Hi Dave,

what exactly do you have to cool down? Is the 5L/week consumed continuously, 
or do you just need the 5L once per week for a single application?

If the consumption is continuously, you might want to try something like a 
helium compressor operating at higher temperature. There was once also a 
device around called "Cryotiger" or similar which could deliver 70K 
continuously.

If you want to go ahead with the daypack version: I would start with a solid 
frame, like an old US Alice pack. Attach a closed dewar with a relief valve 
pointing away (i.e. backwards). Shouldn't be much of a problem, but I would 
only opt for the backpack version if you don't have to climb or jump over 
ditches.

Cheers

Peter


On Thursday 23 February 2006 08:09, Dave Bowling wrote:
> Hi everyone,
>
> We have an application requiring 5 L/ week of liquid nitrogen at a
> remote location.  Physically transporting the LN2 to the field site has
> proven to be unreliable, and we are searching for an alternative.  Can
> anyone recommend a small-scale liquid nitrogen generator at relatively
> low power (a few hundred W)?
>
> Alternatively, has anyone figured out how to safely carry somewhat
> larger quantities (20 L) of liquid nitrogen in a backpack?  (Falling
> down with a standard dewar on your back would be disaster).
>
> Thanks very much,
>
> Best,
> Dave
>
> Dave Bowling
> Dept. of Biology
> University of Utah

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