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neptunium
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have yo looked at cryocooler yet? $20 seems low since everybody on ebay wants one (it seems) but i just got 2 of them and this one is working fine !
right now sitting at -91C ! and dropping!
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neptunium
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-100!!!
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elementcollector1
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Quote: Originally posted by Zyklonb  | | By the way, How do you buy that LN2 generator? (the one I linked) I couldn't find anywhere on the site or any links posted on actually
purchasing the thing. Am I missing something obvious? |
You probably need to contact them to find prices.
How big are these cryocoolers?
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neptunium
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about the size of a vacuum cleaner`s motor so not that big at all....but expansive ! somewhere arround 400 bucks!, however , these unit can run for
years or decades continously without any problem....its worth it !
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Chemosynthesis
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You might also consider PMing ElizabethGreene here. She works at a cryonics institute.
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elementcollector1
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I did not know that. I'm not sure what I would ask, though...
A vacuum cleaner motor is relatively small... Unfortunately, I think I'd need smaller (not knowing the actual dimensions of the motor - glancing at my
vacuum cleaners, it's probably a 6" diameter by 12" height cylinder.
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jock88
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Some light reading on Cryocoolers here:
http://alexandria.tue.nl/extra2/200412821.pdf
Are they dooable in an amateur lab/garage?
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Zyklon-A
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As long as you have plenty of money and room to put stuff, almost anything is doable in an amateur lab. Room isn't the problem for me, it's the
money.
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neptunium
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you can get lucky on ebay sometimes but you`d have to babysit the site because they go fast...
superconductor technology superfilters have one inside its quite a heavy box for shipping but you could still get your hands on one...they run on AC
despite what the label says.... they come in all sizes i bet you could find a smaller one but its gonna be even harder to find...
Or you can always buid a joule thomson exchanger! if you save a bunch of money!
good luck
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elementcollector1
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This is probably a workable size: Cryocooler on Ebay
Might have to shift things around a bit, but it looks doable at the very least. Can't say I like the price, though.
Ha! I couldn't build a miniature vacuum pump when I tried, I doubt I'd have much luck with a miniature JT cooler. Although I will be requesting this:
http://doc.utwente.nl/73913/
Of course, I can't really tell what 'miniature' means in this context...
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neptunium
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the smaller you go the longer it will take to get as low as LN2 temp because you`ll be lacking the power to condense nitrogen out of the air.
more power wil get you there quicker and you`ll end up with more product.
If you are going to spend the money why not make it worth your time ?
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elementcollector1
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If I am going to build the product (keeping in mind that the product has size and power limitations) why not make it worth the build? I don't want to
be carrying around a portable generator on my back...
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neptunium
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i have made some improvement (and spent more than i care to admit) but i think i am getting good at this!
Those cryocooler cost a little but are nowhere near the price on those liquid nitrogen generator!
Here is what i did...
with an older superfilter taken appart to reveal the cryocooler, i built a cooling jacket to go arround it
and fitted it with intake and out for the water .. (water is indeed a much better cooland than air)...
here is what the set up looks like
Despite what is indicated on the superfilter , those things (the cryocooler ) runs on AC! but the rest of the unit is DC powered .. dont waste your
time trying to run it on DC like i did...
Next build a Jacket outta PVC pipe and PVC cement outfitted with in and out for the water ..
with that set up and a Pt probe thermometer in a dewar i was able to get to -195C ! (-320 F!!!)
This is by far the lowest temperarute i have ever been able to obtain in my lab! If i remove the thermometer which is introducing a little bit of heat
from outside i might be able to hit the -200!
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elementcollector1
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http://www.sciencedirect.com/science/article/pii/S0011227598...
Finally found the whole version of that document from earlier, but the build is very confusing...
What is the purpose of the wire insert?
Is it possible to reduce the ridiculous size of the cooling tube?
What is the power supply for this device, and where did they get a figure of "as low as 10 mW" for cooling power requirements?
Still, this looks at least *possible* to build at home... Although that being said, I still have to account for the pressurized input (which will
likely require buying an adorably tiny air compressor).
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Zyklon-A
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Cool! I'm interested in hearing your results, I want a LN2 generator myself, but will wait for someone else to try it before I do! Or I might just buy one, I guess I should contact the people who sell those little
one's.
