jgourlay
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"Retail" liquid nitrogen?
Gents, I live in one of the US's major population/industrial cities. There is liquid nitrogen consumed by and delivered to mfg. companies by the
thousands of gallons daily all around the city.
Now, for obvious reason, "Tri Gas" or "Air Liquide" is not going to fill my coffee mug with nitrogen at the drive through window. But I have several
things I need to do involving it.
So, how do I overcome this? I know, of course, I need a dewar. The real issue is this: how do I adequately educate myself on handling and then
COMMUNICATE that I'm not an insurance risk or a "risk of stupid"?
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The WiZard is In
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Quote: Originally posted by jgourlay  | Gents, I live in one of the US's major population/industrial cities. There is liquid nitrogen consumed by and delivered to mfg. companies by the
thousands of gallons daily all around the city.
Now, for obvious reason, "Tri Gas" or "Air Liquide" is not going to fill my coffee mug with nitrogen at the drive through window. But I have several
things I need to do involving it.
So, how do I overcome this? I know, of course, I need a dewar. The real issue is this: how do I adequately educate myself on handling and then
COMMUNICATE that I'm not an insurance risk or a "risk of stupid"? |
Tell them you are a plumber and have to freeze a pipe. Granted
most plumbers use dry ice, or if they do this often buy a
CO2 tank - blanket pipe freezer.
NB — Dress like a plumber.
Or ... dig out that article 'bout making instant ice cream with
LN2... I have it here somewhere. Google would probable be quicker.
Just for Shits and Giggles tell them you need a tank
of fluorine. Buying a fluorine regulator from them would help.
Just be sure to bring two credit cards .... one may not be enough.
Reminds upon me... year back down on 11th Avenue Manhattan
there was a tank truck of CO2 being pumped down into the
ground.
Sez I to the to da Con Ed (local power/steam company)
What's this?!
There dobe a 'hole bunch of volts power line a coming down
from White Plains to the square block sub-station on 48 or 49th
street (I forget). To keep the cable cool oil is pump through a pipe
containing the cable — down and then back up. The pipe had
sprung a leak. The only way of stopping the oil flow was to
freeze the oil on both sides of the leak.
Must be a heck of a job, they dough an excavation cemented it
in and then placed a trailer over it.
One day walking by someone was using Co<sup>60</sup>
to X-ray some welds. He declined my request to stand
close and work on my tan.
[Edited on 18-5-2011 by The WiZard is In]
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ScienceSquirrel
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Mood: Dogs are pets but cats are little furry humans with four feet and self determination! 
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I suspect that you might be able to buy some from a university or other small scale consumer.
Most people who deal in liquid nitrogen will not be interested in selling a few litres.
I suspect that restaurants, etc that use it to make instant ice cream, etc have a friendly arrangement like this.
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Magpie
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Why not just walk up to the counter at Norgas or Oxarc and ask them if they would fill a small dewar. Tell them you have some background in chemistry
and understand the hazards associated with working with liquid nitrogen. Tell them you want to use if for some demos for your children, like freezing
flowers and tennis balls.
Yesterday I saw such a demo. I asked the chemist why he was not wearing gloves when he poured the N2 from a ~10 liter dewar into a large glass
beaker. He then proceeded to pour about 50mL of liquid N2 onto his hand, letting it quickly run off to the floor.
The single most important condition for a successful synthesis is good mixing - Nicodem
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The WiZard is In
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| Quote: Originally posted by The WiZard is In | | Quote: Originally posted by jgourlay | | Gents, I live in one of the US's major population/industrial cities. There is liquid nitrogen consumed by and delivered to mfg. companies by the
thousands of gallons daily all around the city. |
... dig out that article 'bout making instant ice cream with
LN2... I have it here somewhere. Google would probable be quicker. |
Da instant ice cream is in Theo Gray's book —
Mad Science : Experiments You Can Do at Home But Probably Shouldn't
Bring it along, however, first remove the dust jacket.
PS - Don't wear you clown shoes.
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phlogiston
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@Magpie, I regularly take sample vials floating in a dewar with nitrogen out by hand, without gloves. I did it yesterday, a couple of hundred times,
actually. It doesn't even feel very cold. It feels just a bit like when stick your hand in a common -20C freezer, without touching anything. Look up
"Leidenfrost effect".
I would not pick up that glass beaker he put the nitrogen in, though. It would be easy to get your hand frozen to the glass. (There is no Leidenfrost
to protect you in that case).
If you can't get a dewar, a styrofoam box is pretty effective too, btw. (although a common thermos bottle will probably work quite well I expect, and
is easy to obtain).
[Edited on 18-5-2011 by phlogiston]
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"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer |
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The WiZard is In
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| Quote: Originally posted by Magpie |
Yesterday I saw such a demo. I asked the chemist why he was not wearing gloves when he poured the N2 from a ~10 liter dewar into a large glass
beaker. He then proceeded to pour about 50mL of liquid N2 onto his hand, letting it quickly run off to the floor. |
Gloves - If you use cotton gloves you can kiss your fingers
good-by. The cotton will absorb the LN2 and hold it next to
your skin. Bunch and a half years ago ... I had one of the those
Super-sounder Horns in my pocket. When I bent over
it released whatever freon compound it contained on my pants.
