Optimizing Belt Cleaner Blade Coverage for Enhanced Performance and Longevity
Typically, the blades of a belt cleaner do not cover the entire width of the belt, as the full width is not usually used to carry material. The Conveyor Equipment Manufacturers Association (CEMA) specifies the minimum blade coverage based on belt width. Various belt cleaner manufacturers have their own standards or typical blade coverage. While many manufacturers allow for more than the minimum coverage, the blade width rarely needs to be equal to or greater than the belt width.
For improved cleaning, the width of the material on the belt should be observed or calculated and matched by the cleaner's width. In some cases, providing a blade width that is wider than the material load on the belt can lead to undesirable wear patterns. The center section of the blade will wear faster than the outer sections, due to the higher concentration of abrasive material in the center. Consequently, the outer portion of the cleaning blade may hold the center section away from the belt, allowing carryback to flow between the belt and the blade, accelerating wear on the center section. The material on the belt also provides lubrication and a cooling effect for the blade; therefore, it is important to avoid covering too much of the belt. Without this lubrication, heat buildup on the outer edges can cause the blade to fail or damage the belt.
Reducing blade coverage on the belt can help alleviate heat problems. However, when reducing blade coverage, care should be taken, especially on a cupped belt. If the belt curls over the edge of a cleaner blade, it is exposed to the sharp edge of the blade. Some cleaners use a more flexible, nonmetallic blade on their outer edges to avoid this problem. Another solution is to flatten the belt with the use of hold-down rolls.
In some applications, the blade must be as wide as or wider than the belt. A cleaner used as a squeegee to dry the belt may need to be the full width of the belt to catch all the wet areas. Some materials, like fly ash, spread on the belt or flow horizontally across the belt cleaner. In this case, if the blade does not extend to the full width, the material can build up between the belt and the cleaner support shaft, where it can harden and damage the belt.