Van Air Systems HLSXG-55 - Manual (Page 8)

PAGE 8
5.2 ADJUSTING THE PURGE FLOW
IMPORTANT
NEVER OPERATE THE DRYER WITH THE PURGE METERING VALVE
CLOSED. IF THE VALVE IS CLOSED, THE REGENERATING TOWER
WILL NOT REPRESSURIZE.
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 GAS.
The purge flow can be adjusted to suit the operating conditions. The
micrometer type needle valve is used to set the purge flow as required.
A purge flow of 10 SCFM is required to properly regenerate the
desiccant beds.
Before placing the dryer on stream, check the purge metering valve
setting. Reference FIGURE 5A. The valve is equipped with a set screw,
which must be loosened before the valve is adjusted. Adjust the valve to
the desired setting. Tighten the set screw to prevent tampering.
START UP SECTION 5
MODEL
HLSXG55
PURGE
10 SCFM
FIGURE 5A 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 gas.
Turn on the Power to the dryer.
Observe the dryer for several cycles to 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 customer supplied moisture indicator on the dryer indicates
no moisture, the desiccant bed is conditioned and ready to be placed
on-stream.
5.1 START UP
WARNING
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 SYSTEM WHILE IT IS PRESSURIZED.
Close the inlet and outlet isolation valves. Open the bypass valve. (If
equiped)
Pressurize the piping system to the dryer. Once the system is pres-
surized, slowly open the inlet isolation valve. DO NOT open the outlet
isolation valve.
Turn ON the power supply to the dryer. One tower will pressurize. The
other tower will remain depressurized. The purge valve will open and
purge gas should be exhausting from the dryer.
Dryer will begin a 10 minute cycle. The dryer will operate for 5 minutes
on each tower.
The dryer is equipped with a purge metering valve. The setting should
be checked before placing the dryer on stream. SEE SECTION 5.2.
The desiccant bed should be conditioned per SECTION 5.3 before
placing the dryer on-stream.
Place the dryer on-stream by opening the outlet isolation valve and
closing the bypass valve (If equiped).
5.4 SETTING THE CONTROL PRESSURE REGULATOR
The control pressure regulator is located near the purge exhaust connec-
tion and it is used to protect the pneumatic actuators on the purge and
inlet transfer valves. This regulator should be set at 100 PSIG.
IMPORTANT
DO NOT OPERATE THIS DRYER WITH THE CONTROL AIR
PRESSURE REGULATOR ABOVE 100 PSIG TO PREVENT DAMAGE
TO THE PNEUMATIC CONTROLS.
5.5 DRYER TIMING ADJUSTMENT
For operation at pressures other than 100 PSIG, the repressurization
time may need to be lengthened to allow for complete repressurization.
Consult factory for timing changes.
80 PSIG
2.3 turns
100 PSIG
2.2 turns
125 PSIG
2.0 turns
150 PSIG
1.8 turns
175 PSIG
1.5 turns
200 PSIG
1.3 turns
225 PSIG
1.1 turns
250 PSIG
0.9 turns
NOTE:
Settings are based on gas
specific gravity of 0.61