Compact Heatless Air Dryer

The term "desiccant dryer" refers to a broad class of dryers. Other terms commonly used are regenerative dryer and twin tower dryer, and to a lesser extent adsorption dryer.
The compressed air is passed through a pressure vessel with two "towers" filled with a desiccant material. This desiccant material attracts the water from the compressed air via adsorbtion. As the water clings to the desiccant, the desiccant "bed" becomes saturated. The dryer is timed to switch towers based on a standard NEMA cycle, once this cycle completes some compressed air from the system is used to "purge" the saturated desiccant bed by simply blowing the water that has adhered to the desiccant off.
The duty of the desiccant is to bring the pressure dew point of the compressed air to a level in which the water will no longer condense, or to remove as much water from the compressed air as possible. A standard dew point that is expected by a regenerative dryer is -40 �C , this means that when the air leaves the dryer there is as much water in the air as if the air had been "cooled" to -40 �C . Required dew point is dependant on application and -70 �C is required in some applications.