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The Maximum Mix


Modular Welded-Wire Screen Panels Boost Open Area and Wear Life.

By Carol Wasson

Screening efficiency is measured by the percentage of material that passes through the screen deck when compared to the total amount of the same-size material in the product stream. While some operations settle for moderate efficiency, others are constantly fine-tuning their screening circuits to achieve optimum productivity and profitability. Although there are many factors that affect screening efficiency, one of the key initiatives is finding the “maximum mix” of screen media for each processing phase. When implemented, the maximum mix of strategically-blended modular panels delivers a host of benefits, while lowering operating costs per ton.

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Modular Metaldex panels are applied at the discharge end where increased open area is critical in eliminating recirculating loads.
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When placed in the middle of the deck, Metaldex panels allow greater material retention, giving near-sized particles more opportunity to pass through.

According to Spartanburg, S.C.-based Polydeck Screen Corp., modular synthetic rubber or polyurethane screen panels have gleaned high marks for safety in handling; flexibility in customizing the deck surface; and wear life that’s many times greater than traditional side-tensioned wire cloth. However, some producers perceive that synthetic panels offer less open area. In certain applications, there are those that feel the use of traditional wire cloth is the only way to achieve maximum throughput. Thus, they are often willing to deal with the frequent changeouts, downtime and maintenance costs associated with standard wire cloth – all situations which reduce cost-per-ton efficiencies.

To address these concerns, Polydeck designed and engineered a new modular welded-wire screen panel system, Metaldex, which can be combined with modular synthetic screen panels. When blended together, each in strategic locations, the result is improved efficiency and increased wear life over a conventional wire cloth deck.

Optimum Screening Efficiency

“I see the use of Metaldex panels as a problem solver that you can apply where and when you need them, using them side-by-side with rubber or polyurethane panels,” said Brian Cody, who serves Polydeck as its South Atlantic regional sales manager. He explained that the 1- x 2-ft. panels feature welded wire sections encased within polyurethane borders. “They are much easier to handle than bulky 4- x 8-ft. wire cloth sections, so you can simply plug them into any problem area,” Cody said.

Cody recently consulted with two different granite operations to help them reduce carryover and recirculating load issues. Each applied Metaldex screen panels to a section of the top decks of 8- x 20-ft. triple-deck screens. Cody stressed that the top deck meters the production volume of the plant. “The more you can get through that top deck, the more you can feed the entire plant,” he said.

Both operations had been using rubber panels on the top decks as effective options to handle the abrasive material. However, a portion of near-sized material was not passing through the apertures, causing material to continually loop back to the crusher in a recirculating load, that in turn, caused a bottleneck in feeding the crushers. The operation would then have to throttle back the plant. “Initially, they wanted to remove some of the rubber panels and put in wire cloth to relieve the load and attain more throughput,” said Cody. As an alternative, he presented the concept of placing a 4-ft. section of Metaldex panels in the middle of the top decks. Cody said that when placed between rubber panel sections, the welded-wire panels would create a low point where material would be retained longer and would have more opportunity to pass through. “We were able to reduce the carryover by 50-percent at each plant,” he stressed.

Perhaps the most unique feature of Metaldex, said Cody, is that it’s welded wire versus woven wire, and it’s comprised of abrasion-resistant AR 500 Brinell steel, which provides extended wear life in most applications – up to one-half the wear life of rubber. “One of the granite operations in my region has logged more than 100,000 tons across the screen deck before ever changing out a panel,” he added.

Greater Productivity and Profitability

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To meet the needs of a variety of applications, Metaldex panels are available with apertures ranging from 9/16 in. to 2-1/2 in.

By continually fine-tuning screening circuits, operations can achieve ever-increasing productivity and profitability. “When a screen is operating at peak performance, the bulk of material passes through the apertures as it travels over the first two-thirds of the screen. As the remaining material hits the discharge end of the screen, all the near-sized particles should pass through as well,” said Shane Gee, Polydeck’s regional manager for the South-Central states. “The result is high-value products that meet the most stringent specifications,” he added.

Metaldex panels, explained Gee, offer open area that is at least equal to wire cloth with the same aperture and wire diameter. Importantly, he adds that the modularity of the panels allows operations to apply them at the feed end, or the discharge end particularly, where increased open area is highly critical in eliminating recirculating loads.

Gee worked with a Texas-based limestone operation that faced issues with bed depth on a middle deck. After the installation of Metaldex on the discharge end, the operation increased its screening efficiency by more than 15 percent. Additionally, according to the plant manager, the new panels and its flexible frame and fastening system eliminated the potential of product contamination.

“Since the welded wire insert is embedded in a polyurethane border, it can be easily secured to Polydeck’s Pipetop II stringer system with pin-style fasteners. This stringer system also allows producers to apply ‘the maximum mix’ of metal and synthetic panels on a particular deck to meet the specific product requirements,” said Gee, adding that the modularity of the Metaldex panels means that they don’t have to be crowned, and can be applied to a flat deck that has already been running Polydeck modular synthetic media.

“Processing flexibility is another benefit,” said Gee. With the modularity and the versatile frame system, he said, operations can easily changeout panels, mixing and matching to accommodate varying material feed; or to meet the processing requirements of multiple products.

“As regional managers, we work closely with producers to analyze the applications, evaluate screen performance, and create panel configurations that deliver the desired results,” Gee stressed. “Metaldex is a specialty screen panel that enhances Polydeck’s range of screening solutions. It’s imperative that we listen to customers, solve problems with innovation, and ensure that producers can put more saleable product on the ground,” he said.

Carol Wasson is a Fort Wayne, Ind.-based freelancer.