RogueRose
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Would square filter housing work instead of round ones?
I was looking at sheets of various filters, especially PTFE, and it made me wonder if a square filter housing would work as well as a round one, or if
it would have drawbacks.
The filter paper would be clamped down by the housing, with very adequate to pressure to ensure no leakage around the edges of the membrane or outside
the housing. It would basically make something that works like a syringe filter but much more substantial and replaceable membrane.
The reason being is it would give more surface area being a square and can be more easily cut from sheets, and there is no waste if making filters
yourself.
I only found one instance of square filters and it isn't really in the same useage I'm thinking of, which would work similarly to a capsule or syringe
filter.
https://www.sigmaaldrich.com/catalog/product/sigma/cls431118...
It would be pretty easy to print something to use square filters but I'm not sure if there is any problem with corners, or if they are made in circles
due to ease of use and maybe manufacturing.
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Sulaiman
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If vacuum (reduced pressure) is envisioned then flat surfaces will not be as strong as curved surfaces
- for the same wall material and thickness.
Corners would be a little more difficult to clean than round walls.
Ready made filter papers come in different porosities,
you may have difficulty in getting a range of porosities using paper that is not normally graded for porosity,
you would have to do many tests,
even then, manufacturers probably do not control the porosity of their paper so there may be batch-to-batch changes beyond your control.
For a one-off ptfe membrane filter I see no reason why it would not work,
but why make life difficult when all sizes of round funnels are available ?
Cutting a disc from a square sheet reduces area by the ratio Pi/4 ... 0.7854
cutting multiple circles from a large sheet is a little more efficient,
but overall, is it worth the effort just to offset the 22% loss of area ?
CAUTION : Hobby Chemist, not Professional or even Amateur
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TheMrbunGee
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They would be harder to clean and uneven stresses might cause problems to material at certain pressures. Also round containers are most
volume-material effective.
Other than that - I don't see why not.
EDIT: And the reasons given by Sulaiman.
[Edited on 18-10-2019 by TheMrbunGee]
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