7.4 Stage 3 – Shutting the system down and recovering product
Before shutting your cross-flow filtration system down, you can complete two recovery methods to
maximize the recovery of product. One recovery method helps remove the buildup of product on the
surface of the membrane inside the cassette. The other method helps you recover the most product
volume from the system piping and cassette.
Capturing product from the membrane surface
The first product recovery method involves reducing the cross-flow rate at the end of your
processing step. For example, when you finish processing your product, reduce the cross-flow rate to
1/10 of the recommended processing cross-flow rate. Close the permeate valve or reduce the feed
pressure to 0.3 barg (5 psig). Retentate pressure should be 0 barg (0 psig). Circulate the remaining
product for 15 minutes. This procedure will help recover product buildup from the surface of the
membrane.
Maximizing the volume of product recovered
The second product recovery method maximizes the volume of product you can recover from the
system piping and cassette. The method involves slightly over concentrating the product, then
adding a small volume of permeate back into the system to flush concentrated product from the
feed-retentate loop. This method is described below in the following steps:
Step
Action
1
As the process nears completion, decrease the pump speed to minimize flow rate,
vortexing in the feed tank, and the possibility for product foaming.
2
When you reach the slightly over concentrated volume, collect about 200 to 500 ml of
permeate in a container. Stop the pump and close the permeate valve.
3
Attach a line to the drain valve and connect the other end aseptically to your collection
vessel (
).
Tip:
Many types of pumps will be damaged if you run them dry. Therefore, monitor the liquid
level in the tank and shut off the pump when the tank is empty.
WARNING
If maximum recovery is required, you can remove product from the
system by applying a lowpressure nitrogen flow to the retentate
side of the system. Contact your Cytiva representative for
additional details.
7 Using the Holder
7.4 Stage 3 – Shutting the system down and recovering product
Learning to Use the Kvick Lab Cassette Holder User Manual 18117269 AI
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