Edge mill

Oelmuehle

Edge mill is a type of mill used for crushing or grinding in which stones roll around on their edges on a level circular bed. They were developed in China in the third century and are still used today in areas where access to more sophisticated milling technology is limited. This milling technique is often associated with the processing of materials ranging from ores to agricultural products.

History

The edge mill has its origins in ancient China, and was primarily used for grinding grain, making it an essential part of early agricultural processing. Over time, its use expanded to other materials such as ores and spices, making it a versatile tool in various industries. The technology spread from China to the rest of the world, including Europe, where it was adapted for a wider range of uses.

Design and Operation

The basic design of an edge mill consists of a large, circular stone plate that is mounted horizontally. This plate, often powered by animal, water, or wind power, rotates around a central axis. Smaller stones or metal blades are attached to the plate's edge, and as the plate rotates, these edges grind down the material placed on the bed of the mill.

Materials to be ground are fed into the center of the plate and gradually worked outwards under the rolling action of the edges. The ground material is then collected from the perimeter of the mill. The fineness of the finished product can be adjusted by setting the stones closer or further away from the bed.

Applications

Originally used for grinding grain, edge mills have been adapted for a wide range of applications. In the agricultural sector, they are used for milling grains into flour, crushing sugarcane, and processing spices. In the mining industry, edge mills are employed to crush ores to extract valuable metals. They are also used in the production of traditional medicines, where precise control over the grinding process can affect the quality of the final product.

Advantages and Disadvantages

One of the main advantages of the edge mill is its simplicity. Its basic design makes it easy to construct and operate, requiring minimal technical knowledge. This simplicity also makes it an affordable option for small-scale operations in remote areas.

However, the efficiency of edge mills is relatively low compared to more modern milling technologies. The process can be labor-intensive, and the quality of the ground material may vary. Additionally, the wear and tear on the stones or blades require regular maintenance to ensure consistent performance.

Modern Usage

Despite the advent of more efficient milling technologies, edge mills remain in use in various parts of the world, particularly in developing countries and in applications where traditional methods are preferred for cultural reasons. They are also featured in living history museums and historical sites, where they serve as a demonstration of historical milling techniques.

See Also

• Mill (grinding)
• Watermill
• Windmill