Drying Mode
The saturated compressed air enters the dryer inlet and is directed by the inlet air control valves into the top of one of the two desiccant towers (the On-Line tower). As the air travels upward through the desiccant bed, the moisture in the air adheres to the desiccant beads (adsorbed), lowering the dewpoint of the compressed air stream to -40°F. The air then exits the dryer moisture free and is ready for use.

Regeneration Mode
As the On-Line tower is drying, the Off-Line tower is being regenerated (stripped of moisture or desorbed). After the dry air stream (-40°F or -100°F PDP) exits the On-Line tower, a small amount is then expanded to near atmospheric pressure, where it becomes super dry and is diverted into the top of the Off-Line tower. The super dry, expanded air travels downward through the desiccant bed, stripping the moisture from the activated alumina bed that was adsorbed during the On-Line cycle and sweeps it to atmosphere through the open purge valve.

The entire cycle takes 10 minutes to complete -40°F PDP. The cycle is as follows: The On-Line tower dries or stays on line for 5 minutes. The Off-Line tower regenerates or purges for 4.5 minutes and repressurizes for 30 seconds. The towers are shifted and the entire cycle repeats.

Dryer Construction
The dual tower, compressed air drying system utilizes ASME coded pressure vessels (100 CFM and above). The inlet air flow is controlled by 2 non-lubricated 2-way valves. The purge valves are normally closed so that if the unit is depressurized or there is a power failure, the valves will close, preventing plant air pressure from being purged to the atmosphere. The outlet air is controlled by ball cone style check valves. The purge flow is exhausted through purge mufflers to reduce to reduce the air noise level to below OSHA limits. The entire system is completely pre-piped and wired on a heavy duty, structural steel frame. Only air and electrical connection need to be made.

• Generous quantities of activated alumina desiccant.
• Centrally mounted pressure gauge and relief valves on each tower.
• ASME inspected and stamped and CRN registered pressure vessels (100 cfm and above).
• Purge air mufflers to reduce exhaust noise.
• 115-1-60 NEMA 4x electrical.
• Repressurization of towers before going on drying cycle to prevent desiccant dusting.
• -40°F PDP (pressure dewpoint), lower PDP available.
• Control air line filter.
• Low pressure drops (3 psi max).
• Fail safe mode.
• Dryer sequence lights.
• Reliable & Proven inlet air control valves & purge valves (life time warranty LF Series 25-620 CFM).
• 1 year warranty.
• NEMA 4x.

The solid state timer will provide years of trouble-free operations. The timer replaces the less reliable cam timer and mechanical switches. The advantage of the solid state timer over the cam timer includes:

• More precise tower switching controls.

• Dryer operation sequence lights.

• Tower fail-to-shift alarm (optional).

• No mechanical contacts to corrode or fail.

• Very reliable and easy to maintain.

As pneumatic equipment has become more sophisticated, the need for cleaner and dryer air has increased to maintain reliable plant operation. By removing moisture from your compressed air system, the air dryer enables pneumatic instruments and controls to work properly, preventing corrosion of internal parts that result in malfunctions and downtime. The result is improved efficiency, increased productivity, and overall company profitability.