Sterlco MDB Series Dryers - Manual (Page 14)

This system is a closed loop, because ambient (outside) air is never introduced into the process
air. See Figure 1. Our dehumidifying dryers use the closed loop system, because the process air
is typically much drier than ambient air, even after carrying moisture out of the plastic resin.
Recycling process air maintains drying efficiency at a consistently high level. (see
Figure 1).
Figure 1: Air Flow Diagram.
Ambient
Regen
filter
Regen
bleed
Process air
heater
From
drying hopper
Process
filter
To drying
hopper
Upper valve
Desiccant
beds
Desiccant
beds
Regen heater Regen heater
Lower valve
Regen blower Process blower
Specifying a Drying System
There were many variables considered in the selection of your drying system, including: type of
materials, residence time, throughput of the extruder or injection molding machine, ambient air
moisture and temperature, and the altitude at the processing site. Should your operating
environment change, we can advise you on necessary equipment, process time and temperature
modifications.
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 that is blended with a clay binder and
formed into beads.
General Information 14