Duration on the new EP Extendair cartridges?

***caveseeker7*** · 7th February 2006, 03:11

Quote: (Originally Posted by ScubaDadMiami)

Just as an added "trivia" note, in my Rebreather class, my instructor informs me that there can be as much as 20 percent variation in the ability to absorb CO2 in any given batch of CO2 absorbant.

I find that rather hard to believe.

Even if, is that 20% above, below or around the manufacturer's rating?
The test data I've seen testing scrubber duration varied by less than 10%.

Mark, I don't quite see the similarity between cylinders and absorbant.
Absorbant is a media, used once and tossed. It's gotta last its duration.

Cylinders are a container for media, get used over and over, and from what I gather there is something called metal fatigue coming into play. Now if you want me to rate air to be compressed to 12,000 psi I don't have a problem.

If you want to do a comparison, how about brakes on a car.
- you need them to come to a stop safely
- failure can kill and eventually will
- used pads will decrease performance
- damaged discs will decrease performance
- you need to know they work
- you don't want to hear They're good brakes, you know, they stop my car all the time. I even know a guy down in Florida who drove 120 mph with his buddy, trunk full with rebreathers and stages, brakes worked just fine. But we never tested them.

**Gill Envy** · 7th February 2006, 07:29

Stefan, your comments throughout this have been really engaging, thanks for sharing all that!

And once again, thanks to everyone who dared to share their thoughts!
My O2 cents: (IMHO, with the usual disclaimer of being an Rebreather virgin) I do believe that the canister is too expensive and is not likely to come down in price, DT’s assessment of the situation seems likely correct: “ExtendAir makes money off big contracts (gas anesthesia machines right?) and the scuba market is small in comparison (to the medical market?!)”. if it was a matter of 25% more per hour of operation compared to the average granular scrubber it would not be a big deal, but by my calculations it is a lot more than that ($29/cartridge for 2, maybe three hours of cold water current diving). Stefan’s idea of rating a scrubber with a range of breathing rates and depths sound like it makes a lot of sense. I am one of those people who asks what happens in those cases where people pass out… what unusual circumstances led to that and how can I factor in the worst case scenario to avoid such an unwelcome outcome. The close call I experienced on OC many years ago put a lot in perspective for me. My Atomic B2 allows me to breathe with relative ease at equivalent resp. rate to being at a full sprint… I chose it because there was one time that I was at 120 fsw in a strong down welling, with my life flashing before my eyes it was all I could do to resist the current, with both hands clawing at the sand, my old regulator that I was using at the time breathed like a thin straw that was threatening to implode… the nitrogen and resistance on breathing caused a rush of adrenaline spiraling my cardiac/resp. rate upwards uncontrollably… I even got that subconscious reptilian urge to clear my air passage…gulp!

With the cartridge, or any scrubber, I want to know what it’s capabilities are not just in overall burn time. Under what depth/temperature/resp. rate will the lack of dwell time likely overwhelm it’s ability to “scrub”. Why not do tests in the full range of temperatures and depths encountered by divers: say 35f, 55f and 85f and at three depths each, say 66fsw, 165fsw and 297fsw with relatively high Co2 production with a period of balls out huffing….testing for brief spikes in break through co2. how expensive could this really be, or is it that MFG's are afraid they won't measure up? Then we could each calculate our own comfort zone based on the most like conditions to what we are setting out to do rather than having to play mind games with ourselves about weather we are being conservative enough or not. And on top of that, I’d let the MFG’s off the hook by accepting a clause, like, “this is an estimation based on controlled conditions in a lab, it is impossible to accurately predict the metabolic variations of each user under varying degrees of physical and emotional stress, actual performance may vary, use at your own risk.”

