CCR Dolphin Stock Scrubber Duration?

Yankee Rebel

i know that several people have done Dolphin SCR to CCR Conversions, but one bit of info that i can never seem to find is just what the scrubber duration is in CCR mode?

im pretty tired at the moment, been up all night, and REALLY need to get some sleep, so if i dont make any sense, or ive got my numbers wrong.. i apoligize. from my memory the stock SCR Dolphin scrubber is rated at 3 or 4 hours as a SCR. no one seems to regard the Dolphin scrubber as worth much, neither in design or duration, largely (from again a tired mind) stemming from the scrubber never really scrubbing that much CO2 in SCR mode, as the majority of it is vented out the OP valve, and it having no provision for dealing with water...

for those of you that have done the CCR Dolphin conversions, and kept the stock scrubber, what realistic and safe scrubber times are you getting, or have you gotten in CCR mode? (yes i realize that sorb is cheap, but im looking for whats been done with them, to establish a potential (read HYPOTHETICAL) extreme safe duration for one, and then to find a safe reasonable durationf or one, with a suitable safety margin.)

is the general consensus about the Dolphin scrubber, that its crap, or does anyone have any positive and negative feelingsa bout it theyd like to share?

any and all disclaimers and idiot proof statements of lack of liability go here for the forum, the members, those that reply, and myself the thread starter... its hypothetical based upon what folks have done, not intended to be anyones guidelines for what to do. just because you can run 170+MPH in the fog on a crotch rocket where you cant see the line 2 feet infront of your tire, doesnt mean you should. common sense and personal responsibility apply and all that good stuff...

with that all said... anyone for any input for discussion?

thanks in advance,
Yankee Rebel

wedivebc

Thanks for typing my disclaimer for me. I pushed my scrubber to what I thought was it's max several times when diving in cold <10'C water and only once had what I thought was onset CO2 symtoms. I always used 4-8 sofnolime and after that incident which was a rather deep 40m+ dive on the 4th hr I felt winded and later got a headache but not the killer kind I was expecting. I poured out my scubber upon surfacing and only found a small amount ot purple indicator near the exhale (red) end of the cannister.
I don't know what is all that wrong with the Draeger cannister but it seems to work OK, and traps a fair amount of water compared to some other Rebreather I have owned.

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Cheers,

Dave....

Man is the only animal burdened with the knowledge he will eventually die

mortenkjerulff

I run my scrubber between 3 and 4 hours in CCR mode (that is I throw out the lime once it has been used more than 3 hours with an upper limit of 4 hours), and never had a problem. I dive in relative cold water with bottom temperatures in the 4-8 degree range.
I see nothing wrong with the scrubber design either.

Morten

RonMicjan

Although in theory you should get more duration from the scrubber before conversion, there are so many more variables influencing sorb life that the additional time you may get is overshadowed. 2-4 hours in cold water, 3-6 in warm and all that depends on how hard you are working, what grade of material you use, how old that material is, how deep you go with it, what your personal metabolic rate is and so on. I have used up a load of sorb on my dolphin to the tune of a massive 8 hour headache in 5.5 hours in California waters 60ish F, but have run it to 8 hours in a warm 80+ enviroment, but imagine that near the end of that if I had to kick against a current I would have ended up "toast".

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gibbogeo

I did in this way:

Dive depth more than 40m or cold water or long deco planned: fresh sodasorb, no question.

Dive in the range 20-40m in water around 25° C: 3-4 hours with the same sodasorb.

Dive in pool (29° C) to make test under supervision of someone: used sodasorb till 6 hours.

Without opening and repacking the scrubber.

wedivebc

I don't understand why that would be so. Seems to me SCR sees less CO2 since a portion of it is dumped through the OPV.

__________________
Cheers,

Dave....

Man is the only animal burdened with the knowledge he will eventually die

Scuba_Vixen

I had this same thought as I read the post you're referring to, but then I thought that maybe since there's the lack of fresh colder gas always coming into the loop, that maybe the loop gas temperature is a bit higher CCR than SCR, and that the scrubber may be working more efficiently.

My personal choice has been to figure it's a wash, either way, and expect generally the same depletion of the scrubber in either CCR or SCR mode.

I've never run a scrubber to 4 hrs, even in pool conditions, and never started a serious dive on anything but a new fill. Given the tropically warm water here, maybe I'm being a bit overly conservative. .... Also given that I seldom have someone to dive with, overly conservative is probably good.




Darlene

RonMicjan

right then, fixed that little typo/brain fart

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Yankee Rebel

thankyou for the replies!

it sounds like from everyones responces that the Dolphin scrubber is plenty suitable for my needs and uses. i dont think theres anything wrong with being overly conservative, but its nice to know how far others have pushed theirs. again see disclaimer for this conversation in original post.

for myself, ive got 3 people that i know that dive as well, and of the 3, only the 1 has any interest in rebreathers. im going to end up being in Darlenes shoes before too long, just no one to dive with, and diving a rebreather alone. that is part of the reason i wanted to get a better feel for the Dolphins scrubber, and why i so much appreciate the time everyone took to be upfront and share their experiences and knowledge with me.

thanks again, youve been alot of help.