Van Air Systems D8 - Manual (Page 2)

PAGE 2
SECTION 1 INTRODUCTION
1.0 PURPOSE OF OPERATION
The purpose of installing a Van Air single tower dryer in a
compressed air system is to remove the water vapor (humidity) which
has been drawn into the system at the compressor intake. The Van
Air process dries the air as it flows through the vessel, which is filled
with a special drying agent. The dryer operates automatically. There
are no moving parts and no external source of power is required. If
an automatic drain is installed, a power source is required only to
operate the valve.
The wet air enters the centrally located inlet which channels the flow
into the lower portion of the dryer. Liquid water and solid particles are
separated by gravity and fall to the bottom of the vessel.
The process air moves upward through the bed of desiccant tablets
which attract and absorb the moisture from the air before it flows
through the dryer outlet. The tablets dissolve gradually as they
absorb the moisture.
The tablets create a structured bed that does not crush under its own
weight. In the bed of an operating dryer, the lower tablets are
consumed first.
The tablets in the top portion serve as a reserve supply. When the
reserve supply is depleted, the dryer must be refilled to maintain
performance.
The solution, which consists of dissolved desiccant and water, falls
into the claim area at the bottom of the vessel. The dryer must be
drained at least once a shift to remove the accumulated solution.
FIGURE 1 DRYER DETAILS
SECTION 2 INSTALLATION
2.1 LOCATION
The ability of a dryer to provide dry compressed air depends on the
correct location of the unit. Inlet air temperature and pressure are the
keys to selecting the proper location.
IMPORTANT
ALWAYS PROCESS AIR THROUGH THE DRYER AT THE
LOWEST POSSIBLE TEMPERATURE AND THE HIGHEST
PRACTICAL PRESSURE.
2.1-A INLET AIR TEMPERATURE
The dew point of the outlet air is directly related to the inlet air
temperature and the type of desiccant being used. The lower the inlet
temperature, the lower the dew point of the outlet air. Determine the
lowest ambient temperature where the compressed air is used or
where the lines are located. If you are using DRY-O-LITE or 10BF
desiccants, do not exceed 100 o F inlet air temperature. If you are
using SP desiccant, do not exceed 80 o F inlet air temperature.
2.1-B AFTERCOOLING
Air discharged by the compressor is extremely hot (from 150 o F to
350 o F). An aftercooler, finned tubing or extended run of piping will
usually be necessary to reduce the inlet air temperature to the dryer.
2.1-C OUTDOOR AIR USAGE
If some or all of the air supplied by the Van Air single tower dryer will
be used outdoors, install the dryer outdoors in the coolest possible
FIGURE 2 MAXIMUM CAPACITIES -SCFM (Nm 3 /hr)
MODEL
NO.
D 4
D 8
MAXIMUM
WORKING
PRESSURE
250 PSIG
250 PSIG
200 PSIG
13.8 Bar
18.7
30.1
94
151
100 PSIG
6.9 Bar
10
16
50
80
125 PSIG
8.6 Bar
12.2
19.6
61
98
150 PSIG
10.3 Bar
14.4
23.2
72
116
40 PSIG
2.8 Bar
4.8
7.7
24
38.6
60 PSIG
4.1 Bar
6.5
10.5
33
53
80 PSIG
5.5 Bar
8.3
13.3
41
66
90 PSIG
6.2 Bar
9.1
14.6
46
74
20 PSIG
1.4 Bar
3
4.8
15
24.1
10 PSIG
0.7 Bar
2.2
3.5
11
17.7
5 PSIG
0.3 Bar
1.7
2.7
9
14.5
area. Make sure that the dryer is not exposed to ambient temperatures
below the minimum design temperature stamped on the vessel data
tag. When the dryer will be exposed to the direct rays of the sun,
install a sun shield to protect it (i.e. a roof).
2.1-D INDOOR AIR USAGE
If all of the air from the dryer will be used indoors where temperatures
remain within a fixed range, locate the dryer in the coolest indoor
area. When air equipment or piping is located in an air conditioned
area, install the dryer in the coolest area--usually the air conditioned
area.
2.1-E AIR RECEIVER
The Van Air single tower dryer should be located where it will be
provided with the coolest inlet temperature. If the receiver is located
in an area where the ambient temperature is lower than the outlet air
from the aftercooler, locate the dryer downstream of the receiver to
allow additional cooling of the air before it enters the dryer. (Exception:
In systems where usage creates sudden demands on the air supply,
locate dryer before the receiver to minimize air surges through the
dryer.) If the ambient temperature around the receiver is higher than
the outlet air temperature from the aftercooler, locate the dryer
between the aftercooler and the receiver.
2.1-F SPECIAL EQUIPMENT INSTALLATION
If the Van Air Dryer is being installed on a branch line to protect a
specific piece of air-operated equipment, locate the dryer on the high
pressure side of any pressure regulators.
250 PSIG
17.2 Bar
23.1
37.1
115
185