Cement Americas

APR 2019

Cement Americas provides comprehensive coverage of the North and South American cement markets from raw material extraction to delivery and tranportation to end user.

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www.cementamericas.com • Spring 2019 • CEMENT AMERICAS 31 FEATURE As the center of the blade wears un- evenly, the outer edges create a "smi- ley face" or "mooning." As urethane cleaner blades wear, the surface area of the blade touching the belt increases. This causes a reduction in blade-to-belt pressure and a corre- sponding decline in cleaner efficiency. Therefore, most mechanically ten- sioned systems require periodic adjust- ment (re-tensioning) to deliver the con- sistent pressure needed for effective carryback removal. To overcome the problem of the blade angle changing as the blade wears, a radial-adjusted belt cleaner can be designed with a specially engineered curved blade, known as "CARP" for Constant Angle Radial Pressure. With this innovative design, the changes in contact angle and surface area are min- imized as the blade wears, helping to maintain its effectiveness throughout the cleaner's service life. Air Tensioning New air-powered tensioning systems are automated for precise monitoring and tensioning throughout all stages of blade life, reducing the labor typically required to maintain optimum blade pressure and extending the service life of both the belt and the cleaner. Equipped with sensors to confirm that the belt is loaded and running, the devices automatically back the blade away during stoppages or when the conveyor is running empty, minimizing unnecessary wear to both the belt and cleaner. The result is consistently cor- rect blade tension, with reduced power demand on start-up, all managed with- out operator intervention. For locations lacking convenient power access, one self-contained design uses the moving conveyor to generate its own electricity, which powers a small air compressor to maintain optimum blade pressure at all times. Sensors can be used to back the blade away during stoppages or when run- ning empty. Maintenance Even the best-designed and most effi- cient of mechanical belt cleaning sys- tems require periodic maintenance and/or adjustment, or performance will deteriorate over time. Proper tensioning of belt-cleaning sys- tems minimizes wear on the belt and cleaner blades, helping to prevent damage and ensure efficient cleaning action. Belt cleaners must be engi- neered for durability and simple main- tenance, and conveyors should be designed to enable easy service, includ- ing required clearances for access. Ser- vice chores that are straightforward and "worker-friendly" are more likely to be performed on a consistent basis. Ease of service should be a key ele- ment in any belt cleaner tensioning system. The use of factory-trained and certi- fied specialty contractors can also help ensure that belt cleaner maintenance is done properly, and on an appropriate schedule. Further, experienced service techni- cians often notice other developing sys- tem or component problems that can be avoided if they are addressed before a catastrophic failure occurs, helping conveyor operators avoid potential equipment damaging and expensive unplanned downtime. By setting the cleaning goal necessary for each individual operation and pur- chasing a system adequate for those conditions as laid out in CEMA stan- dards, it's possible to achieve carryback control and yet obtain long life from belt cleaners. The bottom line is that properly installed and adjusted belt cleaners help minimize carryback and spillage, reducing risk and overall oper- ating costs. Information for the article courtesy of Martin Engineering Co.

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