How long will you let the scrubber sit
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SoggyBottoms
CCRX Supporter
thank you. I'm certain there will be some value in all this if someone a bit clever and very impartial can be bothered to trawl the willywaving
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gianaameri
gian @ gian.ameri.name
Another plus for CCRX.
We do not know what we do not know and there is more that we do not know that we know and if some educated and polite people can set their ego aside ("DIS" don't have "ego"), we can learn something new, or by accidental science figure out something we did not know before.
Rather than hoovering each granule individually (I know people who wood), I start a big fan at full speed and let it blow away the dust as I pour the Sofnolime from the Keg into the scrubber from a height (high enough to fill without spilling it).
This would work for both axial and radial scrubbers, and no need of a hoover.
Thereafter, with the radial scrubber, I hoover it externally moving the hoover suction up and down while I rotate the scrubber.
Then, I blow a small amount of SCUBA air to blow of any residue, including the inner radial section, and top and bottom of scrubber, after brushing off any granules stuck to the outside of the scrubber top or bottom (usually crushed).
It is very easy and it does not take long.
gianaameri
gian @ gian.ameri.name
I find the heavier dust particles still make it into the scrubber.
Only the finer ones get blown away, which is great anyway.
It will be interesting to see how this differs with Intersorb 8 - 12 when it gets delivered for free trials by the manufacturer, hopefully this week.
matt
Well-Known Member
Interesting hoovering/fan strategy. I can see how that would reduce the dust. I've never done this, but it is interesting to hear of different techniques.
Does this reduce/eliminate the clumping? I cannot say that I have noticed any bother with clumping, btw, running the scrubber up to 5 hours in cold water (long dive, extra time in shallows) and up to 6 hours in hot water.
I'm diving an unmodified inspo (which I can cay now we are not in the JJ thread!).
Cheers
Matt.
Does this reduce/eliminate the clumping? I cannot say that I have noticed any bother with clumping, btw, running the scrubber up to 5 hours in cold water (long dive, extra time in shallows) and up to 6 hours in hot water.
I'm diving an unmodified inspo (which I can cay now we are not in the JJ thread!).
Cheers
Matt.
lizardland
Active Member
The Mk15 has such a small filling port on the scrubber that you really need to decant the lime into something else to fill it. I use a cheap watering can, pour the lime in from about a foot above it, done outside. Even a slight breeze is enough to blow a decent amount of dust away before filling the scrubber.
There is never any lime dust inside the unit but it also has seriously good filters top and bottom on the scrubber cartridge (porex). No matter how careful I was with dust in my KISS there would always be some in the head. I don't know that I could be arsed hoovering it, I never saw any lime dust deposited in the hoses, I'd expect the corrugations would have been the perfect place for crap to build up.
There is never any lime dust inside the unit but it also has seriously good filters top and bottom on the scrubber cartridge (porex). No matter how careful I was with dust in my KISS there would always be some in the head. I don't know that I could be arsed hoovering it, I never saw any lime dust deposited in the hoses, I'd expect the corrugations would have been the perfect place for crap to build up.
Do I detect a note of cynicism about the value of the experiment? :chuckle:
joshua smith
New Member
That sounds pretty scientifical. Count me in!
joshua smith
New Member
Fascinating. But to make it really scientificish, you must be able to duplicate the results.
tecdiverdude
Southern Moderation
Whilst these replies may be funny, they are aimed at a particular poster.
I will admit the above experiments are a bit out there, I would prefer to see you suggest a better method of testing or contribute with other theories on the Original purpose of the thread.
Please Gentleman, keep it friendly.
I will admit the above experiments are a bit out there, I would prefer to see you suggest a better method of testing or contribute with other theories on the Original purpose of the thread.
Please Gentleman, keep it friendly.
gianaameri
gian @ gian.ameri.name
I think you are limited in some way because (correct me if I am wrong), you have only experience (a lot) with one rebreather and one specific scrubber and one specific scrubber design.
We are all limited, but the more rebreathers and scrubbers and scrubber designs we use, the more we can observe as to how they work differently, and you will also see different rates of clumping, and slightly different behaviours.
