May 13, 2019 Fig. 2. Tray Dryer. Band (Belt) Dryers. A band dryer (Fig. 3) is preferable if the particles to be dried are rather coarse (i.e. between 5 to 10 mm). The particles spread evenly into slowly moving, e.g. 5mm/s, perforated belt. The belt moves into a drying cupboard and heat gas passes downward through the layer