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  1. #21
    Nicotine, valium, vicodin... notdeadyet's Avatar
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    Quote Originally Posted by colinicky View Post
    On that basis common sense would say don’t go into an environment where humans are not meant to breath ! Lol

    Or common sense is to validate your cells on every dive & only replace them when they deviate be they 5 months or 5 years old .
    I just don't understand the rationale behind having > 3. I don't see what there is to gain or what problem it solves versus the complication of additional wiring, connections and less than impressive electronics packages required. Cells have a particular level of unreliability but if I felt it was such that I needed 5 or 6 to make a rebreather reliable then I'd seriously question whether they were actually safe enough to be using at all, regardless of the number.

    We have different definitions of common sense. Waiting beyond the service life to replace a piss cheap component is, in my view, extremely stupid. If anyone is penny-pinching over a set of cells a year when they're walking round with a year's salary for some people strapped on their backs then that sounds a long way from sensible.
    Caliph Hamish Aw-Michty Ay-Ya-Bastard, Spiritual leader of Scottish State in England

  2. #22
    Established TDF Member Barrygoss's Avatar
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    Quote Originally Posted by notdeadyet View Post
    I just don't understand the rationale behind having > 3. I don't see what there is to gain or what problem it solves versus the complication of additional wiring, connections and less than impressive electronics packages required. Cells have a particular level of unreliability but if I felt it was such that I needed 5 or 6 to make a rebreather reliable then I'd seriously question whether they were actually safe enough to be using at all, regardless of the number.

    We have different definitions of common sense. Waiting beyond the service life to replace a piss cheap component is, in my view, extremely stupid. If anyone is penny-pinching over a set of cells a year when they're walking round with a year's salary for some people strapped on their backs then that sounds a long way from sensible.
    It only works as a methodology if the reaction to a cell “failure”/ kaboom, isn’t a dill flush.

    B
    Rebreathers are like women; they pretend to love you, whilst taking all your money and trying to kill you.

  3. #23
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    Quote Originally Posted by Barrygoss View Post
    It only works as a methodology if the reaction to a cell “failure”/ kaboom, isn’t a dill flush.

    B
    Ah but if you want to go back to methodology then obviously none of the above would apply to old day inspo divers as the manual always stated " If in doub't bail out "
    I trust my rebreather implicitly I just don't trust the owner

    Onwards & downwards.

  4. #24
    All hail ZOM Woz's Avatar
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    Quote Originally Posted by Barrygoss View Post
    It only works as a methodology if the reaction to a cell “failure”/ kaboom, isn’t a dill flush.

    B
    There is a fairly recent fatality where the diver was using out of date cells. 2 drifted, he got the warning but didn't do a flush to confirm. The unit pumped in O2, he didn't make it.

    I wouldn't use cells past their "cell by" date, unless it's in my o2 analyser where they're fine and easily testable against 100%.
    I have nothing to do with BSAC any more apart from being a muggle member. So anything I write on here is likely to be complete bollocks. Hooray!

  5. #25
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    Who cares.

    You don't find many Revo divers commenting on the arcane 3 cell systems that puts more reliance upon individual cell reliability. Nor has there been a pile of Revo diver bodies that have toxed/passed out during a dive -- nor have had CO2 hits for that matter.

    Two scrubbers; two completely separate computer monitors; running on five cells; "hybrid" principle encourages running manually in parachute mode reducing solenoid and battery usage, also constant monitoring of the PPO2 across all cells; orifice reducing the speed of O2 consumption at static depth. Plenty of redundancy is at the heart of design. As is the use of written checklists to keep a log of all builds.

    If you must criticise a Revo, then the Revo's loop flooding intolerance is its primary weakness especially if you dive in flat trim.

    But hey, what do I know.

  6. #26
    All hail ZOM Woz's Avatar
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    Quote Originally Posted by Wibs View Post
    Who cares.

    You don't find many Revo divers commenting on the arcane 3 cell systems that puts more reliance upon individual cell reliability. Nor has there been a pile of Revo diver bodies that have toxed/passed out during a dive -- nor have had CO2 hits for that matter.

    Two scrubbers; two completely separate computer monitors; running on five cells; "hybrid" principle encourages running manually in parachute mode reducing solenoid and battery usage, also constant monitoring of the PPO2 across all cells; orifice reducing the speed of O2 consumption at static depth. Plenty of redundancy is at the heart of design. As is the use of written checklists to keep a log of all builds.

    If you must criticise a Revo, then the Revo's loop flooding intolerance is its primary weakness especially if you dive in flat trim.

