To avoid these unwanted scenarios, it’s important to be on the lookout for any potential problems and take proactive steps to prevent them.
With that in mind, let’s explore the three most common conveyor issues: belt mistracking, belt slippage, and material carry-back. What are they? What can cause them? And what can you do to keep them from happening?
The term ‘mistracking’ refers to a conveyor belt that pulls to one side and runs off its intended track. Mistracking is a significant issue that should be addressed immediately since it can lead to additional problems, including belt damage, material spillage, and even damage to the conveyor’s overall structure. There are several factors that can cause belt mistracking and those are misaligned idlers or locked rollers, faulty chute structure skirting, material overload on the belt, and crooked belt splices or worn vulcanized belt splices. Regular inspection and maintenance of your conveyor, along with choosing appropriate, good-quality conveyor components, are all things you can do to prevent mistracking and other issues from possibly occurring. It’s essential to regularly inspect idlers and their rollers to ensure the idlers are aligned properly and the rollers are running evenly. Daily greasing of roller bearings helps to avoid any locked rollers.
It’s a good idea to keep an eye on the chute skirting too, especially at the discharge points. Skirting that doesn’t contain or discharge the material properly can push a belt off track. Overloading the belt with more material than it is designed to handle can also be an issue.
Belt slippage occurs when there is either too little or too much tension in the conveyor belt. Without the proper balance of tension, a belt can slip off of the pulleys and eventually cause further serious problems, such as belt or motor failure. Like mistracking, belt slippage should be corrected right away, or better yet, avoided altogether. To lower the risk of conveyor belt slippage, regularly inspect (and replace if needed) the lagging on the pulleys, especially on the head drive pulley. Incorrectly installed lagging or lagging with a lot of wear can become smooth and lose that all-important grip on the belt. The less grip lagging has, the greater the chance a belt could start to slip. At the same time, a bent or damaged pulley can also affect the tension of the belt and result in slippage, so if you discover any broken pulleys, be sure to replace them sooner rather than later.
Out of the three main conveyor issues, carry-back is probably the most common conveyor issue. The term ‘material carry-back’ refers to material that doesn’t discharge from the bed as it should, but instead gets caught in the bed and is carried back on the return. The carry-back material either falls off the belt under the conveyor (producing what is called ‘tailings’) or continues to build up on the belt. If not controlled and eliminated, carry-back can cause serious damage to belts and other critical conveyor components. Carry-back not only affects the performance of your conveyor, but it can also impact your bottom line, causing significant material loss and creating a need for additional labour to clean up the tailings. Since tailings clean up near a running conveyor is a dangerous task that can risk the safety of your workers, eliminating carry-back on your conveyor is all the more crucial. Some causes of material carryback include poor quality scrapers, improperly installed scrapers, and inappropriate scraper type and size.
A good quality belt cleaning system, also known as ‘scrapers’, is essential to preventing carry-back. A scraper system is made up of primary and secondary blades that are designed to ‘scrape’ material off the belt and greatly reduce or eliminate any carry-back. Primary scraper blades clean the belt at the head pulley, while secondary blades, which are installed at the discharge pulley, remove any residual material remaining on the belt. Using high-performing scrapers is a must to get rid of carry-back since poor quality scraper blades tend to wear out quickly and start to flip or twist, which can make them ineffective. Be sure your primary and secondary scrapers are installed properly because blades that don’t press close to the belt won’t scrape away material. Scraper blades that are the wrong size for a conveyor’s belt or pulleys can lead to carry-back too.
Benjamin Franklin once said, “An ounce of prevention is worth a pound of cure”. When it comes to conveyors, this philosophy couldn’t be truer. West River Conveyors believes in helping you take proactive steps to prevent mistracking, slippage, and carry-back, as well as high repair costs, productivity loss, and safety risks. West River Conveyors has been designing heavy-duty conveyor systems for potash mines and other demanding environments for more than 36 years. West River has proven itself to be a conveyor product expert to the potash industry and can design unique fabrications to maximize your success.