One of the dive rite guys told me over the phone that they had one guy forget to change out the cartridge in between dives and ended up putting 10 hrs on one!! And supposedly “felt just a little funny” at the end of the last dive. Ok, so where does that leave those of us who just think 2-3 hours might be too conservative…Guinea pigs?! If two hours is really the safe limit for the dives I do then no way, I’m out, if 4 hrs is the limit, well then I’m back in the conversation…and if I can dry out or freeze the canister and conserve an unused portion for a week, for those one time after work dives, well then that could tip the scale too. It’s not just a matter of being cheap, I hate being excessively wasteful and I hate feeling like a corporate hore. And of course, if I could choose the cartridge or the granules depending on the application, then I’d be less reluctant to buy the unit.
Rumor has it that the adapter for granules on the optima is coming out in march…I’m not holding my breath, but if it doesn’t come out by the time my excitement to dive bubbleless overwhelms my reluctance to spend 5-10 grand, I may just go for another unit, ironically maybe even a more expensive one like the meg (again, that value calculation is a series of ratios for me…a used inspo or a fully loaded meg are see sawing (the trouble is that my wife wants one too, ahh we can put off having kids and buying that house for a few years can’t we honey?...but really, how can I complain, she’s my dream come true in more ways than one!

).
I’ve heard one shop owner make the mistake of assessing the situation this way…”hey, if your buying a Cadillac then you’re not someone who is worried about saving a few bucks”, and thus he did not think the cost of the cartridge was a big deal. That philosophy starts to mince words…the optima has been promoted as more economically priced eCCR and in any case, some of us sport divers (and apparently sport divers are part of the market the optima is aimed at) who are thinking hard about the long term financial impact buying a rebreather it going to have on our lives are likely to be put off by excessive running cost. Overall value is the deal breaker for all of us isn’t it. I’m guessing there are a lot of folks making the CCR switch who are not rich, but rather water babies who are compelled to make necessary sacrifices to be able to spend a lot more time under water actually exploring what they love.
I was told rather frankly that Micro pore was being given exclusive access to the optima for the first few months to give it a chance to catch on before the granular adapter was released. I spoke to a guy who had the adapter sitting on his desk…word is that it will cost about $200 and is made of stainless steel. Ok dive rite, lay it on the table…and with a solid rating too!

n2diving · 7th February 2006, 12:43

[quote=Genesis]One thing that I find missing from these recommendations is an uncertainty.
[quote]

I'm not clear how it would help.... the problem area would seem to be the 'carbon based lifeform' attached to the loop and related factors such as user error.

Hypotheticly, let's say the manufacturer of the cartridge made the statement "CO2 absorbent capacity is 300 liters +/- 10% with 100% certainty" Would you mind illustrating how you could use that information such that it affected process of determining a duration?

Genesis · 7th February 2006, 13:08

Quote: (Originally Posted by n2diving)

Quote: (Originally Posted by Genesis)

One thing that I find missing from these recommendations is an uncertainty.

I'm not clear how it would help.... the problem area would seem to be the 'carbon based lifeform' attached to the loop and related factors such as user error.

Hypotheticly, let's say the manufacturer of the cartridge made the statement "CO2 absorbent capacity is 300 liters +/- 10% with 100% certainty" Would you mind illustrating how you could use that information such that it affected process of determining a duration?

If you know the capacity with an uncertainty, and you also know your VO2max and typical O2 consumption rates you can then determine an upper boundary on the time that you can put on the scrubber. You also know preemptorily at what point in time you're "screwed" before it happens.

This also allows some clever software work - if you use the controller to add all the O2, and it has a known flow rate, it can then track O2 addition and, given a known "aw $hit!" point, it can warn you are some percentage of consumption of the media.

I agree with your statement that the "carbon based unit" adds error "signal" to the process in multiple ways, from user error to simple variability from person to person. That's why, however, I believe having statements with error boundaries where they can be determined and having them stated helps diminish the range over which performance occurs.

The problem with a pure time rating is that it inherently makes assumptions about the variability of the scrubber media. The data recently released helps, but is not as expositive as many would like - one "dive" to one depth and time in one set of water condtiions only tells you what that one cartridge did. It requires many cartridges to establish that there is no material variability from sample to sample, or if there is, to put a boundary on it.

Explorer · 7th February 2006, 15:04

Quote: (Originally Posted by Gillenvy)

I spoke to a guy who had the adapter sitting on his desk…word is that it will cost about $200 and is made of stainless steel. Ok dive rite, lay it on the table…and with a solid rating too!

