Cryogenic processor with Perlite insulation

[harsh234]

I am designing a cryogenic processor, size 300x300x600mm rectangular with maximum efficiency.

Foam insulation will be very inefficient and other MLI and High vacuum insulation will be very costly.
So i was thinking to use 150mm thick insulation (annular section filled with expanded perlite. just my concern is whether vacuum is needed after loosely filled perlite inside this section, or only airtight section is fine.

or any other option for insulation.

 

[EdStainless]

Please do not double post.

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P.E. Metallurgy, Plymouth Tube

 

[DSB123]

spot-on EdStainless

 

[davefitz]

large cyro installations that use perlite also add a hollow column filled with extra perlite called " stayfulls" to ensure that compaction of perlite over time does not leave an un-insulated void at the top. Also, perlite has traces of asbestos in it, so you may need to add legal weasel-words to your employees contracts.

"In this bright future, you can't forget your past..." Bob Marley