Aggregates Manager Digital Magazine
Issue link: http://read.dmtmag.com/i/301563
AGGREGATES MANAGER May 2014 8 from a standard screening plant. Standard screens have a tipping grid or livehead over the feed hopper to stop large material from going into the hopper. The feeder belt speed can also be adjusted in order to help produce a clean, sized finished product. These screens are at home in a sand and gravel pit, a quarry, and recycled concrete and asphalt jobs, as they often are considered "finishing screens" because they're capable of producing specific sized end products. For applications that aren't all about the specific sizes, there is another option. A scalping screening plant feeds material directly onto a screen as it comes out of the hopper, which eliminates blockages due to oversized, contaminated, and dirty material. The machine is ideal for demoli- tion contractors preprocessing materials like recycled concrete or reclamation applications. Scalping screening plants also are designed to handle much larger, heavier material in larger crushing opera- tions or for producing a gabion stone in a quarry. They are versatile, but aren't an ideal choice for creating a finished prod- uct — especially when the producer needs smaller materials to meet specifications. In fact, scalping screening plants are com- monly used to process scrap metals, sepa- rate recyclables at old slag dumps, and ex- tract rock from dirt on a construction site. Afterward, producers pull in a standard screen to perform the meticulous work. While these units have their differences, the style of screener isn't the only factor one must consider. Plenty of other little factors can make a big difference. Hopper size Let's start where the tough gets going — the hopper. This portion of a screener fluctuates in size and durability. The industry standard hopper is 12 feet wide with an option to upgrade to a 14-foot- wide hopper. Very few manufacturers of- fer a 14-foot-wide hopper off the bat, but a wider hopper is more important than one might realize. Obviously, the wider the hopper, the easier it is to feed the machine. Just an extra 2 feet can capture more product and prevent spillage. The size becomes most pertinent when pairing the screener with the loading machine. For example, excava- tors or equipment with a narrow bucket are ideal for loading a 12-foot hopper, but a 14-foot hopper is wide enough to ac- commodate a wider bucket. By compari- son, a wheel loader bucket can hold ap- proximately twice as much as an excavator bucket. The extra 2 feet of loading space makes a huge difference, so using a wheel loader is a simple way for a company to pick up extra production. Livehead and tipping grid Producers can add a livehead or tipping grid to a screener above the hopper. While they perform a similar duty, they are very different. A tipping grid is the The optional apron feeder, a belt made of metal, is for producers working with large or abrasive material. The standard belt feeder is suitable for sand and gravel operations. It is cost efficient and will hold up well in numerous applications.