Conveyor Maintenance
Tips to Getting the Most From Your Conveyor
Published in Powder Coatings Magazine, March 2007
This article provides tips for increasing the service life of your conveyor system. These include choosing the right conveyor and system design, and paying attention to regular maintenance practices.
I recently talked to a good customer about his varied experiences with two conveyors installed in his plant. The conveyors were installed within two years of each other, but for different purposes and with very different results. I explained that the life span of two identical conveyor systems can be drastically different for many reasons. Here are the key points I related to him.
Tips to increasing conveyor longevity
Avoid weak system design. Many problems can be avoided by conservatively applying some basic rules of design. Do not exceed the manufacturer's published loading limits. So many systems that I encounter have been overloaded, resulting in accelerated wear. A heavy load placed on the chain will obviously result in wear of the chain bearings and the track it runs on. Try to distribute a heavy load over multiple chain hanging points.
Tip: Just as you rotate the tires on your car to maximize their life, move your loads from one chain hanging point to one that is adjacent, and further extend the life of your conveyor.
Don't exceed the chain pull of the drive unit. If you're even close to the limit, consider adding an additional drive unit to effectively cut the chain pull in half. Though a single drive may be able to pull the chain adequately, the weak point in the long term will be those curves that are close to the drive. They will wear out quickly and cause you down time.
Tip: install the largest radius curves possible immediately upstream of the drive.
Choose the right conveyor from the start. For example, if you use a conveyor in a powder coating application and have a great deal of overspray because of your booth, product or spray gun design, don't choose an open conveyor such as an I-beam conveyor. The exposed mechanical components such as open bearings, trolley and chain will become excessively contaminated, causing the bearings to stop turning or contaminating the product below. The chain will need to be removed frequently for cleaning. Consider an enclosed track conveyor for such an application. The moving parts are protected by the track around them.
Tips to avoiding the biggest conveyor problems
A conveyor system that is designed properly can be made to last a good long time with proper maintenance. I have tried to list, in order of frequency, the biggest problems that customers encounter which shorten the life of their conveyors:
Lack of take-up adjustment. This is such a simple adjustment on most systems that it is hard to accept how often it is overlooked. The chain take-up device ensures that the chain is pulled tight as it leaves the drive unit. As wear occurs and the chain lengthens, the take-up extends under the force of its springs. As they extend, the spring force becomes less and the take-up has less effect. Simply compress the take-up springs and your problem goes away. Failure to do this can result in chain surging, jamming, and extreme wear on the track and chain.
Lack of lubrication. Chain bearings require lubrication in order to reduce friction. The chain pull that the drive experiences can double if the bearings are not lubricated. This can cause the system to overload by either its mechanical overload protection or its electrical overload protection. On conveyors that go through hot ovens, lubricators can be left on constantly or set to turn on every few cycles of the chain.
Tip: A modern lubricator with a small "brain" that turns itself on and off according to your needs will make the process easier to manage.
Contamination of track and chain. Paint, powder, acid or alkaline fluids, abrasives, glass bead, steel shot and so on can all lead to rapid deterioration of the track and chain. Ask any bearing company about the leading cause of bearing failure and they will point to contamination. Once a foreign substance lands on the raceway of a bearing or on the track, pitting of the surface will occur, and once the surface is compromised, wear will accelerate.
Tip: Build shrouds around your conveyors to prevent the ingress of contaminants. Better yet, shroud and then pressurize the contained area using a simple fan and duct arrangement.
By Karl Scholz, President PACLINE Overhead Conveyors