A roller mill is a piece of heavy-duty machinery used to crush or grind objects like wheat or rocks. These machines function similar to a steam roller, and pulverize items into smaller particles or fibers. Roller mill machines are widely used in the agricultural and food-processing industries, particularly in grinding grains and barley to make bread, flour, and beer. These machines may also be used to grind rocks during mining operations, or to produce a variety of powders and chemical products.
A standard roller mill uses one or more grinding wheels to reduce objects down into smaller particles. Many feature a gas-powered motor or engine, which is attached to the grinding wheels using a series of belts. These belts cause the rollers to rotate in opposite directions. As objects pass between the wheels, they are subject to friction, which crushes or grinds the material into powder. Depending on the material being processed, the rollers themselves can be made from metal or ceramic.
Buyers can choose from both horizontal and vertical roller mill designs. A horizontal roller mill features two rollers aligned on the same horizontal plane. Materials are dropped down between the rollers and crushed or ground. The ground particles may then pass through smaller sets of rollers below for further refinement.
In a vertical roller mill, the objects being ground are placed on a large spinning plate. Centrifugal force causes the materials to spread out towards the edges of the plate. As they reach the edges, they are ground down by rollers placed around the perimeter of the plate. The powdered particles are then drawn upward due to air or vacuum forces within the unit. Larger, unground particles fall off the edges of the plate, where they can be further ground down.
Compared to other milling techniques, a roller mill allows for fast and efficient breakdown of a wide variety of materials. The rollers on these machines feature a large surface area, which enables users to maximize production rates. Many roller mills are easily adjustable to accommodate different types of materials and applications. This adjustment may be as simple as moving the wheels closer together or farther apart to adjust the friction between the rollers.
Roller mill machines typically require a substantial upfront investment, and may not be the most effective option for small applications. These machines also require a great deal of maintenance due to the wear and tear on the rollers caused by the grinding process. Maintenance requirements are even higher when the mill is used with abrasive materials like rock or metals.