Extendair

**Gill Envy** · 15th September 2006, 00:44

Quote: (Originally Posted by AD_ward9)

We ran tests with Sofnolime hard packed into the same volume as the 5" cartridge (195mm x 124.5mm), in the same canister. The result was 50% better in ExtendAir than on lime.

We have a setup where can test scrubbers down to 1400msw completely under computer control.

What is good news, is the customers we have all agree to publish results as part of the Open Revolution Initiative. Intermediate results are also commercially valuable (costs a lot of money to do and reproduce), but there is agreement to publish the final data in full. Probably happen shortly after DEMA.

Cheers

Alex

If it turns out that the EAC is truly 50% more effiicient and if in fact it handles deep dives without a hitch then i think the scales will tip in it's favor. I would still like to be able to monitor the progression of the reaction front with some sort of temp stick...especially if i were to go beyond the 3 hour rating before a new rating/testing were publically made available. if there were a design that were compatable with the evo, then i would probably use it from time to time...but i would still advocate for rebreather designs that leave that choice in the hands of the user.

the bummer that will continue to weigh negatively for me even as the price per hour becomes more comparable to granular sorb is the fact that it's mesh (Gortex?) is not bio-degradable...can't wait to be muck diving in south jesus indonesia and see one of those things float on by...unless you pack it out of remote locations you can only hope it gets burned, so much of our crap ends up in some poor villagers back yard and sadly on the very reef we have come to enjoy.

E-man · 15th September 2006, 01:40

Quote: (Originally Posted by Gillenvy)

If it turns out that the EAC is truly 50% more effiicient and if in fact it handles deep dives without a hitch then i think the scales will tip in it's favor. I would still like to be able to monitor the progression of the reaction front with some sort of temp stick...especially if i were to go beyond the 3 hour rating before a new rating/testing were publically made available. if there were a design that were compatable with the evo, then i would probably use it from time to time...but i would still advocate for rebreather designs that leave that choice in the hands of the user.

the bummer that will continue to weigh negatively for me even as the price per hour becomes more comparable to granular sorb is the fact that it's mesh (Gortex?) is not bio-degradable...can't wait to be muck diving in south jesus indonesia and see one of those things float on by...unless you pack it out of remote locations you can only hope it gets burned, so much of our crap ends up in some poor villagers back yard and sadly on the very reef we have come to enjoy.

They are about 1% of the said "mesh" and 99% calcium OH...

Genesis · 15th September 2006, 02:49

Hmmmm.....

As I've been musing and hacking away at plastic in my shop making scrubber-looking things, I've been pondering my choice to go loose-pack over the EAs.

My problem with the EA system is practical more than anything else - there's no way to do a coaxial scrubber can reasonably. Oh it CAN be done, but you have to figure out how to run the gas down (or up) around the OUTSIDE of the scrubber, which means you need to make some pretty fancy-dancy stuff - especially if you're going top-down, as flow homogenuity is quite important.

Now Micropore has these cannisters for the Dolphin and Azimuth pre-made, but you'll note they're straight axials, and this is why. For a home-build or something that is going to not be in a case, this can be a significant problem (the external stand-pipe, etc.) Micropore also sells the cannister rebuild kits, which have the cones necessary to get good flow dynamics..... so you've got PART of the puzzle worked out.... just not all of it.

As noted you also have to deal with the water trap/removal issue, but that's not all that tough.

I'd love to see real data that shows what's being claimed here - that the EA is that much more efficient. That might be worth doing if that proves out - even with the additional hassles.

(BTW I was originally planning on using the EAs, then changed my mind. Perhaps I was a bit hasty in that determination......)

koputai · 15th September 2006, 04:16

AD_ward said:

Quote:

3.The old Prism 5.5lb scrubber was before the days of CAD flow analysis.
A modern scrubber design can outrun that easily.

But how does the science of scrubber design fare if everyone uses Micropore cannisters? Won't all scrubbers using said cannisters perform approximately the same?

Quote:

The Prism scrubber is quite a nice design.

Well it should be, it was designed by Carleton!

Cheers,
Jason M.

