Triple-Deck Screening Come of Age at Hillhead 2007 with McCloskey S190-3D
Quarry operators got their first look at a new portable screening plant from McCloskey International at Hillhead 2007, the first of a new generation of triple-deck screenboxes.
According to company president Paschal McCloskey, "The new S190-3D flatdeck screener has come very soon after our introduction of the original S190 screener, because the 3-deck version was part of our design plan right from the outset. As a result, we have been able to remedy many of the problems that other plants have encountered from having a third screen deck retrofitted to existing screeners."
The original S190 two-deck model was introduced in January of this year, the larger of McCloskey's two S-Series flatdeck plants to feature the innovative High Energy screenbox. These screeners provide a significantly longer vibratory stroke with larger bearings than traditional plants, allowing faster, cleaner throughput. They also allow for steeper screen angles than other comparably sized machines and more precise control settings. The S190 is based on a 1,5 m by 6 m screenbox which measures a total of 17,65 m2 of total screening area over its two decks. Its small counterpart, the S130, offers the same features with a 1,5 m by 4,3 m screenbox.
With the S190-3D, McCloskey has beefed up the bearings further, to support the additional weight of material over the three decks, but is otherwise based on the same engineering as the two-deck model.
Throughout the S-Series models, McCloskey has taken pains to ensure that the effective screening area truly measures up to the nominal size of the screenbox. The middle deck of the S190-3D, in fact, provides the same amount of screening mesh as the top deck: a true
1,5 m by 6 m area. Altogether, the three decks provide 27 m2, representing an increase of approximately 35% more active screen than other triple-deck plants.
The difference in processing capacity is simply a reflection of the difference in the origin of screeners in this class.
Paschal McCloskey continues, "We purposely designed the S190 with ample spacing to add a full-size middle deck, and to accommodate the functions that have been a problem for other machines." Previous triple-deck screens have been known to have problems with transferring material from the box to the fourth product conveyor, as well as with providing adequate access for changing screens efficiently. The S190-3D provides major design improvements addressing both of these issues.
While most triple-deck screeners rely on a chute retrofitted into the machine to transfer material from the box to the fourth conveyor, the S190-3D utilizes a small, dedicated conveyor to keep fines moving through the system. According to Paschal McCloskey, "Anyone who has screened a wet or sticky type of material through a 3-deck, knows how ugly things can get when that chute blocks up. A chute works well enough for dry, free-flowing material, but we felt that a conveyor would make this screener far more reliable for a wider range of materials. It just puts some real power to moving the material along, instead of hoping it will find its own way out via a 90° corner!"
The flow of material is also assisted by the steep angle settings available on the S190-3D. Like the three product S190, the new triple-deck offers five settings from 20° up to 30°. While steeper effective angles can improve throughput in any application, the benefit is even more pronounced in a three-deck setup. Traditional triple decks with shallow angle screens can suffer from blinding on the bottom deck, as the middle removes the stone that would otherwise help clean the bottom. With the S190's higher screening angle, the finer wires of the bottom mesh are better able to cut fine sand and gravel to keep the mesh from clogging.
Along with other products in the S-Series line, the productivity of the S190-3D is enhanced by features designed to minimize downtime for travel, set-up and service. Its "travel-out" guarded walkways are fixed in place and require no folding or disassembly for transport. The track-mounted machine is offered with an optional roll-in bogie for highway travel without requiring a float. The plant is also available as a tri-axle wheeled model.
After the screener arrives on site, set-up can be completed in as little as 10 minutes. No tools are required to ready the screener for production from transport mode. While the fixed walkways speed set-up time, they also provide maintenance staff a more stable, secure work platform. When screen changes are required, the tail conveyor drops down out of the way for easy access to the bottom of the screen box.
The large 0,4 m3 'taper out' hopper resists bridging and is equipped with a remote controlled tipping grid. Options include a heavy duty live head. A wash plant version is also available utilizing a high pressure spray box. Conveyors are engineered to maximize stockpiling capacities, with up to 5,2 m stockpile height on the side conveyors.
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