Grinding with VRM SystemsVRM Drive 2 HGRS Tikaria_Mill Workshop SEPT-07 . Separation Drying Separation Feed Material Grinding 2.3 Sections Transport Exhaust gases Raw meal 1.Vertical Roller Mill (VRM) . Grinding Hot gases Energy Drive 3. Details feed gate (air lock) mill exhaust product discharge mill outlet duct separator cage rotor separator guide vanes tailings cone separator discharge flap mill casing roller with tyre or segments water injection rocker arm roller axle table liner dam ring hot gas inlet nozzle of louvre ring grinding table hydraulic cylinder material scraper HGRS clutch and motor Tikaria_Mill Workshop speed reducer with table bearing 3 SEPT-07 .Vertical Roller Mill (VRM) . Working principle Vertical rollerforce mill = Grinding Roller weight + (pressure) Force Roller rolls freely with table Material bed Feed material Table moves with drive Feed size: Max Particle size in feed: 5-8 % of roller diameter f (Roller Ø ) HGRS Tikaria_Mill Workshop 4 SEPT-07 .VRM . Material Flow inside Separator: removes fine material Gas & Product Material Feed Material rejects coarse material Internal gas flow Separator Rejects Internal Circulation Large Material falls through to scraper Material Material & Gas Gas 5 HGRS Tikaria_Mill Workshop SEPT-07 .VRM . VRM .Pfeiffer HGRS Loesche FLS Atox Tikaria_Mill Workshop Polysius 6 SEPT-07 .Some Common Mill Configurations G. Speed control TF HGRS FT Tikaria_Mill Workshop F= Feed P= Product T= Tailings 7 SEPT-07 .VRM . Vane adjustment 2.Built-in Separator conventional rotor type Conventional separator Staticstatictype P P Rotor type F T cage rotor type Cage Rotor type with guide vanes F F T P T F F F P T Separation control: 1. VRM .Separator Fotos Angle affects product sizing Rotor speed affects product fineness Rotor seal affects separator efficiency 8 HGRS Tikaria_Mill Workshop SEPT-07 . VRM .External Circulation fresh feed bucket elevator louvre ring scraper Used for reducing gas flow pressure lost over the mill (less pneumatic internal circulation) collecting conveyor 9 HGRS Tikaria_Mill Workshop SEPT-07 . Rollers & Table .Pressures Maintenance Wear .Temperatures & pressures Hydraulics .Vibration monitor .VRM .Separator (sealing!) & Housing Lubrication & Hydraulics (filters and seals) 10 HGRS Tikaria_Mill Workshop SEPT-07 .Temperature monitor Gas flow .Control & Maintenance Control Gearbox . Example flowsheet Control points 1 gas flow 2 pressure difference 3 return gas flow pressure 4 outlet temperature 5 external recirculation 11 HGRS Tikaria_Mill Workshop SEPT-07 .VRM . small size material. Good for dry.Accessories Pendulum valve Rotary valve Reduces false air entering with feed material. The magnet removes them 12 SEPT-07 . Weigh belt Metal extraction Weighs the passing material ensuring a continuous grinding bed in the mill HGRS Reduces false air entering.VRM . Better for lumpy or humid feed material. Tikaria_Mill Workshop Metal objects damage the roller & table.