Any know of any clean Vacuum Pumps with a good pull?
for distillation purposes
I have a 5cfm rotary vein and it spits stuff out of the exhaust and really messy. looking for a replacement
I was wondering if anyone know of any good oil-less pumps
or atleast the ones that dont spew out anything..
SO far im looking at Welch
zoombafu - 22-11-2011 at 20:17
I would recommend that you get a water faucet aspirator. It suits me well for most vacuum distillations, and you can usually get one for 10-20
dollars. Also no exhaust and spitting out stuff.gtchemen - 22-11-2011 at 22:22
thats an idea but thats alot of water to use...
and what if my station doesnt have a sink??
but your idea might be good for someone else. and what if you use the same water from the aspirator to run the condenser...starman - 22-11-2011 at 22:51
Try using the search function.Quite a lot on the board on this.IIRC specially coated piston type vacuum pumps might be what you're looking for.Endimion17 - 23-11-2011 at 01:14
Fridge compressor. Go to the city dump and get yourself one for few $ at most. Be sure to use a trap between the compressor and your system... and
mind where the exhaust and the intake pipes are.JibbyDee - 25-11-2011 at 14:09
thats an idea but thats alot of water to use...
and what if my station doesnt have a sink??
but your idea might be good for someone else. and what if you use the same water from the aspirator to run the condenser...
Just recycle the water. I use an aquarium pump to flow water through my condensers, I just put the pump in a bucket of water and output the water from
the condenser right back into the bucket. Not only do I not waste a single drop of water, I can even cool the water to 0C by adding ice. You can't do
that with a tap. Magpie - 25-11-2011 at 14:31
I have a 5cfm rotary vein and it spits stuff out of the exhaust and really messy. looking for a replacement
I would run a test on your present vacuum pump before disqualifying it. Run it at no gas flow, ie, run it with the inlet closed tight with a valve or
such. Then see if it continues to spit oil. Let us know the result. bahamuth - 25-11-2011 at 14:34
I have one just like this, ILMVAC:
Good for most purposes like vacuum filtering and super for rotavapping, though not as good for distilling high bp. stuff as it only goes down to
12mbar, have a standard oil rotary for vacuum distilling.
Advantages of a membrane pump like that is that one does not need a cryo trap and such inbetween the pump and apparatus (though one should always),
these membranes are made of a Teflon materiale and have even passed hydrogen chloride through it for an extended period by accident. Easy to pick
apart and clean, easy to put togheter again too. Also gives positive pressure though wouldn't test it to the max, but good for high volume/low
pressure air through a system e.g.
Super duper mega expensive though, got mine from a lab cleaning, they threw this away since no one was using it and they had enough or rotary vanes
lying around.
And in my experiance, some rotary vanes spit out oil from day one, they need a muffler/condenser of sorts not to sputter. Try to fix something up,
like a tubing 30mm wide by 200mm tall with metal shavings, long like the scrubbing thingy as long as one can get copper shavings on a lathe as
filling, confident it will help. Also oil level is critical, so is the amount of air let into the pump, to much and it will blow oil through. That can
be fixed by adding a volume regualtor on the input. Would never get a new pump if the old one still pulled vacuum...Elawr - 3-12-2011 at 11:47
Harbor Freight Tools sells pretty good vacuum pumps for A/C and refrigeration work. If I remember correctly, for less than $200.Magpie - 3-12-2011 at 11:57
Harbor Freight is selling 2.5CFM vacuum pumps made in China for <$100. These are single stage oil pumps (rotary vane I think) that are supposed to
pull 75 microns at no flow. I bought one and have measured the vacuum at 120 microns. This should do just fine for vacuum distillations. How long
it will last probably depends on how clean I keep its oil.
[Edited on 3-12-2011 by Magpie]Hexavalent - 8-1-2012 at 08:48
No need to waste such money . . .just get yourself a dirt cheap car air compressor, and open it up. Most of the time, the input is just a little hole
on the piston (most cheap compressors use the piston concept to push air), on top of which happily will sit a small brass nipple, on top of which you
can place some heavy duty tubing with a hole drilled in the case for it to exit.
Simple, and cheap - mine cost less than £5 to make. (It can actually pull a really good vacuum)
