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Making Oxygen from Nitrogen Generator

Discussion in 'Do It Yourself - DIY' started by SeaWarden, Dec 2, 2019.

  1. SeaWarden

    SeaWarden Nassau Grouper

    # of Dives: 200 - 499
    Location: Singapore
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    Anyone knows how to do this? The system that I am looking at is a Parker Hannifin LCMS30. Is there a different outlet for the 21% oxygen? Without much hacking around, is it even worth taking it from there?

    Will there be other gases that go in or only mostly oxygen?

    Apologies in advance if this sounds amateurish, just trying to see what I can do to start diving trimixes.
     
  2. runsongas

    runsongas Great White

    # of Dives: 500 - 999
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    the lcms30 is a multistage psa generator iirc. it takes in clean, dry air and outputs nitrogen. basically the reverse of a PSA oxygen generator.

    the adsorbed oxygen and moisture is then driven out of the stack during the regen cycle, but that requires use of a purge gas, which is usually dry nitrogen.

    so in essence you would be trying to capture probably moist, and at best only slightly enriched air, at a fairly low pressure out of the exhaust during the regen cycle. good luck.
     
    markmud likes this.
  3. tbone1004

    tbone1004 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: I'm a Fish!
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    @SeaWarden basically what @runsongas said. I don't know what the zeolite is in those sieve beds so it may be capturing the N2 during a purge cycle, but in either instance you would have to basically replumb the inside of the machine to capture what is now the "Exhaust". If you have one and it's cheap, then it may be worth trying to figure out, if you're buying one, then I would find a dedicated PSA oxygen generator. The best you can do with those is 95% O2, 5% argon, though there is usually 1-2% of Nitrogen left in there. Perfectly fine for OC deco and continuous blending of nitrox.
     
    markmud likes this.
  4. SeaWarden

    SeaWarden Nassau Grouper

    # of Dives: 200 - 499
    Location: Singapore
    81
    15
    8
  5. runsongas

    runsongas Great White

    # of Dives: 500 - 999
    Location: California - Bay Area
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    volume is low, generally 1 to 4 lpm, but if you are patient enough and have a booster you don't mind running for extended periods, theoretically possible. issue is the purity drops if you increase the flow rate on the smaller systems because the residence time through the column becomes too short.
     
  6. tbone1004

    tbone1004 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: I'm a Fish!
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    what are you ultimately trying to do with it and how much gas/day do you need? Something like a standard 5lpm oxygen concentrator is only good to feed a 2 MAYBE 3cfm compressor to make EAN32. It's not enough to make any appreciable amount of pure oxygen. I have an invacare homefill setup that has an integrated O2 compressor, but it moves at 1.5-2lpm or about 0.05cfm which is incredibly slow. The concentrator is continuous duty rated, but the compressor is not, but it's essentially good to fill an AL80 every 20-24 hours, albeit only to 2200psi. I don't "rely" on that compressor because you have no idea when it's going to ultimately die. You can daisy chain the concentrators for more flow, but without knowing exactly what you're trying to do with it, it's hard to give suggestions
     
  7. BRT

    BRT Giant Squid

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    I feed about 7.5lpm to pump 32% at 1.8cfm.
     
  8. tbone1004

    tbone1004 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: I'm a Fish!
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    good to know! Which concentrator? I know the one that I have is a 5lpm concentrator, but the output for the compressor is restricted to 2lpm for purity. I may be remembering wrong for the rates, but I remember with that concentrator I was going to have to slow my SA6 down to about 1cfm to get EAN32
     
  9. BRT

    BRT Giant Squid

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    No, I'm feeding it out of a bottle. I wrote a spreadsheet to calculate and it comes out very close to my flowmeter settings so I believe it to be correct. 1.8cfm should be 7.2 lpm of O2 to create 32%. My compressor does between 1.8 and 1.9 cfm and I feed it about 7.5 lpm of O2 to get 32%. I've thought about concentraters but I just don't fill enough tanks to be worth it.
     
  10. SeaWarden

    SeaWarden Nassau Grouper

    # of Dives: 200 - 499
    Location: Singapore
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