Hydronix Hydro-Control VI Installation Manual page 62

System Design
4 Mix Cycle Design
This section details the design of the mix control sequence which can contain up to three water
addition steps along with associated mixing times.
The mix sequence design is usually based on the type of concrete being made, the type of
aggregates or the admixture addition recommendations.
The Complete Mix Cycle
4.1
Figure 42 shows a complete mix utilising all of the basic mix cycle options.
The mixer is loaded and then the start signal is sent to the Hydro-Control. The Hydro-Control
will then run the initial mix cycle time and then adds an optional amount of pre-wet water which
can be used to increase the moisture of the dry materials. Pre-wet water is useful if lightweight
materials or materials with high water absorption values are being used. It is considered best
practice to increase the moisture of raw materials above their Saturated Surface Dry (SSD)
condition wherever possible before the materials enter the mixer. Using pre-wet water can also
reduce the amount of dust generated by the process and reduces wear on the mixer motor and
gearbox
The Hydro-Control signals to the batching control system that the pre-wet has been completed.
The control system then adds the cement and activates the 'Cement In' signal.
The Hydro-Control runs the dry mix time, then adds the main water, then runs the wet mix time
before activating the 'Mix Complete' output. The batching control system can then discharge
the mixer and send back a reset to the Hydro-Control to prepare for the next batch.
Initial
Load
Mix
Mixer
Time
Inputs
Start
Water Meter
Cement In
Reset
Outputs
Coarse Valve
Fine Valve
Pre- wet Done
Mix Complete
62 Hydro-Control VI Installation Guide HD0455 Rev 1.9.0
Pre-wet Pre-wet
Cement
Water Mix
Addition
Addition Time
Time
Figure 42: The Complete Mix Cycle
Dry Main Wet
Mix Water Mix
Time Addition Time
Chapter 5
Mix
Complete/
Discharge