THE TWIN SHAFT MIXING CYCLE

Although the total cycle time is dependent on the speed at which the charging takes place as well as the type of concrete being produced, typically Ocmix twin shaft mixers can produce a batch of wet cast or ready-mix concrete in less than 90 seconds, with dry-cast, block and paver mixes taking a little longer, although we do not recommend twin shaft mixers for dry-cast concrete due to buildup on the shafts.  Note that some admixtures require extra mixing time.  The diagram below assumes that the aggregates are waiting in a skip or hopper, ready for discharge.  Note the Premix time before water is added;  this is essential to proper mixing and fast mixing times. The short total cycle time allows many plants to be upgraded to give double the output by replacing the mixer only, compared with adding a second mixer, which requires extra conveyors, chutes, holding hoppers and often an increase in elevation of bins and weigh hoppers.

Wet cast cycle (typical).  Dry cast not shown - we recommend Planetary for all dry cast applications

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THE PLANETARY MIXING CYCLE

Although the total cycle time is dependent on the speed at which the charging takes place as well as the type of concrete being produced, typically Ocmix planetary mixers can produce a batch of wet cast concrete in less than 120 seconds, with dry cast, block and paver mixes taking a little longer, depending on the type of moisture/water dosing system employed.  Note that some admixtures require extra mixing time.  The diagram below assumes that the aggregates are waiting in a skip or hopper, ready for discharge.  Note the Premix time before water is added;  this is essential to proper mixing and fast mixing times.  Mixer discharge is from 30 seconds for repetitive loads to 40 seconds for full cleanout when running different colored products etc.  Contact us for specific applications.

Wet cast cycle (typical)

Charge aggregates	5s							Refill
Charge cements		15 sec							Refill
Premix time			20 sec							Premix
Charge water				20 sec							Refill
Charge admixes	Air			Other				Refill			etc.
Final mixing time					20 sec.
Discharge time						26-36 sec
Door close							4s
Total cycle time	Beginning to end = 110 to 120 seconds

Dry cast cycle (final water added as moisture is monitored, see "Fast Micromix")

Charge aggregates

5s

Refill

Charge cements

15 sec

Refill

Premix time

20 sec

Premix

Charge main water

15 sec

Refill

Charge admixes

Air

Other

Refill

etc.

Add final water

30-40 sec.

Final mixing time

40-50 sec.

Discharge time

26-36 sec

Door close

4s

Total cycle time

Beginning to end = 125 to 145 seconds