+ Reply to Thread
Page 2 of 2 FirstFirst 1 2
Results 11 to 19 of 19

Thread: Scrubber Duration

  1. #11
    So many CCR So little etc Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase's Avatar
    Join Date
    Jan 2005
    Location
    Kent
    Posts
    5,205
    JJ Hybrid

    Inspo, Hammer Head, KISS rEvo

    Re: Scrubber Duration

    Quote Originally Posted by Rod Abbotson  View Original Post
    Pelagian Diver Controlled Closed Circuit Rebreather

    Never had problem with 6 hours in warm water with either Drager sorb, Soda Sorb, or Sofnolime.

    On the other subject Grace claim on their website that their latest version of Sodasorb out performs Sofnolime and have published test data to supposedly prove it!

    Rod



    With respect Rod I said the oficial test data. IE the lab test results under controled conditions simila to this applied to the KISS, Boris,Inspo,Meg, rEvo?

    6 hours was at what temp? what RMV? what C02 level?

    Who did the trests?

    A figure Mark picked out of the sky doesnt impress me.


    Are they saying 6 hours 15c 40RMV 1.6co2?

    If so lets see the data and we will have a proper basis for comparison.


    ATB

    Mark

  2. #12
    Supporting Member edasque is a splendid one to behold edasque is a splendid one to behold edasque is a splendid one to behold edasque is a splendid one to behold edasque is a splendid one to behold edasque is a splendid one to behold edasque is a splendid one to behold edasque is a splendid one to behold edasque is a splendid one to behold edasque is a splendid one to behold edasque is a splendid one to behold edasque's Avatar
    Join Date
    Apr 2007
    Location
    Boston, MA
    Posts
    1,251
    rEvo III mini

    Re: Scrubber Duration

    But who would fund a test for multiple rebreathers that doesn't have a vested interest in one brand or the other?

    Having run countless application server testing in the 90s, I could see that no test was every unit agnostic. i.e. I'd run test on my application server that were written to highlight a specific optimization for another application server. And this was funded by an 'independent' third party.

    If we want to understand the performance of a specific sorb, it's going to be done under the same env in the same rebreather. Obviously. Additionaly it'd be good to get an understanding of sorb performance for 5C, 15C and 25C.

    If we want comparison between different rebreathers, it has to be done by an independant party with a defined methodology (think DPV tests published here from Taho).

    VR-technology ran tests that with results that were very different from Paul's recent results (leading Paul to question Kevin's methodology).
    Paul does what Paul needs to do which is run tests on his own rebreather so as to (1) reach CE certification (2) establish recommended safety limits for use of his rebreather.

    The closest we might get to a benchmark would be if a third party (RBW/ADM, IANTD, Scubadiving Magazine, ...) were to fund a test. But then again, as I mentioned before, it would be hard to find a series of tests that would not favor any particular model.

    And then, beyond that, testing conditions that are valid for one crowd is not for the other (Northeast/west/Canada vs Florida vs UK).

    And then what would we get ? An idea of scrubber duration and WOB for each unit ? How useful is it really ? On the O2ptima which according to Kurt had a very very bad WOB, I never had any problems (I don't dive very deep) and it seems none of the O2ptima divers ever did.

  3. #13
    RBW Member PaulTG2 is a name known to all PaulTG2 is a name known to all PaulTG2 is a name known to all PaulTG2 is a name known to all PaulTG2 is a name known to all PaulTG2 is a name known to all PaulTG2 is a name known to all PaulTG2 is a name known to all PaulTG2 is a name known to all PaulTG2 is a name known to all PaulTG2 is a name known to all PaulTG2's Avatar
    Join Date
    Mar 2006
    Location
    Virginia, USA
    Posts
    641

    Re: Scrubber Duration

    Hello,

    The people who could test and provide valid real-world numbers will only provide worse-case information of freezing water, very deep, and unrealistic workloads. This leaves us to guess at what is actually practical. Gee, I wonder why...

    If we did't have any lawyers then we wouldn't need one. If we have one we need thousands. Nice work if you can get it.

    Sincerely,

    Paul
    Paul's first law states that the safety of an activity is determined by how forgiving of mistakes the activity is.

    Paul's second law states that the difference between an adventurer and an explorer is whether the doing or the learning comes first.

    "Don't be surprised if at the center of every hurricane in your life is an "I"." --paul gernhardt

  4. #14
    Dive Deep and Dive Long Loanwolf is a jewel in the rough Loanwolf is a jewel in the rough Loanwolf is a jewel in the rough Loanwolf is a jewel in the rough Loanwolf is a jewel in the rough Loanwolf is a jewel in the rough Loanwolf is a jewel in the rough Loanwolf's Avatar
    Join Date
    Jan 2008
    Location
    Seattle
    Posts
    712
    rEvo

    Re: Scrubber Duration

    Quote Originally Posted by edasque  View Original Post
    But who would fund a test for multiple rebreathers that doesn't have a vested interest in one brand or the other?