I saw the SS canister last May in Ottawa. Nice.

Jordan · 7th February 2006, 15:49

After reading Gillenvy's post, I need to make sure everyone knows that:

1)Dive Rite does NOT have any plans of releasing a granular absorbent adapter, especially as early as one month away! It may never be produced! That is definitely a rumor, and only a rumor.

2)Regarding the statement that claims someone from Dive Rite said that someone forgot to change out a cartridge between dives, therefore putting 10 hrs on a single cartridge: Everybody here at Dive Rite says that they did not say anything to that affect, and nobody even knows where this rumor could've come from. I would be very interested if that actually happened though. If you could provide more information, that'd be great. Maybe it did happen with one of the many prototype units out there?? I suspect this was just a rumor too, however.

-Jordan

**Gill Envy** · 7th February 2006, 19:11

ok, well, perfect illustration of how completely crazy it is to have a company named dive rite and a company named dive rite express. I made a mistake, i meant dive rite EXPRESS. it was one of the main guys at dive rite express that told me the story of the guy who forgot to change out his extend air canister and accidently put 10 hrs on it. Just looked back through my early correspondences (3 months old) from dive rite EXPRESS. I only know the guys first name was mark.
As for the canister adapter for the optima, it was Rudi Asseer, CEO, IAND, Inc./IANTD, that said he had the canister on his desk in december and that it was coming out in early spring, i believe march...might have been may. I went to a presentation he gave on the optima and talked to him for a while on the phone. he also said during the presentation that the extendair cartridge would cost about $12... i must have been hearing things...i got pretty excited and then went onto the diver rite express site and nearly fell off my chair...how could a company make such a nice, reasonably priced kit and lock you into paying through the nose in operating costs?
hey, if the canister adapter is not ever coming out then end of discussion for me on buying an optima. I'd consider buying another rebreather that takes both the cartridge and the granules...i do see aplications for the cartridge. I would talk any of my friends out of buying an optima if there may never be another option, just on principle, I don't like not having choices. it's like the propriatary tank valves on the inspiration, it's a major down side...why lock yourself in, you just don't know when you might need to be flexible. Modularity and thus flexibility seems to be the way of the future...leave off the cover, give me a unit that has a wide depth range, give multiple canister sizes for different durations, make it easy to strap on whatever bottles i want and give me a real time po2/deco computer...hmm, that sounds a lot like the meg that is about to be released. Damn it! why does my wife have to want one too?

Jordan · 7th February 2006, 20:22

yep, that was diveriteexpress all right. I hate the fact that the names are so close too, believe me!

In regards to a can able to use granular sorb....if you say that you talked to Rudi and he said he was working on something, then apparently you know more than I do (which wouldn't surprise me). I can tell you that nothing will be coming out next month, that's for sure.

paulraymaekers · 7th February 2006, 20:34

hello once more, is there any xtendair-user who can give me the weight and the dimentions (diameter and lenght) of the EP cartridge??

regards

paul

n2diving · 7th February 2006, 20:43

Regarding cartridge reliabliby.... I was just reminded of this page...
http://www.microporeinc.com/productfrm.html

Quoting from the page...

"The user simply places the cartridge into the canister, without any need for tapping or shaking as the canister is being loaded. As such, the duration variability due to irregular granule settling patterns, as well as variability due to individual loading technique are completely eliminated. Eliminating this variability will directly translate into longer minimum duration, and a +/-5% variation in duration at any test condition (granules can vary up to +/-30%)."

This aligns nicely with a couple of aspects of our discussion....

Micropore is quite comfortable saying that duration for the canister is extremely consistent and that the actual value is +/-5%.... while they didn't assign value for the certainty, from previous conversations with Micropore I would expect it to be asymptotically close to 100%. The multiple test runs at http://www.diveriteexpress.com/libra...graph0cold.pdf
clusters perfectly around 240 minutes +/- 5% and with a bit of math I would personally feel comfortable with accepting as fact that the cartridge (in the O2ptima scrubber only!) has the CO2 absorbtion capacity of 324 liters +/- 5% at a certainty asymptotically close to 100%. For me, while it might add a bit more validity to my earlier math, that doesn't really change any of my previous personal conclusions discussed here... but it might for "Genesis".

