Reading the Tea Leaves/Sodasorb Grains

jkaterenchuk · 3rd August 2008, 01:27

Quote: (Originally Posted by w ripley)

Hey John:

From one view, it would seem that you're leaning towards Obama. From the other, McCain. Hard to tell, if you're breathing from the left or right?

Seriously, my MEG canister looked the same on some dives. Just more tapping... Or, you can pick up a small dental vibrating table and end all the confusion.

How are the wings?

Regards,

Bill

Actually Bill given the I am Canadian and have a Green Card my opinion does not count regarding O or M.

Wing seems good so far. Had it out for 5 dives so far.

John

jkaterenchuk · 3rd August 2008, 01:30

Quote: (Originally Posted by Underwaterbear)

Not sure which absorbent you're using there but I think the uneven pattern is just a product of where the moisture is, rather than strictly where the scrubber is 100% spent.

My understanding is that the indicator dye (I think it's ethyl violet in Sodasorb but it could be phenolphthalein - I can't remember) is activated by the carbonic acid created when C02 dissolves into water produced in the CO2 fixation reaction.

So in your photos the "front " was somewhere just a bit lower down than the lightest pink shading. Of course some of the indicator has probably reverted to white or colorless now that you are not breathing on it.

When you were breathing on it, in the zone of spent and almost spent sorb, the moisture laden with H2CO3 was going where gravity took it, activating the indicator on the surface layers of each granule as it goes. If you were horizontal or thereabouts obviously the moisture tends to fall to the bottom half of the scrubber.

Bottom line I chalk* it up to gravity.

Cheers,
Andrew

* Sorry, couldn't help myself.

That was punny. I will pay attention to the scrubber orientation vs dive position vs purple pattern when I remove it next time to see if it supports your gravity guess. However, I am having difficulty understanding how gravity would have any effect underwater since we are floating weighless.

John

diverklondike · 3rd August 2008, 01:45

John,

I wonder if it is showing that it was not packed evenly...

Just a thought..

m

Shawn · 3rd August 2008, 02:41

For whats it worth I have seen this before and I have figured out how to stop it.

Basically when I was packing my canister I would slap on both sides of the canister creating a vibration so that the media would pack more ( per my instruction from Leon) If I hit one side of the canister harder than the other I would get this color variation.

After spending some time packing and repacking several time to observe this error I noticed that the really hard hits caused the scrubber to unpack or loosen up.

Now I use softer hits to the canister and downward motions, not to mention I go a little slower. This seems to have resolved the issue and I see a much more even distribution of the colored / used media.

I hope that helps you out a little.

jkaterenchuk · 3rd August 2008, 04:09

Jeez guys this is starting to sound like a porn site.....suggestions that I buy a vibrator or slowly stroke the cannister. Next someone will post a video for our enjoyment.

John

Lancer4545 · 3rd August 2008, 07:14

Quote: (Originally Posted by jkaterenchuk)

It is actually packed with Sodasorb 8-12. I have never used 4-8. I will be starting to use some Sofnolime 6-12 in the near future and I will see if that changes the pattern.

John

Hey John,

The Dive Sofnolime 797 I have seen doesn't come with colour indication.........So you might be dissapointed.

To get it packed that little bit tighter, I fit the bottom spring loaded "Wagon Wheel" and bump it a few more times. The spring tends to push it all down a little tighter leaving little chance of any loose spots.

Regards,

Lance

diver1369 · 3rd August 2008, 12:31

One possible consideration. The Meg hose that pumps used gas in to the cannister to be processed by the sorb is on the side, the return hose is in the center. Is it possible that the Meg develops a slightly higher pressure on one side (hence greater gas permeation on that side)? I realize that the gas path on both sides takes it down the outside of the scrubber insert into the plenum at the bottom, from whence it starts its journey through the sorb and you might think that evens out the pressure, but its one thing to be considered. Is the uneven patch always on the same side? (I use Jakub's excellent radial so I don't see this pattern...)

john

mmcauliffe · 3rd August 2008, 15:32

Quote: (Originally Posted by sfldiver)

John,

That looks like Barney pee'd in your kitty litter!

