Unfortunately, designers often focus on the lowest installed cost of the structure around the head and snub pulleys, without allowing enough space for optimum cleaner installation.
Belt cleaners should be installed at an ergonomic height above the work platform to encourage proper inspection and service. Carefully considering the location of cleaners in the design stage will lead to more effective inspections, maintenance and performance.
Belt cleaners can be placed anywhere along the return run of the belt, as long as the belt is supported in some fashion. Because it’s desirable for the carryback cleaned from the belt to return to the main material flow, most belt cleaners are installed inside the discharge chute.
Cleaning on the head pulley – labeled the “primary cleaning position” – is preferred. Cleaning the dirty side of the belt before it reaches a snub, bend pulley or return idlers is considered less desirable, requiring a dribble chute for cleaners in the secondary position.
The secondary position is complicated by another fact: The nature of carryback is such that it can adhere to vertical surfaces and not flow down a sloped dribble chute. A tertiary position is sometimes required for difficult materials or critical applications such as conveying over wetlands. In such cases, tertiary cleaners are often enclosed in a spray box and the effluent is directed to a settling basin.
Belt cleaning pressure & blade wear
Without enough cleaning pressure, the blade cannot stay in contact with the belt, resulting in poor carryback removal effectiveness and increased blade and belt wear.
With too much cleaning pressure, the cleaning performance declines due to deflection of the elastomeric blade or metal blade indentation into the rubber belt. Power consumption also increases dramatically with excessive cleaning pressure.
Keeping a belt cleaner properly tensioned is critical for maximum effectiveness and the lowest cost of ownership. The cleaning pressure usually varies over time based on a maintenance department’s attention or lack thereof.
Final thoughts
Many belt cleaner systems are installed and forgotten. A survey of technicians indicates that about 25 percent of all belts have cleaners installed, and of that percentage, only about 25 percent are properly maintained.
Lack of inspection and maintenance results in a gradually lower level of effectiveness, higher operating cost and an increased exposure to the hazards associated with cleaning up carryback.
Effective belt cleaning starts in the design stage, with adequate space for cleaners and well-positioned work platforms for ergonomic inspection and maintenance access. Service-friendly designs improve production, minimizing carryback and prolonging the life of equipment.
If cleaners are located in the optimum positions and are easy to access, it is more likely that regular inspection, cleaning and maintenance will be performed, delivering optimum results.
Information for this article courtesy of Martin Engineering.