Causes, if not corrected:** A change in the effective diameter of the drum at a certain point, which creates a pulling force on one side of the belt, causing overlap, damage to the belt and drum.

7.6. Unevenly Aligned Support or Return Rollers

• **Why this happens:** Improper installation, deformation of roller brackets, loosening of fasteners, settlement of conveyor supports, shock loads.
• **How ​​to confirm:**
  • Use an inclinometer to check the angle of inclination of the roller axes relative to the perpendicular to the direction of the belt movement. Permissible deviation: no more than 0.5°.
  • Visually inspect the roller brackets for deformation.
• **Which causes, if not eliminated:** Generation of lateral force that displaces the belt, increased wear of the belt edges, damage to the rollers and their bearings.

7.7. Jammed or Poorly Spinning Rollers

• **Why this happens:** Wear of roller bearings, dirt or moisture in the bearings, damage to the roller, deformation of the shaft, accumulation of material between the roller and the frame.
• **How ​​to confirm:**
  • **WARNING: LOTO is required.** Manually spin each reel. It should rotate freely without significant resistance or noise.
  • Use a thermal imaging camera to detect overheated rollers (surface temperature > 40°C during normal operation).
  • Use a vibration analyzer to measure the vibration of the roller bearing assemblies. Vibration > 4.5 mm/s (RMS) indicates critical bearing wear (according to DSTU ISO 10816-3:2004).
• **Causes, if not corrected:** Belt rubbing against stationary roller, accelerated wear of both roller and belt, increased drag, belt overlap, potential fire hazard due to overheating.

7.8. Incorrect Tape Tension

• **Why this happens:** Incorrect adjustment of the tension system (screw, hydraulic, counterweight), natural elongation of the belt over time, damage to the belt, incompatibility of the tension system with the working conditions.
• **How ​​to confirm:**
  • Measure the belt tension with a strain gauge at several points on the working and idle branches.
  • Compare the measured values ​​with the conveyor manufacturer's recommendations (usually 1.5-2.5% of the breaking strength of the belt).
  • Inspect the tensioning system for malfunctions (eg, stuck counterweights, hydraulic leaks).
• **Causes, if not corrected:** Insufficient tension causes tape to slip on the drive drum, vibrate and "float" the tape causing overlap. Excessive tension leads to accelerated wear of the tape, bearings, increased energy consumption, and deformation of the frame.

7.9. Splice Defect (Ribbon Connection)

• **Why this happens:** Poor performance of the splice during installation or repair, use of inappropriate materials, aging of the splice material, mechanical damage to the splice during operation, chemical exposure.
• **How ​​to confirm:**
  • **WARNING: LOTO required.** Carefully inspect the splice for unevenness, delamination, cracks, chips, asymmetric wear.
  • Measure the thickness of the splice and the width of the tape on either side of the splice. A thickness unevenness of > 2 mm or a width difference of > 5 mm across the entire width of the splice is critical.
• **What causes it if not fixed:** The splice acts like a wedge mechanism, constantly shifting the tape to one side as it passes. This leads to accelerated wear of the edges of the tape, drums, rollers and can cause complete destruction of the tape.

7.10. Inefficient Operation of Belt Cleaners

• **Why this happens:** Wiper blade wear, improper belt fit adjustment, squeegee mechanism clogging, improper squeegee type for material being transported, lack of regular maintenance.
• **How ​​to confirm:**
  • Inspect the wiper blades for wear and check that they fit correctly on the tape.
  • Check for material build-up on the drive/tension drum or rollers after passing through the cleaner.
• **What causes, if not eliminated:** Material sticking to the surface of the drums and rollers, resulting in uneven belt contact, misalignment and damage.

7.11. Accumulation of Material on the Conveyor Frame

• **Why this happens:** Material spillage due to bad liners, belt defects, improper loading, lack of side shields, insufficient frequency of cleaning, high moisture content of the material.
• **How ​​to confirm:**
  • Visually inspect the conveyor frame, especially under the rollers and drums, for material build-up.
  • Check loading and unloading areas for spillage.
• **What causes, if not removed:** Accumulated material creates a one-way drag on the belt, causing it to overlap. This results in increased friction, belt edge wear, fire risk and component failure.

8. Step-by-Step Troubleshooting Procedures

IMPORTANT: Before performing any corrective actions, you MUST apply the Lockout/Tag (LOTO) procedure!

8.1. Correction of General Misalignment of the Conveyor

1. Apply LOTO.
2. Use a laser theodolite to accurately measure horizontal and linear frame deviations.
3. Based on the measurements, develop an adjustment plan.
4. Level the supporting structures using wedges, jacks or other mechanisms. Permissible horizontal deviation: no more than ±1 mm per 3 m length.
5. Check the fastening of all supporting elements.
6. After adjustment, perform a test run without load, then under load.

8.2. Correction of Non-central Loading of Material

1. Apply LOTO.
2. Check the loading tray position.
3. Adjust the position of the tray so that the material is fed symmetrically to the center of the belt. Goal: deviation of the loading center from the axis of the tape no more than ±10 mm.
4. Make sure that the material does not exert one-sided pressure on the belt when loading.
5. Check the uniformity of the material flow. Adjust the feeder as needed.
6. Do a trial run with the material, visually assess the centrality.

