LoKi - 6-3-2008 at 13:01
I just got a new vacuum pump 
Now I have no use for my water aspirator and the
pump station I built along with it. The aspirator is pretty good, but I don't have a place to hook it up except to the water recirculator I built, so
I don't know how much vacuum it would pull for you, but attached to the station it pulled around 200 torr. I will sell this stuff piecewise or all
together, depending on who wants what. also included is a funky hookup to allow a condenser hose nozzle at the same time as the water aspirator on
the station. I'll have pictures and specs soon, as well as prices, which are certainly negotiable. U2U me if you're interested
bio2 - 6-3-2008 at 13:27
An aspirator is still handy to have for evaporating solvents.
With a vacuum pump a cold trap is needed even using
a bleed when evaporating solvents. An ice trap really doesn't
do much good either.
Otherwise the solvents dilute the oil and exit via the exhaust contaminating the room and possibly damaging the pump. Oil free pumps of course will
exhaust the fumes but some solvent may condense in the unit. Running a hose off the exhaust also presents pressure drop problems for the pump and the
solvent will also condense in the tubing.
An aspirator should pull near the vapor pressure of the water. 200mm Hg seems high even with warm water. Likely the pressure/flow is too low for the
aspirator design.
[Edited on by bio2]
LoKi - 6-3-2008 at 13:44
I have another pump which doesn't use oil for solvent evap. Yes, 200 torr is high, but like I said, this is using the pump station. It would be much
higher hooked up to a faucet.
LoKi - 6-3-2008 at 13:48
Ok, im trying to upload these pics from my desktop and have realized I don't know how. Little help please?
chemrox - 6-3-2008 at 20:23
I acquired an aspirator pump. I also have a vacuum pump and a water pump (aspirator). I'm not sure what to do wih the aspirator pump as it requires
running water when almost any volatile solvent is involved.
free aspirator pumps to anyone in Australia
Panache - 7-3-2008 at 15:49
As some well know i received some surplus from a uni recently and included were some 200 aspirator pumps from the teaching labs. If any australians
want one u2u me your address and i'll send one to you.
bio2 - 7-3-2008 at 21:17
......I'm not sure what to do wih the aspirator pump as it requires running water when almost any volatile solvent is involved........
Yea and anything else for that matter, lol.
Drunkguy - 11-3-2008 at 16:06
the problem with using a vacuum to evaporate solvents is that without a dryice coldtrap, the DCM/ether etc. are sucked out of the vacuum ENTRANCE
valve with only a small minority of the distilled solvent collecting in the receiver.
Therefore using a water aspirator at least allows the vapors to be flushed down the sink and not into your working space.
The only other way around this that I can think of is a fumehood.
If your solvents are so pricey that u would prefer to recycle them then the best option is to distill them under atmospheric pressure. This may risk
degrading your product a bit because of the extra heat involved, but it could be worth it depending on what (or how sensitive) they are.
[Edited on 12-3-2008 by Drunkguy]