Van Air Systems D12-D36 - Manual (Page 2)

PAGE 2
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 above the sight windows are virtually unused and 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.
The drain solution may contain libricatants and must be disposed of
properly.
FIGURE 1 DRYER DETAILS
SECTION 1 INTRODUCTION
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
In relation to the 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.
2.1-G OPERATING PRESSURE
More air can be processed through the dryer at higher pressures.
Locate the dryer at the highest practical pressure, but do not exceed
the maximum rated working pressure of the dryer. Refer to the
Maximum Capacities chart on Page 3 for the maximum working
pressure for your dryer.
2.2 PIPING AND ANCILLARY EQUIPMENT
Locate the dryer in the proper location as explained in the previous
section.
If the dryer is being installed in an existing piping system, make sure that
the pipe is free of scale and rust.
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 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
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 HIGH-
EST 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 tempera-
ture. If you are using SP desiccant, do not exceed 80 o F inlet air
temperature.
SECTION 2 INSTALLATION