Biomedical Engineering Reference
In-Depth Information
• SALTUS (Meissner), 5 L to 2,000 L, vertical oscillation of a disk or
septum; based on a vibrating disk with conical orifices. Due to the
oscillating movement and the conical orifices, liquid jets develop
at the tapered end of the holes. Thus, an axial fluid flow pattern
is achieved. The frequency and amplitude of the vibration can be
adjusted to provide either vigorous or gentle mixing. The bag is pre-
assembled with the rigid high-density polyethylene (HDPE) vibrat-
ing disks and with tubes, filters, and a sampling port, in addition to a
disposable sensor plate for pH, dissolved oxygen (DO), and tempera-
ture measurement. Due to the frictionless, oscillating movement of
the disk, it can be used where an ultraclean environment is required.
• PedalMixer (MayaBio,
www.mayabio.com
)
, 10 L to unlimited volume,
no stirring device, uses a pedal outside of the bag to push the liquid
to mix, and can be used with any generic bag; this is the lowest-cost
option. The newest type of oscillating system is a patented pedal
system whereby the 2D bag remains stationary on a flat surface and
a pedal pushes at one end of the bag creating waves inside the bag;
a slight tilt of the platform imparts potential energy to the contents,
while the kinetic energy moves the liquid and provides a mixing
profile identical to that obtained using a rocking platform or any
other form of the use of mechanical energy. A significant advantage
of this system is that it can accommodate any size (since no stress is
produced on the bag) and can accommodate all shapes and sizes of
bags, allowing the use of generic bags. (See
Figure 4.1
)
Peristaltic Mixer
• The Flexel3D Palletank for recirculation mixing incorporates one or
two recirculation loops and can be equipped with Sartorius-Stedim's
Mechatronics load cells to facilitate fluid management.
Summary
• A large number of unit operations in bioprocessing involve mix-
ing; fortunately, these are relatively simple operations that are eas-
ily validated.
• The largest mixing operations involve buffer and media prepara-
tion that can involve thousands of liters. Since these components are
