Improved operating results of vertical roller mills due to modified classifier

The LV classifier has been developed within the framework of a new concept to improve the gas and material flows in vertical roller mills. This classi fier is distinguished by pocket-like guide vanes concentrically arranged ar ound the rotor designed as cage. The conversion of vertical roller mills us ually leads to a throughput increase of 12 to 30 % with simultaneous saving s in power consumption of 1.5 to 5.0 kh/t for mill drive and process fan. I n addition to these great advantages, the oscillatory behaviour of the mill is also improved since the bed of material is essentially relieved due to the fines returned. An investment required for the conversion of vertical r oller mills will give a payback within a period of some months to a few yea rs depending on the individual conditions. Until now more than 40 vertical roller mills have successfully been modified all over the world, predominan tly, however in Asian countries such as Thailand, Korea, Japan and India. S o far the conversion has been limited to large vertical roller mills. Howev er within the next few months the first modified mills will be commissioned also for grinding of coal, pet coke, cement clinker and granulated blastfu rnace slag. The new LV technology implemented with more than 40 mills so fa r has resulted in an overall increase of, ew meal of 1750 t/h and a total e nergy saving of 30 MW to this day.