8.3. Replacement/Adjustment of Boot Tray Footers

1. Apply LOTO.
2. Remove worn or damaged footers.
3. Install the new footers, making sure they are properly aligned and free of sharp edges.
4. Adjust the gaps between the footers and the edges of the tape. Recommended gap: 3-5 mm on each side.
5. Check the reliability of the attachment of the footers.
6. Perform a test run.

8.4. Alignment of Drive/Tension Drums

1. Apply LOTO.
2. Use a laser shaft aligner to determine the angle of misalignment of the drum.
3. Loosen the fastening of the drum bearing assemblies on one side.
4. Move or rotate the bearing unit until the axis of the drum is parallel to the axis of the conveyor with a tolerance of ±0.5 mm/m.
5. Tighten the bearing assembly fasteners to the recommended tightening torque (according to the manufacturer's manual, for example 150-200 Nm for M16 bolts).
6. Do a test run with no load, watching the belt move.

8.5. Cleaning or Repairing the Surface of Drums

1. Apply LOTO.
2. **WARNING:** Provide safe access to the reels.
3. Remove all build-up of material from the surface of the drums using brushes, scrapers or other suitable tools.
4. Inspect the drum lining. If the lining is significantly worn or damaged, schedule a repair or replacement.
5. Check the operation of the belt cleaning system (Section 8.10).
6. Perform a test run.

8.6. Alignment of Support and Return Rollers

1. Apply LOTO.
2. Identify the clips causing the match (as per the diagnostics in section 5).
3. Loosen the fixing of the roller brackets.
4. Using an inclinometer or a level, adjust the position of the roller so that its axis is perpendicular to the axis of the tape. Permissible deviation: no more than 0.2°.
5. Tighten the brackets. Tightening torque: 80-100 Nm for M12 bolts.
6. Do a test run while watching the tape move.

8.7. Replacing Jammed or Badly Rotating Rollers

1. Apply LOTO.
2. Dismantle the faulty roller, observing safety.
3. Install the new roller, making sure it rotates freely.
4. Make sure the roller brackets are installed level and perpendicular to the belt axis (Section 8.6).
5. Tighten the fasteners to the recommended torque.
6. Perform a test run.

8.8. Tape Tension Adjustment

1. Apply LOTO (if tension system requires).
2. Measure the current tension of the tape with a strain gauge.
3. Adjust the tension station (screw, hydraulic, counterweight) to achieve the manufacturer's recommended tension value (for example, 1.8-2.0% of the breaking strength of the tape).
4. **CAUTION:** Adjust tension gradually, evenly on both sides, to avoid warping of the drum.
5. After adjusting the tension, perform a test run and check the tape alignment. Re-adjustment may be necessary.

8.9. Tape Splice Repair or Replacement

1. Apply LOTO.
2. **IMPORTANT:** Splice repair or replacement requires specialized skills and equipment. If the defect is significant, it is recommended to involve qualified personnel.
3. If it is a mechanical splice, check and replace the damaged elements. Tighten the fasteners to the recommended torque.
4. If it is a vulcanized splice, asymmetry > 2 mm or significant damage requires full replacement or professional repair.
5. After repair/replacement, perform a thorough visual inspection and splice thickness/width measurement.
6. Perform a test run.

8.10. Maintenance and Adjustment of Belt Cleaners

1. Apply LOTO.
2. Check out the tape cleaners. Replace worn blades.
3. Adjust the fit of the cleaners to the tape according to the manufacturer's recommendations. Ensure uniform and tight contact across the entire width of the belt.
4. Check the tensioning mechanisms of the cleaners for efficiency.
5. Do a test run to see how well the cleaning works.

8.11. Cleaning the Conveyor Frame from Accumulated Material

1. Apply LOTO.
2. **WARNING:** Use appropriate PPE (gloves, goggles) and safe cleaning methods (brushes, shovels).
3. Carefully remove all accumulated material from the conveyor frame, rollers, drums and other elements.
4. Identify the source of material spillage and eliminate it (eg adjust footers, repair tape).
5. Regularly check the cleanliness of the conveyor.

9. Preventive Measures

Regular maintenance and proactive measures are critical to prevent belt misalignment and ensure reliable conveyor operation.

10. Spare Parts and Components

It is critical to have the necessary spare parts available to ensure smooth operation and quick elimination of conveyor belt overlaps. UNITEC-D GmbH offers a wide range of high-quality components that meet CE and UkrSEPRO standards.

Visit our UNITEC-D E-Catalog for ordering and detailed information on the range of spare parts and components.

11. Links

• DSTU EN 619:2018 (EN 619:2002, IDT) – Equipment for continuous transportation. Safety and electromagnetic compatibility (EMC) requirements
• DSTU EN 1037:2018 (EN 1037:1995 + A1:2008, IDT) – Machine safety. Prevention of unexpected start.
• DSTU ISO 9001:2015 – Quality management systems. Requirements
• DSTU ISO 10816-3:2004 – Vibration. Evaluation of machine vibration based on the results of measurements on stationary parts. Part 3. Industrial machines with a nominal power of more than 15 kW, a nominal speed of 120 to 15,000 rpm.
• NPAOP 29.2-1.04-07 – Occupational safety rules for the operation of lifting cranes, lifting devices and related equipment.
• Operation and maintenance manuals from conveyor system manufacturers (OEM).
• Internal standards of safety and operation of the enterprise.