Chapter 8 Using Moisture Control; Moisture Control And Homogeneity; Figure 16: Mix Trace Showing Homogeneity; Figure 17: How The Deviation Is Calculated - Hydronix Hydro-Control VI Operator's Manual

Chapter 8
This chapter describes how to select between using CALC Mode and AUTO Mode for a given recipe
and how to configure and optimise a recipe for that mode.

1 Moisture Control and Homogeneity

The aim of moisture control is to accurately reach a chosen moisture target in the shortest time
possible for a homogenous mix.
The sensor shows the dispersal of the moisture and other materials as they move around the
mixer. The trace from the sensor accurately shows the state of homogeneity as shown in Figure
16. A mix is homogenous when the materials are all evenly mixed and the water has been
dispersed throughout the mix. When the sensor signal is stable (when it reaches a flat line), the
mix has reached a homogenous state.
The degree of homogeneity required can be defined by the user and this will affect the mix time.
The Mix Log shows the homogeneity of the mix by displaying a deviation which is calculated as
the difference between the maximum and minimum values seen during the averaging time as
shown in Figure 17. This calculation is performed at the end of the Dry Mix and Wet Mix phases.
If the deviation is higher than that required, then the mix times must be extended to allow the mixer
more time to homogenise the raw materials.
During the wet mix stage, it may not be important to have a completely stable signal when the
system is used for general production, as the requirement for homogeneity will depend on the
product being made and whether more mixing happens after the discharge from the mixer.
If using the Auto-track function then it is important to ensure that the deviation limit parameters
used in the recipe are not set too high.
It is always best to view deviations in unscaled units as this is not affected by any calibration values
that are defined in the recipe.
Moisture Materials Materials
Loading mixing

Figure 16: Mix trace showing homogeneity

Moisture

Figure 17: How the deviation is calculated

Using Moisture Control
Mix becoming
homogenous
Time
Recipe
Averaging
Time
Deviation
Time
Hydro-Control VI Operators Guide HD0456 Rev 1.7.1 41