DryingThe dry air blower [9] pulls in humid return air through the upstream return air filter [13] from thedrying bin [16] containing the plastic granulate to be dried. The blower pushes the return air throughthe bottom switching valve [8] to the drying agent cartridge 2 [11]. Drying agent therein removes thehumidity from the air. The dried air, now called dry (process) air, passes through the top changeovervalve [5] back into the drying bin [16] and remains there for drying.