Kaeser externally heat regenerative desiccant dryers produce dew points as low as -4°F, and down to -40°F if equipped with the optional “Purge Booster”. Twin desiccant beds of activated alumina alternate between drying and regenerating, with regeneration being accomplished with heated process air (7%) reduced to near atmospheric pressure before entering the tower and passing downward through the “wet” desiccant bed. The heated purge air, which becomes extremely dry by the reduction in pressure, readily drives adsorbed moisture off of the desiccant preparing it for another adsorption cycle. The moisture-laden purge air exhausts to atmosphere during the regeneration process. Solid state logic accurately controls inlet and purge valves which direct wet compressed air to the regenerated tower, and heated purge air to the tower in need of regeneration. The process of adsorption and desorption can be repeated several thousand times before the desiccant must be replaced. | 
