hkparker - 23-2-2012 at 23:16
I'll need demonstration sized amounts (<3L) of liquid nitrogen in a few months. I was wondering if anyone has had experience purchasing before. I
know if the standard places to look but from what I've read its pretty hit and miss, so I was wondering if anyone has successfully got it from a
supplier, and what the most reliable place to look would be. Thanks!
marko - 24-2-2012 at 01:43
Around here, all the gas houses are geared to industry and don't really seem to be helpful, unless you're leasing something. Might have better luck
where you are, though.
Most heavy machine shops will have a dewar of it around, handy for shrinking interference-fit bearings and shafts, etc. Maybe they'll trade you some
for a case of beer...?
Neil - 24-2-2012 at 08:53
If you are not daft or sketchy go to your local universities and find the mystical keeper of N2 on the physics department campus. If they do not
assent to giving you some then try the other departments that carry N2 - normally they all have their own guardians and eventually one will be
sympathetic...
DieForelle - 26-2-2012 at 14:20
I tried to obtain this about 8 years ago during the internet's first "liquid nitrogen ice cream" craze. (remember?)
The majority of the gas suppliers I contacted in a major metropolitan area didn't want to bother with me, but a couple said they would begrudgingly
fill a real Dewar if I brought one in. They would also sell a new one for >= 500 clams. So I set about looking for one...after a couple weeks I
spotted an ad for a used smallish (30L?) Dewar from a local Vet's office. They wanted $200 for it. I tried to get them to take $150 and she said
she'd get back to me...she never did. I moved on...
MyNameIsUnnecessarilyLong - 26-2-2012 at 15:34
If you have the technical skills and time, you could generate your own LN2 with something like this:
http://benkrasnow.blogspot.com/2008/08/diy-liquid-nitrogen-g...
http://www.youtube.com/watch?v=14B8LynojI4
He says it cost him about $500 to gather all the parts, and it produces about 1L a day from using 9.6 kWh of power, which at his electricity rates
equates to $1.15/liter.
Edit: That's probably not practical to DIY in a few months. But if you plan to give regular demonstrations, or use cold traps and dewars a lot, then
it would make sense.
I used to be able to get LN2 from a local coating/deposition company that had their own generator, but the people I went through for that have long
since retired.
And I did recently try my local university, but they told me no since they stock only a small 1gal dewar of it and have to import the LN2 each
morning. Though, most large universities should be better equipped than this and have their own LN2 generator. I'm sure they're quite concerned with
liability so I doubt you'll be able to get any without being good buddies with the people there.
Welding shops are probably your best bet. Go to the smaller shops that don't look like they get a lot of business. They'll probably be more expensive
but less likely to turn you down.
[Edited on 2-27-2012 by MyNameIsUnnecessarilyLong]
Formatik - 26-2-2012 at 16:16
Hospitals and some medical clinics have liquid nitrogen (e.g. to freeze off warts and preserve human tissue). But don't just start popping into
hospitals asking for liquid nitrogen, if you have an inside source there you may be able to get a hold of some. Use a strong but very lightly capped
plastic thermos can for short term transport if you have no Dewar flask. I know universities have a lot of liquid nitrogen especially around the
chemistry and physics departments, I have not tried there.