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Fittings & Valves
Watts Fluidair

How do they Work?

As the wet compressed air flows through the inlet port and down the bed of desiccant, the desiccant (silica gel) beads absorb the water vapor and aerosols.  The silica gel beads are so effective in absorption the air humidity can be reduced down to a -40° F pressure dew point.  Unless your compressed air is exposed to a temperature below the due point, there will be no further condensation forming in your air lines.

The microscopic pores of each silica gel bead are structured to attract and hold large capacities of moisture and prevent it from traveling downstream.

After the moisture has been removed, the dry air passes through a sintered bronze element, up the center tube, and out the outlet port.  As long as the desiccant is replaced regularly, your equipment will receive ultra dry, moisture-free air.

As the desiccant becomes saturated with moisture, the dew point will begin to rise.  This is evident when the blue silica gel desiccant beads in the sights glass change to pink, indicating the need for desiccant replacement. Simply remove the flange and bowl and replace with new desiccant or regenerate saturated desiccant by heating to 275°F.

Desiccant dryers are a convenient and cost effective means of ensuring your sensitive pneumatic applications are never exposed to damaging moisture. Compact in size, and no external power sources required, the Watts Fluid-Air desiccant dryers can be used almost anywhere.

Why Watts Desiccant Dryers?

Watts Fluid-Air desiccant dryers are the simplest and most reliable method of insuring your sensitive pneumatic equipment is not exposed to damaging moisture. When air is compressed, the temperature of the air is increased as is its capacity to hold moisture.  As the hot moist air travels downstream through the lines, it cools, allowing the moisture to condense.  After coolers, filters, drain traps, and drip legs are effective for removing liquid condensate.  But for removing residual water vapor and aerosols, use the Watts Fluid-Air Desiccant Dryer.


The flow capacities in the table are nominal ratings provided for reference.  These capacities are recommended for minimal pressure drop and average desiccant life.
A supply of low flow/low humidity air will provide longer desiccant life; where as high flow/high humidity air will require more frequent desiccant changes.
Installed in an application with intermittent flow, Watts desiccant dryers will typically dry air for weeks before the silica gel desiccant requires replacement or regeneration.

Recommended Installation

Always place a moisture separator and/or particulate filter upstream to remove bulk liquids.
Always place a coalescing filter upstream to remove oil. Desiccant coated with oil will not absorb moisture.
A 5 micron (or smaller) particulate filter is recommend downstream to remove desiccant dust.

Standard Features

Steel Bowl with Integral Sight Glass
Zinc Body
Sintered Bronze Elements DD15 & DD30: 90 µM DD60: 40 µM
Maximum Operating Temperature: 180° F
Maximum Working Pressure: 300 PSI
Optimum Working Temperature: Below 100° F

Part #

Pipe Size (NPT) Flow Capacity Desiccant needed in Lbs
DD15-02* 1/4" 15 SCFM 2-1/2
DD15-03* 3/8" 15 SCFM 2-1/2
DD15-04* 1/2" 15 SCFM 2-1/2
DD15-06 3/4" 15 SCFM 2-1/2
DD30-03* 3/8" 30 SCFM 5
DD30-04* 1/2" 30 SCFM 5
DD30-06* 3/4" 30 SCFM 5
DD30-08 1" 30 SCFM 5
DD60-04* 1/2" 60 SCFM 10
DD60-06* 3/4" 60 SCFM 10
DD60-08 1" 60 SCFM 10



* These dryers supplied with reduced bushing.
Note: Desiccant must be ordered separately.


Indicating Silica Gel Desiccant

Part # SGM100-1 contains 6 bags of .88 lbs (5 lbs)
Part # SGM100-4 contains 4 boxes of SGM100-1 (20 lbs)

Watts Fluid-Air's 100% indicating silica gel provides for maximum moisture absorption and dew points down to -40°F.
Outstanding features of the SGM100 include:

High absorption capacity- The average surface area for each bead is over 200 ft2!
Low abrasion, due to high mechanical strength for long service life.
Ideal packing in bowl due to bead shape.
Uniform color change.
Excellent regeneration characteristics.
Each package contains 6 bags of .88lbs

As the silica gel beads absorb moisture, the change from blue to pink, indicating the need for replacement or regeneration. 
The desiccant can be regenerated by heating in a drying over to a temperature above 212°F, but not over 350°F.
Desiccant may also be regenerated in microwave ovens.