Electronics > Mechanical & Automation Engineering

low temperature coolants?

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jpanhalt:
You over complicate things with no purpose.  In the mid-1960's we routinely did spectroscopy and a few reactions at -70 °C.  We did IR spectroscopy with liquid nitrogen cooling (Nujol mulls and glasses), and a few IR studies at liquid helium (4° to 5°K).

First, decide what you want to do. 

coppercone2:
ok thanks for the tip

coppercone2:
I bought a molybdenum crucible (yikes at the price!) for low temperature experiments  :D

I don't see a good way to do fluid experiments without more exotic materials, say a freeze crystal machine that might work with something caustic or acidic. I thought about it on and off for months! At least not one without wishy washey hopes about ions and reactivities. I think molybdenum has a chance maybe.


The idea is to setup a water cooled peltier stack inside of a insulation cube, so I can chill it down as much as I can. With a beaker and thermal paste, I got to around -50C IIRC for a few mL of alcohol in a 25ml flask.

I hope that with the thermal mass of the molybdenum, I can freeze crystalize some stuff like tin chloride and quickly throw it into a vacuum funnel to get some purified reagents

coppercone2:
on a brand name stacked module, I managed to cool a 1oz nickel crucible of propylene glycol to -42 degrees C

slurpy

as for my fluid cryo-cooler,

I need to try making a proper circuit, i.e. pump bracket and polyiso insulation. my loop area is too big and its admitting too much heat, plus its like some weird over sized keychain. I think I shall mount it on my optics plate.  :-//

I want to see the performance on the minimum loop, then see what adding 'transmission' leanght lines to it does

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