Filtration > conventional media
What's wrong with conventional microfiltration media?
To the right is a picture of well-known metal microfilter, taken using an electron microscope - note the 100 micron scale bar at the top, below it is the same filter's pore size distribution obtained from a Coulter Porometer and based on an old ASTM technique for pore size analysis:
according to the analysis the modal pore size is 3.5 microns and there are no pores bigger than 5.5 microns, but
the scale bar clearly shows surface pore openings up to 40 microns in diameter; much bigger than the pore size distribution suggests.
At low solids concentration, the microfilter can only achieve its rated pore size capacity by capturing particles within the matrix of the filter; i.e. it is really a depth filter.
Deposition of particles within the matrix leads to long-term membrane fouling; i.e. low permeate flow rates. Even when clean, the pressure drop required to pass the fluid through the filter is high, especially with viscous fluids, because of the tortuous pore channel required to capture the particles.
The irregular pore distribution, and shape, is even more of a problem when attempting to use this type of filter for emulsion generation: the emulsion size (and size distribution) will depend on the surface pore openings and not the 'equivalent' pore size of the tortuous pore through the microfilter.
How is Micropore Filtration media different?
If you look at the media pages you will see that our filtration media, or our emulsion generation media does not use tortuous pore channels to achieve the pore rating of the filter. The microfiltration media is similar to very fine sieves. Hence, there is no internal deposition of solids and the pressure drop required to pass liquids through the media is low, even for viscous liquids. The uniform surface pores are ideal for the generation of uniform drops in emulsion production.
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