Extendair

jaap · 14th September 2006, 11:28

Quote: (Originally Posted by AD_ward9)

The point with the water is that the reaction absorbing CO2 generates water. In the case of granules it is mostly absorbed, which is why the granules are hard caked together, like mortar, after use. That does not happen with ExtendAir cartridges. The water runs down the cartridge and must be collected, then removed. The amount of water can be large: a litre in some tests! There is a good and bad side to this:

1. The WOB stays the same throughout the dive, instead of increasing during the dive with granules.
2. You have to have a means to get rid of the water, preferably automatically.

Cheers,

Alex

A liter of water from one Extendair cartridge!? If my chemistry is not wrong that would translate into something like an absorption of ~1400l CO2!

This is under the assumption that absorption of 1 CO2 makes the scrubber produce approx 1 H20.

Also if that much water is produced and not retained in the cartridge matrix how come the Extendairsystem is designed the way it is. The conical and O-ring sealed part in the ends of the scrubber should trap the water inside the cartridgecompartment? For me it looks like the system as it is today does not have any means to separate any water formed inside the cartridge from the cartridge?

I have an Extendair-scrubber but I don't use it since it is such a hassel to get cartridges to Sweden or any EU country.

Do you have any idea if the Extendair system will be sold in the EU anytime soon?

SteveL · 14th September 2006, 12:37

Quote: (Originally Posted by silent running)

The USN tested the MK15.5 with the 8lb axial scrubber-very large diameter/surface area-and got the same duration as the old Prism 5.5lb scrubber...

Whats this?? I thought the 15.5 scrubber was a hallmark in design and that it was one of the most efficient scrubbers ever produced.

Do you have any more info or some test date on this - I would like to find out more.

Thanks and Regards,

Steve L

iain-hsm · 14th September 2006, 13:59

Quote: (Originally Posted by jaap)

A liter of water from one Extendair cartridge!? If my chemistry is not wrong that would translate into something like an absorption of ~1400l CO2!

This is under the assumption that absorption of 1 CO2 makes the scrubber produce approx 1 H20.

Also if that much water is produced and not retained in the cartridge matrix how come the Extendairsystem is designed the way it is. The conical and O-ring sealed part in the ends of the scrubber should trap the water inside the cartridgecompartment? For me it looks like the system as it is today does not have any means to separate any water formed inside the cartridge from the cartridge?

I have an Extendair-scrubber but I don't use it since it is such a hassel to get cartridges to Sweden or any EU country.

Do you have any idea if the Extendair system will be sold in the EU anytime soon?

I would assume during the breathing trials 100% humid air or gas is used. The effect of temperature and humidity on breath samples is also an effect on the amount of water used by the humidifier to create the 100% humidity. I suggest the amount of distilled water consumed by the humidifier should be noted and in addition disclosed if it is at the 1.6 l/min C02 rate that is driving the chemical action.

The effect of humidification and warmed air or dry and cold air on the accuracy of a canister duration trial is the most interesting part to me, It shows the importance of a reference model using a conventional agreed system, IMHO that model should be examined to a referenced lung model but I can live with BS EN. (have to?)

Constancy of the values set for temperature, relative humidity and absolute humidity in the lung model if given for all measurements in both the dry and cold air tests would give a better understanding between granular type absorbents and the fabric deposited absorbents. But design considerations of the breathing bags also have a marked effect on the amount of water getting to the canister. However non more than a "hot" lime. Most granular limes are around 14% to 17% effective (Hot) if the cartrige type has increased the potency of the chemical by 30% one would expect a corresponding increase in C02 uptake. Iain Middlebrook

AD_ward9 · 14th September 2006, 16:02

Quote: (Originally Posted by silent running)

Alex, thanks for the water amount clarification, a ltr of water sounds like a good level of flood tolerance.

But the above explantion sounds a bit odd to me. The gas flow in a radial is "worse" than an axial. What do you mean by worse? If the more tightly packed radial allows for a more optimal usage of the sorb, what's worse about that? A more densely packed scrubber would increase dwell time, slowing the velocity and thus efficiency, no?

