The term "desiccant dryer" or heatless Air 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 media such as activated alumina, silica gel, molecular sieve or other desiccant material. This desiccant material attracts the water from the compressed air via adsorption. As the water clings to the desiccant, the desiccant "bed" becomes saturated. The dryer is timed to switch towers, 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 (−40 °F); 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 (−40 °F). Required dew point is dependent on application and −80 °C dew point is also in some applications. Our some dryers come equipped with a dew dependent switching (DDS) which allows for the dryer to detect dew point and shorten or lengthen the drying cycle to fulfill the required dew point. It will take many times significant amounts of energy which is one of the largest factors when determining the proper compressed air system.

Heatless type air dryers are required in pharmaceutical, powder conveying systems, Pneumatic conveying of hygroscopic materials e.g. Plastic raw materials, cement conveying, high quality painting jobs in auto industry and CNC machines etc. Advance International provides spares also (Candle Filter, Valves, Silica Gel, Molecular Sieve, Activated Alumina & Carbon)and servicing for all other makes and types of dryers also. Advance International is supplying Heatless Air Dryer with capacity of 3000 CFM at 6 Kg/ cm2 and design upto 80 Kg/cm2.