They are self-cleaning fine screens. These screens are perfect for the special treatment of fibrous wastewater such as those originating from the textile or pulp and paper industries. They are used to protect the heat exchangers. As the water crosses through the submerged portion of the disc, the solids are held back on the screening media. As the disc rotates, the solids are lifted above the water level where they are removed by a series of spray nozzles mounted on a spray header. They are available in different ranges, with different diameters.