The large variations in granular duration that were mentioned earlier are not a surprise to me and I've heard similar numbers for years. I think I know the actual study that determined the +/- 30% value, but I'm going to check first to be sure. If I remember that study correctly, part of the variation is the result of differences between individual packing technique and part is the difference between packs by the same individual... but the range between the highest and lowest durations when both factors were considered it wht yielded the 30% variation value. The high variation in duration of hand packed granular scrubbers has always been one of the reasons I've cautioned that scrubber duration recommendations should not be exceeded.

Regarding the anecdote about the error of grossly exceeding the duration of the canister and living to tell about it.... I heard the story second hand, it occurred to an instructor in the Caymans diving in very shallow and very warm water on a SCR (not an O2ptima)... although it seems reasonable I don't know it's veracity... it serves only to illustrate that exceeding that duration of the cartridge is not a good idea, that the cartridge duration recommendations do indeed have a safety margin in them, and that loading a cartridge in the scrubber is so quick and easy it actually creates new issues regarding user error... i.e. nothing is fool proof. It in no way should suggest anyone try it themselves (unless they wish to win a "Darwin Award").

7th February 2006, 03:11	#31 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,451	Quote: (Originally Posted by ScubaDadMiami) Just as an added "trivia" note, in my Rebreather class, my instructor informs me that there can be as much as 20 percent variation in the ability to absorb CO2 in any given batch of CO2 absorbant. I find that rather hard to believe. Even if, is that 20% above, below or around the manufacturer's rating? The test data I've seen testing scrubber duration varied by less than 10%. Mark, I don't quite see the similarity between cylinders and absorbant. Absorbant is a media, used once and tossed. It's gotta last its duration. Cylinders are a container for media, get used over and over, and from what I gather there is something called metal fatigue coming into play. Now if you want me to rate air to be compressed to 12,000 psi I don't have a problem. If you want to do a comparison, how about brakes on a car. - you need them to come to a stop safely - failure can kill and eventually will - used pads will decrease performance - damaged discs will decrease performance - you need to know they work - you don't want to hear They're good brakes, you know, they stop my car all the time. I even know a guy down in Florida who drove 120 mph with his buddy, trunk full with rebreathers and stages, brakes worked just fine. But we never tested them. __________________ Cheers Stefan "Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"
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7th February 2006, 07:29	#32 (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: Duration on the new EP Extendair cartridges? Stefan, your comments throughout this have been really engaging, thanks for sharing all that! And once again, thanks to everyone who dared to share their thoughts! My O2 cents: (IMHO, with the usual disclaimer of being an Rebreather virgin) I do believe that the canister is too expensive and is not likely to come down in price, DT’s assessment of the situation seems likely correct: “ExtendAir makes money off big contracts (gas anesthesia machines right?) and the scuba market is small in comparison (to the medical market?!)”. if it was a matter of 25% more per hour of operation compared to the average granular scrubber it would not be a big deal, but by my calculations it is a lot more than that ($29/cartridge for 2, maybe three hours of cold water current diving). Stefan’s idea of rating a scrubber with a range of breathing rates and depths sound like it makes a lot of sense. I am one of those people who asks what happens in those cases where people pass out… what unusual circumstances led to that and how can I factor in the worst case scenario to avoid such an unwelcome outcome. The close call I experienced on OC many years ago put a lot in perspective for me. My Atomic B2 allows me to breathe with relative ease at equivalent resp. rate to being at a full sprint… I chose it because there was one time that I was at 120 fsw in a strong down welling, with my life flashing before my eyes it was all I could do to resist the current, with both hands clawing at the sand, my old regulator that I was using at the time breathed like a thin straw that was threatening to implode… the nitrogen and resistance on breathing caused a rush of adrenaline spiraling my cardiac/resp. rate upwards uncontrollably… I even got that subconscious reptilian urge to clear my air passage…gulp! With the cartridge, or any scrubber, I want to know what it’s capabilities are not just in overall burn time. Under what depth/temperature/resp. rate will the lack of dwell time likely overwhelm it’s ability to “scrub”. Why not do tests in the full range of temperatures and depths encountered