And the "If you put the same weight of granules into an axial, it would last longer than for the radial" part, I don't get it. The USN tested the MK15.5 with the 8lb axial scrubber-very large diameter/surface area-and got the same duration as the old Prism 5.5lb scrubber...
Andy

1. Worse means less even.
2. You are correct on radials allow denser packing before hitting the WOB limits. This is where radials score. However, for the same weight of scrubber material, an axial will give longer life if designed well.
3.The old Prism 5.5lb scrubber was before the days of CAD flow analysis.
A modern scrubber design can outrun that easily. New Prism scrubbers are developed with CAD flow analysis tools, from a discussion with Peter R, so should be better still. The Prism scrubber is quite a nice design.
4. 1ltr is not flood tolerance: the litre should be removed. It does not hang about in the scrubber, as it does with granules. It falls to the bottom of the scrubber and ends up in counterlungs and breathing tubes, from where it needs to be dumped.
5. There are lots of very bad axial scrubber designs. I note the recent advice from APD on packing. We had noticed the Inspo design is extremely hard to pack without having tunnelling: in fact even with breathing machines to measure it, we fail to avoid tunnelling more often than not. I just got off the phone with another company with extensive lab test experience on the Inspo scrubber and they too confirmed that it is hard, in their experience, to get less than 0.1 to 0.2% of CO2 leaving the Inspo scrubber when filled with granules. They said they always have to test it vertical to get sensible results. I concur with these percentage figures. APD modified their packing advice after buying an ANSTI machine and, I suspect, seeing for themselves how badly it performs. This tunnelling issue is a major problem with axial designs using granules. I would welcome rings like on the Dolphin, or some other arrangement, as an upgrade to the Inspo scrubber to overcome this, or a change to ExtendAir (which I did on my Inspo).

Cheers

Alex

paulraymaekers · 14th September 2006, 17:01

Quote: (Originally Posted by AD_ward9)

This tunnelling issue is a major problem with axial designs using granules. I would welcome rings like on the Dolphin, or some other arrangement, as an upgrade to the Inspo scrubber to overcome this, or a change to ExtendAir (which I did on my Inspo).

Cheers

Alex

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

Claudio · 14th September 2006, 19:38

From what I read, is not at all clear if extend air cartrigde offer greater duration time.
-) The data on Extend Air Web Site speak about a duration x1.5/x2; this means that with my Inspo it could be arrived until 6 hours? I have many doubts and perplexity to such purpose....
-) the published data in the Dive Rite Web Site with regard to the O2ptima Reb do not indicate longer times that three hours.
-) AD_ward9 speaks about a great efficiency and duration, but I have not read its data.
Claudio

silent running · 14th September 2006, 20:20

Quote: (Originally Posted by SteveL)

Whats this?? I thought the 15.5 scrubber was a hallmark in design and that it was one of the most efficient scrubbers ever produced.

Do you have any more info or some test date on this - I would like to find out more.

Thanks and Regards,

Steve L

Hello Steve L, yes the 15.5 is one of the most efficient axial scrubbers
ever, larger surface area and shorter grain boundry than any other axial flow scrubber. I'll see if I can find the test results/comparison... -Andy

chunter · 14th September 2006, 21:27

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

silent running · 14th September 2006, 21:55

Quote: (Originally Posted by SteveL)

Whats this?? I thought the 15.5 scrubber was a hallmark in design and that it was one of the most efficient scrubbers ever produced.

Do you have any more info or some test date on this - I would like to find out more.

Thanks and Regards,

Steve L

Steve, if you look at the SMI site under the testing, there's a bit at the begining of one of the tests about how the Navy was looking for a replacement for the MKs and the new CCR had to meet or exeed the performance of the MKs in terms of scrubber duration and other characteristics. The 5.5 Prism scrubber met this same standard with 2+ lbs less sorb and exceeded others, like WOB. The actual test results for the MK 15.5 are in the NEDU library, but the same criteria are detailed in the NEDU tests of the Prism, all of which are on the SMI site... -Andy

**Gill Envy** · 14th September 2006, 23:47

Quote: (Originally Posted by Scuba_Vixen)

One of the other benefits of the EAC, lies in it's ability to be removed and stored while you put in a fresh one for a big dive, and then go back and use the rest of the time on the one you took out for lesser dives.

Depending on how your dives go, it could be cost effective to not have to dump partially used sorb, if this occurs on a regular basis

Darlene

this is nifty indeed, something i haven't thought of. since i dive more often than my wife, i have used the extra scrubber canister and temp stick to accoomplish the same much of the time.