I had a back/blue/red mark that looked like it came from a
horror movie.
As an example - there are several different bands and at least
two different sizes.
http://www.amazon.com/Falcon-Safety-Super-Sound-Horn/dp/B000...
This crib'd from :—
CRC Handbook of Laboratory Safety 2nd ed.
Cryogenic Safety p.574-578
When there is a possibility of personal contact with a cryogenic
fluid, full face protection, an impervious apron or coat, cuff-less
trousers, and high-topped shoes should be worn. Watches,
rings, bracelets, or other other jewelry should not be permitted
when personnel are working with cryogenic fluids. Basically,
personnel should avoid wearing anything capable of trapping
or holding a cryogenic fluid in close proximity to the flesh. Gloves
may or may not be worn, but if they are necessary in order to
handle containers or cold metal parts of the system, they should
be impervious, and sufficiently large to be easily tossed off the
hand in case of a spill. A more desirable arrangement would be
hand protection of the pot holder type.
You can get away w/ spilling LN2 on your hands as it has a
low specific gravity and rapidly boils pushing it away from your
skin. Those of us who live in norther climes ... are well aware of
the dangers of cryogenic liquids e.g., gasoline - diesel fuel stored
out of doors in the winter.
Isn't there something out there on U-tube or same such about
putting LN2 in your mouth - swallowing it?!
Hummm does gifted mean an idiot in Hindu?
http://www.mainsquare.org/showthread.php?p=102248
I expect there are a SL of such out in the aether.
[Edited on 18-5-2011 by The WiZard is In]
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Neil
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Given the expansion of LN2 as it vaporizes, swallowing it is likely to distend/wreck your gut...
http://pediatrics.aappublications.org/content/105/1/121.abst...
Further precautions are never kneel on the floor when working with LN2, you will not feel it freezing your knees caps. When working with it
on a table make sure you keep space between yourself and the table. LN2 wicks up into fabric and can soak into shirts/pants/non impervious aprons.
Ship yards and high output precision machine shops go through LN2 like it's water, they might be of service. You could also check around the web and
see if there are any overclocking fanatics around you, they may have a line on cheap/not bulk nitrogen.
Steel lined thermoses work very well for holding LN2, I've seen them outlast thermoses specifically designed to hold LN2. I'd stay away from glass
lined thermoses... I also tape any glassware, just in case. Watch out for LO2 condensing on cooled apparatus, it's chilly!
If you are transporting LN2 it's advisable not to ride elevators do to the risk of suffocation if the vacuum in the dewar/thermos fails (the inrush of
air flash boils the LN2 suffocating you). Ditto for traveling with LN2 in a car.
And if you get really good and practice hard, you can lock the carbonation of soda pop into LN2 ice cream making a cross between ice cream and
poprocks, it is fantastic.
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jgourlay
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Otay....
Now I know never to kneel in, swallow, or submerge my cotten glove wrapped cabeza into the LN.
Any more tips on how to get some?
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Neil
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Bloody Hell! Cotton gloves are bad. Touch something cold once and the frozen condensation will rub onto the glove and then
melt, touch it again and the glove will freeze to what ever you touched and then most amusingly of all it will freeze to you.
Not to mention cotton soaks up LN2 and when it's held in a fabric the Leidenfrost effect takes a vacation as per the wizards post; your hand freezes
to the glove and then your skin is toast. I'd rather be naked then wearing cotton gloves while working with LN2.
Have you tried to contact Air liquide/Prax/Tri Gas?
Often they are very reasonable. If you don't sound insane you maybe able to rent a smaller Dewar from them. They normally transport and sell in the
160L/180L size but they might be able to do something in the 25L size.
As a side note take a look at the heat capacity of LN2 and all that data. It takes almost 180L of LN2 to cool a room temperature 180L Dewar down to
the -196 needed to maintain the N2 as a liquid at room pressure. 1L of nitrogen poured into a warm 1L thermos boils down to 600-500ml. (Which is why
it's so damn expensive, when you buy 180L you pay for at least 360L)
The point of what is now a ramble is that your need may be larger then you think. Assume 50% wastage and at 22PSI in a commercial Dewar your going to
have a daily loss of about 3% of your total volume of LN2. So plan you usage time wise, as well.
Edit: Got rid of random italics
[Edited on 20-5-2011 by Neil]
[Edited on 20-5-2011 by Neil]
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jgourlay
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Neil, great advice. Thanks!
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jgourlay
Hazard to Others
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Neil, thanks for the details.
I've run into several situations like this. I'm thinking maybe the thing to do first is what all my elders have been dripping on me to do for years:
start a little business, even if it's an "Assumed Name Certificate". Tax bennies (theoretically), and it makes me look "official". Something with
the name "Engineering" in it.
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