Fluid Bed Dryers are used to dry moist plastic material. The material to be dried is fed onto a bed of perforated metal that shakes. Air is blown through the holes to dry the material as it conveys the material as it drys. They are called "fluid" because the air is forced at a proper volume to lift the bed of plastic in the air so that the air has maximum contact with the material. Witte is the most common brand found in the plastics industry.