14th September 2006, 11:28	#21 (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: 451	Re: Extendair Quote: (Originally Posted by AD_ward9) The point with the water is that the reaction absorbing CO2 generates water. In the case of granules it is mostly absorbed, which is why the granules are hard caked together, like mortar, after use. That does not happen with ExtendAir cartridges. The water runs down the cartridge and must be collected, then removed. The amount of water can be large: a litre in some tests! There is a good and bad side to this: 1. The WOB stays the same throughout the dive, instead of increasing during the dive with granules. 2. You have to have a means to get rid of the water, preferably automatically. Cheers, Alex A liter of water from one Extendair cartridge!? If my chemistry is not wrong that would translate into something like an absorption of ~1400l CO2! This is under the assumption that absorption of 1 CO2 makes the scrubber produce approx 1 H20. Also if that much water is produced and not retained in the cartridge matrix how come the Extendairsystem is designed the way it is. The conical and O-ring sealed part in the ends of the scrubber should trap the water inside the cartridgecompartment? For me it looks like the system as it is today does not have any means to separate any water formed inside the cartridge from the cartridge? I have an Extendair-scrubber but I don't use it since it is such a hassel to get cartridges to Sweden or any EU country. Do you have any idea if the Extendair system will be sold in the EU anytime soon?
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14th September 2006, 12:37	#22 (permalink)
SteveL Custom Title Allowed! Current Rebreather/s: MK 15.X Other Rebreather/s: Inspiration Classic Join Date: Nov 2005 Location: Sydney Australia Posts: 222	Re: Extendair Quote: (Originally Posted by silent running) The USN tested the MK15.5 with the 8lb axial scrubber-very large diameter/surface area-and got the same duration as the old Prism 5.5lb scrubber... Whats this?? I thought the 15.5 scrubber was a hallmark in design and that it was one of the most efficient scrubbers ever produced. Do you have any more info or some test date on this - I would like to find out more. Thanks and Regards, Steve L
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14th September 2006, 13:59	#23 (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 jaap) A liter of water from one Extendair cartridge!? If my chemistry is not wrong that would translate into something like an absorption of ~1400l CO2! This is under the assumption that absorption of 1 CO2 makes the scrubber produce approx 1 H20. Also if that much water is produced and not retained in the cartridge matrix how come the Extendairsystem is designed the way it is. The conical and O-ring sealed part in the ends of the scrubber should trap the water inside the cartridgecompartment? For me it looks like the system as it is today does not have any means to separate any water formed inside the cartridge from the cartridge? I have an Extendair-scrubber but I don't use it since it is such a hassel to get cartridges to Sweden or any EU country. Do you have any idea if the Extendair system will be sold in the EU anytime soon? I would assume during the breathing trials 100% humid air or gas is used. The effect of temperature and humidity on breath samples is also an effect on the amount of water used by the humidifier to create the 100% humidity. I suggest the amount of distilled water consumed by the humidifier should be noted and in addition disclosed if it is at the 1.6 l/min C02 rate that is driving the chemical action. The effect of humidification and warmed air or dry and cold air on the accuracy of a canister duration trial is the most interesting part to me, It shows the importance of a reference model using a conventional agreed system, IMHO that model should be examined to a referenced lung model but I can live with BS EN. (have to?) Constancy of the values set for temperature, relative humidity and absolute humidity in the lung model if given for all measurements in both the dry and cold air tests would give a better understanding between granular type absorbents and the fabric deposited absorbents. But design considerations of the breathing bags also have a marked effect on the amount of water getting to the canister. However non more than a "hot" lime. Most granular limes are around 14% to 17% effective (Hot) if the cartrige type has increased the potency of the chemical by 30% one would expect a corresponding increase in C02 uptake. Iain Middlebrook
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14th September 2006, 16:02	#24 (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: 1,868	Re: Extendair Quote: (Originally Posted by silent running) Alex, thanks for the water amount clarification, a ltr of water sounds like a good level of flood tolerance. But the above explantion sounds a bit odd to me. The gas flow in a radial is "worse" than an axial. What do you mean by worse? If the more tightly packed radial allows for a more optimal usage of the sorb, what's worse about that? A more densely packed scrubber would increase dwell time, slowing the velocity and thus efficiency, no? And the "If you put the same weight of granules into an axial, it would last longer than for the radial" part, I don't get it. The USN tested the MK15.5 with the 8lb axial scrubber-very large diameter/surface area-and got the same duration as the old Prism 5.5lb scrubber... Andy 1. Worse means less even. 2. You are correct on radials allow denser packing before hitting the WOB limits. This is where radials score. However, for the same weight of scrubber material, an axial will give longer life if designed well. 3.The old Prism 5.5lb scrubber was before the days of CAD flow analysis. A modern scrubber design can outrun that easily. New Prism scrubbers are developed with CAD flow analysis tools, from a discussion with Peter R, so should be better still. The Prism scrubber is quite a nice design. 