AD_ward9 · 15th September 2006, 05:06

Quote: (Originally Posted by chunter)

One thing I haven't seen is any discussion on the depth limitation of the EAC. If the EAC is better for all intents and purposes, why the 160 foot (or whatever it is) depth limit? Is it simply that the EACs haven't been tested past 160'?

Also, in the Inspiration, the EAC adapter makes it so that the cartrige only fills 2/3 of the internal diameter of the standard canister, so even though it may be lb. for lb. more efficient, what is the duration of the EAC in the Inspiration? What CO2 flow rates were used and at what temp?

Aloha,
Charlie

We have done breathing resistance tests on the EAC to 500m on air (!) and helium, from 10l/min to 90l/min. EACs are not limited by gas flow over that range. We are extending these tests to 1400msw (700msw max dive, x2 for safety) and will publish the curve for air. The bottom line is the EAC has 1/3rd the breathing resistance of a 195mm long 36mm internal diameter hose. This means the EAC WOB is much less than for granules.

On scrubber operation, the EAC is not depth limited, but duration will reduce with depth, except that using helium, the duration increases compared to using air at the same depth.

For deep dives, I would not use anything other than EAC due to the safety issues. Not a wet statement: I have experienced floods, tunnelling, bad lime etc, and reviewing the performance between granules and EAC, there is no competition.

Cheers,
Alex

silent running · 15th September 2006, 06:29

Alex, thanks again for all the info.

I'm presuming that because of the low resistance for the EAC it's supposed to offset some of the breathing disadvantages of the BMCLs in your Open Rev CCR. Is this correct? And how does the WOB of your unit compare to a OTSCL unit with a radial, in a horizontal position? Is the hydrostatic loading still a factor with the BMCLs on the Open Rev. in a horizontal position? Sorry if you've gone over this before.. -Andy

AD_ward9 · 15th September 2006, 07:20

Quote: (Originally Posted by silent running)

Alex, thanks again for all the info.

I'm presuming that because of the low resistance for the EAC it's supposed to offset some of the breathing disadvantages of the BMCLs in your Open Rev CCR. Is this correct? And how does the WOB of your unit compare to a OTSCL unit with a radial, in a horizontal position? Is the hydrostatic loading still a factor with the BMCLs on the Open Rev. in a horizontal position? Sorry if you've gone over this before.. -Andy

The OTSCL/BM counterlung issue is resolved by deducting the appropriate hydrostatic pressure from the 25mbar allowance. 1mbar per cm from the lung centroid. Position is not a debating point: one simply has to take the worst case position, so the number to use is the worst case offset from the lung centroid. For OTSCL, the offset is less than for BM, by a factor depending on the backplate design.

We have used 40mm ID breathing hose, with 36mm ID P Ports, to get the WOB down as low as reasonably possible. The counterlungs are 4.5l, though some people will want 6l. At least one version will meet the 25mbar limit at a depth in excess of 200m in the sports version using heliox, and 60m on air.

The breathing resistance of the EAC is so low, under all conditions, it is not a significant part of the WOB. The mushroom valves, mouthpiece and shut off valve are the primary obstructions that cause the breathing resistance to be what it is.

Cheers,
Alex

silent running · 15th September 2006, 08:00

Quote: (Originally Posted by AD_ward9)

We have used 40mm ID breathing hose, with 36mm ID P Ports, to get the WOB down as low as reasonably possible. The counterlungs are 4.5l, though some people will want 6l. At least one version will meet the 25mbar limit at a depth in excess of 200m in the sports version using heliox, and 60m on air.

The breathing resistance of the EAC is so low, under all conditions, it is not a significant part of the WOB. The mushroom valves, mouthpiece and shut off valve are the primary obstructions that cause the breathing resistance to be what it is.