    Having run countless application server testing in the 90s, I could see that no test was every unit agnostic. i.e. I'd run test on my application server that were written to highlight a specific optimization for another application server. And this was funded by an 'independent' third party.

    If we want to understand the performance of a specific sorb, it's going to be done under the same env in the same rebreather. Obviously. Additionaly it'd be good to get an understanding of sorb performance for 5C, 15C and 25C.

    If we want comparison between different rebreathers, it has to be done by an independant party with a defined methodology (think DPV tests published here from Taho).

    VR-technology ran tests that with results that were very different from Paul's recent results (leading Paul to question Kevin's methodology).
    Paul does what Paul needs to do which is run tests on his own rebreather so as to (1) reach CE certification (2) establish recommended safety limits for use of his rebreather.

    The closest we might get to a benchmark would be if a third party (RBW/ADM, IANTD, Scubadiving Magazine, ...) were to fund a test. But then again, as I mentioned before, it would be hard to find a series of tests that would not favor any particular model.

    And then, beyond that, testing conditions that are valid for one crowd is not for the other (Northeast/west/Canada vs Florida vs UK).

    And then what would we get ? An idea of scrubber duration and WOB for each unit ? How useful is it really ? On the O2ptima which according to Kurt had a very very bad WOB, I never had any problems (I don't dive very deep) and it seems none of the O2ptima divers ever did.
    I see were you are coming form. But I think their are enough people out there that would be willing to donate their rig and sorb to the cause. Just like the scooter roundup so funding is minimal. If it were to be done under CE standards then yes you would wind up with a list of units and what their scrubber duration and WOB are. I personally think that is a good beach mark for comparing units and does not favor any particular unit. A unit is what a unit is. Then everything else is just cosmetics, gadgets, and comfort in the differences of the units. But if you were comparing units then it has to be done by a certified standard and CE has the only one I know of. At that point it does not matter either who does it as long as the test rig is certified.

    If that is a problem then do it by the testing standards that were set out in the 70's by the United States Pharmacopeia-National Formulary (U.S.P.-N.F.) for testing sorb. Or use the CE standards for testing sorb which I believe are the same. That is what has been done in the past that is still what is used in the states today for testing and certification of medical sorb. But kick it up to 1kg or 3kg of sorb in the tube to simulate a scrubber and all are tested with the same parameters. Then their is no individual unit parameters in it just the sorb. And this does not need to be done by a third party. All you need is a certified test rig running CE standards. I think it would be nice to see the difference in the sorbs under controlled tests. I have not seen any new data in years on diving grades and the companies keep changing and improving their products. This is something that would be nice to have done each year. To see any differences in the Diving products from manufacturing as well. Medical is tested in this manor but marine grade is not. Or if it is I have not been able to find the data and I have called several of the manufacturers and asked for it.
    Last edited by Loanwolf; 12th May 2009 at 02:14.

  5. #15
    RBW Member lancsman is on a distinguished road lancsman is on a distinguished road lancsman's Avatar
    Join Date
    Oct 2005
    Location
    UK, Flitwick
    Posts
    67

    Re: Scrubber Duration

    Surely we need a way of measuring the CO2 absorbed so we can wark out how much is left. As rebreather divers we do need to have reasonable understanding of maths so a simple table of CO2 (based on O2 usage)absorbsion per KG for temp of depth would work. The manufacturers could provided this so all we need to do is a simple calculation.

    Duration in Ltrs O2 = depth temp table unit x volume of Scrubber.

    Mark

  6. #16
    Mr Fox Soggyfox is a name known to all Soggyfox is a name known to all Soggyfox is a name known to all Soggyfox is a name known to all Soggyfox is a name known to all Soggyfox is a name known to all Soggyfox is a name known to all Soggyfox is a name known to all Soggyfox is a name known to all Soggyfox is a name known to all Soggyfox is a name known to all Soggyfox's Avatar
    Join Date
    Nov 2005
    Location
    Guildford UK
    Posts
    514
    Sentinel

    KISS

    Re: Scrubber Duration

    why aren't the test done at some approaching a 'normal' level?

    why were the criteria for the tests set at those levels?

