Hot air dryer ASA Series

rotary drumbatchfor the food industry

OPIS DZIAŁANIA Roll driers belong to contact driers with adhering layer of dried material. They use cylinder heated with steam and put on the outside moist material. Dried material is spread on the rotating roll in thin layer with uniform thickness. During the partial rotation the product is dried and cut with special knife. Such drying system is used for liquids, various gel types and paste consistence substances. Product may be obtained in form of film, flakes and powder. The condition of roll drier use is the product ability to laminar adherence to the roll. This method is limited for foaming and melting products. Roll driers demonstrate higher energetic efficiency than pneumatic driers. Heat energy supplied to the cylinder inside is almost completely transferred to the dried, moist material. The energy amount, supplied by steam is almost the same as the amount required for product heating, water evaporation and overcoming the energy of water and product bonding. Depending on product type and heating steam pressure, 1 kg of evaporated water requires 1.2 – 1.5 kg of steam. Condensate is removed from the drier drum through the same head, which supplies steam. Vapours with low density are collected to the hood and taken away with air. High temperature of drying roll, due to momentary contact time, does not have negative influence on product properties. Drier configuration is adapted to dried product characteristics. The main criterion of driers division is dried product feeding method.