[mechanical_fish]

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.

[tptacek]

Static hold time: 100 days. Evaporation rate: 0.20 liters/ per day. 2.25" Necktube inside diameter. 15" Outside diameter. 25.50" Overall height. Empty weight: 23 lbs. Full weight: 60 lbs.

:)

[mechanical_fish]

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.

$500, eh? Hmmmmmmmmmmmmm.

[tptacek]

I felt bad about the purchase before we actually used it, but now I'm feeling like it made at least as much sense as the circulator did as a purchase. Malort ice cream!