Rotary screens are commonly used in food machinery to separate particles by size. The process involves a rotating drum with a mesh or perforated sheet. Generally these screens consist of a cylindrical drum with an inclined feed inlet at one end, a discharge at the other end and an axial mesh that is wrapped around the circumference of the drum. The mesh can either be of plain weave or a perforated sheet.
As the drum rotates, product entering through the feed inlet passes over the mesh and the sizes particles are separated and discharged at the other end. The size range for separation is generally in the range of 10 – 1000 microns. The inclined design of the inlet and the circumference of the drum promote the movement of the particles to the mesh. The cylindrical mesh is rigid and maintains a uniform mesh size all around the drum.
The mesh can also be constructed of different materials to suit the application. Typical materials used are stainless steel, bronze, aluminum and rubber. Different mesh materials can also be used to suit specific needs and applications. Generally, stainless steel is used for food applications and bronze is used in industrial applications.
The rotary screen can be designed in custom sizes depending on the application. Screen sizes can be up to 6 feet in diameter with lengths up to 12 feet. The screen capacity, or the amount of product it can process, is also dependent on the size of the drum, electric motor and other components.
The design and operation of rotary screens is also very simple, with no complicated moving parts. The advantage of this simplicity is that there is very little maintenance required in comparison to other types of food machinery. As an added bonus, the screens are usually very quiet in operation.
Rotary screens are a very efficient type of food machinery and they can be used in a wide variety of applications. They are used predominantly for separating particles by size and can be applied in industries such as cereal processing, flour, malting, seed cleaning and grading, food production, and animal feed.
Generally, rotary screens perform best in applications where the materials are steady with a uniform size and are free from large chunks or contaminants. In the food industry, the use of rotary screens is the most cost-effective method for material classification, and they are widely used in the production of food stuffs such as bread, pasta, noodles, and other processed foods.
In summary, rotary screens are widely used for separating materials by size and are an essential piece of food machinery in the food industry. They have a simple design, are easy to use and maintain, and are reasonably priced. With these benefits, a rotary screen can be an indispensable part of any food processing plant.
