Grain Systems PNEG-1851 - Manual (Page 41)

5
The Drying Modes
Topics Covered in this Chapter
▪ Continuous Flow Mode
▪ Staged Batch Mode
▪ Selecting a Drying Mode
Continuous Flow Mode
The continuous flow mode is a grain drying method where grain enters and exits the dryer in one continu-
ous, uninterrupted cycle. Consequently, the metering rolls turn constantly, at a speed defined by the control
parameters.
As with any drying mode, the main objective is to obtain the appropriate outgoing moisture content for the
type of grain that you are drying. This is accomplished by passing heated air through the grain, thus lower-
ing the moisture level. In continuous flow drying, wet grain is loaded in the dryer wet bin, dried in the grain
columns, and then either cooled and unloaded (in dry and cool operation), or simply unloaded and then
cooled in external cooling bins (in full-heat operation). For details on the full-heat and dry and cool opera-
tions, see
Grain Drying: Full-Heat or Dry and Cool, page 80 .
Control Parameters
In continuous flow, the dryer monitors the following two control parameters in an attempt to attain consis-
tent outgoing moisture:
• Grain temperature
• Outgoing grain moisture
Depending on actual temperature and moisture readings obtained during the drying process, the dryer’s
unload speed is automatically adjusted via preset control schemes. Increasing or decreasing the unload
speed affects the length of time that the grain remains in the dryer, thereby resulting in heating the grain
more or heating it less.
Control Schemes
Control schemes are preset drying strategies designed to aid the user in achieving the desired outgoing
moisture content. Each control parameter has specific control schemes to choose from. The figure that fol-
lows shows the control schemes that are available for each control parameter.
PNEG-1851 Vision N2 41