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. It was lightweight enough to bob upward at the slightest pressure, releasing gas. It probably had a design with channels such that the lip never sealed completely anyway.
They could easily preserve LN for days. Dewars are impressive.
Wow, I forgot just how many days that was, I see. Though I now remember that one of my labs had a storage dewar full of precious biological samples that was a bigger version of this design, and we only refilled it a couple times a month.
tptacek|11 years ago
:)
mechanical_fish|11 years ago
$500, eh? Hmmmmmmmmmmmmm.