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Does anyone know where I might be able to get some liquid nitrogen - about 200-300ml? Ideally in Herts/North London.
As far as I can see, the recommendation is that you find someone who produces it (or has it as a by-product) then talk to them nicely........showing how you understand how to handle it and you are responsible.....
Any ideas?
Thx
can't offer any help on where to get it...
but have to ask - what do you want it for?
My first thought was warts :whistle:Quote:
Originally Posted by Yliander
My next thought was frozen semen :sick:
I'm trying not to have any more thoughts :eek:
God, I do hope not :eek: as I have a funny feeling I'm going to be involved with this at some stage :sick::rofl:Quote:
Originally Posted by Andy McGregor
Fuffy bunnies, fluffy bunnies, FLUFFY BUNNIESQuote:
Originally Posted by Lory
FLUFFY BUNNIES
DO NOT THINK OF LORY COLLECTING SEMEN SAMPLES...
.. TOO LATE :blush:
.. although she's welcome to collect a sample any time she likes :devil:
Try your Practice Manager at your GP surgery to ask where they purchase their supplies fromQuote:
Originally Posted by JiveLad
My thoughts excactly :eek:Quote:
Originally Posted by Andy McGregor
I do a bit of schools liason work for my employer (GlaxoSmithKline) down in Kent and we occasionally have requests from school science departments for liquid nitrogen or carbon dioxide ice which we feel able to meet.
The big worry for a company of this size is not the cost (we have two tankers of liquid nitrogen delivered a week) but the worry that either the teachers or the pupils will get injured and then sue us for compensation for giving something dangerous away.
So if you feel that you can convince someone that you are a comeptant person toe be handling this stuff (like a teacher or the like) then I would suggest approaching a chemical manufacture, someone like air products or Linde, some food processors use it for quick freezing of foods, tyre recyclers use it to free the rubber and break it off of the tyre casing, and asking them. Be prepared to bring your own glass lined thermos flask to take it away in. Do not screw the lid down on the thermos flask - the gas that is boilling will need to escape - and they will immediately know that you are not competant to handle it.
I've used LN2 in the past. Your best bet might be a University, particularly one that uses electron microscopes. You'd probably need to be good friends or have good contacts though. Other users include the food industry, hospitals (preservation of samples), and materials testing laboratories. Ideally you need to find somewhere that stores it in dewars, rather than using it directly from a pressurised tank.
I wouldn't bother asking for 200-300mL, small quantities boil off very rapidly. Ask for at least 1 litre. As Chef said, you'll need a vacuum flask, but it needs to be vented. You'll also need well insulated gloves and goggles. Gloves and footwear should not be porous or you could risk the protective wear becoming frozen to your hand or foot in the event of spillage.
LN2 is very cheap as it is a 'waste' product of producing liquid oxygen. It is delivered with a tanker into large dewars. However, incidents like this may deter people from supplying it to casual users. In the past people have also been asphyxiated when using it in small rooms (the expansion liquid to gas is about 800 times I think).
Hey, remember what 'YOUR' job was last time????:whistle::wink:Quote:
Originally Posted by Maxine
I always understood it was thinking of eating spinach that was recommended...Quote:
Originally Posted by Andy McGregor
You know, there are medical treatments that might help with that (I'm told). In the meantime, have a kleenex...Quote:
DO NOT THINK OF LORY COLLECTING SEMEN SAMPLES...
.. TOO LATE :blush:
I'd read that you need to press your tongue into the roof of your mouth. It works for me, possibly it's an NLP thing :innocent:Quote:
Originally Posted by David Franklin
Quote:
Originally Posted by Chef
Ok so...........Quote:
Originally Posted by Bubble
1. Need a special vented flask suitable for LN
2. Should be 1l+ capacity
3. Need special gloves/goggles
(4. I should put on a tweed jacket with leather elbow patches and pretend I am a chemistry teacher.)
Follow-up questions:
1. With regard to not screwing the lid down on the flask, how do you ensure that the LN doesn't spill out? If I have the flask in (say) the boot of my car - it is potentially going to spill out - so what is the recommended approach?
2. How long will 1l of LN last in the flask, if it is not screwed down?
Thanks!
