27
Section 6:
Operation
Operation
Background / Function of the dryer
PRODRY is designed to provide a smooth, controlled and
uninterrupted delivery of dry compressed air. Wet air passes
through a pre-filter and travels down to the bottom valve
assembly. The air is then fed through the bottom of the
desiccant bed and moves through the high performance
desiccant until it becomes dry. On exit from the desiccant
cartridge, the air is passed through the outlet valve assembly.
During this process, the dryer control system cycles the process
air between the two desiccant towers. While one tower is on
stream removing water vapour, the other is being carefully
depressurised in preparation for regeneration. The desiccant
bed is regenerated by expanding a small amount of dry
process air, or purge air, through the saturated desiccant.
Purge air passes to atmosphere through the silencer, which is
fitted to an exhaust valve. The chamber is then repressurised,
with the control system assuring each chamber is at full
operational pressure prior to changeover.
This ensures a reliable and efficient operation. The air stream is
switched and the cycle repeats on a continuous basis.
Detailed Operational Description - LED Controller
•
Refer to detailed operational schematics, figure(s)
6.3 - 6.8.
•
LED Controller operates on a standard timed cycle as
detailed in Figures 6.3 through 6.8.
•
Panel LED’s illuminate to indicate various service
warnings, refer to Troubleshooting in Section 11 for
specific details.
•
To reduce purge loss during periods of low and / or no
air demand the Energy Management feature may be
utilised. A detailed description is given in Section 7.
•
For remote indication of any faults, the Alarm Contacts
may be utilised to send a signal to a light or remote
service panel. Further details are given on page 26.
Detailed Operational Description - DMC Controller
•
Refer to detailed operational schematics, figure(s) 6.3
- 6.8.
•
DMC Controller operates on a standard timed cycle as
detailed in Figures 6.3 through 6.8.
•
Operational status is displayed in text form on the LCD
display.
•
When installed, a hygrometer allows the DMC controller
to shut off the purge when the outlet dewpoint is within
one of three selectable dewpoint ranges. The ranges are
controlled by a switch located on the upper back side of
the DMC controller as detailed in figure 6.1.
•
Range 1: -20°C (-4°F)
Required outlet pressure dewpoint:
Purge shut off value:
Purge turn on value:
-20°C (-4°F)
-23°C (-9.4°F)
-21°C (-5.8°F)
•
Range 2: -40° (-40°F)
Required outlet pressure dewpoint:
Purge shut off value:
Purge turn on value:
-40°C (-40°F)
-43°C (-45.4°F)
-41°C (-41.8°F)
•
Range 3: -74°C (-100°F)
Required outlet pressure dewpoint:
Purge shut off value:
Purge turn on value:
-74°C (-100°F)
-76°C (-104.8°F)
-74°C (-100°F)
27
PRODRY PD0046 - PD0360 Instruction Manual
|
Walker Filtration
|
Section 6: Operation
Operation
Background / Function of the dryer
Detailed Operational Description - LED Controller
PRODRY is designed to provide a smooth, controlled and
uninterrupted delivery of dry compressed air. Wet air passes
assembly. The air is then fed through the bottom of the
desiccant bed and moves through the high performance
desiccant until it becomes dry. On exit from the desiccant
cartridge, the air is passed through the outlet valve assembly.
During this process, the dryer control system cycles the process
air between the two desiccant towers. While one tower is
on stream removing water vapour, the other is being carefully
depressurised in preparation for regeneration. The desiccant
bed is regenerated by expanding a small amount of dry
process air, or purge air, through the saturated desiccant.
Purge air passes to atmosphere through the silencer, which is
with the control system assuring each chamber is at full
operational pressure prior to changeover.
switched and the cycle repeats on a continuous basis.
•
•
•
•
•
Detailed Operational Description - DMC Controller
•
•
•
•
•
•
•
Fig ure 6.1: Dewp oin t selecti on switc h cont rol
Range 2: -40° (-40°F)
Required outlet pressure dewpoint:
Purge turn on value:
Range 3: -74°C (-100°F)
Required outlet pressure dewpoint:
Purge turn on value:
DMC Controller operates on a standard timed cycle as detailed
Operational status is displayed in text form on the LCD display.
Range 1: -20°C (-4°F)
Required outlet pressure dewpoint:
Purge turn on value:
-20°C (-4°F)
-23°C (-9.4°F)
-21°C (-5.8°F)
-40°C (-40°F)
-43°C (-45.4°F)
-11°C (-41.8°F)
-
74°C (-100°F)
-76°C (-104.8°F)
-74°C (-10
0
°F)
When installed, a hygrometer allows the DMC controller to shut
selectable dewpoint ranges. The ranges are controlled by a
switch located on the upper back side of the DMC controller as
If the hygrometer is not installed, the DMC controller
will default to the standard timed cycle of operation.
R
LED Co ntro ller operates on a standard timed cycle as detailed
in Figure s 6.3 through 6.8.
Panel LED’s illuminat e to indicate various service warnings,
refer to T
To re duce purg e los s dur ing periods of low and / or no air
de m and the Energy Management feature may be
utilised
. A
detailed description is given in Section 7.
For remote indication of any faults, the Alarm Contacts may
be utilised to send a signal to a light or remote service panel.
Further details are given on page 26.
Figure 6.1: Dewpoint selection switch control
If the hygrometer is not installed, the DMC controller
will default to the standard timed cycle of operation.
