ACS 255 User Manual
Closed Loop and Heat Recovery Option
After bed breakthrough (see Process/Regeneration Cycle) the desiccant is hot and needs to be
cooled down to avoid a temperature spike when the beds are switched. Instead of using ambient
air to cool down the desiccant, the closed loop option recirculates a portion of the dry air from the
desiccant bed currently on-line for the process. This approach avoids introducing moisture from
the ambient air normally used to cool down the desiccant, also referred to as “pre-loading”. This
option may be required for high humidity environments.
cooled down to avoid a temperature spike when the beds are switched. Instead of using ambient
air to cool down the desiccant, the closed loop option recirculates a portion of the dry air from the
desiccant bed currently on-line for the process. This approach avoids introducing moisture from
the ambient air normally used to cool down the desiccant, also referred to as “pre-loading”. This
option may be required for high humidity environments.
The closed loop option may use an air to air or a water to air heat exchanger to cool the air before
it passes through the desiccant. If a water to air heat exchanger is used then a water source is
required (see section 3-5)
it passes through the desiccant. If a water to air heat exchanger is used then a water source is
required (see section 3-5)
The heat recovery option utilizes an air to air heat exchanger to pull heat from the exhaust of the
regeneration cycle that would otherwise have been wasted. The recovered heat is then used to
pre-heat the air in the regeneration cycle before it reaches the regeneration heaters reducing the
amount of energy required to heat the air which translates to higher efficiency and lower
operating costs.
regeneration cycle that would otherwise have been wasted. The recovered heat is then used to
pre-heat the air in the regeneration cycle before it reaches the regeneration heaters reducing the
amount of energy required to heat the air which translates to higher efficiency and lower
operating costs.
Process Heat Recovery Option
In high temperature applications the air returning from the drying hopper is at an elevated
temperature that requires cooling before it returns to the dryer. The process heat recovery option
uses an air to air heat exchanger to pull heat from the air returning from the drying hopper and
then the recovered heat is used to pre-heat the process air before it reached the process heaters.
This reduces the amount of energy required to heat the process air which increases efficiency and
decreases operating costs. This option is deal for high temperature applications.
temperature that requires cooling before it returns to the dryer. The process heat recovery option
uses an air to air heat exchanger to pull heat from the air returning from the drying hopper and
then the recovered heat is used to pre-heat the process air before it reached the process heaters.
This reduces the amount of energy required to heat the process air which increases efficiency and
decreases operating costs. This option is deal for high temperature applications.
Modular Convey Options
The midsized dryer line are designed to easily add a full range of convey options all of which are
controlled from the dryers touch screen. There are many variables to consider when adding a
convey system including dry air convey, proportioning, hopper and machine convey, among
others. For this reason consult sales who can advise you on necessary equipment.
controlled from the dryers touch screen. There are many variables to consider when adding a
convey system including dry air convey, proportioning, hopper and machine convey, among
others. For this reason consult sales who can advise you on necessary equipment.
Material Overdrying Protection
Material Overdrying Protection is an automatic system used to reduce the chance of over-drying,
and possibly melting, the resin in the drying hopper. Material Overdrying Protection activates
when the return temperature is above a set value, indicating that all the resin in the hopper is dry.
and possibly melting, the resin in the drying hopper. Material Overdrying Protection activates
when the return temperature is above a set value, indicating that all the resin in the hopper is dry.
The control system monitors the return air temperature and automatically changes the process air
setpoint to the SET BACK SETPOINT value when the return air temperature rises above the set
back temperature. The process air setpoint returns to normal when the return air temperature falls
below the SETUP TEMPERATURE value. The target values for changing the process air
setpoint can be adjusted on the Mat Protect screen.
setpoint to the SET BACK SETPOINT value when the return air temperature rises above the set
back temperature. The process air setpoint returns to normal when the return air temperature falls
below the SETUP TEMPERATURE value. The target values for changing the process air
setpoint can be adjusted on the Mat Protect screen.
Recommended Temperature Settings
Drying Temperature (ºF)
160 180 200 220 240 260 280 300 320 340 360
Set Back Setpoint
130 145 160 175 190 210 225 240 170 260 290
General Information
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