Storing part-used scrubbers

I don't know when it happens, but I do know the sorb loosens up in an AP scrubber at some point between packing, diving, getting it home, unpacking, storing and pulling it out of the bag to put back in the unit.

My tap-tap-tapping now goes to the point where I can shake the canister without it resembling a maraca, ie no loose material inside. But when I go to use it again I find that there's definitely some movement in it and it needs re-tapping and tightening of the retainer.

I guess it's happening during the ride home from the dive site on the boat and in the car, so channelling is a possibility if you don't square it away before diving again. Leaving it in the unit ready for another dive would remove the opportunity to notice this.
 
Captain Starfish said:
I don't know when it happens, but I do know the sorb loosens up in an AP scrubber at some point between packing, diving, getting it home, unpacking, storing and pulling it out of the bag to put back in the unit.

My tap-tap-tapping now goes to the point where I can shake the canister without it resembling a maraca, ie no loose material inside. But when I go to use it again I find that there's definitely some movement in it and it needs re-tapping and tightening of the retainer.

I guess it's happening during the ride home from the dive site on the boat and in the car, so channelling is a possibility if you don't square it away before diving again. Leaving it in the unit ready for another dive would remove the opportunity to notice this.
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I largely agree. In the course of use a packed scrubber is prone to a degree of clumping which may create some localised channeling. There is no doubt that I can retighten a scrubber compression nut following part use and I always do so. It's mindful to be aware that minor localised clumping / channeling may not be a serious implication with an axial scrubber as the relatively long path through the media provides a certain 'fail-safe'. However the comparatively shorter path with a radial may not provide the same degree of protection.

Sent from my SM-T800 using Tapatalk
 
Captain Starfish said:
I don't know when it happens, but I do know the sorb loosens up in an AP scrubber at some point between packing, diving, getting it home, unpacking, storing and pulling it out of the bag to put back in the unit.

My tap-tap-tapping now goes to the point where I can shake the canister without it resembling a maraca, ie no loose material inside. But when I go to use it again I find that there's definitely some movement in it and it needs re-tapping and tightening of the retainer.

I guess it's happening during the ride home from the dive site on the boat and in the car, so channelling is a possibility if you don't square it away before diving again. Leaving it in the unit ready for another dive would remove the opportunity to notice this.
Click to expand...

I don't have this problem in either a Meg axial or radial - even after hours of driving or bumpy boat rides. Are you packing it enough?
 
i may have unfounded concerns regarding channelling in a scrubber that has been used once and then stored. I just wonder whether any testing of this has been done i.e. Used scrubber in various states of use being left for different periods of time, in different orientations. Does the storage temperature of a partially used scrubber have an impact - is a partially used scrubber more susceptible to channelling after being dropped/transported etc,etc. It may be the answer to all these questions is - no it's fine, but it would be good to see some testing around this, and know what the safe margins of operation are. I guess the tamperiing (deliberate or non deliberate) of a scrubber left for a period of time is still something to also consider separately...
 
at the risk of going off at a bit of an angle packing a scrubber too loose is a risk, there is a myth that say "if I pack my scrubber too tight it will increase WOB " I wont (as long as the loop is designed properly) or "if I pack my scrubber too tight it wont work properly" It will.
in the testing we did under ce test conditions we could increase the duration of the scrubber by up to 20mins by packing it as tight as we could.
I should add this has been tested by us in the JJ-CCR only I have no idea if t will be the same for other units
 
I don't know when it happens, but I do know the sorb loosens up in an AP scrubber at some point between packing, diving, getting it home, unpacking, storing and pulling it out of the bag to put back in the unit.

My tap-tap-tapping now goes to the point where I can shake the canister without it resembling a maraca, ie no loose material inside. But when I go to use it again I find that there's definitely some movement in it and it needs re-tapping and tightening of the retainer.

I guess it's happening during the ride home from the dive site on the boat and in the car, so channelling is a possibility if you don't square it away before diving again. Leaving it in the unit ready for another dive would remove the opportunity to notice this.
Click to expand...


Perhaps that is an indication that the design of your RB is shit..
 
Interesting info thanks. Did you get 10% more material in with the hard-pack/+20min duration? Do you have any theories on clumping; does it matter/why caused, etc.?

