Looking for Information on Vacuum Chambers

Factor in internally supported surface area and maximum atmospheric pressure expected.

That's fine for the the external mechanical stress loading a vacuum chamber will reach under low or medium vacuum level. To obtain any higher vacuum level will also require an understanding of material outgassing, pump capabilities along with seal conditions.

Just wanted to say thank you to everyone that's posted so far. You're actually correct. I was looking into what it would take to do a home based unit similar to a harvest right. I doubt it would ever get passed the "I wish I could build this" stage, from what I've seen about the design principals, but it is interesting seeing the engineering behind the products.

they suck

It's dangerous. You'll put your eye out.

Hire a mechanical engineer.

Thank you for the links SolarEagle. From some of the other responses, I see that designing this myself is way out of my league. The advice to hire an engineer, or to buy something pre-made is very good advice. Thank you, and everyone else that's responded for all the information.

Excellent! I particularly like your paper from Cern.

You might also look at commercial products and just copy what they've done.

I haven't checked but I imagine they have drawings of their products available.

Many offer CAD files, even.

Considerations in Vacuum Vessel Design - Vac Aero

Vacuum Chamber Design Considerations for CANDLE

Vacuum chamber design.

There's a video on YouTube somewhere of a collapsing rail tanker. It's quite spectacular.

This is how NOT to design vacuum chambers.

Railroad tank car vacuum implosion - YouTube

And why NOT to "ride the rails".

That poor hobo!

I disagree. That tank car failed spectacularly but there is no significant shrapnel and if this car was moving the wheels may have stayed on the track. Planning for controllable failure modes is a clever design that most misunderstand.

We had a liquid nitrogen cooled detector that was housed in a breadbox size aluminum casting. The casting walls and lid were about 3/8 in (10 mm) thick. The lid was held on by only four flimsy 4-40 plated brass screws that created the pressure to keep multiple gaskets sealed. A visiting scientist wished to try and reduce the LN2 consumption rate (so they could sleep through the night) by increasing the number of these bolts since there was plenty of space to do this. I contacted the company that designed the detector and they strongly urged that this not be done and insisted that this would void all existing or implied warranties and liabilities. The extra bolt holes were never installed.

On a very humid night with this sleeping scientist at the experiment the pressure relief and tiny dewar fill line iced over one night. Those four bolts were stretched until they snapped from the liquid to gas over pressure. Nobody was hurt, the detector was easily repaired, the scientist was woken but underwear was soiled. The incident report had an interesting calculation in it that was not mentioned anywhere in the text. If the proposed number of extra bolts were added to the lid, the bolt strength would have exceeded the aluminum case burst pressure pressure.

Point was that the vessel was not designed for vacuum service.

As the internal pressure was lowered it failed, in a pretty spectacular way.

"if this car was moving the wheels may have stayed on the track."

Look closely at the car during the implosion, the trucks get pulled off the ground about 4-6 inches before Gravity shakes of its *WTF* and remembers its job.

Only takes 2-3 inches to pop a rail wheel off the track, so if that had happened while the car was rolling, it would have been a case of Train Car Dominoes, and a Very Bad Day for the rail company AND the community the train was in when it happened.

(Notice how trains never seem to have problems in the middle of B.F. Nowhere? They always seem to have their disasters in 'sleepy little communities unaware of the potential danger rolling through town.')

That's it!

You could try searching for rectangular flat surfaces stress, thickness, or pressure formulas. Full vacuum is approximately 14.7 psi. Hoop stress applies to cylindrical surfaces. If you can make your surfaces suitably rounded, thinner material will suffice (e.g., fairly shallow bowl and dome shapes).