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In article <20JUL199513002157@orion.cmc.uab.edu>, mann@orion.cmc.uab.edu wrote:

> What is a good way to transport liquid nitrogen (inexpensively) ,
> about 20 miles.  It has to be taken from our laboratory to a 
> High School classroom.  Remember it is very hot and humid in 
> Alabama this time of year. 
> 
> Our goal is to do this without having to buy an expensive dewar flask.
> 

A thermos _is_ a dewar flask.  See if you can round up enough for the trip.

Oh, and _don't_ screw the top onto the thermos to make a seal.  You'll
need to allow boiloff, so you don't build up pressure in the thermos and
cause it to explode.

--Tom

--
The opinions expressed herein are mine and mine alone.  Keep your filthy hands off 'em! 

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In article <20JUL199513002157@orion.cmc.uab.edu>,
RANDY P. MANN <mann@orion.cmc.uab.edu> wrote:
>What is a good way to transport liquid nitrogen (inexpensively) ,
>about 20 miles.  It has to be taken from our laboratory to a 
>High School classroom.  Remember it is very hot and humid in 
>Alabama this time of year. 
>
>Our goal is to do this without having to buy an expensive dewar flask.


well, why don't you just use a thick styrofoam container like what is
used to ship hot nucleotides (ie, from NEN) or even a couple of
thermos' would work fine.  

- -pat

p.s. sorry you have to use vnews on a VAX for news!!

- -- 
patrick finerty = zinc@zifi.genetics.utah.edu = pfinerty@nyx.cs.du.edu
U of Utah biochem grad student in the Bass lab - zinc fingers + dsRNA!
** FINGER ME for my pgp public key ** crypto for the masses!
zifi runs LINUX 1.2.11 -=-=-=WEB=-=-=->  http://zifi.genetics.utah.edu 

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mann@orion.cmc.uab.edu (RANDY P. MANN) writes:

>What is a good way to transport liquid nitrogen (inexpensively) ,
>about 20 miles.  It has to be taken from our laboratory to a 
>High School classroom.  Remember it is very hot and humid in 
>Alabama this time of year. 

>Our goal is to do this without having to buy an expensive dewar flask.

How much LN are you talking about here?  Are you going to walk or drive
the 20 miles?  I've kept a quart of LN in a regular (metal) coffee thermos
for a week with no significant loss.  If you need to transport a gallon
or more, I'd buy a plastic insulated water jug like the type you use for
picnics or on construction sites.  The plastic probably won't crack.
Basically, any covered container will work well enough if you have only
a 30 minute drive or so.  There would be moderate evaporation loss with
an uncovered container in that length of time (10% to 50% of a gallon is
my rough guess) and you wouldn't want to use an uncovered container anyway
because of the safety hazard (frost burns).  There would be very little
evaporation loss with a loosely covered container in thirty minutes (<10%).
And remember, LN is about the same price as milk, so buy more than you 
think you'll need.  It's cheap and fun to play with.

-- 

"Warm...warmer...disco." - Pulp Fiction

In article <ts_zemanian-2007951158120001@ts_zemanian.pnl.gov> ts_zemanian@pnl.gov (Thomas S. Zemanian) writes:
>A thermos _is_ a dewar flask.  See if you can round up enough for the trip.

Have you actually tried this? It could be bad advice to recommend this
if you're not sure it'll work. Two things that might go wrong: first,
the thermos might break immediately from thermal shock. Second, it
might break somewhere en route due to material brittleness at low
temperatures.

>Oh, and _don't_ screw the top onto the thermos to make a seal.  You'll
>need to allow boiloff, so you don't build up pressure in the thermos and
>cause it to explode.

