The pre-cleaning screen is a preliminary cleaning equipment used in flour mills or grain processing plants to separate large debris, such as straw and masonry to improve the raw grain quality .

The pre-cleaning sieve has the characteristics of large output, simple structure, convenient operation, low power consumption, certain cleaning effect, and dust. And working principle is mainly based on the particle size, using a certain size of the screen to move relative to the grain. Generally, the large amount cannot pass through the screen, and the grain passes through the screen under the action of gravity to obtain preliminary cleaning and cleaning efficiency. More than 90%.

There are many types of precleaning screening, and cylindrical pre-screening is a common pre- cleaning device.