When planning a bulk materials handling operation, choosing the right machine to do each job is very important. Machinery has evolved into extremely efficient “tools of the trade” since the pick and shovel. Unfortunately, the mindset of many managers for choosing a belt cleaning system is still in the days of the pick and shovel, Today, belt cleaners are engineered machines, each carefully designed to do a specific task.
Installed on the face of the head pulley below the material trajectory, a primary or pre-cleaner uses a urethane blade to remove the overburden of material from the belt.
Secondary cleaners are installed to remove fines and sticky clays at the point where the belt leaves the head pulley or along the return. Shock absorption is built into the cleaner or tensioning device, allowing metal belt splices to pass without damage.
Tertiary or final cleaners should clean grooves, cracks and abrasions in the belt cover while removing water.
The criteria to choose a belt cleaning system should be as carefully developed as the considerations for selecting a continuous miner, roof bolter or underground equipment.
How Clean Is Clean?
The first thing to consider is the operation’s goals for the cleaning system. Do you want a belt that won’t drop “too much” material, or do you need a belt that is “white glove” clean. Are you trying to keep regulatory agencies – EPA, OSHA, MSHA, State DEQ or neighbors – happy? Or is your goal to reduce cleanup labor and improve idler life? And most important: given the realities of maintenance budgets and staffing, what level of cleaning are you willing to accept?
It is best to know – and spell out – in advance what the goals are for the performance of a cleaning system.
Next, the conveyor itself must be considered. You must note the “measurables” for the conveyor, including:
- Belt Speed
- Belt Width
- Width of the material on the belt
- Head Pulley Diameter
- Type and Condition of Splices
- Specifications of the Belt, including manufacturer, and cover thickness
- Condition of the Belt Cover (cuts and grooves)
- Types and Locations of take-up units
- Drift Back
- Clearances to install and service cleaners
These specifications establish a “duty range” for the cleaning system – medium, heavy or extra heavy-duty.
Conveyed Material Characteristics
The next criteria that must be considered are the characteristics of the material, including:
- Clays (“stickiness”)
- Moisture Content
- Lump Size (Maximum and Typical)
- Tons Per Hour
When specifying a belt cleaner it is best to consider the material in its worst state. That way, the cleaning system will be prepared for adverse conditions when they inevitably occur.
Cost vs. Price
Finally, the issue of cost must be considered. Too often, price is the first criteria to be evaluated when purchasing a component. It is better to place this issue at the end of the selection process.