Liquid Nitrogen Generator

[dmuz]

I'm just glad I don't live in Datchworth, or Hertfordshire for that matter...

[scaryjim]

... getting hold of dry ice should be simplier.

Order frozen foods from the right online retailers and they ship it to you with packets of dry ice in the bottom! I amused my kids for about quarter of an hour watching it racing around a bowl of water

I believe Goodness Direct (a very nice specialist vegetarian retailer) do it, to name one.

[Funkstar]

I didn't know that Jim, almost worth ordering some just for the packaging

[SiM]

I am thinking of buying this.

Check these chavs out: http://www.youtube.com/watch?v=cTP4yp8y_NA

Edit: Haven't watched it yet but maybe you should watch this:
http://www.youtube.com/watch?v=d11TF...eature=related

[Blastuk]

Oh yes, this is a good idea, high pressures, rocket fuel...bits and pieces cobbled together.. this won't end bad at all!

[Flibb]

Did a bit more looking in to this earlier, its an intersting idea. Found this for liquid helium
http://www.fisica.unipa.it/amorphous/heliumlab.html

From the little reading I did the problem appears to be getting it cold enough, the system relies on cold gases being recirculated (or pre cooled) but your engine will introduce contaminants and probably sieze once it starts to pump thats assuming the recirc gets cold. You could probably pick up a cheap compressor on ebay with enough pressure, but capacity would be limited. My point about oil contamination is only really a problem at high pressure, lubrication on high pressure pumps causes the oil to explode. Theres various stories of people lubricating gas bottle threads, attaching a regulator, cracking the tap and the reg disapearing through the ceiling.

I had originally thought te pressures were much higher than you are talking about, we work at around 300bar with our supply, when gas is allowed to expand rapidly you do get quick and dramatic cooling of the fittings. Our site liquid N2 contains around 100 tons, when decanting static can be a hazard due to oxygen condensing on the fittings. Personally I would love to see how cold an output could be produced using a small lab scale version of this, but I think commercial ones rely on a vacumn insulation of various parts.

[laywill]

I have looked at "poor man's liquid nitrogen" but the acievable temperatures are actually quite poor compared to proper LN2. As I said in an earlier note, using components designed to work at similar pressures - i.e. gas main piping, converted 4stronke engines for compressors - will minimise anything going *POP*

I am still optimistic. It could work...

[laywill]

Sorry, missed your last post Flibb.

I was working off somecalculations a friend did for me, so perhaps adding a bit of extra pressure wouldn't go a miss, and I agree that a compressor of eBay is probably a smart idea.

[holy god of nil]

Why do you, a 17 year old, need liquid nitrogen? More to the point you really are going to blow yourself up in an horrific accident, getting and putting together the parts capable of withstanding that pressure and that temperature is really not an 'ooh I'll bodge something in the backyard' kind of thing, however 'fun' it might be.

[laywill]

I'm fully aware of that!

Liquid nitrogen is the overclocker's best friend! Also I just wasnt ot see if it really can be done!

[Georgy291]

Why do you, a 17 year old, need liquid nitrogen? More to the point you really are going to blow yourself up in an horrific accident, getting and putting together the parts capable of withstanding that pressure and that temperature is really not an 'ooh I'll bodge something in the backyard' kind of thing, however 'fun' it might be.

i hate people like this, stopping any kind off back yard research.

I was building home rocketry, trying to get the rockets to go as high as possible and then it got stopped exactly like this

[kalniel]

I was building home rocketry, trying to get the rockets to go as high as possible and then it got stopped exactly like this

So wait until you're old enough to blow yourself up without anyone's permission. Hopefully common sense will have also matured, but if not there's always the darwin awards.

[Georgy291]

So wait until you're old enough to blow yourself up without anyone's permission. Hopefully common sense will have also matured, but if not there's always the darwin awards.

blow your self up? the age has got nothing to do with this. there is no difference in intelligence with someone who is 17 or 18. People who attempt projects like this usually know or have some sort off a idea what they are doing. He has done some research in what he has to do and what is involved, there for he should in theory know what safety precautions to take.

same goes with me when i was doing my home rocketry i had a very good idea off what i was doing, i didnt know exactly, and yes things did go bang but as you can see im still here.

so what your saying just because something is dangerous to be attempted it shouldn't be done by someone in their own home?

right time for me to sell my mountain bike

[killie99]

LN2 is pretty nasty stuff, I use it at work on a regular basis. You will more than likely end up doing yourself some serious injury (skin burns) or killing yourself, especially if you use it in a confined space with little ventilation.
The oxygen level doesn't need to drop by much before you start feeling giddy, and if you are unlucky you'll keel over - that's when it gets worse. Nitrogen is heavy and sinks to the floor, depriving you of even more oxygen, and before you know it, you'll have suffocated and died - I'm not exaggerating, you'll die.

Do yourself a favour, find another project!

[laywill]

@Georgie: Someone else on my wavelength! Nice one!

@Killie99: Thanks for your response. As I mentioned in one of the original posts, we have a field behind the house which I can use, meaning I will be outside! Handily, we have some building work going on and several 1 ton bags of gravel which could, if need be, be moved to from a defnesive barrier behind which I can cower if all goes wrong.

I am still in the initial planning stages of the project, and am trying to find a way of making sure aht all my calculations are correct first. I am planning to get hold of a very small amount of LN2 to find its molecular density when liquified. (Thanks go out to all my teachers: Mrs Walker, Mr Brien, Dr Guy and Mrs Mills) Using that knowledge I can then calculate required temperatures and pressures more accurately and thus give me a better idea of what I will need.

I must also point out, that if you can buy personal liquid nitrogen generators (which to be fair use cascade phase change cooling instead - maybe that should be looked into...) and it can be done using pressure on a moderate scale, then this project is theoretically possible.

Having spoke to the technology teachers, they reckon that using mild steel piping would reduce chances of an explosion because rather than shatter in true Hollywood style, it tends to rip and burst meaning no flying shards of pipe heading towards me!

Its coming together. Perhaps details first, but a bit of maths and we shall see...

[marshalex]

i recommend getting hold of a copy of a good physical chemistry textbook (i recommend atkins) as that will give you all the data you need and gives a mass amount of formulas and tips on calculations. It is a university grade textbook (and the bain of my existance for the last 4 years) but its great for data and formulas. pV=nRT is the most important formula i'd say personally, however it does require that you know how much your going to use (detailed explanation is in the above textbook)
btw good luck with it and keep posted on how it goes!