A rotary feeder is a device used to control the flow of bulk materials from one part of a system to another. It consists of a rotating wheel or drum with chambers that fill up with material and then discharge it in a controlled manner. This device helps in managing the flow of materials, ensuring a consistent and even distribution. Rotary feeders are commonly used in industries like food processing, pharmaceuticals, and manufacturing, where they play a crucial role in handling powders, granules, and other bulk substances efficiently.