In some industries much of the compressed air system is outdoors or minimally protected from the elements. Outdoor operation is typical in aggregates (asphalt and concrete), mines, lumberyards, rail yards, and other industries.

Constantly changing temperatures, dust, precipitation, and UV light challenge both the air compressor and the air dryer. In dusty operating environments the condenser of a refrigerated air dryer tends to become coated. This reduces the effectiveness of the dryer and causes water to form in downstream pneumatic equipment. Most control systems on refrigerated dryers are not designed for exposure to UV light and precipitation.

In these type of settings I almost always recommend a deliquescent dryer. Deliquescent dryers have no moving parts and no electrical power requirement.  The dryer consists of a single tank filled with water absorbing pellets called Dry-O-Lite desiccant tablets.

This type of dryer is often installed outdoors. In aggregate industries models D8 and D12 are the most commonly selected sizes.  (A cutaway of model D12 is pictured above.)  Models D8 and D12 are sized for 50 CFM and 100 CFM, respectively, and paired with air compressors ranging from 10 to 20 horsepower.

There are just a few keys for successful use of a deliquescent air dryer.

1. Allow the compressed air to cool to within a few degrees of the surrounding air before sending it to the dryer.This can be accomplished with an after-cooler or an extended pipe run.In intermittently flowing air systems, the compressor tank will act as a sufficient cooler.
2. Drain the air dryer after each 8 hours of operation.Consider installing an automatic tank drain on the dryer.
3. Install a filter after the dryer.This filter both removes oil mist and dust from the air line.
4. Add new Dry-O-Lite desiccant every 2-3 months or as required.

I offer both models for great prices and with free shipping to U.S. addresses (lower 48 states).  Send me an email to discuss your application and learn if this is the right solution for your outdoor compressed air dryer requirement. tyler@moistureboss.com.