A Rotary Screen, also known as a trommel screen or drum screen, is a mechanical screening machine used to separate materials by particle size. It consists of a cylindrical drum (typically made of steel or stainless steel) that is perforated or woven with openings of a specific size. The drum is mounted at an angle or horizontally and rotates on its axis, allowing materials to pass through the screen surface while larger particles remain inside the drum until they exit at the discharge end.