10
START UP
SECTION 5
5.1 START UP
WARNING
The required purge flow for this dryer is 200 SCFM. This flow is required
to properly regenerate the desiccant beds.
BEFORE STARTING THIS DRYER, FOLLOW THE INSTALLATION
INSTRUCTIONS AND PROCEDURES COMPLETELY. SERIOUS
PERSONAL INJURY CAN RESULT IF INSTRUCTIONS ARE NOT
CAREFULLY AND COMPLETELY FOLLOWED.
DO NOT REMOVE, REPAIR, OR REPLACE ANY ITEM ON THIS
DRYER WHILE IT IS PRESSURIZED.
Make sure the Stop button is pressed.
If the dryer is being started up for the first time, or after the
desiccant has been changed, the purge mufflers must be removed.
The dryer should be operated until no desiccant dust is visible at
the purge valves. Then the mufflers can be reinstalled. See Section
2.1 for safety precautions concerning desiccant dust.
If the dryer is being operated at a pressure other than rated inlet
conditions, the purge metering valve must be adjusted to maintain 200
SCFM purge flow.
Determine the dryer minimum operating pressure. Using the chart
in Figure 5A, find the valve setting for that pressure. The valve
is equipped with a set screw which must be loosened before the
valve is adjusted. Adjust the needle valve to the desired setting.
Tighten the set screw to prevent tampering.
FIGURE 5A PURGE METERING VALVE SETTINGS
WARNING
WHEN OPERATING THIS DRYER WITHOUT THE MUFFLERS
INSTALLED, USE HEARING PROTECTION.
If bypass piping was installed on this dryer as outlined in SECTION 4.2,
close the inlet and outlet isolation valves. Open the bypass valve.
Pressurize the air system. Once the air system is pressurized, slowly
open the inlet isolation valve. DO NOT open the outlet isolation valve.
To start the dryer, press the Run button which will light the Run LED.
One tower will already be pressurized. The other tower will depres-
surize. The purge valve on the tower that is not pressurized will be
open, air should be exhausting from the muffler.
60 PSIG
3.2 turns
80 PSIG
2.95 turns
100 PSIG
2.80 turns
125 PSIG
2.65 turns
FACTORY
SETTING
150 PSIG
2.60 turns
175 PSIG
2.50 turns
5.2 ADJUSTING THE PURGE FLOW
IMPORTANT
NEVER OPERATE THE DRYER WITH THE PURGE METERING
VALVE CLOSED. IF THE VALVE IS CLOSED, THE TOWERS WILL
NOT REPRESSURIZE AND SWITCHING FAILURE WILL OCCUR.
DO NOT ADJUST THE PURGE METERING VALVE ABOVE OR
BELOW THE RECOMMENDED SETTING FOR THE OPERATING
CONDITIONS OF THIS INSTALLATION. IMPROPER SETTING MAY
CAUSE POOR DRYER PERFORMANCE AND/OR EXCESSIVE USE
OF PROCESS AIR.
The purge flow can be adjusted for the operating conditions. This
dryer is equipped with a micrometer type needle valve.
The valve can be adjusted to the desired setting.
This dryer was shipped with the purge flow set for the rated inlet flow
At 150 PSIG. Reference Section 3 for rated flow. This setting should
be correct for most installations. Before placing the dryer on stream,
check the purge metering valve setting.
5.3 CONDITIONING THE DESICCANT BED
To condition the desiccant bed, the dryer is operated without any outlet flow,
while the towers regenerate with purge air.
To start the dryer, press the RUN button which will light the Run LED.
The dryer should be set on the 10 minute time cycle. Observe the dryer
for several cycles. Make sure that it is operating properly.
At initial start up or after extended shutdowns (over one month), the dryer
may take 24 to 48 hours of continuous operation for the bed
to be conditioned. Moisture that has accumulated on the desiccant bed
should be removed before the dryer is placed on stream.
Once the moisture indicator on the dryer turns blue, the desiccant
bed is ready. Place the dryer on stream by opening the outlet isolation
valve. Make sure that the by-pass valve is closed.
PRINCIPLE OF OPERATION
SECTION 6
6.1 PRINCIPLE OF OPERATION
The RD1600A Heatless Regenerative Air Dryer utilizes the
pressure swing principle of operation. The desiccant bed in one
tower dries the air stream while the desiccant bed in the
other tower is regenerated.
A purge of dry air is used for tower regeneration. It is taken from the
outlet of the dryer.
The dryer is equipped with a purge metering valve to allow
the correct amount of dry air to flow into the regenerating tower.
The heat created during adsorption of moisture in the drying tower
is retained in the desiccant bed and increases the moisture
removal capacity of the purge air.
The timing cycle of the dryer is controlled by two 3-way pilot valves.
A patented shuttle valve system is used to repressurize, changeover,
and depressurize the towers. The inlet transfer valve is controlled by
the pilot valves. The movement of the shuttle in the inlet
transfer valve mechanically actuates the external pneumatic
limit switches, which open the purge valves and depressurize the tower.
The shuttle cannot shift until the tower pressures are nearly equal.
The dryer cannot depressurize until the shuttle has fully seated and
the one of the limit switches is engaged.
To achieve maximum performance from this dryer, it should be
operated continuously. Operating this dryer for single shift periods
may result in varied outlet dew point performance.
The dryer operation consists of four stages; REPRESSURIZATION,
CHANGEOVER/DEPRESSURIZATION, DRYING and
REGENERATION.