Cheers,
Alex

Alex, thanks for the details, I'm aware that the dsv and it's components are a big part of the WOB. What kind of flow did you do those WOB tests with? Was it that breathing machine? -Andy

iain-hsm · 15th September 2006, 13:44

Quote: (Originally Posted by paulraymaekers)

or use a doubble axial scrubber like in the rEvo: during diving gasflow is vertical :-)
conc dwell... no more :-) just listening and having fun
conc efficiency of granular lime: max 17% ???? euhh
sounds odd to me :-) just calculate the amount of CO2 that can be absorbed theoretically/kg lime, and see what is achieved in reality..
paul

Paul
Just Listening and having Fun? please join in make it more fun. LoL. What I said was 14 to 17% (a rough figure) but if you want it specific:
Sodasorb 12 to 19% High performance diving Grade 18%, Medical grade 16%

jaap · 15th September 2006, 14:46

Quote: (Originally Posted by iain-hsm)

Paul
Just Listening and having Fun? please join in make it more fun. LoL. What I said was 14 to 17% (a rough figure) but if you want it specific:
Sodasorb 12 to 19% High performance diving Grade 18%, Medical grade 16%

Yes but these things really depend on how big the actual scrubebr is, don't they?

I would guess that any SCUBA-sized scrubber is limited by spiking breakthrough not by even depletion of the material.

If the scrubber is really big the front end of the scrubber can be used alot more before any breakthrough. I hope somebody with experience of massive scrubbers will jump in, but I heard from a friend that the massive scrubbers on submarines are usually run something like 20 times longer/kg than the same scrubbermaterial in a rebreather.

