A highly loaded piece of rotating equipment such as a conveyor pulley will no doubt experience some level of deterioration over time.
Pulleys will eventually start to show signs of wear and will either need to be refurbished or replaced with a new one. Usually, a failing pulley will show a few symptoms that can alert the maintenance team there is an issue and potentially avoid a pulley failure.
Pulley failures can have catastrophic consequences and take extended periods of downtime to repair, so understanding the warning signs is key.
Here are some of the most common signs your pulley needs replacing or refurbishing.
Visibly worn pulleys
The first action maintenance teams can take is checking if the pulley passes the eye test. Over time, the pulley and its various components will eventually start to show visible signs of wear, especially those pulleys in harsh environments.
Things to check for include:
- Visible damage to the end plate, bearing housing, shaft and lagging
- Material build up on pulleys (tail pulley/drive pulley/stacker bend pulley)
- Excessive or uneven wear and deterioration of the lagging
- Noticeable deflection or noise coming from the pulley
- Visible cracks on the shaft, especially near a drive coupling or any changes in shaft diameter.
- Damage to locking assembly bolts
Regularly walking the conveyor system to check for damage is good practice for maintenance teams.
Out of square pulleys
When a pulley is not mounted level and square to the centre line of the conveyor belt it can cause issues such as poor belt tracking and premature pulley or bearing failure and must be resolved. This happens due to various reasons including:
- Misalignment of take up trolley or guide rollers missing
- Take up trolley misalignment or obstruction
- Worn or damaged pulley lagging
- Worn guide liners
Things to look for:
- Worn and damaged pulley lagging
- Missing guide rollers on trolley
- Visual inspection of the skew on the trolley
- Take-up trolley doesn’t move freely or sticks in spots
- Worn guide liners on take up pulley
- Vibration, noise, or heat in the bearing area
- Build-up of material in lagging
Another warning sign that a pulley needs replacing or refurbishing is a damaged bearing. This can be quite serious and can lead to a range of issues.
Early detection can allow the maintenance team to replace at risk bearings during scheduled downtime and avoid a catastrophic failure.
Damaged bearings often show the following symptoms:
- Changes in vibration, noise, or heat in the bearing area
- Contamination in the bearing area
- Uneven resistance
- Changed lubrication conditions
Pulley lagging issues
Often the most visible signs of deterioration can be found on the pulley lagging. Pulley lagging plays a key role in protecting the pulley and assists in transferring energy from the pulley to the belt.
General wear and tear can occur on the lagging and when left unchecked can cause major issues for the conveyor.
Things to look for:
- Signs of excessive belt travel and a history of tracking issues.
- Worn out lagging or bulging that could mean the lagging has lost adhesion to the shell.
- Rocks caught in lagging
- Splitting of the shell
PROK offer a range of pulley lagging options to suit every situation, including customised systems. If you’re not sure what the right solution is for your Pulleys, PROK can find the best option for your operating environment, budget and performance expectations. Find out more here.
PROK engineers and technical sales staff have inspected many pulleys that have prematurely failed in service, and there are some common issues that are present. Understanding some of these common issues may save the conveyor from experiencing significant downtime, and save money in the long run.
Its team of engineers can also provide on-site conveyor support to help improve conveyor performance, including diagnosing common conveyor issues.