What type of screen is described as a circular perforated disk, sometimes with supporting bars?

The correct answer is the disk screen. This type of screen is characterized by its circular perforated disk shape, which allows for effective separation of materials based on size while also providing structural support through additional bars as needed. Disk screens are designed specifically to enhance the sorting and classification of bulk materials, making them useful in various applications, such as in wastewater treatment and aggregate processing.

Disk screens operate through a process where materials are fed onto the surface of the disk. As the disk rotates, the smaller particles pass through the perforations while larger particles are pushed aside, allowing for efficient screening. The design of circular perforations aids in reducing clogging issues that may arise with other types of screens.

The other options, such as grating screens, mesh screens, and vortex screens, have different structural designs and mechanisms for material separation. Grating screens typically consist of parallel bars or slats without the perforated circular design. Mesh screens use a woven fabric of wires, presenting a flat surface with openings, which is suitable for finer separations. Vortex screens utilize a vortex flow to separate materials, relying on fluid dynamics and different principles than those employed by disk screens.