I would like to know if I can somehow join a run-of-the-mill vacuum cleaner to that little offpipe on a vacuum flask, so I can do vacuum filtration. I
have rubber tubing that can most likely connect to said flask, so how would I go about doing this while keeping most of the vacuum intact, and without
breaking the flask (implosion in case of too much vacuum)? (Is it even possible a vacuum cleaner would be strong enough to do so?)Endimion17 - 3-9-2012 at 00:54
Put some kind of tubing through a cork that fits in the vacuum cleaner and then join that and the vacuum adapter. I've done that a million times for
vacuum filtration and it works well.
Always let the cleaner some "free air" as its engine isn't designed to tolerate complete suffocation. Anyway, I sincerely doubt letting the machine
work for extended amount of time is ok for its engine.
Also, it's designed to suck air. If you're planning to use it for distillation of flammable solvents like ether or ethanol, expect an explosion in
your lab because there are sparks inside. I'm not kidding, don't do it.
No, vacuum cleaners aren't nearly strong enough to implode anything but someone's lungs. I've been measuring the pressure long ago, and while I don't
remember the exact figures, it's not impressive.
[Edited on 3-9-2012 by Endimion17]Dave Angel - 3-9-2012 at 09:16
Put some kind of tubing through a cork that fits in the vacuum cleaner and then join that and the vacuum adapter...
Sounds familiar! In the days before my lab pumps I used a similar set up to turn a (what became long suffering) vacuum cleaner into a 'pump'. Just to
build on what Endimion17 has said, I used parts like those below to make an adapter, although the plastic part had a bit of a taper
to it:
I too successfully performed filtrations with this set-up, and even used it to aid HNO3 distillation! I didn't think it'd last with such an
agressive environment but it never stopped working. Still, I'd definitely advise the acquisition of, say, a diaphragm pump as soon as you can budget
for one, or at least a water driven aspirator.MR AZIDE - 3-9-2012 at 10:20
Why not use on of those VAX orange carpet shampooer / vacuum cleaners. Those are designed to have liquids sucked into their tank, unlike a normal
dust only vacuum, and so would be safer to use rather than have liquid potentially going down the tube directly to the turbine of the motor.SM2 - 4-9-2012 at 06:29
Use a Dyson, and you'll never lose suction. Put a trap loop in line to make sure you don't let the vacuum cleaner asphyxiate. And like many have
said, have plenty of make-up air. That should be easy enough simply with a certain type of bad connection.elementcollector1 - 4-9-2012 at 08:58
"Certain type of bad connection"
I don't follow. A loose cork, a second tube that leads to nothing, what?zed - 11-9-2012 at 13:05
Umm. No need to improvise in that manner. For about $15.00, you can acquire a tap-water powered aspirator pump.
Such pumps produce pretty high vacuums, and they do not blow you to Kingdom Come, when you momentarily forget that you are currently filtering a
flammable solvent.
True, the aspirator pump uses quite a bit of water, but there is nothing to stop you from re-using that water in the garden or otherwise recycling it.elementcollector1 - 11-9-2012 at 13:21
Well, I'd like very much to not pay money, and instead opt for a DIY solution with readily available materials.zed - 12-9-2012 at 13:04
So, build an aspirator pump. It can't be that hard.Dr.Bob - 14-9-2012 at 11:17
You do have to be careful with a vacuum cleaner, as even small amounts of hexane (or other solvents) can catch fire when sucked through one, as a lab
mate discovered once when trying to vacuum up spilled used silica gel that still had traces of hexanes in it. The vacuum cleaner made a few bangs
like a car backfiring (back when they had carburetors, old people will understand me...) or a gun firing as the hexane caught fire.
An aspirator works well for the lab, and it is very easy to just use a small pump in a 5 gallon bucket or so to create a half decent vacuum with an
aspirator for a few dollars. Or you can buy the same thing from Aldrich for $800:
No offence but vacuum from a vacuum cleaner? That tramp on the corner gives a better vacuum..
Seriously just buy a aspirator or one of those Nalgene hand vacuum pumps .
Read this, 800mbar isn't much of a vacuum... A Vacuum Life
Also, recirculating aspirator systems may, dependent on what you are filtering, be a really stupid idea because of vapors etc. of the solvents and
such to accumulate in the aspirator system..
Said it before and will say it again, a PTFE membrane vacuum pump is the most well spent money I ever did for my home lab..elementcollector1 - 14-9-2012 at 12:28
"That tramp on the corner gives a better vacuum.."
... No comment necessary.
But is it enough to affect filtration? What bar vacuum is used in a standard fumehood? Something of that strength should be able to give good results
with a Buchner funnel.
EDIT: And yes, I'll look into the hand pump vacuum.