To answer your questions.Quote:
Originally Posted by JiveLad
1) There is nothing special about the thermos flask itself. Some insulating flasks are basically two plastic shells with foam inbetween them and these are fine for icy drinks or hot coffee. Liquid nitrogen at -196 degC would cause the plastic to become brittle (even rubber will shatter like glass at this low temperature) and fracture which may release liquid nitrogen into the space between the plastic shells. There is a good possibility that the rapid boiling of the LN2 MAY turn the outer casing into shrapnel. A glass dewar flask will not become brittle at these temperatures and so we only use glass or metal insulating flasks at work. To stop the LN2 spilling out we transport the stuff very varefully with a nice thick block of polystyrene foam on the lid held in place by rubber bands. No lid that you use should allow the container to become pressurised. Do not transport it with a person holding it or supporting it. Wedge it somewhere in your boot or rear footwell. If it falls over DO NOT attempt to stop it. So it is best to locate it in your vehicle in a place where you cannot intervene even by reflex action.
I will say this next bit in capitals
CONTACT BETWEEN BARE SKIN AND LIQUID NITROGEN, OR SURFACES COOLED BY IT, WILL RESULT IN INSTANT FROSTBITE AND DEATH OF THE SKIN.
2) The capacity of the insulating flask is up to you but the more you have in one flask the slower the rate of boil off purely because in a larger vessel there is a lower ratio of surface area (heat transfer surface) to volume. In a 1 litre flask expect about half of it to still be there in 5 hours.
3) Special gloves/ Goggles. The chances of you getting some of this in your eye by accidental splashing are remote because it will most likely be fully vaporised before it can reach you. Having said that a pair of goggles are never a bad idea if you are working with something unfamilair. The gloves should be non absorbant because if a spill soaks into the material it could freeze your skin to the material and stop you from being able to minimise the damage by ripping the glove off. If you don't have special gloves your next best option would be to put on some winter insulating gloves and then a pair of rubber gloves (big ones) over the top of that.
4) Most teachers don't seem to wear tweed jackets these days but you will need to have a convincing reason to talk someone into letting you have some of this and take the risk that you could hurt yourselve. So you have to safisfy someone that you are a responsible person for this dangerous material and that there is something in it for them (usually the education of the next generation of scientists).
Your follow up qestions.
1) answered this one above
2) Also answered this one above but I can say that if you do screw the lid down your LN2 will last about 3 minutes because the resulting blast will scatter it over a 2 metre radius.
Would really like to know what you are going to do with this. Getting it and handling it are both not easy things for people outside of the business. You must have a major bee in your bonnet to go to the trouble.
Bloody hell, Jivelad, what on Earth do you want this stuff for? :eek:
Thanks everyone - and particularly to Chef for the detailed - and interesting answers. What continues to amaze and delight me is the generosity of people on the Forum - and the depth and breadth of knowledge on all topics outside of dancing!! Thank you! :clap::cheers:
Anyway, I have decided that LN is too problematic and have discovered an alternative approach which should produce a similar effect to that which the LN was to be used for. (Hopefully to be done in the next few weeks......then it can be revealed :D).
Something like this. The polypropylene ones are probably the cheapest. Note the lack of a screw thread on the top. The cap just pushes on loosely.Quote:
Originally Posted by JiveLad
Best to have a flask much larger than what you need so when it sloshes it doesn't spill. I used to fill almost to the top, but all I did was walk along a corridor and up some stairs, taking care to keep it steady. Things will be rather different in a car!!! The best option would be a large evacuated metal dewar only 1/4 full, but they cost £1000s.Quote:
Originally Posted by JiveLad
Probably mostly gone in about 12 hours. Screwing the lid on is not an option!!!Quote:
Originally Posted by JiveLad
:yeah:Don't stick your finger (or any other appendage) in it just to check if it really is cold!Quote:
Originally Posted by Chef
It's not that dangerous, however, like a lot of substances, it has to be treated with respect. I'd happily use LN2 all day, compare that to HF, which I only used when nothing else would work.Quote:
Originally Posted by David Bailey
Anyway, LN2 is really good fun :D
This demo is brilliantly done :lol: