This is a short video of multiple clips I took from my liquid nitrogen dewar repair project. So I got this Chinese LN2 dewar in a broken state for free from a local entrepreneur and I decided to repair it and revacuum it just like I did one time before already.
The background is that anyone who wants to do extreme overclocking here in Northern Europe especially pretty much has to get their own dewar(s). Liquid Nitrogen as a substance is not really meant for consumers in the first instance, and the gas companies usually offer 1 month rental times as minimun when renting a dewar, and that is not really an option as the cost is high and we often don't need to rent them for that long, usually for just for a weekend or so. And the cost of these dewars is usually really high, this Chinese dewar costs around 500-600 euros + value added tax on top, and the really high quality ones even more. The big white dewar you see in this video costs over 1000-1200 euros new.
As the dewars can also leak very easilly, especially these relatively cheap Chinese ones, one could easilly thought of repairing one. This Chinese dewar's vacuum is held by only a single o-ring as a stock configuration, so that is not really firm or long-lasting solution. Vacuum can leak from the tiniest hole or gap possible so they do get damaged very very easilly.
The idea what I did here is to fix the custom vacuum pump hose fitting to the outside surface of the dewar so that it won't leak and so that we can revacuum the space between the two flask layers.
I asked a friend who has a professional lathe to drill the original metal piece that connects this third party fitting to the outside surface of the dewar, and of course secured by an o-ring just like at stock. I also add some black putty to add some extra security to prevent the vacuum from leaking. Then I just use a relatively cheap two-stage Value vacuum pump to suck the space empty to reform the vacuum and that is pretty much it. For the best end-result you should use a very high-end two or three stage vacuum pump to get 15 micron air pressure or lower.
The total cost for me to get this dewar fully working again was only 12 euros, which I paid to my friend to drill the metal piece for the hose fitting if I exclude the cost of the vacuum pump as I have used it before already. The vacuum pumps usually cost 150-200 euros mininum and onwards.
The process guide was originally published at HWBOT forum by a user called "BarboneNet", but the pictures of the original guide thread do not show-up anymore so it can't be utilized like before: community.hwbo...
Follow me at HWBOT: hwbot.org/user...
The vacuum pump used on this video: elgracool.pl/p...
Background music provided by Epidemic Sound - www.epidemicso...
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10 сен 2024
