18
Start up of cassettes
t
After 30 minutes, sterilization is completed. Close valves V
3
|V
4
.
t
Close valve V
1
on the feed line, V
2
on the retentate line. Open V
5
to apply sterile
filtered stabilizing pressure of 14.5 psi|1.0 bar|100 kPa. At this point, shut off the
steam supply.
t
Allow the holding device to cool down for 90 minutes. During cool down V
5
has to
remain open.
t
After 90 minutes cool down time close V
5
.
t
Vent system through upper permeate valve V
3
. Do not open V
3
completely. Only
vent excess pressure. If sterile air venting is required, please implement
a sterilizing air filter.
t
Using a torque wrench, alternately retighten the stainless steel pressure compen-
sating nuts to the torque indicated [
Æ
Chapter “5.2 Clamping Forces”, page 12].
t
After steam sterilization is completed flush filter cassettes with RO water until
system has reached room temperature, this will also ensure that the membranes
will not dry out.
5.6.2 In-Line Steam Sterilization of Sartocon
®
Ultrafilter Cassettes
Ultrafilter cassettes are sterilized through the retentate and the permeate flowpaths
simultaneously to maintain equal pressure within the cassette.
Stabilizing pressure inlet
Cassette
Permeate
Permeate
Feed Line
V
2
V
5
P
P
2
P
3
P
1
P
4
V
1
V
4
V
3
Steam
generator
V
6
Retentate Line
Diagram of the crossflow system for in-line steam sterilization
of polyethersulfone Ultrafilter cassettes.
V
1
–V
6
: valves; P
1
–P
4
: pressure gauge, P: pump
t
Assemble system as shown on the diagramm.
t
Open V
2
, V
3
, V
4
, V
6
and V
1
, close V
5
.
t
Install cassettes into filter holder.
t
Attach a RO water source to the feed line.
t
Rinse cassette with RO water for 5 minutes at an inlet pressure of 29 psi|2 bar|
200 kPa and retentate pressure of 7 psi|0.5 bar|50 kPa. Adjust valve settings to
achieve pressure values if needed.
t
Drain the system.
t
Close valve V
2
. Connect V
2
at the retentate line with a steam generator.
t
Exchange torque the normal operation nuts to the pressure compensating torque
nuts. For specific information related to the filter holder see user manual of the
installed filter holder.
t
Use a torque wrench to tighten the compensation nut to the first notch