Hygroscopic resins are very often used in injection moldnig, blowing and extrusion. If nor properly treated during process such materials trapping water moisture withinthe granules can negatively affect the final result and quality of the product with the risk of consistent defected parts. In order to avoid defects during plastic processing Plastic Systems has developed a wide rang of precise, reliable and efficient dehumidifying dryers with process airflow ranging from 40 to 5000 m³/h. The range of Plastic Systems dessicant dryers, DR series, includes rotor-bed, single and double tower for desiccant molecular sieves containing, single, double and multi blower units, and microprocessor or Siemens PLC controls. The high-tech technics and theories applied to the dehumidifier design have brought to optimised solutions obtaining desiccant drying units with high performances in terms of high efficient use of molecular sieves, low air pressure drops in the air piping proper heat exchanging systems, counter-current flows bteween process and regeneration airflows together with a low energy consumption. The very high performances permit a very efficient dehumidification of all the hygroscopic olastic materials with a consistent high quality production.