15th September 2006, 00:44	#31 (permalink)
Gill Envy Shearwater Copis Diver Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,302	Re: Extendair Quote: (Originally Posted by AD_ward9) We ran tests with Sofnolime hard packed into the same volume as the 5" cartridge (195mm x 124.5mm), in the same canister. The result was 50% better in ExtendAir than on lime. We have a setup where can test scrubbers down to 1400msw completely under computer control. What is good news, is the customers we have all agree to publish results as part of the Open Revolution Initiative. Intermediate results are also commercially valuable (costs a lot of money to do and reproduce), but there is agreement to publish the final data in full. Probably happen shortly after DEMA. Cheers Alex If it turns out that the EAC is truly 50% more effiicient and if in fact it handles deep dives without a hitch then i think the scales will tip in it's favor. I would still like to be able to monitor the progression of the reaction front with some sort of temp stick...especially if i were to go beyond the 3 hour rating before a new rating/testing were publically made available. if there were a design that were compatable with the evo, then i would probably use it from time to time...but i would still advocate for rebreather designs that leave that choice in the hands of the user. the bummer that will continue to weigh negatively for me even as the price per hour becomes more comparable to granular sorb is the fact that it's mesh (Gortex?) is not bio-degradable...can't wait to be muck diving in south jesus indonesia and see one of those things float on by...unless you pack it out of remote locations you can only hope it gets burned, so much of our crap ends up in some poor villagers back yard and sadly on the very reef we have come to enjoy. __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°>
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15th September 2006, 01:40	#32 (permalink)
E-man On the loop! Current Rebreather/s: Inspiration Classic Optima Other Rebreather/s: Titan Join Date: Sep 2005 Location: Eastern Coast ;) Posts: 212	Re: Extendair Quote: (Originally Posted by Gillenvy) If it turns out that the EAC is truly 50% more effiicient and if in fact it handles deep dives without a hitch then i think the scales will tip in it's favor. I would still like to be able to monitor the progression of the reaction front with some sort of temp stick...especially if i were to go beyond the 3 hour rating before a new rating/testing were publically made available. if there were a design that were compatable with the evo, then i would probably use it from time to time...but i would still advocate for rebreather designs that leave that choice in the hands of the user. the bummer that will continue to weigh negatively for me even as the price per hour becomes more comparable to granular sorb is the fact that it's mesh (Gortex?) is not bio-degradable...can't wait to be muck diving in south jesus indonesia and see one of those things float on by...unless you pack it out of remote locations you can only hope it gets burned, so much of our crap ends up in some poor villagers back yard and sadly on the very reef we have come to enjoy. They are about 1% of the said "mesh" and 99% calcium OH...
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15th September 2006, 02:49	#33 (permalink)
Genesis Bubbless Box of Death Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Oct 2005 Location: Sunny Florida Posts: 1,394	Re: Extendair Hmmmm..... As I've been musing and hacking away at plastic in my shop making scrubber-looking things, I've been pondering my choice to go loose-pack over the EAs. My problem with the EA system is practical more than anything else - there's no way to do a coaxial scrubber can reasonably. Oh it CAN be done, but you have to figure out how to run the gas down (or up) around the OUTSIDE of the scrubber, which means you need to make some pretty fancy-dancy stuff - especially if you're going top-down, as flow homogenuity is quite important. Now Micropore has these cannisters for the Dolphin and Azimuth pre-made, but you'll note they're straight axials, and this is why. For a home-build or something that is going to not be in a case, this can be a significant problem (the external stand-pipe, etc.) Micropore also sells the cannister rebuild kits, which have the cones necessary to get good flow dynamics..... so you've got PART of the puzzle worked out.... just not all of it. As noted you also have to deal with the water trap/removal issue, but that's not all that tough. I'd love to see real data that shows what's being claimed here - that the EA is that much more efficient. That might be worth doing if that proves out - even with the additional hassles. (BTW I was originally planning on using the EAs, then changed my mind. Perhaps I was a bit hasty in that determination......) __________________ "A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American." http://www.denninger.net http://www.diversunion.org/liability.htm - Fix the Diving Cert racket
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15th September 2006, 04:16	#34 (permalink)
koputai Subsea Systems Current Rebreather/s: MK 15.X Other CCR Other SCR Other Rebreather/s: Not Bought Yet Other CCR Other SCR Join Date: Jul 2005 Location: Sydney, Australia Posts: 326	Re: Extendair AD_ward said: Quote: 3.The old Prism 5.5lb scrubber was before the days of CAD flow analysis. A modern scrubber design can outrun that easily. But how does the science of scrubber design fare if everyone uses Micropore cannisters? Won't all scrubbers using said cannisters perform approximately the same? Quote: The Prism scrubber is quite a nice design. Well it should be, it was designed by Carleton! Cheers, Jason M.
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15th September 2006, 05:06	#35 (permalink)
