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Integrated Fire Protection System
D
Air Supply - Preaction System
FM-076A-0-86C
4. Air supply options
4.1 Dehydrator
The Viking dehydrator is a manually regenerated
desiccant-type air dryer. The desiccant acts as a moisture
indicator by changing color, and is visible through the sight
glass.
Technical Information
1. The desiccant is silica gel having a -40°F (-40°C) dew
point at a maximum 180°F (82°C) temperature with a
regeneration temperature of 275°F (135°C). When the
silica gel color changes from dark blue to light pink or
clear, it has become saturated with moisture and must
be changed.
2. The unit has a maximum drying capacity of 8100 ft
3
(229 m
3
) of air to -40°F (-40°C) atmospheric dew point
at inlet condition of 100 PSI (689 kPa), 50% relative
humidity, 70°F (21°C) and 15 scfm (25.5 Nm
3
/hr) before
the desiccant becomes saturated.
3. The maximum air flow rating is 15 scfm (25.5 Nm
3
/hr) at
100 PSI (689 kPa) per unit.
4. All ratings are based on 100°F (38°C) saturated inlet air
temperatures at 100 PSI (689 kPa).
5. The aluminum bowl holds 2.5 lb (1.13 kg) of desiccant
and is rated for a maximum temperature and pressure
at 180°F (82°C) and 300 PSI (2.68 kPa).
6. The silica gel desiccant is provided in a sealed 2.5 lb
(1.13 kg) bag.
7. The unit has 1/4”-NPT (8 mm) threads on the inlet and
outlet.
8. The dehydrator is available as a package unit (Viking
P/N 16854), which includes the dehydrator, desiccant,
and mounting brackets.
9. The unit is to be used on compressed air service only.
Operation of dehydrator
The dehydrator directs the incoming air down through the
silica gel desiccant. The silica gel absorbs the moisture
without physically changing. As the relative humidity
increases, the silica gel begins to change color from dark
blue to light pink, indicating the desiccant must be
replaced.
To make dehydrator functional
1.
CLOSE
drain valve
(E12)
.
To drain dehydrator input line
1.
CLOSE
air shut-off valve
(E14)
.
2.
OPEN
drain valve
(E12)
to drain input line then
CLOSE
it.
3.
OPEN
air shut-off valve
(E14)
.
To replace desiccant
Once it has been drained,
CLOSE
the air supply control
valve to the dehydrator.
Turn the clamp ring left while holding the bowl, and exert a
downward pull until the clamp ring, and the bowl drop free.
Pour out used desiccant.
Follow instructions described on Viking data sheet #276
(form No. F_011711) provided with the silica gel recharge.
Maintenance
The dehydrator must be regularly inspected to ensure the
drying capability of the desiccant. Replace the desiccant
when the color has changed from dark blue to light pink.
In addition, the recommended condensate trap should be
drained on a regular basis. The frequency of the required
maintenance is dependent upon the relative humidity and
volume of air to be dried. Regular maintenance of the air
supply equipment, such as draining condensation from the
air compressor receiver, will increase the life of the
desiccant.
