Pore sizes in foamed and closed mesh filters |
Foamed (Cellulose) filters are available with pore sizes from 0.2
to 8 µm. |
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Poresize (µm) |
Water stream |
Bubble point (bar) |
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0.2 |
25 |
4.2 |
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0.8 |
200 |
1.2 |
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5 |
570 |
0.5 |
|
8 |
750 |
0.3 |
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Bubble point test use the fact, that liquid is trapped due to capillary forces and surface tension in the pores of a filter. The minimum pressure neccessary to press the liquid through the pores depends on the largest poresize. This pressure is called bubble point (pressure). |
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Closed mesh fabric can be generated in varios ways defined by filament diameters and binding keys (Binding keys are according DIN ISO 9354). |
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Binding key: 30-01 07-01-03 |
Binding key: 20-04 04-01-01 |
Binding key: 20-03 03-01-01 |
There
are no common accepted methods to measure the porosity of closed
mesh filters.
JOMESA conducted bubble point tests with various
closed mesh filters and found bubble points values around 0.2 bar
for all of these fabrics. However the uncertainties are too large,
so that we rule out this method as relevant for filtration
aspects.
Therefore we do not specify the bubble point value for
our fabric.