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Effective DSV designs?

Discussion in 'Rebreather Diving' started by Fibonacci, May 23, 2019.

  1. rjack321

    rjack321 Captain

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    8,606
    2,498
    113
    The golem DSV leaks via the vent holes if the knob is not turned completely to closed loop mode. The bubbling when you exhale is immediately noticeable. The BOV version is not as sensitive to not completely turning the knob into CC mode.
     
    Fibonacci likes this.
  2. rjack321

    rjack321 Captain

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    8,606
    2,498
    113
    The ISC DSV spiders are really cleverly designed so it takes serious effort to assemble things backwards. I'm not even sure its possible to reverse the flow at all.

    The Golem spiders are quite ingenious in the way they are not reversible by accident through routine disassembly and cleaning. But if you break the DSV or BOV down completely to the overhaul level of disassembly you are able to reverse the flow direction.

    The Kiss DSV I used for ~6 months was finicky, the flappers were excessively delicate, and it didn't have these subtle safety features. Both the ISC and the kiss DSVs are in my spares box. I would use the ISC DSV but the flow direction is wrong for my Kiss.

    I dive with a golem BOV or DVS depending on the unit (Meg 2.7 or kiss sidewinder) I'm using. I like the golem knob, the way the hoses attach/detach for cleaning, and the ability to rotate a hose during the dive. I don't like the golem HUD attachment that I'm stuck using for my shearwater HUD. The ISC HUD attachment when used on a golem BOV is less than ideal as well.
     
    Fibonacci likes this.
  3. happy-diver

    happy-diver Skindiver ScubaBoard Sponsor

    # of Dives: I just don't log dives
    Location: queensland Melbourne Victoria diver
    822
    481
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  4. happy-diver

    happy-diver Skindiver ScubaBoard Sponsor

    # of Dives: I just don't log dives
    Location: queensland Melbourne Victoria diver
    822
    481
    63
    Inside German and Russian rebreathers and stuff I've seen this, with lungs and stuff
    I've done a couple of mouthpieces and all my double enders just in case of mix up :letsparty:

    Very tough stuff, as tight as you do or don't want it



    but what I'm using is some kind of fine woven nylon or polyester builders line
     
    Fibonacci likes this.
  5. txaggie08

    txaggie08 Barracuda

    # of Dives: 100 - 199
    Location: Vidor, TX
    217
    48
    28

    For doing what he did, I'd go get some 60# power pro fishing line and a bit of ca glue or head cement. I use that not all over the place in whip building, fishing rod building, and general rigging.
     
  6. Brad_Horn

    Brad_Horn Nassau Grouper

    98
    22
    8
    If you're interested in a bit more depth regarding what makes an effective DSV from an engineering perspective and the opportunity cost of certain design decisions see pages 30-50 http://www.deeplife.co.uk/or_files/FMECA_OR_V4_140831.pdf
    That also includes the respective WOB of a number of DSV with relevant bore and flapper valve sizes for comparison.

    Also a bit more on why the fine detail of the testing of the DSV and the specific flapper valves used may be important. http://www.deeplife.co.uk/or_files/Fault_Study_CO2_Bypass_110314.pdf
     
  7. Fibonacci

    Fibonacci Manta Ray

    # of Dives: 500 - 999
    Location: Melbourne, Australia
    530
    434
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    These sort of empirical data and detailed FMEA studies are exactly what I am after.
    Very interesting, will read in detail over the weekend, thank you VERY much...!
     
    Brad_Horn likes this.
  8. JohnnyC

    JohnnyC Divemaster

    # of Dives: 0 - 24
    Location: United States
    3,138
    3,279
    113
    If only they were from a trustworthy source. There's not a damn thing that Open Safety/APOC/Deep Life/Alex Deas/Brad Horn puts out that should be trusted.
     
    rjack321 and shoredivr like this.
  9. Brad_Horn

    Brad_Horn Nassau Grouper

    98
    22
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    Fibonacci, You're most welcome.

    Don't know if your interest is just theoretical but if you want to buy any of the components: flappers, spiders, breathing hoses or complete ALVBOV for comparison purposes contact sales@opensafety.eu They've supplied these parts to a number of rebreather manufacturers and homebuilders who just want individual parts are happily supported. While OSEL sell DSVs for military users, they don't have an application for these for the recreational market, but do have them in stock and the CC mode WOB is the same as the ALVBOV.
     
    Fibonacci likes this.

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