flat surface of the shaped screen wire allows a greater quantity of smaller diameter crushed rock to fall through rather than bounce over the screen, causing quick stratification. Because the material separates readily, more screen area is available for remaining material to be sized. Te result is that near size material moves through the screen earlier allowing for a higher feed rate. “With shaped wire, you have more open

area in the panel. Te wire is elongated. Te shape acts like a dam to water: the rock hits the flat area and bounces through instead of continuing to ride over the top of it,” explains the quarry production supervisor. In an effort to improve efficiency

and production, he has used and tested several types of shaped wire, along with traditional round wire, in the past few years. “If you run production with shaped, wire such as Hi-Rise you can capture a lot more material,” the quarry supervisor says. “Our studies have shown that with such high efficiency wire screen, instead of conventional round woven top, you can get 25% to 30% more through.” He notes that he ran at least 300,000 tons of course grained granite using the shaped high efficiency wire screen so far.

As a manager whose sole focus is on safely and efficiently increasing production, the supervisor translates what such an efficiency boost actually means for the industry. “In my plant, right now, if I run only conventional, old school round wire screen, I would probably have to crush rock 12 to 14 hours a day, where I can now achieve the same production in eight hours with high-efficiency, shaped wire screen.” According to the production supervisor,

the increased production efficiency also reduces employee fatigue and crusher wear and tear. “If you run a crusher 12 hours to

Every rock that rides over is rock that aggregate producers are not making money on

make the same tonnage you could in eight, you are putting much greater wear on the machine for no reason.”

LIMESTONE CASE STUDY For a limestone quarry in Western New York specialising in crushed limestone, hot mix asphalt, landscape boulders, rip rap, and high calcium agricultural lime, reducing production downtime and was the main issue, according to their quarry superintendent. “We were not getting the wear life that we expected out of the traditional round wire screen. If we wanted a greater open area percentage on our screen deck, we needed to go to a smaller diameter wire, so wear and production downtime was an issue.” When the limestone quarry switched to shaped wire screen, the wear and production issue was resolved.

In the case of Hi-Rise, the shaped wire extends wear life with greater height and wear surface to abrading rock material, which results in a longer lasting screen panel. In addition, the flat sides of the shaped wire wear more slowly than standard round wire because it presents less surface area to such abrasion. As a result, the screen panel holds accurate sizing longer, further prolonging usable life. “With the Hi-Rise wire screen, we can use a heavy diameter wire, but still get the same open area percentage so we do not have to change the screens as much. In fact, we are probably getting 20% to 30% longer life span from our wire screens now and spend much less on maintenance,” the superintendent says. As far as production, the limestone

Plant screening stations are the “cash box” of the aggregate operation

quarry superintendent estimates that the switch to shaped wire screen has enabled producing considerably more. “We also have more open area and more screen efficiency with the shaped wire screen. So, we are producing about 20 tons more per hour with it than our previous round wire screen,” mentions the superintendent. While the cost of the shaped wire is slightly more than traditional round wire, the gainsin production and wear life make ROI extremely quick. “In terms of increased production as well as reduced downtime, screen maintenance and labour, I would say our ROI is essentially immediate. Tis screen innovation is definitely the way of the future.” 25

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