12
Next, Purge Supply Valve
(E)
and Right Tower Purge
Exhaust Valve
(D)
are opened, and the Heater is
turned on. The Venturi Blower Intake Shutoff Valve
(F)
is opened. Purge air passes through the venturi
blower, drawing in ambient air, augmenting the purge
air flow before passing through the heater. The
heated purge air then flows through the Right Purge
Check Valve, down through the right tower, and
exits through the Right Tower Purge Exhaust Valve
(D)
. The Heater operates until the bed temperature
sensor signals heating is complete. Venturi Blower
Intake Shutoff Valve
(F)
closes, dry purge flow pro
-
vides partial cooling while recovering heat to drive
additional moisture from the bed.
Finally, the Right Tower Depressurization Valve
(C)
and the Right Tower Purge Exhaust Valve
(D)
are
closed. The right tower slowly repressurizes to full
line pressure and is ready to go back on-line.
2. Right Tower Drying – Left Tower Regenerating
At the start of the Right Tower Drying cycle, Right
Inlet Valve
(B)
opens, Left Inlet Valve
(A)
closes to
isolate the two towers. Wet, compressed air flows
up through the right tower where it is dried. The dry
air exits the dryer through the Right Outlet Check
Valve.
Next, the Purge Supply Valve
(E)
is closed and the
Left Tower Depressurization Valve
(C)
is opened.
The left tower is slowly depressurized through an
exhaust muffler.
Next, Purge Supply Valve
(E)
and Left Tower Purge
Exhaust Valve
(D)
are opened, and the Heater is
turned on. The Venturi Blower Intake Shutoff Valve
(F)
is opened. Purge air passes through the venturi
blower, drawing in ambient air, augmenting the purge
air flow before passing through the heater. The
heated purge air then flows through the Left Purge
Check Valve, down through the left tower, and exits
through the Left Tower Purge Exhaust Valve
(D)
. The
Heater operates until the bed temperature sensor
signals heating is complete. Venturi Blower Intake
Shutoff Valve
(F)
closes, dry purge flow provides par
-
tial cooling while recovering heat to drive additional
moisture from the bed.
Finally, the Left Tower Depressurization Valve
(C)
and the Left Tower Purge Exhaust Valve
(D)
are
closed. The left tower slowly repressurizes to full
line pressure and is ready to go back on-line.
Figure 6 shows the air sampling system for the de-
mand cycle (Energy Management System – EMS)
option. A 3-way pilot valve directs an air sample
from the drying tower to the EMS sensor. The EMS
sensor detects the relative humidity and temperature
of the air sample. The air sample then exhausts to
atmosphere. The drying tower remains on-line until
the moisture front arrives at the sensor.
P
EMS
LEFT
TOWER
RIGHT
TOWER
Figure 6
Optional Moisture Sensing
Energy Management System (EMS)
Figure 4
Fixed Cycle Operation
Left Chamber Drying – Right Chamber Regenerating
Figure 5
Demand Cycle Operation with Venturi Blower
Left Chamber Drying – Right Chamber Regenerating
