The twin tower design allows for continious adsorption of water vapor from compressed air by using hygroscopic dessicant with high crush strength and a high surface/volume ratio.Drying is accomplished by passing compressed air through one dessicant bed adsorbing moisture while the other is being simultaneously regenerated with the expanded purge air.

Regeneration of dessicant is accomplished without the use of heat. The wet bed is dried by diverting a small portion of the super dry air from the outlet at near atmospheric pressure. The purge flow rate is adjustable to suit the specific outlet conditions(desired dew point).The super dry air flows in a counter direction through the wet bed, sweeping all the water vapour previously absorbed by the dessicant.

YAD ensures pressure equalization in the twin towers prior to switching. This prevents line surge and minimizes dessicant attrition.The tower being reactivated will be gradually re-pressurized at the end of its reactivation cycle before switch over takes place. Purge flow and depressurization are in downward direction, counter flow to the drying air flow.