VRM Spares | Louvre Rings Nozzles Armor Plates | ATF

The louvre ring encircles the grinding table and controls the velocity and distribution of hot drying gas entering the grinding chamber. Gas flows through the angled vanes of the louvre ring, carrying fine ground material upward toward the separator while coarse particles fall back onto the table. Wear occurs from material spillage over the table edge and from entrained particles in the gas stream. In high-temperature applications (coal mills, hot raw meal), the louvre ring also faces thermal stress that can cause warping or cracking if the alloy is not suited to the temperature range.

VRM separators classify the ground material by particle size. Static separators use fixed guide vanes to direct airflow. Dynamic (or high-efficiency) separators add a rotating cage or rotor that creates a centrifugal classification effect, enabling tighter control of product fineness. Both types experience wear from the abrasive fine particles in the airstream. Guide vanes and rotor blades can be replaced individually during shutdowns.

The dam ring sits at the outer edge of the grinding table and controls the depth of the material bed. Proper bed depth is essential for stable grinding — too thin and the rollers contact the table directly (causing vibration and accelerated wear); too thick and grinding efficiency drops. Scraper blades remove ground material from the table surface and direct it toward the discharge. Both components are subject to abrasive wear and should be inspected at every shutdown.