Maui3
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Vacuum Pump
Does anyone a recommendation to a place to buy a vacuum pump for vacuum filtration and rotovap?
It's probably cheapest to buy used.
I don't know a lot about vacuum-things, so I might sound very dumb. How do I check, and how strong of a vacuum is usually used for vacuum filtration
and rotovaps?
Thank you!
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Sir_Gawain
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I don’t know about rotovap, but for vacuum filtration I would recommend a water aspirator. They’re very cheap, and you don’t have to worry about
corrosive chemicals damaging it. I 3d printed one and it pulls a strong vacuum just using water from the tap.
“Alchemy is trying to turn things yellow; chemistry is trying to avoid things turning yellow.” -Tom deP.
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Maui3
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Not a bad idea!
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Dr.Bob
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For a rotovap, a simple membrane pump works well or you can try a simple HVAC pump like Northern Tool or Harbor Freight sells. An asirator for a
rotovap is going to use a lot of water. But for filtering things, an aspirator is generally OK. Neither needs a supper string vacuum, unless you
are trying to rotovap DMF or such.
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Maui3
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Thank you Dr.Bob I will look more into that.
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Sulaiman
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I do not use my HVAC vacuum pump for filtration because;
. Very low pressures boil water, solvents etc. at room temperatures
. Many filter-vapours can damage the oil or aluminium of the pump
. HVAC pumps are very noisy, not designed for continuous duty and consume a few hundred watts of electrical power.
A small hand pump or a water aspirator seem popular choices for filtration,
I like cheap 12Vdc vacuum pumps because they work well,
run for days with no problems, not too noisy, consume little power,
are cheap enough to be semi-disposable, and I have 12Vdc supplies available.
My -75 kPa pump filters a little quicker than my -65 kPa pump.
(I think / it seems logical that) filtration flow rate is directly proportional to the pressure difference
(until other effects such as boiling occur)
CAUTION : Hobby Chemist, not Professional or even Amateur
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Keras
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For vacuum filtration I use a cheap Chinese pump (see picture).
I was expecting low quality, but it’s reasonably sturdy and does a good job for the price. Even if it’s given for 12 VDC, I rarely have to push it
over 4 V to get good filtration.
I even used it once for vacuum distillation, and I was surprised at how well it worked. It was almost as good as my water aspirator.
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