Belt conveyors
Belt conveyor inspection, protection devices and safety
Quick answer
A running and static inspection checklist, the devices that protect the belt and a safety reminder about stopping distance.
Running inspection (conveyor moving)
- Drive motor cooling fins and fan inlet clear of build-up; electrical connections unstrained.
- Final drive: belts, sheaves or coupling in good order; no unusual noise or vibration in the drive train; base sound and bolts tight.
- Guards intact and well supported.
- All rolls (troughing, return, training, snub) for build-up, wear and damage; mark any that are seized.
- Belt condition: cuts, holes, damaged splices; tracking along both runs.
- Support structure, head and tail pulleys (lagging, build-up), discharge chute, pull-cord switch.
- Take-up system, skirt boards and seals, loading position (centred, not overloaded), inlet chute, belt cleaners and protection devices.
Static inspection (conveyor stopped and locked out)
The same list, but with the belt stopped, so you can see lagging wear, roll damage, splice and cleaner condition up close. Add a check of the drive reducer oil level and a look at the general condition and cleanliness of the equipment.
Protection devices
| Device | What it does |
|---|---|
| Interlock | If a conveyor stops, everything feeding it stops too, so nothing loads onto a stopped belt |
| Side-travel (drift) switch | Stops the belt if it moves too far off centre |
| Zero-speed or motion switch | Compares tail pulley speed with head pulley speed; trips on slip or a torn belt |
| Overload | Trips the motor on excess current, for example from a jam |
| Plug detector | Signals a blocked chute |
| Training idlers, guide rolls | Keep the belt aligned |
| Belt cleaners, deck plates, return scraper | Keep spillage and build-up from trapping material under the belt. A V-type return scraper at about 60 degrees sits just before the tail pulley |
| Backstop (holdback) | Stops a loaded incline belt from running back. Ratchet and pawl, band brake or over-running clutch types |
| Torque limiter | Fluid coupling or soft starting to cut start-up stress |
Safety
- Never work on a moving belt. Lock out and check that the belt you are working on is the one that is locked out.
- Never cross over a belt or work under a moving one. Never shovel material onto a moving belt.
- A pull-cord or overtravel switch is not a lockout.
- A loaded belt conveyor stops like a train. A 900 mm wide, 300 m long conveyor can carry about 40 tonnes of material on a belt of about 10 tonnes, which is around 50 tonnes to stop. Never count on a pull cord to stop the belt quickly.
Takeaway. Walk the whole conveyor on every inspection, loaded and stopped. Dirty rolls, worn lagging and a drifting belt are early warnings of the bigger problems.
Put it to work in the tool