Rotery screen constructed out of perforated plate alongwith center shaft supported on heavy bearings, drive through crown and pinion gear covered at top with discharge chute.Coolers also have a rotating shell but they are of smaller size does not require refractories since they are being used to cool the material; usually the material is received from Rotary Kiln for cooling. Mostly air is being used, and sometime water is also being spread on shell keep the shell cool.