Sciencemadness Discussion Board

Good starter vacuum?

Saganism - 3-1-2013 at 12:56

I'm writing this topic to hopefully get some reviews or opinions on whether or not the vacuum listed is a good vacuum to start off with. What are the differences between diaphragm pumps and rotary vane? I believe thats the two different types.

Is this a good vacuum to start?
http://www.harborfreight.com/25-cfm-vacuum-pump-98076.html

Hexavalent - 3-1-2013 at 13:02

There are numerous threads discussing vacuum pumps, please UTFSE.

For vacuum filtrations and some distillations, I'm sure that pump will suffice. Actually, for some filtrations, it may even be a trifle strong, but the vacuum it pulls can be regulated.

However, I don't think the innards are made from PTFE or another fluroropolymer (probably aluminium or a steel), so you may have some issues with the vapours you pass through the pump.

Saganism - 4-1-2013 at 06:47

Thanks. Would a trap with something to absorb the vapors work? perhaps bubbling it through water? or would that not really be possible?

Hexavalent - 4-1-2013 at 06:56

Ideas for a trap were discussed here;

http://www.sciencemadness.org/talk/forumdisplay.php?fid=5

I'm still looking for something suitable for my own pump, actually. Ideally, you need a dessicant to absorb water vapour, and an acid/base scrubber or similar to absorb gases such as HCl, SO2, NOx, NH3 etc.

CaliusOptimus - 4-1-2013 at 07:27

Those harbor freight pumps are fine for non-corrosive work. I've used mine directly for distilling glycerol. For anything else you will definitely need a regulator or needle valve. A gauge is convenient as well, like a mityvac tee'd into the line. Has anyone mentioned TFSE?

Thread saver:

Hexavalent - 4-1-2013 at 07:50

Yes, I have :P

Magpie has a post somewhere on the forum showing his use of a 'T' adapter to incorporate a vacuum gauge into the vacuum line during a distillation, and it has been shown here several methods of controlling the strength of a vacuum;

https://www.sciencemadness.org/whisper/viewthread.php?tid=21...

https://www.sciencemadness.org/whisper/viewthread.php?tid=22...

Saganism - 5-1-2013 at 20:10

Thanks for the info.

turd - 6-1-2013 at 11:22

Quote: Originally posted by Hexavalent  
Actually, for some filtrations, it may even be a trifle strong, but the vacuum it pulls can be regulated.

How can a pump be too strong for vacuum filtration? It's not like you could ever reach significantly more than 1 bar of pressure difference just by applying a vacuum. The question is rather who in his right mind would use a rotary vane pump for vacuum filtration?

Edit: Ugh - stupid error.

[Edited on 6-1-2013 by turd]

Mailinmypocket - 7-1-2013 at 08:45

Since my manual vacuum pump broke a few months ago I have been using a rotary vane pump for filtrations, with a bleeder valve, vac gauge and various traps depending on what is being filtered. It is a pain in the ass, but if you put thought into the set up it isn't all that bad.

photoelectrical - 7-1-2013 at 16:26

Would a coleman quickpump (used for inflating/deflating air mattresses) work well as a vacuum pump for distilling nitric? with a baking soda/water gas washer?

Saganism - 7-1-2013 at 20:25

So, turd, as for vacuum filtrations, I have a water aspiration I haven't setup yet. I'm looking into a recycling aspirator pump system. Could a simple 'king- 160 submersible pump' provide enough force in my aspiration for efficient filtration? I believe it would.