Heatless Compressed Air Dryer system (air drier) and gas dryer system for moisture removal in air & gases, These Compressed gas and air dryers (air driers) find use in majority of Industrial compressed air system and pneumatic applications. These air and gas dryer (air drier) are also offered for High Pressure gas and air drying system and applications. Following is a brief description of the working of these compressed air dryers and gas dryer systems.. A Heatless compressed air dryer (drier) is the simplest form of dessicant type gas or air dryer (drier) for achieving a dew point of -40°C or better for compressed air systems and other gas and air dryer (drier) applications . PROCESS - Wet incoming Compressed air after passing through pre filter passes through the slide piston valve assembly and is directed towards adsorber chamber I where the compressed air passes upward through the desiccant (Activated Alumina / Molecular Sieves). Compressed Air drying takes place by adsorption. Dry Compressed air from adsorber chamber I then passes through the Check valve assembly and then through the after- filter to the application or work area. While Compressed air is being drying in chamber I the desiccant in chamber II where the desiccant has been wetted in the previous cycle is being simultaneously regenerated. The chamber II is depressurized to atmosphere through the purge valve in the downward direction. A portion of the dry compressed air passes through the needle valve / orifice plate through the desiccant and flushes out the desorbed moisture. When the regeneration is complete, the purge valve is closed and the tower is slowly repressurised to line pressure for a smooth changeover. A drying period of 5 minutes provides an efficient dew point of -40°C or better (at atmospheric pressure). In regeneration process approximately 30 seconds are required for repressurization.