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The Volatile Chemist
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Funny. I saw this post yesterday and today I saw an instructables about it. I haven't read it yet, I'll do so in a bit, but I thought it'd be
applicable.
http://www.instructables.com/id/Homemade-liquid-nitrogen-gen...
[Edited on 5-22-2014 by The Volatile Chemist]
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Bezaleel
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That's a great achievement, neptunium! ::thumbs up::
On the other hand, reaching that temperature is one thing, but generating LN2 may require so much power that you will only be able to have
no more than just a few drops of it.... I'm very interested to hear your further progress.
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neptunium
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true, i have only been able to get a few drops from condensation but the temperature is there and the cryocooler is rated for a few hundred watts.
i have had leaks problems with the cooling jackett but i should be able to get as much as i want given enough time...
https://www.youtube.com/watch?v=51a7X7lblMc
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smaerd
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Wow neptunium! -195*C that's impressive. My physics professor told our class that he hand built the cryogen system to do his doctoral thesis(at least
I believe so). I'm really taken back by peoples home efforts at cryogenics. I didn't realize many people were willing to work with the Joule Thomson
effect given the pretty extreme pressures involved here. Forget who it was, maybe it was magicjigpie, used to have in their signature "Friends don't
let friends build autoclaves", or something like that. Love to see results, if you could post a basic schematic or sketch I'd love to see it. One day
when I build a home I wouldn't mind having something set up to get liquid air.
The Volatile Chemist - https://www.youtube.com/watch?v=LWM3ZImmVWQ his pressure swing absorber is pretty intense!
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Bezaleel
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I'm impressed!!! (which I don't say often)
You shared some photo's above, but I'd certainly be interested in a more detailed write-up. E.g. what you based your choice of cryopump on. And how
did you remove the oxygen, H2O, CO2 and noble gases from your air? Or did you use nitrogen from a pressure bottle as input? More technical details?
(If time permits, of course.)
Do you have any special experiments in mind you created you LN2generator for?
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The Volatile Chemist
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Slick!
Those low temperatures are insane (-195!)! If you put Ice around the thermometer probe, would that limit heat intake?
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Zyklon-A
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neptunium, is that your video? Or did you just post a link to a video you were copying.
If that is you video, then you just made liquid air, not nitrogen (of course you know this).
Seems like a risky way to handle liquid are.
Cardboard? The nitrogen will boil off more rapidly than the oxygen, and will take heat out if the air, thus possibly cooling more oxygen to below its
boiling point. So the concentration of liquid oxygen will steadily rise, which could be dangerous near carbon containing compounds (eg. Cardboard).
I'm sure you've thought this through though.
Assuming that is your video.
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neptunium
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no i just copy the link in response to Bezaleel...
I have had some power issue with my variac lately , but i also noticed a change in the design of those
cryocooler.
the one i have is an older model and takes about 2 to 3 hours to reach these temperature thus not powerful enough to generate a sufficiant amount of
liquid air..
the newer unit can get low fast! very fast and within a few seconds generate a few ml of liquid air.
Yes Zylonb i`ve wrok with detectors cooled by LN2 and was trainned to handle it and air at cryo temperature, however there is no danger with the few
drops i generated but you are correct this must be kept in mind and it fascinates me to see the clea liquid slowly turning light blue! and responding
to a magnet!
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imsmooth
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I'm sure, as someone commented above, you've seen this video:
https://www.youtube.com/watch?v=DaViMXLPkbA
This is a summary of my efforts making LN2 without the aid of a pre-made cryocooler. I did it the old-fashioned way. As an added benefit, I used
pure N2 from a homemade pressure-swing adsorber.
The tutorial for the LN2 generator is at http://homemadeliquidnitrogen.com
The pressure swing adsorbed is at http://homemadeliquidnitrogen.com/PSA
I also put together a highly accurate cryogenic digital thermometer. It is more accurate than the Auber, which I initially used, and measures to
tenths of a degree, which helps me follow the cooling process more closely. You can read about this at http://homemadeliquidnitrogen.com/crybaby
Hopefully, this will help those of you interested in this.
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j_sum1
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@imsmooth
Seriously cool. And not a bad video at all -- good skills there too.
Surprisingly, your cat took that quite well.
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