Great, I just sprayed coffee all over my screen.

jkaterenchuk · 3rd August 2008, 21:18

Here are some updated pictures taken immediately following my dives today showing the orientation of the scrubber canister compared to the diver.

If diver is in prone/horizontal dive position then

first pic = looking from divers left side
second pic = looking from divers right side
third pic = looking from above diver
fourth pic = looking from below diver

I do not believe this is a packing issue. Unless maybe the scrubber is packed too tight and it constricts the flow of gas. I took my time packing the scrubber to ensure it was tight in order to rule out too loose a packing.

It's very interesting that if you are looking at a diver in prone position coming directly at you then the area of least CO2 absorbtion seems to be the right lower quadrant (3 oclock to 6 oclock) by a factor of about 3x compared to the left upper quadrant (9 oclock to 12 oclock).

If would be interesting to hear from those that have done some scrubber design modeling on what I am seeing. It would seem that scrubber duration is significantly impacted by this phenomon.

John

Underwaterbear · 4th August 2008, 16:54

Cool, thanks for doing the experiment. I'd say that I have to retract the gravity theory...unless you swim around on your back! I still think it has to be something to do with where the moisture is concentrated in the working scrubber.

One thing for sure...you are right on about the uneven use being important for duration considerations.

3rd August 2008, 01:27	#11 (permalink)
jkaterenchuk . Current Rebreather/s: Inspiration Classic Megalodon Classic Kiss Other Rebreather/s: Join Date: May 2006 Location: Lititz, PA Posts: 1,086	Re: Reading the Tea Leaves/Sodasorb Grains Quote: (Originally Posted by w ripley) Hey John: From one view, it would seem that you're leaning towards Obama. From the other, McCain. Hard to tell, if you're breathing from the left or right? Seriously, my MEG canister looked the same on some dives. Just more tapping... Or, you can pick up a small dental vibrating table and end all the confusion. How are the wings? Regards, Bill Actually Bill given the I am Canadian and have a Green Card my opinion does not count regarding O or M. Wing seems good so far. Had it out for 5 dives so far. John
(Offline)

3rd August 2008, 01:30	#12 (permalink)
jkaterenchuk . Current Rebreather/s: Inspiration Classic Megalodon Classic Kiss Other Rebreather/s: Join Date: May 2006 Location: Lititz, PA Posts: 1,086	Re: Reading the Tea Leaves/Sodasorb Grains Quote: (Originally Posted by Underwaterbear) Not sure which absorbent you're using there but I think the uneven pattern is just a product of where the moisture is, rather than strictly where the scrubber is 100% spent. My understanding is that the indicator dye (I think it's ethyl violet in Sodasorb but it could be phenolphthalein - I can't remember) is activated by the carbonic acid created when C02 dissolves into water produced in the CO2 fixation reaction. So in your photos the "front " was somewhere just a bit lower down than the lightest pink shading. Of course some of the indicator has probably reverted to white or colorless now that you are not breathing on it. When you were breathing on it, in the zone of spent and almost spent sorb, the moisture laden with H2CO3 was going where gravity took it, activating the indicator on the surface layers of each granule as it goes. If you were horizontal or thereabouts obviously the moisture tends to fall to the bottom half of the scrubber. Bottom line I chalk* it up to gravity. Cheers, Andrew * Sorry, couldn't help myself. That was punny. I will pay attention to the scrubber orientation vs dive position vs purple pattern when I remove it next time to see if it supports your gravity guess. However, I am having difficulty understanding how gravity would have any effect underwater since we are floating weighless. John
(Offline)

