Cell culture fermentation is a very sensitive process and contamination of the broth may cause severe loss. So, from design point of view, components causing contamination should be eradicated. One area which forms a threat for cross contamination is the hole through which the agitator is inserted into the reactor. Though the double mechanical seal is an effective way of controlling leakage, it is always better to look for a opening free coupling between the drive and the agitator. This can be achieved by using a magnetically coupled agitator.
MAGNETICALLY COUPLED – ADVANTAGES
Magnetically coupled agitator enables the total integrity of the tank. No shaft is led through the tank wall, which may cause leakage and thereby challenge the sterility of the vessel and its contents.
Absolutely tight system
No danger of contamination and leakage.
High explosion prevention.
Optimal for aseptic production.
No influence on the integrity of the system.
Easy cleaning and sterilization
Can be done directly in the vessel by steam or water.
Control of temperature
The optimised mixing effect allows a temperature control, which was more difficult before at batch wise sterilisation.
Low shearing force
The careful mixing allows handling of sensitive products e.g. proteins, cells, blood fractions or factors.
Assembling and dismantling is very easier comparing a top-driven mixer which often requires a mechanical lifting device.
BOTTOM DRIVEN MAGNETIC AGITATOR
When the agitator is places in the bottom side of the vessel (Dish), it is termed as bottom driven.
MAINPARTS OF MAGNETIC STIRRER
Drive (gear drive): Can be AC or DC motor and Explosion proof if possible.
Welded flange: Welded to the vessel dish and holds the housing for drive magnet.
Adapter flange: Between motor and welded flange.
Journal: Contains the bushings made of tungsten – carbide and with minimized particle ejection.
Magnet housing: With magnet carrier (driven magnet) and shaft.
The Magnetic Mixer is designed for liquid mixing applications and complies with the most stringent cleanability and sterilizability requirements. Magnetic Mixers are totally cleanable and sterilizable in place (CIP/SIP). This factor is very important in the cGMP compliant
Vessels other than Bioreactors like media preparation, buffer preparation, etc., which are part of the bioprocess require mixing. Magnetic mixers are used in these types of vessels. The Magnetic Mixers are similar to the Magnetic agitator other than the impellers and normally come without a shaft.