Aggregates Manager Digital Magazine
Issue link: https://read.dmtmag.com/i/113147
TECHNOLOGY A three-phased approach to screening, with the proper media used during each phase, can improve operational efficiency. A three-stage blending process can yield maximum efficiency and prolong wear life. by Florian Festge T hey say good things come in threes. In the case of screening for aggregate operations, profit comes in three distinct phases: layered, basic, and sharp screening. But how good they are — whether they maximize efficiency and improve the potential for success — depends on having the right screen media on the deck for each of the three phases. A relatively new method for achieving that goal is a blended screen media approach that incorporates the right screen media for each phase and the right mix of media for the process overall. The goal in implementing a blended solution is to find the optimal combination of open area and durability. Hit the sweet spot, and an operator can maximize product quality and profits by increasing efficiency of classification while minimizing downtime and maintenance costs. Three distinct phases and outcomes During the first phase of screening, the layered phase, a deep bed containing coarse and fine particles hits the screen at the feed end of the deck. In the basic phase, the particles begin to stratify as fine material settles at the bottom and larger material climbs to the top of the bed. The sharp phase occurs toward the discharge end of the deck. It is during this final phase that the near-size particles move into direct contact with the screen media and have the last opportunity to fall through the openings. There are typically two scenarios aggregate operations want to avoid when it comes to screening. The first situation is the result of a deck that completes screening too early. In this scenario, particles travel only about a third of the way down the deck until all the undersize material has passed through AGGREGATES MANAGER March 2013 33