dewar

This is an easier thing to verify than that a dewar is food-safe (because who knows where it's been).

There's no knowing what nasties a used dewar might have been contaminated with (heavy metals, scary organics, etc).

It turns out LN2 is cheap and easy to get, but a Dewar flask costs around $400.

The Dewar is a giant thermos containing enough liquid helium to keep the satellite's sensitive instruments cooled to below 4 degrees kelvin for the duration of the experiment (1 year).

LN2 was used as a sort of buffer/insulator but has been replaced by cryocooler cooled dewar.

Here in London, just renting a dewar as a one-off and filling with culinary-grade LN2 was amazingly expensive (several hundred pounds).

A dewar would keep a feedline pressurized for, eh, maybe week, maybe weeks.

So his little 20 liter dewar should have cost maybe $20 to fill.

Also remember - any dewar itself, improperly handled, can be a bomb!

When he came back, the dewar had exploded, pretty much along the weld seams, strewing the metal body and super-insulation all over the lab.

If the supply of LN was cut, the LN on each dewar would take months to evaporate -- And the patients are stored upside-down, so the head is the last thing to reach thermal equilibrium.

I assume it loses more LN to the atmosphere than a pressurized dewar; on the other hand, the explosion risk isn't big.

Also, "...and Dewar clearly shared (rather than reciprocated) this admiration."

The "cap" is a long styrofoam tube with a plastic top that comes on and off with no resistance (if you upended the dewar, that cap would slide right out).

The non-pressurized LN dewars I've seen had a "plug" that was just a cylinder of foam that slid into the neck of the dewar, with a light plastic cap on top.

We got price quotes without telling them the application, so I'm pretty sure we're not paying a "foodie" price, but rather a "you're using a super small dewar and so effectively pay way more" penalty.

They're the exact same technology, but the term 'Dewar Flask' implies a much higher grade.