Layout of purge air regulation for reducing air consumption
Application note
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Energy management function at adsorption dryer PDAD
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1.10 Page 9 of 17
2.2
Use of a manual switch for purge regulation
This is the simplest setup. When air is not used downstream from the dryer, the purge function is shut down by
means of a manual switch. This layout is frequently used in systems which act upon the point of consumption
(point-of-use or POU systems). For example, if the dryer is only used to supply suitably dried air to a certain
machine or application, the dryer is only needed when the machine is running and can be shut down either
manually or possibly via additional contacts in the machine’s on/off switch.
It’s very important to understand that the purge function can
only
be shut down at times when little or no air is
required. If this function is shut down at any other time, the drying agent cartridges may be permanently damaged
thus resulting in the loss of drying performance, and possibly a mechanical defect as well. The cartridges may
never be entirely saturated!
The following drawing (figure 2) shows how the above mentioned components might be connected for regulation
of a dryer’s purge function. Please note that specific details regarding the components are manufact
urer-
independent
–
the manufacturer’s specifications must be complied with in any case.
Figure 2:
Use of a manual switch for purge air regulation
Dryer
regulator
Pin 2
Pin 1 (reads out +5 V DC signal)
Manual switch
(installed in the field)
Signal output
Return signal
* Current-free when closed
–
open to deactivate the purge function
Current-free
when closed *
