Sooner Boomer
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"Cool pics"... We began each run with three 50 gallon dewars; two were plumbed up and ready to go with a third for backup. Having this much LN2 on hand made us popular. People were constantly dropping by to "borrow a cup". I hated these dewars. The valves were crap, and leaked continuously, both gas and liquid. The pressure relief valves would "dump" without warning, scaring the bejeebers out of anyone in the room.
When filling an empty container (inside is at room temp.), you first need to "temper" the container to chill down the inside. You do this by putting a little LN2 in, then waiting a bit for it to boil off, chilling the container. Lather, rinse, repeat, then fill the container. One day, the post-doc was tempering a glass two liter dewar. I was standing about four feet away, watching. With a large bang, that end of the room was suddenly filled with fog and silver "snow". The dewar was old, and had apparently (and suddenly) reached the end of its service life and imploded. The silver snow was the reflective coating inside the vacuum bottle. It happened so quickly I didn't even have time to flinch. Thankfully, no one was hurt, not even a scratch.
This is one of the grad students tempering and filling a 5 gallon dewar...
When filling an empty container (inside is at room temp.), you first need to "temper" the container to chill down the inside. You do this by putting a little LN2 in, then waiting a bit for it to boil off, chilling the container. Lather, rinse, repeat, then fill the container. One day, the post-doc was tempering a glass two liter dewar. I was standing about four feet away, watching. With a large bang, that end of the room was suddenly filled with fog and silver "snow". The dewar was old, and had apparently (and suddenly) reached the end of its service life and imploded. The silver snow was the reflective coating inside the vacuum bottle. It happened so quickly I didn't even have time to flinch. Thankfully, no one was hurt, not even a scratch.
This is one of the grad students tempering and filling a 5 gallon dewar...