Harvest Step - Thermo Scientific gibco CTS Rotea User Manual

Chapter 4 Protocol Building Blocks
4
Concentrate Recovery

Harvest step

The Harvest step enables a high product concentration to be delivered by minimizing dead volume in
the fluid path between the tip of the CFC Chamber and the output valve. It can only be selected as a
step type if one of the output valves E, F or H is active for the step and the pump is set in the reverse
flow direction, eg:
The Harvest step holds off the opening of the output valve until the Cone to Valve Volume has been
pumped from the tip of the cone.
Since the Harvest step delays changeover of the valves, the step before Harvest needs to have a
legitimate flow path that can be sustained during the initial harvest period, such as a Pause step.
The Cone to Valve Volume relates to the volume in the rotary coupling, pump tube and kit tubing
between the tip of the cone and the output valve. The default Cone to Valve Volume is 0.5 mL and can
be adjusted to further optimize the Harvest step.
Once the Cone to Valve Volume has been drawn out of the CFC Chamber, the programmed valve
settings for the step are enforced and the triggers enabled.
From a practical perspective:
• If you set a volume trigger of 4 mL without a Harvest step, a volume of 4 mL will be delivered to
the output bag, but this will include the Cone to Valve Volume which does not have cells from the
fluidized bed in it.
• If you enable the Harvest step and place a volume trigger of 4 mL on that step, then 4 mL of
concentrate will be delivered to the output bag.
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CTS ™ Rotea ™ Counterflow Centrifugation System Process Design User Guide