Cold Storage/Shipping 2

[Genetics]

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!

 

[Compositepro]

There are strict regulations on shipping dry ice and liquid nitrogen. Nitrogen is deadlier because there are no warning signs of asphyxiation. There are many suppliers of ice packs for your temperature range that are non hazardous and therefore less expensive to ship.

 

[iainuts]

I agree with Compositepro, there isn't any need to use LN2 for 5-10 C below. Just to respond to your question though, I'm assuming the "dry shipper" you're refering to that's charged with LN2 is a vacuum jacketed vessel of some kind. If so, it would have multi layer insulation (MLI) in the vacuum space. They don't use foam.

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.

 

[Genetics]

Thanks! Couple of points. First, we know that Liquid N2 is overkill for the temps that we need. The reason we have considered it is simply because a)our customers have tanks and tanks of it at all of their facilities; b) they don't have dry ice easily available; c) airlines hate dry ice because the CO2 messes with their environment systems on the plane and d) we can't seen to get conventional "gel ice packs" to keep the little (200ul) sample tubes cold enough to stay frozen solid. We would never want to place liquid N2 into the package, for safety as Compositpro mentions. But, these "dry shippers" are devices in which you place some liquid N2 for about 10 minutes, pour it all off, and the permeable foam (?) or walls are now "charged" and will maintain minus 300F in a totally liquid-free environment for several days! So, we thought maybe a piece of such ?foam? capable of being cold-charged, could be placed into each package to allow shipping in summer in places like Arizona. (btw: I'm new to this forum but it is wonderful; thank you)

 

[EdStainless]

There are special low temp gel packs available.
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

 

[Genetics]

Dear EdStainless (nice name)
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.

 

[iainuts]

There's no rules against naming companies that I'm aware of. I think in general, people want to give unbiased opinions so I've often found myself leaving out specific names of companies when the question is as generic as yours. Besides, I don't have any connections to gel pack manufacturers.

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.

 

[unclesyd]

A local seafood company still uses dry ice for shipping frozen seafood tin the US, mainly NYC.
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

http://www.coldchaintech.com/products/gel-packs.php

 

[HDS]

I haven't used it but these things are designed for your job.

http://www.nanocool.com/

If those don't work call FedEx. They have experts in such things that can help.

 

[unclesyd]

You might want to look at Aerogel insulated shipping containers from Marathon.

http://www.marathonproducts.com/products_packaging.html

http://www.marathonproducts.com/images/pb-aerogel.pdf

 

[HDS]

Here is exactly what you are looking for.

http://www.chartbiomed.com/p_vapor_shippers.cfm