1. Problem description and scope
Belt off-axis (off-center) is a critical problem, leading to premature belt edge wear, conveyor belt damage, cargo spillage, and the risk of production line shutdowns. This manual is intended for the diagnosis of rubber cloth or steel wire belt conveyors used in the mining, energy and industrial sectors.
Severity classification: Critical (requires immediate intervention if edges are damaged or contact with structure).
2. Safety measures
ATTENTION: All inspection and maintenance work is carried out only after performing the LOTO (Lockout/Tagout) procedure. It is necessary to make sure that the drive is de-energized and the accumulated energy (belt tension) is blocked. Use PPE: helmet, safety glasses, work gloves and special shoes. When working near moving parts, it is forbidden to be in loose clothing.
3. Necessary tools
| Tool | Specification | Range | Purpose |
|---|---|---|---|
| Laser level | Rotary | ±0.5 mm/m | Checking the parallelism of the drums |
| Torque wrench | For bolted connections | 10-200 Nm | Adjustment of tension devices |
| Metal roulette | Accuracy class II | 5-30 m | Measurement of diagonals |
| Vibroanalyzer | Portable | 10-1000 Hz | Diagnosis of the condition of the bearings |
| Cord or thread | Kapronova | - | Control of the straightness of the pond |
4. Initial assessment checklist
| Verification | action |
|---|---|
| Visual inspection of the edges of the tape | Are there delaminations or tears? |
| Availability of material on the drums | Is there sticking (growths)? |
| Condition of roller bearings | Do all rollers spin freely? |
| History of accidents | Was the loading tray misaligned? |
5. Systematic flow of diagnostics
- Load Check: If the belt only comes down under load, check the center of the load. The tray should direct the flow exactly in the center.
- Checking the drums: Check the perpendicularity of the drive and tail drums to the longitudinal axis of the conveyor using a laser level. Tolerance: no more than 1-2 mm per 1 m of drum width.
- Checking the roller supports: If the rise is in a separate area, check that the rollers are not jammed and that they are perpendicular to the belt.
- Tension check: If the tape runs down the entire length, check the tension is even. Insufficient tension leads to loss of controllability of the tape.
6. Matrix "Symptom - Cause"
| Symptom | Probable reasons | Diagnostic test | Expected result |
|---|---|---|---|
| East of the tape along the entire length | Uneven tension, skew of drums | Tension measurement, laser inspection | Tension symmetry |
| East of the tape on the site | Jammed rollers, dirt on the drum | Manual scrolling, review | Free rotation |
| East only under load | Decentralized loading | Monitoring the flow | Weight in the center |
7. Root cause analysis
Uneven tension: Occurs due to misadjustment of screw or hydraulic tensioners. This causes the tape to bend and behave erratically. Requires device synchronization.
Material Sticking (Build-up): Sticking to the drum changes its effective diameter, which causes the tape to go in the direction of less resistance (where the diameter is larger). Requires installation of effective cleaners.
Violation of the geometry of the pond: Due to vibration or subsidence of the foundation, roller supports can shift. It is necessary to check the straightness of the pond with the help of a level.
8. Removal procedures
- Adjusting the drums: Loosen the fastening of the bearing assemblies. With the help of jacks and control measurements, set the drum strictly perpendicular. Fasten with the tightening torque according to the manufacturer's instructions.
- Cleaning: Remove build-up from the drums by mechanical means (do not use percussive tools that damage the lining). Install or adjust scraper cleaners (recommended clamping pressure — 0.5-1.0 bar).
- Roller Bearing Replacement: Replace any jammed or damaged rollers. Use rollers with certified bearings (DIN 6204/6304).
9. Preventive measures
| The reason | Prevention strategy | Monitoring method | Recommended interval |
|---|---|---|---|
| Sticking | Installation of cleaners | Visual inspection | Every week |
| Roller wear | Planned replacement schedule | Vibration test | Every month |
| Skew of the drum | Geometry control | Geodetic survey | Quarterly |
10. Spare parts and components
| Description | Specification | When to replace | Category UNITEC |
|---|---|---|---|
| Conveyor roller | Diameter 89-159 mm | When noise/wedge occurs | Conveyor components |
| Tape cleaner | Polyurethane knife | When the knife wears up to 10 mm | Cleaning systems |
| Bearing unit | Self-centering | According to the lubrication schedule | Bearings |
The complete range of components is available in our catalog: https://www.unitecd.com/e-catalog/
11. Links
- DSTU ISO 21183-1:2018 (Conveyor belts)
- Technical regulations EN 618-1 (Safety of conveyors)
- Manuals of manufacturers of drive drums
