Screens are selected based on the type of material, throughput, product gradation, the top size in the crusher output, desired percentage of efficiency and the cut size. “An accurate choice is essential as a screen can act as a bottleneck for the capacity requirements of a project,” says Vivek Bhatia, MD & CEO, thyssenkrupp Industries India. “Normally, in the aggregate market, where the efficiency of screening is not of paramount importance, a circular motion screen is the most widely used,” he adds. “However, in the mining sector, where the efficiency of screening is of prime importance owing to the moisture in the feed, the most commonly used screens are circular motion screens, linear motion screens, flip flop screens and banana screens, which offer higher efficiency and higher ‘GD2’ value.” “Prescreens are advised if the run-off mine has more fines, like in iron ore,” recommends Vadiraj Pappu, Business Head, Mining & Construction Equipment Division, Voltas. “High-frequency screens are preferred in sand applications while elliptical motion screens take care of high moisture.” “High-frequency screens play a role in profitably manufacturing high-quality sand,” says Raj Shrivastav, Executive in Charge, Crushing & Screening, TIL Ltd. “The Astec-TIL high-frequency screen model 2618VM is ideal for post-screening applications and offers high-frequency vibration on all decks. Inclined high-frequency screens, flip-flop screens and resonance screens with air classifiers are used for dry classification and for fine screening where water is scarce.” Udayan Chakravorty, Cluster Head, Sales and Marketing, Taurian Minerals Processing sees a lot of potential in the dry screening of sand, to make it more suitable for special concreting by reducing the percentage of ultra fines. Water scarcities and environment consciousness will make these screens the best answer for manufactured sand users. In terms of the screen set-up, most Indian users buy track-mounted mobile screens for versatile operations, says Gopi Krishna More, Managing Director, Torsa Machines. “New-generation screens can be installed without any civil work and relocated after completion without any additional mobilisation expense.” - CHARU BAHRI