Dual Bed Dryers Dual Bed (also called Twin Tower) dryers used to
be the most commonly purchased type of resin dryer. In fact, it
is estimated that there are between 10 and 20,000 of these
dryers still in use today despite their disadvantages. Dual Bed
dryers consist of two beds (or towers) of desiccant beads,
process and regenerative blowers, process and regeneration
heaters and valves to re-direct the airflow. While one bed of
desiccant supplies dry process air to flow through the drying
hopper, the other bed – with saturated desiccant – is
regenerated, by forcing hot air through it. When the
regeneration is complete, that bed becomes the one supplying the
dry process air and the first bed goes into the regeneration
mode. Dual Bed dryers are commonly used because they attained a
-40˚ dew point and generally do a good job of drying most
resins. They do have their disadvantages: In recent years, there
have been great advances made in drying technology and several
types of dryers now overcome the disadvantages