The Parker Airtek Externally Heated and Blower Purge Desiccant Air Dryer uses the absorption method to remove moisture from compressed air. Nominal pressure dew point of -40°F (-40°C) is achieved by directing the flow of saturated compressed air over a bed of desiccant.
The most commonly used desiccant in the desiccant air dryer is activated alumina, a spherically shaped, hygroscopic material, selected for its consistent size, shape and extreme surface to mass ratio. This physically tough and chemically inert material is contained in two pressure vessels commonly referred to as “dual” or “twin” towers. As the saturated compressed air flows through the bed of the “on-line” tower, its moisture content adheres to the surface of the desiccant.
The dry compressed air is then discharged from the vessel into the distribution system.
An Allen-Bradley® PLC cycles the ow of compressed air between the towers. While one tower is “on-line” drying, the other tower is “off-line” regenerating. Regeneration, sometimes referred to as “purging”, is the process of stripping the accumulated moisture from the “off-line” bed.
Both types of Parker Airtek Heat Reactivated Dryers combine heat with either a small portion of the dried compressed air or with forced ambient air to affect regeneration. The heated, low pressure purge air flows gently through the regenerating bed, adsorbing the moisture that accumulated on the surface of the desiccant during the drying cycle and exhausting it to the atmosphere.