Liquid Nitrogen

[quakerboy]

Where can I get it? How much is it? Can I legally have it? Is it indeed the perfect alternative to air conditioning that my brain tells me it is?


On a more serious note, I seem to remember they had it stored in what looked like a regular gas tank in the chem lab, then had dewars to transport it out for experiments and demonstrations and whatnot. How long can you store it in a Dewar? Can you keep it liquid with just pressure in the gas tanks, or was there something else in play that my memory is skipping over? And if you can, is there any reason I could not have a tank of it?

[Ptah]

1. We use it at work sometimes. Here's a Youtube showing uphill quenching ----->

http://www.youtube.com/watch?v=wXELsXxs8QU

[quakerboy]

4. What is uphill quenching?

Wikipedia did not provide an answer, and I am momentarily boycotting Google. And I didn't see anything in the video that made me go "uphill, that makes sense"

And can you provide me a tank of nitrogen? Do you happen to know what sizes the tanks are available in? and how much they cost?

[AngryAmish]

5. NO sex threads!

[Ptah]

8. Good questions, quakerboy.

What is uphill quenching?

We use it to prepare components for use in a cyrogenic instrument.
We boil in water, then submerge in liquid nitrogen. the specification calls for seven boil-cool cycles.
This results in components the behave better at the temperatures of the instruments.
My understanding is that forcing the temperature change improves (reduces) the expansion/contraction.

Wikipedia did not provide an answer, and I am momentarily boycotting Google. And I didn't see anything in the video that made me go "uphill, that makes sense"

Yes, uphill doesn't seem to describe the process. I don't know why it is called that.

And can you provide me a tank of nitrogen? Do you happen to know what sizes the tanks are available in? and how much they cost?


The liquid nitrogen storage tank at work is about eight feet in diameter and about forty feet tall.
Can't hook you up, sorry.

[NNadir]

11. There are small portable tanks on wheels readily available.

Many labs use them.

[Brother Buzz]

2. Our good friend keeps her prize winning bull sperm in a liquid nitrogen thermos

As a courtesy, she stores the thermos in the town doctors office so they can benefit from having liquid nitrogen around.

[quakerboy]

3. seems like it could be handy

I just want to play. And I assume that a tank rental would cost less than a 200-600 dewar, while keeping better, longer. But I don't know what kind of hurdles you have to jump to get such a thing.

[Brother Buzz]

6. If you need to play, perhaps you should start with dry ice and work up to the liquid nitrogen

Dry ice is easier to acquire, and relatively cheap compare to liquid nitrogen, plus you don't need to invest in storage equipment that's any more sophisticated than a sports cooler. Plenty of bang for the buck.

[quakerboy]

7. been there, done that

I was a Bio Major with a key to the labs. I've done dry ice, and even done the liquid nitrogen thing. Ive done way to many potentially dangerous things with chemicals. The only one I couldn't wrangle was Cesium. And I could have had that, it was in the catalog, if I could have dug up the price of a nice house to pay for it. It wasn't in the budget just for me to play with, and I couldn't think of any legitimate reason to need it for a course.


I want to go back to my supposedly misspent youth, but I no longer have an active tie to any lab to acquire supplies.

[Catshrink]

15. Alkalai metals

I love showing this video to my students about the reactivity of alkalai metals:

http://www.youtube.com/watch?v=m55kgyApYrY

It's the "dog's nuts."

[quakerboy]

17. They are certainly fun to observe. Or do

But the lower down the chart, the more expensive, by the catalogs i was using. Particularly if you want any real quantity. But If I am ever overly rich, after I fix all the worlds problems, I will buy dead land somewhere, make a lake, and drop a brick of francium into it.

[Orsino]

9. You can carry it in a paper cup.

Now, a tank will store it indefinitely, but only if you can keep it at the temperature of, well, liquid nitrogen. Otherwise, it will slowly sublimate, and the pressure will eventually rupture any container.

[NNadir]

10. You can get it from gas companies, including welding gas companies.

You will probably need a business account, or else you will need to place a large deposit on the cylinder.

There is no legal restriction to having it, but it is dangerous and give you serious burns, although a small spill usually is insulated by a layer of poorly thermally conducting gas.

It can remain a few hours in a Dewar, depending on conditions, the size of the Dewar, etc. However it is slowly displaced by oxygen when open to the air, and this can cause a dangerous oxidizing condition, especially if you keep refilling the Dewar without allowing complete evaporation. Water ice will also form in the Dewar and small amounts of dry ice.

All liquid nitrogen tanks are vented and will boil off eventually; generally it is a function of use how long the tanks last. Almost no one buys a tank of liquid nitrogen just to see how long it takes for the tank to empty.

It's fun to play with it, I have to admit.

[quakerboy]

21. Thats what I was hopeing

As to the cylinder deposit, I have no problem returning it, so a deposit is not a problem to me.

Do you know how long to boil off a tank? Assuming a reasonably portable (eg the 3 foot tall by about a foot diameter tank), are we talking days, weeks, or months? I used them in the lab, but I never thought to check how much they held or how long it would last.

[Taverner]

12. Can you store food using liquid nitrogen?

As in, could you pour a bunch on a steak, and then throw it in the freezer?

[mike_c]

13. it should be very effective for flash freezing food....

It's inert and plenty cold enough.

[MajorChode]

19. I think it was Alton Brown that made ice cream with it

[IDemo]

14. I used thousands of dollars worth of the stuff monthly on my former job

Torturing circuit boards in environmental chambers by repeatedly ramping the temperature up and down between -45°C and 100C° (which equals 212° Fahrenheit). There were oxygen sensors on the wall to sound an alarm if a nitrogen leak caused a potentially fatal drop in the oxygen level of the lab.

[quakerboy]

18. Now theres a question

How much does it take to drop the o2 level to a dangerous range?

[IDemo]

23. Here's a good link regarding LN hazards:

http://www.admin.ox.ac.uk/safety/s403.shtml

The normal oxygen content of room air should be about 20.6%. If it falls much lower than 18%,you'll pass out and asphyxiate with no warning. I couldn't say as to the actual amount needed to reduce oxygen levels by percentage point, but it will expand 700 times in volume from liquid to gas states, so likely not very much.

[Orrex]

16. For God's sake! Don't release nitrogen into the atmosphere--you'll kill us all!

You sick bastard! What the hell's the matter with you!?!?!

[Richardo]

20. I just shipped four of these liquid nitrogen tanks from a shop in China to the US

Government need lots of LIN for rocket launches, which they get from the company I work for. Tanks are 85,000 gallons each.

On edit - that's not me standing there.

[quakerboy]

22. How much does one of those bad boys run?

Now that's enough to really make air conditioning redundant!