Air dryers should be used when the compressor is operated in freezing or high humidity conditions. In both these cases it is necessary to remove as much moisture as possible from the air supplied to the pumps. There are three types of drying systems available:

Refrigerated. Selected when the air temperature will remain above 50°F.
Regenerative Desiccant. Preferred in low temperature conditions below 50°F
Membrane. Usually chosen for applications where there is relatively low air consumption.

Refrigerated Dryers
Refrigerated air dryers use mechanical refrigeration to lower the air temperature of the compressed air. This results in a lowering of the dew point that causes the moisture in the air to condense into liquid and be removed from the compressed air stream.

Regenerative Desiccant
These dryers use a dual tower design, each filled with a desiccant media that will remove water from the air stream. The dual tower design allows one tower to dry the air while the other tower is regenerated. Maximum bed life is from 3 to 5 years. These dryers consume about 10% of the air supply produced by the compressor for regeneration of the desiccant bed.

Membrane Dryer
The compact membrane dryers use a molecular design that can provide atmospheric dew points as low as -40°F. The system comprises densely packed hollow fiber membranes to diffuse the water vapor. No power source is required and the only maintenance needed is the periodic changing of a pre-filter element when the indicator on the dryer shows red.

TR-749	Membrane Dryer, 10 cfm
TR-335	Refrigerated Dryer, 15 cfm, 115 V, single phase
TR-336	Refrigerated Dryer, 25 cfm, 115 V, single phase
TR-337	Refrigerated Dryer, 55 cfm, 115 V, single phase
TR-338	Desiccant Dryer, 25 cfm, 115 V, single phase
TR-739	Desiccant Dryer, 60 cfm, 115 V, single phase