Compressed air enters the dryer and is directed to a tower by the inlet valves. It then proceeds up through the tower, gives up its moisture and then exits through the outlet check valve. A portion of the dry air called â€œpurgeâ€ is metered and expanded to atmospheric pressure through an orifice assembly. The purge air enters the regeneration tower through the purge check valve, the purge air then utilizes a result of the adsorption process called Heat of Adsorbtion to facilitate regeneration of the desiccant. The moisture is picked up by the purge air and exits to the atmosphere through the purge exhaust valve and muffler. The drying and regenerating cycles occur simultaneously for 5 minutes. Just prior to the end of the 5 minute cycle the purge valve closes and the regeneration tower repressurizes before the inlet valves invert and the process starts again.