The material a quarry processes and the procedures it employs to do so largely determine the kind of screens it should install. There are advantages and disadvantages associated with using poly screens.
To supply manufacturers with clean aggregates to make concrete, bituminous mixes and roadbases, quarries are obliged to wash their materials. It’s a key part of the classification process and removes clay, silt, shale, soft stone, roots, twigs and other debris that tarnish the integrity of the final product.
Depending on the type of screens a quarry uses, unwanted material may clog apertures and decrease operational efficiency. Polyurethane resolves this issue, as it becomes slippery when it comes into contact with water. Sediment is easily separated from the final product, creating a more effective washing process.
On a side note, authorities across the globe are developing guidelines to assist quarries in either reducing the amount of water they use or implementing more efficient washing methods. For example, Holcim Australia created a water management plan for its Lynwood Quarry – stating its intent to capture run-off and reduce its dependence on external water supplies.
Poly ripple screens also reduce pegging and blinding. While the latter occurs when screening media encounters sticky, fine material, the former transpires when irregular products enter the screen apertures but are unable to pass through.
Quarries are always going to encounter pegging and blinding, but there are ways to reduce the frequency of these issues. The nature of the poly material is key.
Due to the substance’s flexibility, the screens bend slightly when exposed to vibrations. This allows any gravel or stone to pass through the apertures. Think of an hourglass shape. When material gets stuck in the centre, vibrations expand it, so products are expelled.
One advantage poly screens have over their wire counterparts is they can sustain operations for a longer period. This durability is due in part to the nature of the material itself and its light weight, which decreases the amount of maintenance operators need to conduct on it.
Although it’s not the solution for every application, poly screening media has a role to play in certain situations, and to the benefit of quarries.
Source: The Locker Group