  7. #17
    rEvo's daddy
    paulraymaekers has a reputation beyond repute paulraymaekers has a reputation beyond repute paulraymaekers has a reputation beyond repute paulraymaekers has a reputation beyond repute paulraymaekers has a reputation beyond repute paulraymaekers has a reputation beyond repute paulraymaekers has a reputation beyond repute paulraymaekers has a reputation beyond repute paulraymaekers has a reputation beyond repute paulraymaekers has a reputation beyond repute paulraymaekers has a reputation beyond repute paulraymaekers's Avatar
    Join Date
    May 2005
    Location
    belgium
    Posts
    4,073
    rEvo

    Re: Scrubber Duration

    Quote Originally Posted by lancsman  View Original Post
    Surely we need a way of measuring the CO2 absorbed so we can wark out how much is left. As rebreather divers we do need to have reasonable understanding of maths so a simple table of CO2 (based on O2 usage)absorbsion per KG for temp of depth would work. The manufacturers could provided this so all we need to do is a simple calculation.

    Duration in Ltrs O2 = depth temp table unit x volume of Scrubber.

    Mark
    duration is far from linear even with constant temp

    a scrubber double size can have 4 times duration easely in cold conditions

    paul
    www.rEvo-rebreathers.com
    ...."Yes you have to pre-breathe to activate the scrubber sorb, anyone who says different doesn't know what they are talking about!"...
    .... to get more accurate CO2 injection in the breathing machine we put 2 mass flow controllers in series ...
    .... The noise is a few tens of nano-volts, so DL were able to reduce the output voltage ...
    .... radial scrubbers give longer dwell time than axials...
    .... the earth is flat and ...

  8. #18
    RBW Member Kermit has a spectacular aura about Kermit has a spectacular aura about Kermit has a spectacular aura about Kermit has a spectacular aura about Kermit has a spectacular aura about Kermit has a spectacular aura about Kermit's Avatar
    Join Date
    Apr 2007
    Location
    Hexham, Northumberland
    Posts
    176
    Submatix mCCR

    Re: Scrubber Duration

    Quote Originally Posted by paulraymaekers  View Original Post
    duration is far from linear even with constant temp

    a scrubber double size can have 4 times duration easely in cold conditions

    paul
    My own experience with small scrubbers (<2kg) is that they can be very susceptible to to breakthrough under load. They may be fine at high loading when fresh and capable of working OK for hours under light loading but put 90 minutes on my 1.7kg scrubber then work it hard and it breaks through immediately.

    There would have to be a great deal of comparative testing at varying loads to give any real life information on this.
    Regards
    Ian

  9. #19
    Dive Aqaba Owner Rod Abbotson is a glorious beacon of light Rod Abbotson is a glorious beacon of light Rod Abbotson is a glorious beacon of light Rod Abbotson is a glorious beacon of light Rod Abbotson is a glorious beacon of light Rod Abbotson is a glorious beacon of light Rod Abbotson is a glorious beacon of light Rod Abbotson is a glorious beacon of light Rod Abbotson is a glorious beacon of light Rod Abbotson is a glorious beacon of light Rod Abbotson is a glorious beacon of light Rod Abbotson's Avatar
    Join Date
    Dec 2007
    Location
    Aqaba, Jordan
    Posts
    673
    Pelagian

    Dolphin, GAF

    Re: Scrubber Duration

    Quote Originally Posted by Mark Chase  View Original Post
    With respect Rod I said the oficial test data. IE the lab test results under controled conditions simila to this applied to the KISS, Boris,Inspo,Meg, rEvo?

    6 hours was at what temp? what RMV? what C02 level?

    Who did the trests?

    A figure Mark picked out of the sky doesnt impress me.


    Are they saying 6 hours 15c 40RMV 1.6co2?

    If so lets see the data and we will have a proper basis for comparison.


    ATB

    Mark


    Hi Mark,
    I was just pointing with the link to Rebreather Lab where it states a duration of 4 hours in cold water and 6 hours in warm water. That, in fact, is one of the reasons I put this post in the first place....to find some other opinions...
    We have been using the units as per manufacturers instructions for 6 hours in water temps of 20-25 degrees C good viz and very little current.

    SAC rates of divers using the units are low 15-18 liters per min on OC

    Also been using an SCR Dolphin with Draegersorb for 6 hours at a time...I think this was when I got worried as most out there are saying basically no longer than 3 hours on the Dolphin...

    Then again we are new to rebreathers here and try to avoid anything that would increase SAC rates...ie hard work underwater....when doing any work UW I take open circuit .. most commercial work I get here is over 60m (200ft) as only ones with kit to get there! Helium costs are high but not a problem when billing for you gas!

    Wont take the SCR deeper than 60m but would like to start to explore 60-120m in the area on CCR...when noy working big savings on Helium costs once bail out established (calculated at a higher SAC rate than metioned above).

    Anyway seems weve been pushing the standard Dolphin scrubber a bit maybe 4 hours would be a safe regimen.

    As for the Pelagian it was tested in 2005/6 by the manufacturer...what tests were actually done - only known to Andy. That discussion should be switched to a Pelagian thread.

    cheers
    Rod

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts