There are many reasons for conveyor failure, but regular inspection and subsequent planned preventive maintenance is always far more efficient and less costly than breakdown, downtime and repair. It should be noted that conveyor belt maintenance includes proper care of the belt and also care and maintenance of the hardware, which includes idlers, pulley and belt cleaners.
Often though, it is not just a lack of proper maintenance that leads to failure. For example, belt speeds and feed configurations or even the feed material may have been changed to meet new production requirements. However, what may seem like a simple adjustment to meet demands can cause ongoing problems for the conveyor, by affecting the belt tension and the counterweight, or take-up arrangement may not be applicable to the new belt speed or capacity. This, in turn, can reduce the life of the belt componentry and be the root cause of material spillage.
Without exception, one of the most common conveyor problems is the belt alignment or tracking. To better understand this problem, it is first necessary to understand exactly what alignment actually means. A belt is considered to be tracking properly (aligned), when the edges of the belt constantly remain within the width of the pulley faces and within the confines of all the rolling components (idlers and return pulleys), while the conveyor is under full load. To achieve this, it is critical that all the components be square, relative to one another. Likewise, the belt material must be free from defects, squarely spliced and correctly tensioned.
Another area requiring careful attention is the conveyor transfer points. Loading the conveyor centrally is essential in maintaining proper tracking, as it is almost impossible to achieve and maintain proper tracking if the loading is off-centre.
Consideration must also be given to the consequences of impact at the transfer points. Correctly designed and installed support systems aid the proper tracking of the belt and can also dramatically improve material containment; in turn, this will help to reduce maintenance requirements.
It is not just at transfer points where attention should be paid to cleanliness. The importance of maintaining a clean conveyor belt and hardware needs to be emphasised strongly. For example, a conveyor with ‘carryback’ unchecked could be responsible for far more serious problems, which will guarantee the requirement for constant attention to containing material spillage and conveyor asset damage.
Therefore, it is highly recommended that conveyor belt scrapers and ploughs be used, and careful attention should be paid to the correct positioning and adjustment of these scrapers during maintenance inspections.
As with any continually operating machinery, a readily available supply of commonly used, spare parts minimises downtime, and ultimately reduces the breakdown and scheduled maintenance costs. But in today’s cost-conscious world, simply ‘having a few spares in stock’ is no longer an acceptable approach.
When it comes to spare parts, companies that rely heavily on their conveyor systems should pay special attention to the following points:
? Check the maintenance history to see what would be an acceptable minimum level of commonly used parts and never let supplies get below that level.
? Ensure that spare parts are stored correctly and safely. It is no use having minimum levels if when the parts are required, they are not in good condition due to poor storage procedures.
? Consider ‘component standardisation’. Standardising on components for all conveyors, wherever possible, can lead to significant savings in spare parts by reducing inventory requirements and reducing downtime. It also virtually eliminates the requirement for ‘specialist knowledge’ of a particular conveyor system.