Flash Dryers and Coolers
Flash dryers are also known as pneumatic dryers. Flash dryers are used for drying free flowing powders or cakes containing moisture. A typical flash dryer consists of a long tube or duct called the flash duct, which is used to convey the product along with the hot air. The product gets dried as it travels in this flash duct and is then separated in cyclone or bag filter. The feeding system consists of a hopper having a screw conveyor at the bottom. Flash dryers are suitable for heat sensitive products. Even the heat sensitive products can be dried at high inlet air temperatures due to very low residence time of the product in the flash duct. The air can be directly or indirectly heated using steam, thermic fluid, oil, gas or solid fuel and is handled by centrifugal fans.
Flash coolers are also known as conveying coolers. The principle of operation of flash coolers is similar to flash dryers except that the product comes in contact with ambient or cool air instead of hot air. Flash coolers are mostly used as ancillary systems to drying systems to cool the product while conveying it for storage.