Good advice, although then I wonder how to ensure that it can't
spill, which you certainly don't want.
	Doug
-- 
Doug Merritt				doug@netcom.com
Professional Wild-eyed Visionary	Member, Crusaders for a Better Tomorrow

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In article <dougDC2wA2.IJs@netcom.com>, Doug Merritt <doug@netcom.com> wrote:
>In article <ts_zemanian-2007951158120001@ts_zemanian.pnl.gov> ts_zemanian@pnl.gov (Thomas S. Zemanian) writes:
>>A thermos _is_ a dewar flask.  See if you can round up enough for the trip.
>
>Have you actually tried this? It could be bad advice to recommend this
>if you're not sure it'll work. Two things that might go wrong: first,
>the thermos might break immediately from thermal shock. Second, it
>might break somewhere en route due to material brittleness at low
>temperatures.

I have tried it on numerous occasions.  It works.  I use a
stainless-steel thermos; I suspect you wouldn't want the kind with a
glass interior.

>>Oh, and _don't_ screw the top onto the thermos to make a seal.  You'll
>>need to allow boiloff, so you don't build up pressure in the thermos and
>>cause it to explode.
>
>Good advice, although then I wonder how to ensure that it can't
>spill, which you certainly don't want.

While I'm all for caution, I think it's possible to go overboard.
Obviously, you should try to put it somewhere where it won't spill,
but it's not the end of the world if it does.  Just don't keep it on
your lap!

Actually, a friend of mine was taking liquid nitrogen to a school
for some sort of presentation a couple of years ago, and his thermos
did spill in the back seat of the car.  It produced a big
plume of water vapor, surprising both him and some other drivers, 
but other than that there was no harm done.  He had to go back and
get more, so maybe he was a little bit late for his presentation.

-Ted

According to Thomas S. Zemanian <ts_zemanian@pnl.gov>:
> In article <20JUL199513002157@orion.cmc.uab.edu>, mann@orion.cmc.uab.edu wrote:
> 
> > What is a good way to transport liquid nitrogen (inexpensively) ,
> > about 20 miles.  It has to be taken from our laboratory to a 
> > High School classroom.  Remember it is very hot and humid in 
> > Alabama this time of year. 
> > 
> > Our goal is to do this without having to buy an expensive dewar flask.
> > 
> 
> A thermos _is_ a dewar flask.  See if you can round up enough for the trip.
> 
> Oh, and _don't_ screw the top onto the thermos to make a seal.  You'll
> need to allow boiloff, so you don't build up pressure in the thermos and
> cause it to explode.


In our lab we use cheap, hardware store thermoses as dewars, but we
file off the threads on the cap and bottle.  This guarantees that
no one will screw on the cap, and keeping the lid on keeps the 
N2 from boiling off a little longer.


Pete

>What is a good way to transport liquid nitrogen (inexpensively) ,
>about 20 miles.  It has to be taken from our laboratory to a 
>High School classroom.  Remember it is very hot and humid in 
>Alabama this time of year. 

You don't say how much....  if the amount is small (say only a litre or 
less at the receiving end), then the simplest and cheapest way is to use a 
couple of small evacuated thermos flasks..... they type kids use to take 
drinks to school.  They usually have small knecks, are evacuated in the 
same way as the larger "research dewars" that we have in our labs, and are 
very cheap.  I got one recently at K-Mart for a couple of dollars.

HOWEVER!  do NOT screw on the top of the flask after you put LN 
in.....simply leave the flask open to the air.

The temperature in your region is of little significance compared to the 
temperature of LN.  However, the number of "bumps in the road" might!  
Agitation is the only cause of increased boiling in the system I describe;  
without agitation, the LN will not all boil off over a period of many 
hours.

In article <dougDC2wA2.IJs@netcom.com>, doug@netcom.com (Doug Merritt) wrote:

> In article <ts_zemanian-2007951158120001@ts_zemanian.pnl.gov>
ts_zemanian@pnl.gov (Thomas S. Zemanian) writes:
> >A thermos _is_ a dewar flask.  See if you can round up enough for the trip.
> 
> Have you actually tried this? It could be bad advice to recommend this
> if you're not sure it'll work. Two things that might go wrong: first,
> the thermos might break immediately from thermal shock. Second, it
> might break somewhere en route due to material brittleness at low
> temperatures.