The scrubber you use has a hydrophobic membrane top and bottom. Good for keeping dust in (so the dust does not affect you, in my scrubber with a big metal mesh the dust can be a big problem). It is also good to keep water out (i.e. the condensation dripping down from the top of the head, which you can see sitting on top in water form, on top of the hydrophobic membrane, which you find quite soaked after a long dive) - BUT, equally, with the design you use, you keep the dust inside, and any condensation/water which may form inside, hence you see a lot more clumping than in other scrubbers.
I never quite understood what cause clumping, but I think after my experiment that it is
1. Caused by Sofnolime + H2O (condensation...)
2. Exacerbated by Sofnolime Dust
3. Aggravated by long time storage after use
I do not think that "clumping" is inconsequential. I believe,
4. it reduces the absorption ability of Sofnolime
5. MOST SERIOUSLY AND IMPORTANTLY: it can create a channel and cause CO2 bypass (a low probability event, random, and unpredictable).
These are my thoughts, but I'd like to hear from the "experts" (as I am admittedly not one and I am just trying to understand by observation):
a. What are the causes of "clumping?"
b. Can it be ruled out that it reduces CO2 absorption?
c. Can it be ruled out that it may cause channelling and CO2 by-pass?
d. Is it exacerbated by storing the scrubber after use?
e. How can it be reduced?
f. Have they tested the scrubber not just after one exposure under EN14143:2003, but the same scrubber after many repeat dives over several days, and what are the results (and absent the testing how can they recommend usage of the same scrubber over multiple dives/days)?
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matt
Well-Known Member
I admit I have not read the T&C but can a moderator confirm or deny that having fun in a thread is/isn't allowed as I am confused about how serious this is. For me the fun appeals, if punctuated with some decent replies.
Thanks
Matt.
matt
Well-Known Member
Correct. For me a rebreather is a tool for a job; a means to an ends and not the ends in itself.
I only dive Inspiration, but I like to know about other units/styles...
OK. That makes sense. Yes - the inspo has the hydrophobic scrims rather than the megs metal mesh. I've dived with some meg divers (of course) and see them filling all the time using the just tip it in method. One of them will even dive all week (6 gas dives) on the same scrubber :crossfing
True, after a long dive you can pour it off.
I'd never even realised that the clumping was dust related. Sometimes it is there, sometimes not. Maybe this is to do with where in the tub you're filling from - I'll pay more attention and see if that's it.
I always thought it was an artifact of a) excessive moisture and b) over-packing. I get less clumping if I loose pack - sometimes none at all, but I like the dust idea.
#4 could be true but I'm unsure of #5 - once packed we can assume no channel as the material's shape is "self-packing". Are you saying that by adding water (moisture) and swelling the material (or dust) than a channel may form? Why would it? If anything is it not slightly more compact?
Me neither - I'm just a MP punter.
I think this test is not done, not part of the standard and the results unpublished - maybe Martin/Paul or someone else can come along and tell us.
I know that Paul does this type of thing - his results on cold-start scrubbers was fascinating (to me at least).
Cheers
Matt.
gianaameri
gian @ gian.ameri.name
This thread exist because we don't know.
We don't know because there has not been any proper, methodical, and scientific testing (mine is certainly not, can't be, never will).
Having observed the clumps in different scrubbers and those I created artificially, most definitely I think it could cause CO2 by-pass.
BUT it is those who profit from the rebreather trade who have to show that what they commandeer in rebreather instruction manuals and rebreather training is safe.
If they don't test the scrubber over multiple dives/days, we will never know.
Bythesea
New Member
Hear here...
Bythesea
New Member
So, the experiment continues, the very same scrubber has sat for yet another week and today saw me to 41.1M and back....
So, in summary, it had done
2 x 25M dives
Sat for two weeks
1 x 32M dive
Sat for one week
1 x 40M dive....
the scrubber has not been kept in a bag, it has sat sometimes in the cupboard and at other times in the bucket with the lid on.
I therefore conclude that it is safe to use a scrubber that has been sat so long as it remains uncontaminated.
I think I will bin it now and put some fresh in...
matt
Well-Known Member
Personally, in cold water, I wouldn't stray much from <50m 100 mins, <20m 140 mins, 180 mins max. regardless of any storage conditions.
Matt.