Biomedical Engineering Reference
In-Depth Information
Millipore has developed a derivative hollow fiber system, Pellicon, and
here is how it compares with standard hollow fiber filters:
Hollow Fiber versus Pellicon 2—Summary
Feature
Hollow Fiber
Pellicon 2
Robustness and reliability
Fiber is prone to stress
failure
Very robust
Pressure capability
Low
High
Membrane choices
1. Polyethersulfone
1. Polyethersulfone
2. Regenerated cellulose
3. PVDF (for MICRO
filtration)
Flow rate required to operate
TFF processes
High flow rate resulting in
• High energy
consumption
• Large piping
• Compromised
concentration ratio
• Increased demand for
floor space
Low low rate resulting in
• Low energy consumption
• Small piping
• High concentration ratio
• Compact system size
Linear scale-up
Compromised by
differences in the length of
the flow channel in
laboratory versus process
scale cartridges
Identical length of flow
channel in all cartridge sizes
to facilitate predictable
scaling results
Consistency of retention
relative to retentate channel
design
Compromised consistency
due to
• Open flow channels, no
internal mixing
High consistency due to
• Built-in static mixer,
efficient internal mixing
Consistency of retention
relative to the retentate flow
channel length
Compromised consistency
due to
• Long flow channels
High consistency due to
• Very short flow channels
Flat sheets can be arranged in a stack in place of pleated or hollow fiber filter
media. The sheets are sealed so that they leave channels open to allow feed
to pass through.
Conclusion
From prefiltration to remove large sediments to harvesting bacterial cultures
to removing viruses in the final stages of biological drug manufacturing, fil-
ters play one of the most important roles. There are dozens of companies spe-
cializing in specific filtration processes and giants dominate the market with
their Millipore Pod
®
system, the Pall Stax
®
system, or Sartoclear
®
XL Drums
from Sartorius-Stedim. They also keep bringing newer filters, housings,
