BioPharma - Centrifuge
An initial separation is made in the centrifuge. During the separation process, you see a change in the concentration of the undissolved substances (suspension). This change can be measured.
A turbidity meter: the objective sight glass
A cloudiness or turbidity meter detects the products present that are not dissolved in the medium (suspended solids) much more accurately than the human eye. That is why old-fashioned sight glasses are a thing of the past. Turbidity meters not only detect the smallest concentration of particles in a pure solution, they even notice small differences in turbid media. Depending on the application and the purpose of the measurement, different measuring principles are available. What they have in common is that they are all based on the scattering of light.
NIR Absorption
This technique is used for medium to higher measuring ranges. The light from the emitted light beam is scattered in all directions, thus also at an angle of 180°. This fraction is sent by an optical fibre to the detector where the difference in intensity with the emitted light beam is measured.
Forward scattering
If the intention is to measure very low turbidity, it is best to choose a “forward scattering” system. The light scattered by the particles is measured at a small angle (10-12°). The calibration curve in the transmitter displays the turbidity in the desired unit.
Ensure safety using an inline oxygen analyser
Due to the presence of volatile solvents and the high speed of the centrifuge, there is always a risk of explosion. This can be avoided by ensuring that no oxygen is present.
This absence of oxygen must, of course, be permanently monitored. A GPO (Gas Phase Oxygen) sensor can be used for this purpose. These are fast and compact optical sensors that are easy to integrate. For larger installations, it is best to use a laser oxygen analyser (TDL, Tunable Diode Laser). The extremely fast response time (approx. 2 seconds) means you are really protected.
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