by divers: say 35f, 55f and 85f and at three depths each, say 66fsw, 165fsw and 297fsw with relatively high Co2 production with a period of balls out huffing….testing for brief spikes in break through co2. how expensive could this really be, or is it that MFG's are afraid they won't measure up? Then we could each calculate our own comfort zone based on the most like conditions to what we are setting out to do rather than having to play mind games with ourselves about weather we are being conservative enough or not. And on top of that, I’d let the MFG’s off the hook by accepting a clause, like, “this is an estimation based on controlled conditions in a lab, it is impossible to accurately predict the metabolic variations of each user under varying degrees of physical and emotional stress, actual performance may vary, use at your own risk.” One of the dive rite guys told me over the phone that they had one guy forget to change out the cartridge in between dives and ended up putting 10 hrs on one!! And supposedly “felt just a little funny” at the end of the last dive. Ok, so where does that leave those of us who just think 2-3 hours might be too conservative…Guinea pigs?! If two hours is really the safe limit for the dives I do then no way, I’m out, if 4 hrs is the limit, well then I’m back in the conversation…and if I can dry out or freeze the canister and conserve an unused portion for a week, for those one time after work dives, well then that could tip the scale too. It’s not just a matter of being cheap, I hate being excessively wasteful and I hate feeling like a corporate hore. And of course, if I could choose the cartridge or the granules depending on the application, then I’d be less reluctant to buy the unit. Rumor has it that the adapter for granules on the optima is coming out in march…I’m not holding my breath, but if it doesn’t come out by the time my excitement to dive bubbleless overwhelms my reluctance to spend 5-10 grand, I may just go for another unit, ironically maybe even a more expensive one like the meg (again, that value calculation is a series of ratios for me…a used inspo or a fully loaded meg are see sawing (the trouble is that my wife wants one too, ahh we can put off having kids and buying that house for a few years can’t we honey?...but really, how can I complain, she’s my dream come true in more ways than one! ). I’ve heard one shop owner make the mistake of assessing the situation this way…”hey, if your buying a Cadillac then you’re not someone who is worried about saving a few bucks”, and thus he did not think the cost of the cartridge was a big deal. That philosophy starts to mince words…the optima has been promoted as more economically priced eCCR and in any case, some of us sport divers (and apparently sport divers are part of the market the optima is aimed at) who are thinking hard about the long term financial impact buying a rebreather it going to have on our lives are likely to be put off by excessive running cost. Overall value is the deal breaker for all of us isn’t it. I’m guessing there are a lot of folks making the CCR switch who are not rich, but rather water babies who are compelled to make necessary sacrifices to be able to spend a lot more time under water actually exploring what they love. I was told rather frankly that Micro pore was being given exclusive access to the optima for the first few months to give it a chance to catch on before the granular adapter was released. I spoke to a guy who had the adapter sitting on his desk…word is that it will cost about $200 and is made of stainless steel. Ok dive rite, lay it on the table…and with a solid rating too! __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°> Last edited by Gill Envy : 7th February 2006 at 07:55.
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7th February 2006, 12:43	#33 (permalink)
n2diving Custom Title Allowed! Current Rebreather/s: Optima Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Feb 2005 Location: Florida, USA Posts: 272	Re: Duration on the new EP Extendair cartridges? [quote=Genesis]One thing that I find missing from these recommendations is an uncertainty. [quote] I'm not clear how it would help.... the problem area would seem to be the 'carbon based lifeform' attached to the loop and related factors such as user error. Hypotheticly, let's say the manufacturer of the cartridge made the statement "CO2 absorbent capacity is 300 liters +/- 10% with 100% certainty" Would you mind illustrating how you could use that information such that it affected process of determining a duration?
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7th February 2006, 13:08	#34 (permalink)
