At the beginning of a process RF heats the material quickly, evenly and helps move the moisture to the surface. The overall time is shortened in the falling rate zone because the whole product has been heated, not just the surface. The even heating avoids a dry outer layer that causes uneven dispersion of sizing and additives in the product. Another application for RF preheat is curing processes. The RF is very good at quickly heating the product to a consistent temperature, after which conventional methods are very good at maintaining the temperature for a dwell or cure time.

DRYING CURVE, RF PREHEAT