    But hey, what do I know.
    So take the 2 big problems out of the equation- the stupid meaty bit wearing the unit and the demonstrably unreliable galvanic cells.
    I have nothing to do with BSAC any more apart from being a muggle member. So anything I write on here is likely to be complete bollocks. Hooray!

  7. #27
    Established TDF Member Paulo's Avatar
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    Quote Originally Posted by Wibs View Post
    Who cares.

    You don't find many Revo divers commenting on the arcane 3 cell systems that puts more reliance upon individual cell reliability. Nor has there been a pile of Revo diver bodies that have toxed/passed out during a dive -- nor have had CO2 hits for that matter.

    Two scrubbers; two completely separate computer monitors; running on five cells; "hybrid" principle encourages running manually in parachute mode reducing solenoid and battery usage, also constant monitoring of the PPO2 across all cells; orifice reducing the speed of O2 consumption at static depth. Plenty of redundancy is at the heart of design. As is the use of written checklists to keep a log of all builds.

    If you must criticise a Revo, then the Revo's loop flooding intolerance is its primary weakness especially if you dive in flat trim.

    But hey, what do I know.
    There are so many issues in there that it is hard to find a place to start. But lets start drip feeding them so you do not get confused:

    1. "orifice reducing the speed of O2 consumption" - can you please explain how supply is controlling demand?
    JJ wanker

  8. #28
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    Quote Originally Posted by Wibs View Post
    Nor has there been a pile of Revo diver bodies that have toxed/passed out during a dive -- nor have had CO2 hits for that matter.
    Define 'pile', as there are at least 14 odd known rEvo fatalities and who knows how many further undocumented fatalities on the rEvo.... https://www.opensafetyglobal.com/Saf...ase_100725.xls
    With limited - and it would appear zero formal - accident investigation, having been conducted on rEvo fatalities, how do you rule out any causation?

    Only trend analysis I could parse together was that rEvo fatalities tend to drift away and be unrecovered or sink (if the gag straps missing) during ascent inclusive RS.
    Bar the dual Winn incident, in which case the planned dive appears to have exceeded the CE test envelope for scrubber duration on depth, temp and possibly workload if they had a scooter issue, so could possibly be attributed to poor dive planning.

    Quote Originally Posted by Wibs View Post
    Two scrubbers;
    or what could be alternatively described as a single two-part axial scrubber with large cooling chamber in the middle....

  9. #29
    Nicotine, valium, vicodin... notdeadyet's Avatar
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    Quote Originally Posted by Wibs View Post
    Who cares.

    You don't find many Revo divers commenting on the arcane 3 cell systems that puts more reliance upon individual cell reliability. Nor has there been a pile of Revo diver bodies that have toxed/passed out during a dive -- nor have had CO2 hits for that matter.

    Two scrubbers; two completely separate computer monitors; running on five cells; "hybrid" principle encourages running manually in parachute mode reducing solenoid and battery usage, also constant monitoring of the PPO2 across all cells; orifice reducing the speed of O2 consumption at static depth. Plenty of redundancy is at the heart of design. As is the use of written checklists to keep a log of all builds.

    If you must criticise a Revo, then the Revo's loop flooding intolerance is its primary weakness especially if you dive in flat trim.

    But hey, what do I know.
    I don't think "arcane" means what you think "arcane" means. 3 cell systems have been near enough standard for about 50 years. If how they work is a mystery then a lot of people need to put their units on ebay. And how does the orifice reduce the speed of consumption? Curiousity about how a system works and why design choices were made seems a reasonable thing to do. I guess rebreather diving has become woke, questioning a system is apparently a microaggression now.

    What problem is 4+ cells solving?
    Last edited by notdeadyet; 16-08-2021 at 10:58 AM.
    Caliph Hamish Aw-Michty Ay-Ya-Bastard, Spiritual leader of Scottish State in England

  10. #30
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    Quote Originally Posted by Brad_Horn View Post
    Define 'pile', as there are at least 14 odd known rEvo fatalities and who knows how many further undocumented fatalities on the rEvo.... https://www.opensafetyglobal.com/Saf...ase_100725.xls
    With limited - and it would appear zero formal - accident investigation, having been conducted on rEvo fatalities, how do you rule out any causation?

    Only trend analysis I could parse together was that rEvo fatalities tend to drift away and be unrecovered or sink (if the gag straps missing) during ascent inclusive RS.
    Bar the dual Winn incident, in which case the planned dive appears to have exceeded the CE test envelope for scrubber duration on depth, temp and possibly workload if they had a scooter issue, so could possibly be attributed to poor dive planning.


    or what could be alternatively described as a single two-part axial scrubber with large cooling chamber in the middle....
    Unverified, inaccurate and accident records are not credible sources of data.


    Sent from my iPhone using Tapatalk


 
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