Cold Storage/Shipping
Cold Storage/Shipping
(OP)
We have need for a styrofoam-type shipping container that we could use to send biologicals (a total of 10ml only) and keep the sample frozen for 24 hours. Our customers do not have easy access to dry ice but they all have liquid nitrogen. There are 'dry shippers' that can be charged with liquid N2 and the foam lining maintains the cold without any risk of liquid spill during transport. But they are heavy, with stainless steel outer jackets, and expensive. What is the foam that is used in these Dewar-type flasks, or is there a foam that would work for keeping a small box cold by "charging it" with L-N2? For us, "frozen" is only 5-10 degrees below 0C. We do not need super cold temperatures. But, with easy access to liquid N2, we were hoping that we could construct/design/order shipping containers (hundreds, about 18"cube, ideally)that could be used for this purpose. Any thoughts?
Many thanks!
Many thanks!





RE: Cold Storage/Shipping
RE: Cold Storage/Shipping
The reason dry ice is useful is because it changes phase at -40. Similarly, you'd need something to change phase, preferably from solid to liquid at the temperature you need. I'd think there are all sorts of fluids that change phase from solid to liquid at a given temperature and could be custom engineered to do so at a very specific temperature. I'm sure there must be many manufacturers of ice packs that could fix you up. You could also freeze those ice packs quickly with LN2.
RE: Cold Storage/Shipping
RE: Cold Storage/Shipping
Combine this with a high performance insulation for the inner box (use styro for the outer) and you should be set.
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Plymouth Tube
RE: Cold Storage/Shipping
So, I guess there are rules about naming companies here? Can you give me a hint on how to find such "special low temp gel packs"? I could google it perhaps but we have looked Hard and couldn't find what it sounds like exists out there. Many Thanks.
RE: Cold Storage/Shipping
I'm a bit confused as to what temperature you want the gel pack to work at. You mentioned -5 to -10 C but you also mention charging this foam at -300 F so perhaps you'd like it much colder than -10 C?
Your description of a dry shipper is interesting, I've not heard of them. But they'd need to have a fairly high thermal mass to work and I don't know of any foam meeting that requirement. The whole idea behind gel packs is to have a material that changes state from solid to liquid so the latent heat can be absorbed at the phase change temperature, thus giving you a high thermal mass around the transition temperature.
I'm sure the manufacturers of gel packs can custom make one to any degree you wish pretty much. Food grade d-Limonene for example, will change phase around -140 F which should be plenty cold for most applications. Mixing with water or other liquids would change that temperature. Other things like vegtable oils can also be used. Finding the right mix should be fairly easy for a gel pack manufacturer.
Once you have the right gel pack, having a small box you can drop it in and fill with LN2 to freeze it would be easy. Maybe that's your shipping container if it's something a bit more substantial than a cardboard box.
RE: Cold Storage/Shipping
Here two gel ice pack producers that I'm familiar with from having used them or seen them used mainly for shipping seafood both frozen and fresh. I seen the Techni Ice used on shipments from several countries for frozen seafood.
http://www.techniiceamerica.com/usagetips.html
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RE: Cold Storage/Shipping
http://www.nanocool.com/
If those don't work call FedEx. They have experts in such things that can help.
RE: Cold Storage/Shipping
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RE: Cold Storage/Shipping
http://www.chartbiomed.com/p_vapor_shippers.cfm