4. 1ltr is not flood tolerance: the litre should be removed. It does not hang about in the scrubber, as it does with granules. It falls to the bottom of the scrubber and ends up in counterlungs and breathing tubes, from where it needs to be dumped. 5. There are lots of very bad axial scrubber designs. I note the recent advice from APD on packing. We had noticed the Inspo design is extremely hard to pack without having tunnelling: in fact even with breathing machines to measure it, we fail to avoid tunnelling more often than not. I just got off the phone with another company with extensive lab test experience on the Inspo scrubber and they too confirmed that it is hard, in their experience, to get less than 0.1 to 0.2% of CO2 leaving the Inspo scrubber when filled with granules. They said they always have to test it vertical to get sensible results. I concur with these percentage figures. APD modified their packing advice after buying an ANSTI machine and, I suspect, seeing for themselves how badly it performs. This tunnelling issue is a major problem with axial designs using granules. I would welcome rings like on the Dolphin, or some other arrangement, as an upgrade to the Inspo scrubber to overcome this, or a change to ExtendAir (which I did on my Inspo). Cheers Alex Last edited by AD_ward9 : 14th September 2006 at 16:25.
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14th September 2006, 17:01	#25 (permalink)
paulraymaekers rEvo's daddy Current Rebreather/s: rEvo Other CCR Home Build Other Rebreather/s: rEvo Other CCR Home Build Join Date: May 2005 Location: belgium Posts: 1,506	Re: Extendair Quote: (Originally Posted by AD_ward9) This tunnelling issue is a major problem with axial designs using granules. I would welcome rings like on the Dolphin, or some other arrangement, as an upgrade to the Inspo scrubber to overcome this, or a change to ExtendAir (which I did on my Inspo). Cheers Alex 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 __________________ www.rEvo-rebreathers.com .... the earth is flat, Elvis is alive, and radial scrubbers give longer dwell time than axials...
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14th September 2006, 19:38	#26 (permalink)
Claudio New Member Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Other CCR Join Date: Nov 2005 Location: ITALY - Trento Posts: 64	Re: Extendair From what I read, is not at all clear if extend air cartrigde offer greater duration time. -) The data on Extend Air Web Site speak about a duration x1.5/x2; this means that with my Inspo it could be arrived until 6 hours? I have many doubts and perplexity to such purpose.... -) the published data in the Dive Rite Web Site with regard to the O2ptima Reb do not indicate longer times that three hours. -) AD_ward9 speaks about a great efficiency and duration, but I have not read its data. Claudio Last edited by Claudio : 15th September 2006 at 06:18.
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14th September 2006, 20:20	#27 (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: 1,832	Re: Extendair Quote: (Originally Posted by SteveL) Whats this?? I thought the 15.5 scrubber was a hallmark in design and that it was one of the most efficient scrubbers ever produced. Do you have any more info or some test date on this - I would like to find out more. Thanks and Regards, Steve L Hello Steve L, yes the 15.5 is one of the most efficient axial scrubbers ever, larger surface area and shorter grain boundry than any other axial flow scrubber. I'll see if I can find the test results/comparison... -Andy
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14th September 2006, 21:27	#28 (permalink)
chunter I like diving Current Rebreather/s: Sport Kiss MK 15.X Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Classic Kiss Join Date: Jul 2006 Location: Honolulu Posts: 478	Re: Extendair 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
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14th September 2006, 21:55	#29 (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: 1,832	Re: Extendair Quote: (Originally Posted by SteveL) Whats this?? I thought the 15.5 scrubber was a hallmark in design and that it was one of the most efficient scrubbers ever produced. Do you have any more info or some test date on this - I would like to find out more. Thanks and Regards, Steve L Steve, if you look at the SMI site under the testing, there's a bit at the begining of one of the tests about how the Navy was looking for a replacement for the MKs and the new CCR had to meet or exeed the performance of the MKs in terms of scrubber duration and other characteristics. The 5.5 Prism scrubber met this same standard with 2+ lbs less sorb and exceeded others, like WOB. The actual test results for the MK 15.5 are in the NEDU library, but the same criteria are detailed in the NEDU tests of the Prism, all of which are on the SMI site... -Andy
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14th September 2006, 23:47	#30 (permalink)
Gill Envy Shearwater Copis Divers Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,315	Re: Extendair Quote: (Originally Posted by Scuba_Vixen) One of the other benefits of the EAC, lies in it's ability to be removed and stored while you put in a fresh one for a big dive, and then go back and use the rest of the time on the one you took out for lesser dives. Depending on how your dives go, it could be cost effective to not have to dump partially used sorb, if this occurs on a regular basis Darlene this is nifty indeed, something i haven't thought of. since i dive more often than my wife, i have used the extra scrubber canister and temp stick to accoomplish the same much of the time. __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°>
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