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Vacuum chambers

  1. Sep 22, 2016 #1
    Hey all,

    I'm a bit of a food geek and a DIY nut and I'm looking to build my own vacuum sealer for as cheap as possible. My question to you guys, is what is the cheapest material I can use that will still withstand the pressure as well as maintain the airtight seal needed? I am looking to get a 99.5% vacuum in the chamber itself, and I would like it to be square so I can fit my sealing device in there. Thanks for all your help!
     
  2. jcsd
  3. Sep 22, 2016 #2

    berkeman

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    Staff: Mentor

    Welcome to the PF.

    AFAIK, you don't need a vacuum chamber to make a vacuum sealer. Just use a pump to pump the air out of the sealing bag...

    http://www.pickyourown.org/productpics/foodsaverV2460.jpg
    foodsaverV2460.jpg
     
  4. Sep 22, 2016 #3
    Sorry, should have been a bit more specific in the original post. That works for basic 'vaccing' but doesn't allow you to put liquids in the bags, nor is it strong enough to do things like compressed fruit.

    It's a bit of overkill, but I like projects
     
    Last edited: Sep 22, 2016
  5. Sep 22, 2016 #4

    berkeman

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    The problem with DIY vacuum chambers is that they can be pretty dangerous. I've worked with setups like the one below, and they are relatively safe. I'd recommend just buying a vacuum pump and Bell jar to keep your setup safe.

    http://physics.sierracollege.edu/DemoRoom/Pictures/Demonstrations/4e20_40.jpg
    4e20_40.jpg
     
  6. Sep 22, 2016 #5
    Unfortunately, there is no way to seal a bag in a rig like that. I understand there are risks, but I have access to welding supplies or I can purchase a pre-built acrylic box if I need to, but I suck at math, I have no way to calculate how much pressure will be applied to the walls while under vacuum, nor what type of material can withstand said pressure. I also want a reason to play around with a raspberry pi, and arduino with sensors to control things
     
  7. Sep 26, 2016 #6

    CWatters

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    Well you know it's going to be somewhere between zero and about 14.7 psi.
     
  8. Sep 27, 2016 #7

    JBA

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    Because of their inherent resistance to buckling under external pressure using a spherical shell made up of two mating hemispheres made of a non-shattering material such as polycarbonate is also an option (assuming you want to be able to view what is happening inside the vessel) but the shell thickness still has to be selected based upon the pressure differential.
     
  9. Sep 27, 2016 #8

    Baluncore

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    The product in a bag (is held between two soft foam blocks) in a vacuum chamber with the sealing device around the top of the bag. The chamber is evacuated. The bag seal is welded, then the air pressure restored to the chamber.

    I see no reason why you must have a rectangular vacuum chamber.

    Maybe you should explain better how your vacuum sealing process will work.
     
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