Genesis Bubbless Box of Death Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Oct 2005 Location: Sunny Florida Posts: 1,397	Re: Duration on the new EP Extendair cartridges? Quote: (Originally Posted by n2diving) Quote: (Originally Posted by Genesis) One thing that I find missing from these recommendations is an uncertainty. I'm not clear how it would help.... the problem area would seem to be the 'carbon based lifeform' attached to the loop and related factors such as user error. Hypotheticly, let's say the manufacturer of the cartridge made the statement "CO2 absorbent capacity is 300 liters +/- 10% with 100% certainty" Would you mind illustrating how you could use that information such that it affected process of determining a duration? If you know the capacity with an uncertainty, and you also know your VO2max and typical O2 consumption rates you can then determine an upper boundary on the time that you can put on the scrubber. You also know preemptorily at what point in time you're "screwed" before it happens. This also allows some clever software work - if you use the controller to add all the O2, and it has a known flow rate, it can then track O2 addition and, given a known "aw $hit!" point, it can warn you are some percentage of consumption of the media. I agree with your statement that the "carbon based unit" adds error "signal" to the process in multiple ways, from user error to simple variability from person to person. That's why, however, I believe having statements with error boundaries where they can be determined and having them stated helps diminish the range over which performance occurs. The problem with a pure time rating is that it inherently makes assumptions about the variability of the scrubber media. The data recently released helps, but is not as expositive as many would like - one "dive" to one depth and time in one set of water condtiions only tells you what that one cartridge did. It requires many cartridges to establish that there is no material variability from sample to sample, or if there is, to put a boundary on it. __________________ "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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7th February 2006, 15:04	#35 (permalink)
Explorer I will teach you a..... Current Rebreather/s: Evolution Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Alberta, Canada Posts: 773	Re: Duration on the new EP Extendair cartridges? Quote: (Originally Posted by Gillenvy) I spoke to a guy who had the adapter sitting on his desk…word is that it will cost about $200 and is made of stainless steel. Ok dive rite, lay it on the table…and with a solid rating too! I saw the SS canister last May in Ottawa. Nice. __________________ 20 dwarves, 20 dwarves, 20 dwarves took turns doing handstands on the carpet
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7th February 2006, 15:49	#36 (permalink)
Jordan EBT called me stroppy! Current Rebreather/s: Optima Other Rebreather/s: Join Date: May 2005 Location: Garner, NC Posts: 226	Re: Duration on the new EP Extendair cartridges? After reading Gillenvy's post, I need to make sure everyone knows that: 1)Dive Rite does NOT have any plans of releasing a granular absorbent adapter, especially as early as one month away! It may never be produced! That is definitely a rumor, and only a rumor. 2)Regarding the statement that claims someone from Dive Rite said that someone forgot to change out a cartridge between dives, therefore putting 10 hrs on a single cartridge: Everybody here at Dive Rite says that they did not say anything to that affect, and nobody even knows where this rumor could've come from. I would be very interested if that actually happened though. If you could provide more information, that'd be great. Maybe it did happen with one of the many prototype units out there?? I suspect this was just a rumor too, however. -Jordan __________________ Is it clear? No. Well, let's go anyways. "Those who would sacrifice a little freedom for a little order, will lose both, and deserve neither." Thomas Jefferson
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7th February 2006, 19:11	#37 (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: Duration on the new EP Extendair cartridges? ok, well, perfect illustration of how completely crazy it is to have a company named dive rite and a company named dive rite express. I made a mistake, i meant dive rite EXPRESS. it was one of the main guys at dive rite express that told me the story of the guy who forgot to change out his extend air canister and accidently put 10 hrs on it. Just looked back through my early correspondences (3 months old) from dive rite EXPRESS. I only know the guys first name was mark. As for the canister adapter for the optima, it was Rudi Asseer, CEO, IAND, Inc./IANTD, that said he had the canister on his desk in december and that it was coming out in early spring, i believe march...might have been may. I went to a presentation he gave on the optima and talked to him for a while on the phone. he also said during the presentation that the extendair cartridge would cost about $12... i must have been hearing things...i got pretty excited and then went onto the diver rite express site and nearly fell off my chair...how could a company make such a nice, reasonably priced kit and lock you into paying through the nose in operating costs? hey, if the canister adapter is not ever coming out then end of discussion for me on buying an optima. I'd consider buying another rebreather that takes both the cartridge and the granules...i do see aplications for the cartridge. I would talk any of my friends out of buying an optima if there may never be another option, just on principle, I don't like not having choices. it's like the propriatary tank valves on the inspiration, it's a major down side...why lock yourself in, you just don't know when you might need to be flexible. Modularity and thus flexibility seems to be the way of the future...leave off the cover, give me a unit that has a wide depth range, give multiple canister sizes for different durations, make it easy to strap on whatever bottles i want and give me a real time po2/deco computer...hmm, that sounds a lot like the meg that is about to be released. Damn it! why does my wife have to want one too? __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°>