Cheers
Matt.

ccrdave said:
at the risk of going off at a bit of an angle packing a scrubber too loose is a risk, there is a myth that say "if I pack my scrubber too tight it will increase WOB " I wont (as long as the loop is designed properly) or "if I pack my scrubber too tight it wont work properly" It will.
in the testing we did under ce test conditions we could increase the duration of the scrubber by up to 20mins by packing it as tight as we could.
I should add this has been tested by us in the JJ-CCR only I have no idea if t will be the same for other units
Click to expand...
 
rjack said:
I don't have this problem in either a Meg axial or radial - even after hours of driving or bumpy boat rides. Are you packing it enough?
Click to expand...

For a bit of (short) entertainment watch the official AP video on how to pack a scrubber. It takes two coffee filters and about two minutes. You only need to tap it two or three times gently then, according to the video... you're packed!
 
Perhaps compare and critique with this:

[video=youtube;E2NItHuTar8]https://www.youtube.com/watch?v=E2NItHuTar8[/video]
 
Matt, you owe me lunch, a keyboard and a new office chair. Just spat my sandwich out and p*ssed myself laughing.
 
matt said:
Interesting info thanks. Did you get 10% more material in with the hard-pack/+20min duration? Do you have any theories on clumping; does it matter/why caused, etc.?

Cheers
Matt.
Click to expand...

yes Matt bottom line was harder pack means more sofnolime, It was surprising how a little more sofnolime (by weight) amounted to a fairly large increase in time. in my opinion clumping is caused by locally active parts of the sorb producing more water, have you noticed how it seem to clump around the central rod,? my opinion is thats where most of the reaction is. interestingly enough in my experience the harder the pack the clumping was more consistent across the reactive surface but overall it was less evident
 
ccrdave said:
yes Matt bottom line was harder pack means more sofnolime, It was surprising how a little more sofnolime (by weight) amounted to a fairly large increase in time. in my opinion clumping is caused by locally active parts of the sorb producing more water, have you noticed how it seem to clump around the central rod,? my opinion is thats where most of the reaction is. interestingly enough in my experience the harder the pack the clumping was more consistent across the reactive surface but overall it was less evident
Click to expand...

Interesting that the hard pack didn't increase WOB. Personally I can't detect WOB differences in my Inspo and I've tried packing all ways. The loose method (per the video) is too loose for me; I'm a medium packer. And I typically do use the temp-stick for duration estimation (especially in warm-water).

My observation for clumping is that the harder you pack it the more clumping you get. I always wondered if this is caused by dust created by crushing - i.e. moisture+dust causes clumping?

I've never seen anything that said clumping was an issue - just something to observe. But I also didn't see the latest papers on this, have to wait until it is out. There used to be a video of someone hoovering their scrubber, I recall who but cannot find the video anymore.

Cheers
Matt.
 
We actually tested the hardest pack on a breathing machine, again under ce conditions, no difference in wob but like I said before loop design is very important part of this. As im sure are aware it impossible to tell by just diving it
Witchcraft and science!! Matt
 
ccrdave said:
We actually tested the hardest pack on a breathing machine, again under ce conditions, no difference in wob but like I said before loop design is very important part of this. As im sure are aware it impossible to tell by just diving it
Witchcraft and science!! Matt
Click to expand...

Completely agree that you cannot tell the difference in WOB that can easily be detected by a machine. Complete voodoo, just like mixing gas ;-)

Also (and this also depends on the scrubber design) I have seen a cartridge so over-full on the inspo that the side of the canister bulges out and the canister no longer moves freely in the bucket. I would think this certain to give CO2 by-pass on a dive. In the old-days I remember that there were reports that you could tighten the canister-nut so much that the end of the canister could be broken off!

Cheers
Matt.
 
ccrdave said:
We actually tested the hardest pack on a breathing machine, again under ce conditions, no difference in wob but like I said before loop design is very important part of this. As im sure are aware it impossible to tell by just diving it
Witchcraft and science!! Matt
Click to expand...

I've never felt any difference packing Sofnolime (D shaped cross section) but on a trip I had to switch to using Divelime (cylindrical cross section) initially I packed it the same and it breathed very similar but was frightening loose when I came to empty it.

Next pack I did as hard as I would have done with Sofnolime and I felt it breathed Noticeably worse- I postulate that you can pack small cylinders with less remaining space than small D x-sections, a practical mathematical problem I suspect :-)

I have no machine data but the difference was sufficient that I won't buy it again despite the price difference...
 
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