A-DRY desiccant adsorption compressed air dryers

Desiccant adsorption compressed air dryer A-DRY has been designed to separate water moisture from compressed air thus reducing the dew point in the system. A-DRY is a range of products offering our customers a wide array of dried air solutions with volumetric flow rates ranging from 6 Nm3/h to 200 Nm3/h. An innovative new design of desiccant adsorption dryer A-DRY, developed with consideration of our customers, enables fast and reliable installation, use and servicing. Installation is simple with our ready to use controller while minimising the number of parts and motions required for assembly and disassembly makes servicing fast and reliable.

A Dry BM Heatless regeneration adsorption compressed air dryers


operating pressure 4 to 16 bar
operating temp. range
 1,5 to 50 °C
pressure dew points -40 °C (-25 °C / -70 °C)
flow rate 6 to 200 Nm³/h
standard colour RAL 5012
average compressed air consumption  15-20%


• compressed air systems

Typical applications for the adsorption dryers are outdoor installations where the risk of freezing occurs and applications with high quality requirements in terms of air dryness (PDP < +3°C) such as the process air in process industry (food and beverage, pharmaceutical, electronic, chemical, …). The most common adsorption dryers are heatless regeneration adsorption dryers due to their simplicity reliability and relatively low investment costs.


Compact A-DRY series dryer consists of upper and lower control block, controller with LED display and two alternately operated columns filled with desiccant. Adsorption takes place under pressure in the first column while the second column regenerates with a portion of already dried compressed air at ambient pressure.

When the first column is saturated to a certain level column switch-over is carried out and the process of adsorption continues in the second column without any drop of pressure at the outlet of the dryer. Regeneration of saturated desiccant is possible because a small portion of already dry compressed air is decompressed and when expanded it becomes extremely dry. 

This portion of extremely dry decompressed air also called “purge air” is then fed through the saturated column in the reverse flow direction in order to remove the adsorbed water molecules from the desiccant and release them back to the ambient.

Operating cycles

A-DRY dryers can operate in two operating modes based on setting of the controller.

Fixed cycle mode
Switch over between columns is timer controlled. Due to high quality adsorbent and advanced control method adsorption cycle is extended to 10 minutes resulting in lower amount of switch overs thus lower consumption of compressed air and less wear of vital components.
Adsorption = 5 min
Regeneration = 4 min
Pressure build up = 1 min

Variable cycle mode (Dew point dependent switch over)
If dew point sensor is connected to the controller duration of adsorption can be extended based on reading of the sensor while regeneration is still carried out in just 4 minutes. Operating dryer in variable cycle mode can result reducing average purge air consumption to an extremely low values (even below 3%).

Stand-by mode
A-DRY series adsorption dryers have an option to receive a stand-by signal from the compressor or other compressed air supply. While in the stand-by the air can flow freely through both towers in direction from the inlet to the outlet of the adsorption dryer. Meanwhile the adsorption dryer controller is in the stand-by mode and ready to resume with the normal operation as soon as it gets the appropriate signal. The stand-by signal is relayed to the A-DRY adsorption dryer through a stand-by contact on the controller by a connected switch.

Easy maintenance

Due to innovative column design desiccant replacement can be done in a few minutes. Complete column can be removed from the dryer just by releasing four top nuts and by removing side locking screws. Column can then be refilled or completely replaced with a new one. When the column is removed clear access to the check valve and the purge nozzle is available without the need to dismantle complete adsorption dryer. Valves and membranes are located underneath the lower control block and can be accessed and replaced in a quick and easy way.

Technical data

a dry



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Omega Air d.o.o. Ljubljana
Cesta Dolomitskega odreda 10
1000 Ljubljana
+386 (0)1 200 68 00