The Importance of Selecting the Proper Screen Media for Vibrating Screens

May 15, 2019

As higher volume throughputs force mining operations to play catch-up, older woven wire screening solutions are falling out of favour. In order to keep up with current and future demand, abrasion-resistant engineering plastics are being pressed into service. An engineered polyurethane screen, vibrating its heavy aggregate load, can handle abrasive forces that older screening solutions cannot. Turning up the aggregate velocity, here’s a look at what happens before engineering plastics take over.
Devoid Of a Fatigue-Resistant Match

Without an abrasion resistant vibrating screen in place, the existing aggregate-sifting material ages. Fatigue accumulates rapidly, with nicks and score marks spreading. Those perfectly engineered media apertures once sorted out the undersized minerals, then the process advanced towards the next downstream station. Torn up by the continual rubbing, all of the mineral grades are now mixing together. Granted, a maintenance technician can replace the worn screens, but that takes time. The instances of downtime, when added together, represent an unacceptable period of offline inefficiency. Consequently, the first job undertaken is the selection of a screen media type that’ll offset the abrasive fatigue. Absorbing impact energy, wear-life enhanced polyurethanes are the superior choice.
Optimized Screen Media Selection

If the vibrating screens on a high-volume ore processing line just needed a tougher than nails material, then every screening deck would be fitted with perforated steel plates. Obviously, that’s not the case. There are many different types of screen media, and they all serve different, purpose-driven roles. For starters, heavier mineral loads require stronger vibrating screens. That’s a simple enough flow characteristic to gauge, right? But smaller and lighter ore samples can also simulate that heavy impact rate. Moving at high velocities, the smaller but coarser aggregate causes as much abrasive collision damage as a heavier but slower moving load. Again, although not as tough as those perforated steel plates, energy-absorbing polyurethane screens are designed to dampen high-velocity, kinetically charged collisions.

When the wrong screening media is selected and fitted to a vibrating screening deck, all sorts of time-consuming issues crop up. The woven wire splits under a heavy load, so the undersize and oversize mixes. A maintenance routine fixes the issue, but the fix is temporary. Downtime periods amass, mining managers take notice, and the operation gets a bad reputation. Even when a suitable media type is picked out by a competent processing engineer, problems are still possible. Pegging and blinding problems take place because the apertures are too small, too large, or just shaped incorrectly. Unless the screen media on a vibrating deck is made of the right material and profiled with the right apertures, this stage of the extraction and sorting process will become a production bottleneck.

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