11
At time equal to 4.3 minutes,
the purge valve closes.
The purge air entering the tower starts to repressurize
the chamber.
At time equal to 4.4 minutes,
the repressurizing valve
is energized to open and repressurize the tower to line
pressure (standard with models 400 scfm and larger).
At time equal to 5 minutes,
the left tower inlet valve
opens, and the right tower inlet valve closes, so the flow
of wet air/gas is switched from right chamber to the left
chamber.
At time equal to 5.1 minutes,
the right tower purge
valve opens to commence the regeneration cycle and
the above process is then repeated on the opposite
towers
Shutdown Procedure
Heatless type dryers operate on a standard time cycle of
10 minutes, 5 minutes drying and 5 minutes
regenerating. This cycle should not be interrupted. If the
dryer needs to be shut down for a certain shift or
weekend; the dryer should be turned off at the end of the
5 minute regenerating cycle, and with both towers at line
pressure. If servicing is required advance the time
sequence so the purge valves close, and pressurize
both towers. At this time, the dryer can be turned off.
For normal dryer shutdown, wait until both towers are at
line pressure. At this time the purge valves will close.
1.
If the compressed air system has been piped
with a bypass around the dryer, then the
following should be completed
:
a. Open the bypass valve to allow process flow to
continue downstream. Then close the dryer
outlet isolation valve on the dryer bypass piping.
b. Push the OFF button.
c. Close the dryer inlet isolation valve on the dryer
bypass piping. At this time the dryer is isolated
and can be depressurized for servicing.
2.
If the compressed air system has not been piped
with a bypass, then the following should be
completed:
a. Push the OFF button.
b. The tower switching valves are normally open
valves; therefore, with the power off the inlet
valves to the towers will be open, and the purge
valves will close. This will give you extended
drying time until desiccant chambers are
saturated.
