Computer Controlled Magnetic Stirring -old
Magnetic stirrers are a favorite in biological and pharmaceutical labs because they allow researchers to experiment with a wide range of mixing and stirring options. When the technique is refined, the magnetic mixer serves in a pilot plant or production capacity.
CAT Scientific offers a variety of hotplate magnetic stirrers that can function individually or in tandem with remote operating capability provided by programmable logic controllers (PLC) and/or manufacturing execution systems (MES). Several options are available for interconnection such as RS485 or RS232 interfaces to specialized vendor software*.
Accommodating Variables in Magnetic Stirring
CAT hotplate magnetic stirrers operate over a wide range of stirring speeds and temperatures. Variations in both of these parameters are often required. These can include programmed on-off cycles, variations in stirring speed, mixing cycles from minutes to hours, rpm changes for long or short durations and temperature changes of long or short duration.
Automated lines such as described introduce other performance requirements, namely reliability because the units are not monitored 100% of the time by personnel. Temperature sensors such as the CAT PT100 platinum temperature probe play an important part in equipment monitoring and can initiate a unit shutdown in the event of equipment malfunction or temperature excursions.
Special Magnetic Stirrer Requirements Accommodated
Processes may call for introducing dry chemicals into the solution during mixing operations. Because there is no physical connection between the free container magnet and the motor-powered mixer magnet two points should be kept in mind. First, chemicals should be introduced slowly to avoid clumping at the bottom of the container. This could cause the rotating magnet to go off center. Second, a stronger rotating magnet can be specified in the base of the mixer to keep the rotating magnet on center. Stronger motor-driven magnets can also be specified if containers have a thick walls and bottoms.
This point is particularly important when operations are controlled remotely by PLC or MES systems as an off-center stir bar may not be immediately noted by monitoring personnel.
I guess that the point I want to bring across here is if you don’t see the magnetic stirrer you want on our website simply ask us for a recommendation. We’re glad to help you solve challenges in your research or production facility.
*An example of CAT Scientific software is described in our article, ‘Using Programming Software for Magnetic Stirrers’.