Dryer should be designed for getting quality of compressed air as per ISO 8573 at the most economical costs. Generally for higher quality dry air and Pressure dew point below 2° C, Pressure Swing Adsorption type system is applicable. Heatless Air dryer is most economical PSA system to achieve the pressure dew point (-) 20° C or less.
Heatless dryer removes moisture with PSA system. Where Activated Alumina or Molecular Sieves used as desiccant. This system contains two vessels or tower with three nos. of Filters. Where pre and Oil filter are being used to arrest the physical moisture and oil and dust and the accumulated water and oil remove through Automatic Drain valve, which has fitted with filter housing.
Then the compressed air passes through 3/2 way valve controlled through controller and it travels upwards through the desiccant tower. where one tower running as drying mode and where compressed air get dries during travel upwards through desiccant bed and lastly before reaching the area of application works the same passes through after filter, where the filter element arrest the fine dust particle (if any) carry over from the desiccant while other tower being regenerate with dry purge air and reactivate the desiccant for further process/ drying. After certain time air flow direction shifts. Before change the airflow gradually repressurizd and depressurized completed by air.