35
Section 7:
Energy Management
Energy Management
Overview
Regenerative dryers must expel a portion of the process air
in order to free themselves of accumulated moisture. During
periods of low air demand, however, this air loss is not
necessary and is therefore undesirable. In many cases, the
compressor runs almost continuously in order to keep up with
the dryer’s purge loss.
All Walker Filtration dryers are equipped with an Energy
Management feature that allows the purge to be shut off
during periods of low or no demand. The dryer controller
is fitted with a set of field accessible contacts, that can be
employed to shut off the solenoid valves which control the
purge function of the dryer, therefore eliminating any air loss
from the dryer.
Developing a Purge Control Strategy
In order to utilise this function, the operator must provide a
switching system that provides acceptable logic to indicate to
the dryer that there is little or no air demand. On the following
pages, some examples of commonly used switching systems
are provided in ascending order of complexity.
Using a Manual Switch for Purge Control
The simplest of arrangements, a manual switch may be
employed to shut the purge off when the air downstream of
the dryer is not being used. Commonly used on point of use
systems. For example, if the dryer is only used to supply air of
an appropriate dryness to a specific machine or application,
the dryer will only be required when the machine is in use and
may be shut off either manually or possibly via extra contacts
provided in the machine’s on/off switch.
It is extremely important to understand that the purge may
only be shut off during periods of low or no demand. This
feature, if used otherwise, can result in permanent damage
to the desiccant beds resulting in loss of drying capacity
and possibly mechanical failure. The cartridges must not be
allowed to become fully saturated at any time.
The following schematic ( Fig 7.1) offers an overview of the
devices mentioned as they might be connected for use in
controlling a dryer’s purge function. Please note that specific
details differ between device manufacturers, so in all cases the
manufacturer’s specifications should be adhered to.
Please note that the Energy Management feature
should not be used when a hygrometer is
installed in the dryer.
Fig 7. 1 Manual switch purge control (LED Controller)
35
PRODRY PD0046 - PD0360 Instruction Manual
|
Walker Filtration
|
Se ct io n 7:
Energy Management
Energy Management
Fig 7. 1 M anu al switch p urge c ontro l (LED Controller)
Overview
Regenerative dryers must expel a portion of the process air
in order to free themselves of accumulated moisture. During
periods of low air demand, however, this air loss is not
necessary and is therefore undesirable. In many cases, the
compressor runs almost continuously in order to keep up with
the dryer’s purge loss.
All Walker Filtration dryers are equipped with an Energy
Management feature that allows the purge to be shut
during periods of low or no demand. The dryer controller
employed to shut the solenoid valves which control the
purge function of the dryer, therefore eliminating any air loss
from the dryer.
Developing a purge control strategy
In order to utilise this function, the operator must provide a
switching system that provides acceptable logic to indicate to
the dryer that there is little or no air demand. On the following
pages, some examples of commonly used switching systems
are provided in ascending order of complexity.
Using a manual switch for purge control
The simplest of arrangements, a manual switch, may be
employed to shut the purge when the air downstream of
the dryer is not being used. Commonly used on point of use
systems. For example, if the dryer is only used to supply air of
the dryer will only be required when the machine is in use and
may be shut either manually or possibly via extra contacts
provided in the machine’s on/ switch.
It is extremely important to understand that the purge may
only be shut during periods of low or no demand. This
feature, if used otherwise, can result in permanent damage
to the desiccant beds resulting in loss of drying capacity
and possibly mechanical failure. The cartridges must not be
allowed to become fully saturated at any time.
The following schemati
er an overview
of the devices mentioned as they might be connected for use in
details d er between device manufacturers, so in all cases the
N.C.*
Manual Switch
(Field Installed)
* Normally Closed, open to turn purge off
LED Controller
Pin 1
(Puts out
+5 VDC
signal)
Pin 2
Signal Out to Switch
Signal Back
Fig 7.2 Ma nual switch p urge c ontro l (DMC Controller)
N.O.*
Signal Out to Switch (+24 VDC)
Manual Switch
(Field Installed)
* Normally open, close to turn off purge
Pin 1
Pin 2
Signal Out to Switch
Signal Back
DMC
Controller
1
2
3
1
2
3
Please note that the Energy Management feature should
not be used when a hygrometer is installed in the dryer.
Fig 7.2 Manual switch purge control (DMC Controller)
35
PRODRY PD0046 - PD0360 Instruction Manual
|
Walker Filtration
|
Se ct io n 7:
Energy Management
Energy Management
Fig 7. 1 M anu al switch p urge c ontro l (LED Controller)
Overview
Regenerative dryers must expel a portion of the process air
in order to free themselves of accumulated moisture. During
periods of low air demand, however, this air loss is not
necessary and is therefore undesirable. In many cases, the
compressor runs almost continuously in order to keep up with
the dryer’s purge loss.
All Walker Filtration dryers are equipped with an Energy
Management feature that allows the purge to be shut
during periods of low or no demand. The dryer controller
employed to shut the solenoid valves which control the
purge function of the dryer, therefore eliminating any air loss
from the dryer.
Developing a purge control strategy
In order to utilise this function, the operator must provide a
switching system that provides acceptable logic to indicate to
the dryer that there is little or no air demand. On the following
pages, some examples of commonly used switching systems
are provided in ascending order of complexity.
Using a manual switch for purge control
The simplest of arrangements, a manual switch, may be
employed to shut the purge when the air downstream of
the dryer is not being used. Commonly used on point of use
systems. For example, if the dryer is only used to supply air of
the dryer will only be required when the machine is in use and
may be shut either manually or possibly via extra contacts
provided in the machine’s on/ switch.
It is extremely important to understand that the purge may
only be shut during periods of low or no demand. This
feature, if used otherwise, can result in permanent damage
to the desiccant beds resulting in loss of drying capacity
and possibly mechanical failure. The cartridges must not be
allowed to become fully saturated at any time.
The following schemati
er an overview
of the devices mentioned as they might be connected for use in
details d er between device manufacturers, so in all cases the
N.C.*
Manual Switch
(Field Installed)
* Normally Closed, open to turn purge off
LED Controller
Pin 1
(Puts out
+5 VDC
signal)
Pin 2
Signal Out to Switch
Signal Back
Fig 7.2 Ma nual switch p urge c ontro l (DMC Controller)
N.O.*
Signal Out to Switch (+24 VDC)
Manual Switch
(Field Installed)
* Normally open, close to turn off purge
Pin 1
Pin 2
Signal Out to Switch
Signal Back
DMC
Controller
1
2
3
1
2
3
Please note that the Energy Management feature should
not be used when a hygrometer is installed in the dryer.