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7th February 2006, 20:22	#38 (permalink)
Jordan EBT called me stroppy! Current Rebreather/s: Optima Other Rebreather/s: Join Date: May 2005 Location: Garner, NC Posts: 226	Re: Duration on the new EP Extendair cartridges? yep, that was diveriteexpress all right. I hate the fact that the names are so close too, believe me! In regards to a can able to use granular sorb....if you say that you talked to Rudi and he said he was working on something, then apparently you know more than I do (which wouldn't surprise me). I can tell you that nothing will be coming out next month, that's for sure. __________________ Is it clear? No. Well, let's go anyways. "Those who would sacrifice a little freedom for a little order, will lose both, and deserve neither." Thomas Jefferson
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7th February 2006, 20:34	#39 (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: Duration on the new EP Extendair cartridges? hello once more, is there any xtendair-user who can give me the weight and the dimentions (diameter and lenght) of the EP cartridge?? regards 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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7th February 2006, 20:43	#40 (permalink)
n2diving Custom Title Allowed! Current Rebreather/s: Optima Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Feb 2005 Location: Florida, USA Posts: 272	Re: Duration on the new EP Extendair cartridges? Regarding cartridge reliabliby.... I was just reminded of this page... http://www.microporeinc.com/productfrm.html Quoting from the page... "The user simply places the cartridge into the canister, without any need for tapping or shaking as the canister is being loaded. As such, the duration variability due to irregular granule settling patterns, as well as variability due to individual loading technique are completely eliminated. Eliminating this variability will directly translate into longer minimum duration, and a +/-5% variation in duration at any test condition (granules can vary up to +/-30%)." This aligns nicely with a couple of aspects of our discussion.... Micropore is quite comfortable saying that duration for the canister is extremely consistent and that the actual value is +/-5%.... while they didn't assign value for the certainty, from previous conversations with Micropore I would expect it to be asymptotically close to 100%. The multiple test runs at http://www.diveriteexpress.com/libra...graph0cold.pdf clusters perfectly around 240 minutes +/- 5% and with a bit of math I would personally feel comfortable with accepting as fact that the cartridge (in the O2ptima scrubber only!) has the CO2 absorbtion capacity of 324 liters +/- 5% at a certainty asymptotically close to 100%. For me, while it might add a bit more validity to my earlier math, that doesn't really change any of my previous personal conclusions discussed here... but it might for "Genesis". The large variations in granular duration that were mentioned earlier are not a surprise to me and I've heard similar numbers for years. I think I know the actual study that determined the +/- 30% value, but I'm going to check first to be sure. If I remember that study correctly, part of the variation is the result of differences between individual packing technique and part is the difference between packs by the same individual... but the range between the highest and lowest durations when both factors were considered it wht yielded the 30% variation value. The high variation in duration of hand packed granular scrubbers has always been one of the reasons I've cautioned that scrubber duration recommendations should not be exceeded. Regarding the anecdote about the error of grossly exceeding the duration of the canister and living to tell about it.... I heard the story second hand, it occurred to an instructor in the Caymans diving in very shallow and very warm water on a SCR (not an O2ptima)... although it seems reasonable I don't know it's veracity... it serves only to illustrate that exceeding that duration of the cartridge is not a good idea, that the cartridge duration recommendations do indeed have a safety margin in them, and that loading a cartridge in the scrubber is so quick and easy it actually creates new issues regarding user error... i.e. nothing is fool proof. It in no way should suggest anyone try it themselves (unless they wish to win a "Darwin Award"). Last edited by n2diving : 7th February 2006 at 21:51.
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