AD_ward9 So much more to learn Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Jun 2005 Location: Scotland Posts: 1,732	Re: Extendair Quote: (Originally Posted by chunter) One thing I haven't seen is any discussion on the depth limitation of the EAC. If the EAC is better for all intents and purposes, why the 160 foot (or whatever it is) depth limit? Is it simply that the EACs haven't been tested past 160'? Also, in the Inspiration, the EAC adapter makes it so that the cartrige only fills 2/3 of the internal diameter of the standard canister, so even though it may be lb. for lb. more efficient, what is the duration of the EAC in the Inspiration? What CO2 flow rates were used and at what temp? Aloha, Charlie We have done breathing resistance tests on the EAC to 500m on air (!) and helium, from 10l/min to 90l/min. EACs are not limited by gas flow over that range. We are extending these tests to 1400msw (700msw max dive, x2 for safety) and will publish the curve for air. The bottom line is the EAC has 1/3rd the breathing resistance of a 195mm long 36mm internal diameter hose. This means the EAC WOB is much less than for granules. On scrubber operation, the EAC is not depth limited, but duration will reduce with depth, except that using helium, the duration increases compared to using air at the same depth. For deep dives, I would not use anything other than EAC due to the safety issues. Not a wet statement: I have experienced floods, tunnelling, bad lime etc, and reviewing the performance between granules and EAC, there is no competition. Cheers, Alex Last edited by AD_ward9 : 16th September 2006 at 07:24.
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15th September 2006, 06:29	#36 (permalink)
silent running Mature mouth breather Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Jun 2005 Location: U.S.A. Brooklyn, New York Posts: 1,813	Re: Extendair Alex, thanks again for all the info. I'm presuming that because of the low resistance for the EAC it's supposed to offset some of the breathing disadvantages of the BMCLs in your Open Rev CCR. Is this correct? And how does the WOB of your unit compare to a OTSCL unit with a radial, in a horizontal position? Is the hydrostatic loading still a factor with the BMCLs on the Open Rev. in a horizontal position? Sorry if you've gone over this before.. -Andy
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15th September 2006, 07:20	#37 (permalink)
AD_ward9 So much more to learn Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Jun 2005 Location: Scotland Posts: 1,732	Re: Extendair Quote: (Originally Posted by silent running) Alex, thanks again for all the info. I'm presuming that because of the low resistance for the EAC it's supposed to offset some of the breathing disadvantages of the BMCLs in your Open Rev CCR. Is this correct? And how does the WOB of your unit compare to a OTSCL unit with a radial, in a horizontal position? Is the hydrostatic loading still a factor with the BMCLs on the Open Rev. in a horizontal position? Sorry if you've gone over this before.. -Andy The OTSCL/BM counterlung issue is resolved by deducting the appropriate hydrostatic pressure from the 25mbar allowance. 1mbar per cm from the lung centroid. Position is not a debating point: one simply has to take the worst case position, so the number to use is the worst case offset from the lung centroid. For OTSCL, the offset is less than for BM, by a factor depending on the backplate design. We have used 40mm ID breathing hose, with 36mm ID P Ports, to get the WOB down as low as reasonably possible. The counterlungs are 4.5l, though some people will want 6l. At least one version will meet the 25mbar limit at a depth in excess of 200m in the sports version using heliox, and 60m on air. The breathing resistance of the EAC is so low, under all conditions, it is not a significant part of the WOB. The mushroom valves, mouthpiece and shut off valve are the primary obstructions that cause the breathing resistance to be what it is. Cheers, Alex Last edited by AD_ward9 : 15th September 2006 at 07:28. Reason: Typos, as usual
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15th September 2006, 08:00	#38 (permalink)
silent running Mature mouth breather Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Jun 2005 Location: U.S.A. Brooklyn, New York Posts: 1,813	Re: Extendair Quote: (Originally Posted by AD_ward9) We have used 40mm ID breathing hose, with 36mm ID P Ports, to get the WOB down as low as reasonably possible. The counterlungs are 4.5l, though some people will want 6l. At least one version will meet the 25mbar limit at a depth in excess of 200m in the sports version using heliox, and 60m on air. The breathing resistance of the EAC is so low, under all conditions, it is not a significant part of the WOB. The mushroom valves, mouthpiece and shut off valve are the primary obstructions that cause the breathing resistance to be what it is. Cheers, Alex Alex, thanks for the details, I'm aware that the dsv and it's components are a big part of the WOB. What kind of flow did you do those WOB tests with? Was it that breathing machine? -Andy
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15th September 2006, 13:44	#39 (permalink)
iain-hsm Custom Title Allowed! Current Rebreather/s: MK 15.X Other CCR Other SCR Other Rebreather/s: Other CCR Other SCR Join Date: Mar 2005 Location: Loughborough England uk Posts: 347	Re: Extendair Quote: (Originally Posted by paulraymaekers) or use a doubble axial scrubber like in the rEvo: during diving gasflow is vertical :-) conc dwell... no more :-) just listening and having fun conc efficiency of granular lime: max 17% ???? euhh sounds odd to me :-) just calculate the amount of CO2 that can be absorbed theoretically/kg lime, and see what is achieved in reality.. paul Paul Just Listening and having Fun? please join in make it more fun. LoL. What I said was 14 to 17% (a rough figure) but if you want it specific: Sodasorb 12 to 19% High performance diving Grade 18%, Medical grade 16%
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15th September 2006, 14:46	#40 (permalink)
jaap Normal people worry me Current Rebreather/s: Classic Kiss Other CCR RB80 / Clone Ray Other SCR Home Build Other Rebreather/s: Other CCR RB80 / Clone Ray Other SCR Home Build Join Date: Jun 2005 Location: Stockholm Sweden Posts: 445	Re: Extendair Quote: (Originally Posted by iain-hsm) Paul Just Listening and having Fun? please join in make it more fun. LoL. What I said was 14 to 17% (a rough figure) but if you want it specific: Sodasorb 12 to 19% High performance diving Grade 18%, Medical grade 16% Yes but these things really depend on how big the actual scrubebr is, don't they? I would guess that any SCUBA-sized scrubber is limited by spiking breakthrough not by even depletion of the material. If the scrubber is really big the front end of the scrubber can be used alot more before any breakthrough. I hope somebody with experience of massive scrubbers will jump in, but I heard from a friend that the massive scrubbers on submarines are usually run something like 20 times longer/kg than the same scrubbermaterial in a rebreather.
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