 I don't think any of these objections are likely to cause problems, but
if you're worried use the stainless steel type rather than the glass
type.  If you do use the glass type, test one first against thermal shock
(the plastic sheath should contain any shards.)
> 
> >Oh, and _don't_ screw the top onto the thermos to make a seal.  You'll
> >need to allow boiloff, so you don't build up pressure in the thermos and
> >cause it to explode.
> 
> Good advice, although then I wonder how to ensure that it can't
> spill, which you certainly don't want.

Well, you needn't leave the lid entirely off.  Just don't screw it down to
make a seal.  Or, you might bore a 1/4" hole through the lid to allow
venting.  It'd be unlikely to slosh out, then, and only a small amount
would be lost before it could be righted, should it tip over.

--Tom

--
The opinions expressed herein are mine and mine alone.  Keep your filthy hands off 'em! 

I've already seen a reply to this that suggests use of a thermos. That's fine as
a thermos is a dewar bottle in disguise after all. BUT, don't screw the lid on
tight as you would for coffee. The vapor must be allowed to escape or dangerous
(explosive) pressures will build up. Also, I guess I would look for one with a
glass liner as being most likely to withstand the extreme cold.


Tim Sullivan (sullivan@kenyon.edu)


In article <20JUL199513002157@orion.cmc.uab.edu>, mann@orion.cmc.uab.edu
(RANDY
P. MANN) writes:
> What is a good way to transport liquid nitrogen (inexpensively) ,
> about 20 miles.  It has to be taken from our laboratory to a 
> High School classroom.  Remember it is very hot and humid in 
> Alabama this time of year. 
> 
> Our goal is to do this without having to buy an expensive dewar flask.
> 
> Thanks, 
>  -Randy Mann mann@orion.cmc.uab.edu         *"Any closet is a walk in     
>   University of Alabama at Birmingham       * closet, if you try hard      
>   Center for Macromolecular Crystallography * enough." -Steven Wright        
>   1918 Univ. BLVD. BHSB RM233               * Phone (205) 934-0956
>   Birmingham, AL 35294-0005                 * Fax   (205) 934-0480

I use a stainless steel thermos. Glass thermos will probably break.
I have tried glass dewars too, but these were made from 0.5 cm thick
pyrex glass.

I once had a friend of mine holding the thermos while i was pouring
liquid nitrogen from the 50 litre thermos. Unfortunately I accidentally
poured rather a lot over his fingers. He immediately lost the thermos, and
started studying his fingers with a speed and expression of pure panic.
He looked quite relieved when he found out he were all right.

Maybe I should have told him that a couple of seconds contact with
liquid nitrogen is harmless, because of an air cushion effect when
the nitrogen boils due to the high temperature of skin. However,
after a very few seconds that effect disappears, and you get instant
frostbite, or skin death if you wait.

Kim0

In article <1995Jul24.195810.1@kcvax1>,
Tim Sullivan x5830 <sullivan@kenyon.edu> wrote:
>I've already seen a reply to this that suggests use of a thermos. That's fine as
>a thermos is a dewar bottle in disguise after all. BUT, don't screw the lid on
>tight as you would for coffee. The vapor must be allowed to escape or dangerous
>(explosive) pressures will build up. Also, I guess I would look for one with a
>glass liner as being most likely to withstand the extreme cold.

No, don't use glass. Metal is the thing.
Only pyrex glass have any chance of surviving  such a temperature change.
Virtually all metals can manage the cold. I once used Pb, led, and it was
just as soft and malleable when cooled by liquid nitrogen.

Kim0

Just a cautionary note - I don't wish to be patronising, but make sure if
you're
transporting LN in a car, keep all the windows open. Suffocating isn't that 
difficult in enclosed spaces.
Cheers,
Charlie