technology
Many mining and aggregates operations have long used traditional products, such as woven wire cloth, for screens with great results. But for operations experiencing high wear and frequent screen changeouts, it’ s worth looking into engineered screen media. Materials such as polyurethane, rubber, and perforated steel plates often handle heavy and abrasive materials better than woven wire. But operators need to know how to choose the best screen media for their operation.
The difference between using‘ good enough’ screen media and optimal screen media for the application can be unwanted downtime and expense. Consider three things when selecting the best engineered screen media for an application. First, look at all aspects of an aggregate or mining operation and any challenges to increasing production rates and profitability. Second, look at the composition of the material going through the vibrating screen and consult an expert from a reputable company to match the best screen media to the application. Finally, learn to install and maintain the screen media properly.
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The first step towards selecting the most productive screen media involves answering several questions. What material is being processed? Is the screen media reaching a suitable lifespan for the operation? And what sort of challenges are occurring with the current screen media?
Consider the types of material going through the vibrating screen. Factors such as material size, weight and abrasiveness all come into play during the selection process. For example, screening gravel typically requires media with higher wearability to handle the material’ s abrasiveness. Materials with top sizes as large as 25cm, on the other hand, require screens that are more durable because of the constant high impacts.
Next, look at the vibrating screen itself and complete a vibration analysis. Some analysis systems are designed to safely monitor vibrating screen performance in real time and detect irregularities before small problems lead to diminished performance or bigger issues. In some instances, the machine may be running perfectly, but changing the screen media can prevent screening irregularities and the resulting damage.
Consider the three phases that material goes through within the vibrating screen, from layered to basic to sharp. Producers can customise the screen deck with various types of screen media through each phase by accounting for open area and wear life to maximise productivity in each phase.
In the layered phase, as material of all sizes hits the screen deck, the media should handle a deep bed depth, high impact, and a mix of coarse and fine particles. Material should stratify in the middle of the deck during the basic phase, and near-size and oversize particles should be at the top of the material being screened. Virtually all undersize material should
QUARRY SA | march 2017 _ 29