Sterling 882.00291.00 Manuel D’Utilisation

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15, 30, & 60 cfm Compact Dryers 
 
10 
 
Chapter 2:  Functional Description 
2-1  Models Covered in This Manual 
This manual provides operation, installation, and maintenance instructions for 15, 30 and 60 
cfm dehumidifying dryers. Model numbers are listed on the serial tag. Make sure you know 
the model and serial number of your equipment before contacting the manufacturer for parts 
or service. 
Our dehumidifying mini dryers are designed to generate heated dehumidified air (at a very 
low dew point) at carefully controlled temperatures for use in plastic drying systems. The 
dryer circulates hot air through a column of plastic resin in the large drying hopper.  The resin 
in the hopper is discharged through a slide gate in a “first in, first out” manner. 
2-2 General 
Description 
 
The Drying System 
Dehumidifying dryers are used to generate very low dew point air heated to a controlled 
temperature for drying plastic pellets and regrind. 
Our dryers force hot, dry air through resin in a drying hopper, where air picks up moisture 
from the material and draws it back to the dryer.  In the dryer, a desiccant bed strips moisture 
from the air.  The dried process air is then re-heated and delivered back into the drying 
hopper for more moisture removal. 
Portion of the low dew point process air is directed to the desiccant tank that is off process. 
This air is heated to approximately 450°F (232°C) before entering the bed that is in 
regeneration. The moisture is then forced from the desiccant before being exhausted into the 
atmosphere. A small amount of ambient air is introduced into the process return air filter to 
make up for the air lost during the bed regeneration. To compensate for the humidity content 
in the air, this dryer is supplied with the proper amount of desiccant. 
What is desiccant? 
Desiccant is a material that attracts and holds (absorbs) water from the air. The desiccant our 
dryers use is a synthetic crystalline metal aluminosilicate blended with a clay binder and 
formed into beads. 
The Process/Regeneration Cycle 
Our dryers have two desiccant beds. While one bed is on-line in the process air loop, the 
other is off-line, being regenerated. 
When a desiccant bed is on-line, it absorbs moisture from the process air. In time, the bed 
becomes saturated with moisture and needs to be regenerated. The dryer automatically 
redirects the process airflow to the second bed, and starts the regeneration cycle on the first 
bed. 
During regeneration, the dryer system heats the very low dew point air and forces it through 
the desiccant bed. The moisture driven off the bed bleeds to the atmosphere.