3rd August 2008, 01:45	#13 (permalink)
diverklondike RBW Member Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Oct 2005 Location: Delaware, USA Posts: 1,713	Re: Reading the Tea Leaves/Sodasorb Grains John, I wonder if it is showing that it was not packed evenly... Just a thought.. m
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3rd August 2008, 02:41	#14 (permalink)
Shawn RBW Member Current Rebreather/s: Megalodon Other CCR RB80 / Clone Other Rebreather/s: Other CCR RB80 / Clone Join Date: Oct 2007 Location: Kansas City Kansas Posts: 157	Re: Reading the Tea Leaves/Sodasorb Grains For whats it worth I have seen this before and I have figured out how to stop it. Basically when I was packing my canister I would slap on both sides of the canister creating a vibration so that the media would pack more ( per my instruction from Leon) If I hit one side of the canister harder than the other I would get this color variation. After spending some time packing and repacking several time to observe this error I noticed that the really hard hits caused the scrubber to unpack or loosen up. Now I use softer hits to the canister and downward motions, not to mention I go a little slower. This seems to have resolved the issue and I see a much more even distribution of the colored / used media. I hope that helps you out a little.
(Offline)

3rd August 2008, 04:09	#15 (permalink)
jkaterenchuk . Current Rebreather/s: Inspiration Classic Megalodon Classic Kiss Other Rebreather/s: Join Date: May 2006 Location: Lititz, PA Posts: 1,086	Re: Reading the Tea Leaves/Sodasorb Grains Jeez guys this is starting to sound like a porn site.....suggestions that I buy a vibrator or slowly stroke the cannister. Next someone will post a video for our enjoyment. John
(Offline)

3rd August 2008, 07:14	#16 (permalink)
Lancer4545 RBW Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jun 2007 Location: Cairns QLD Australia Posts: 745	Re: Reading the Tea Leaves/Sodasorb Grains Quote: (Originally Posted by jkaterenchuk) It is actually packed with Sodasorb 8-12. I have never used 4-8. I will be starting to use some Sofnolime 6-12 in the near future and I will see if that changes the pattern. John Hey John, The Dive Sofnolime 797 I have seen doesn't come with colour indication.........So you might be dissapointed. To get it packed that little bit tighter, I fit the bottom spring loaded "Wagon Wheel" and bump it a few more times. The spring tends to push it all down a little tighter leaving little chance of any loose spots. Regards, Lance __________________ You can run but you can't hide! ISC Appointed Megalodon Dealer for East Australia http://www.closedcircuitdivers.com.au info@closedcircuitdivers.com.au
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3rd August 2008, 12:31	#17 (permalink)
diver1369 RBW Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Maryland, USA Posts: 87	Re: Reading the Tea Leaves/Sodasorb Grains One possible consideration. The Meg hose that pumps used gas in to the cannister to be processed by the sorb is on the side, the return hose is in the center. Is it possible that the Meg develops a slightly higher pressure on one side (hence greater gas permeation on that side)? I realize that the gas path on both sides takes it down the outside of the scrubber insert into the plenum at the bottom, from whence it starts its journey through the sorb and you might think that evens out the pressure, but its one thing to be considered. Is the uneven patch always on the same side? (I use Jakub's excellent radial so I don't see this pattern...) john
(Offline)

3rd August 2008, 15:32	#18 (permalink)
mmcauliffe New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jun 2008 Location: Cave Country, Luraville Florida Posts: 58	Re: Reading the Tea Leaves/Sodasorb Grains Quote: (Originally Posted by sfldiver) John, That looks like Barney pee'd in your kitty litter! Great, I just sprayed coffee all over my screen.
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4th August 2008, 16:54	#20 (permalink)
Underwaterbear A Prismer in Megland Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: May 2005 Location: Seattle, WA Posts: 198	Re: Reading the Tea Leaves/Sodasorb Grains Cool, thanks for doing the experiment. I'd say that I have to retract the gravity theory...unless you swim around on your back! I still think it has to be something to do with where the moisture is concentrated in the working scrubber. One thing for sure...you are right on about the uneven use being important for duration considerations.
(Offline)

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