Vacuum Belt Freeze Dryer

Vacuum belt / band driers consist of a housing with built-in conveyer belts for the product running over heating plates. Automatic belt control ensures precision belt operation. The belts run parallel to one another and a metering pump with oscillating application nozzle is assigned to each individually controlled belt. The shift in the boiling point under vacuum provides for a low evaporation temperature and therefore gentle product temperature. Pumpable products usually run through a highly viscous, frequently sticky phase during the drying process. This formation of vapor bubbles in the product results in a dry cake on the belt toward the end of the drying process. The temperature to which the product is subjected during the drying process has a significant effect on the achievable product quality. The belts run over a number of heating zones and over a cooling zone at the end. Steam, pressurized water or thermal oil can be used for heating; each zone can be controlled separately, allowing the temperature of the heating surfaces to be adapted to the specific requirements of the product. The entire vacuum belt / band drying system is controlled by a stored program control (SPC) and operated over a control panel or PC. All parameters and errors are logged. Recipe mode, hand-over protocol, supervisor, server link, and operating and maintenance instructions via PC are possible. The dry cake is cooled to a brittle breakage consistency in the final zone, then chopped up with a guillotine and crushed up in a breaker or granulator..