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Scuba Forum / General / June 2005Tankless SCUBA someday?
http://www.gizmodo.com/gadgets/gadgets/index.php#tankless-underwater-breathing-a pparatus-105999 This is either the scam of the century or a pretty ground-breaking piece of news. An Israeli company has patented and prototyped a tankless underwater breathing apparatus that separates absorbed gas in water. By using a small centrifuge, this system extracts breathable oxygen in depths up to 200 meters. The system can run for an hour on one battery. http://www.isracast.com/tech_news/310505_tech.htm Mike B http://www.gizmodo.com/gadgets/gadgets/index.php#tankless-underwater-breathi ng-apparatus-105999 > This is either the scam of the century or a pretty ground-breaking piece > of news. An Israeli company has patented and prototyped a tankless [quoted text clipped - 3 lines] > > http://www.isracast.com/tech_news/310505_tech.htm A mechanical device, with multiple failure modes, so you would have to carry OC bailout anyway. I wonder how much noise the centrifuge makes? > A mechanical device, with multiple failure modes, so you would have to > carry > OC bailout anyway. > > I wonder how much noise the centrifuge makes? I've seen a working liquid air scuba unit, small enough to be more than competitive. Figured it as next generation, IF. Curtis > > A mechanical device, with multiple failure modes, so you would have to > > carry [quoted text clipped - 4 lines] > I've seen a working liquid air scuba unit, small enough to be more than > competitive. Figured it as next generation, IF. So, instead of watching an SPG, you will be watching a battery meter and a dissolved 02 meter... >> > A mechanical device, with multiple failure modes, so you would have to >> > carry [quoted text clipped - 8 lines] > So, instead of watching an SPG, you will be watching a battery meter and a > dissolved 02 meter... Not the one I was referring to, believe it just measures amount of liquid remaining, similar to how an analyzer works, no moving parts except in the regulators. Still a long ways from our market. Curtis In article <e8Fne.877635$w62.710432@bgtnsc05-news.ops.worldnet.att.net>, Curtis <cavey_curtis@yahoo.com> wrote: > >> > A mechanical device, with multiple failure modes, so you would have to > >> > carry [quoted text clipped - 12 lines] > remaining, similar to how an analyzer works, no moving parts except in the > regulators. Still a long ways from our market. When you say "liquid air" is this a mix of liquid nitrogen and liquid oxygen, or are the two gasses stored seperately and mixed as they're delivered to the regulator? > When you say "liquid air" is this a mix of liquid nitrogen and liquid > oxygen, or are the two gasses stored seperately and mixed as they're > delivered to the regulator? Liquid air, delivering the air at ambient temperature in water or comfortably chilled in air (firefighter use). Believe liquid mix was also considered, as it is not really that much different to this particular science. Curtis > > [quoted text clipped - 9 lines] > So, instead of watching an SPG, you will be watching a battery meter and a > dissolved 02 meter... ... and, of course, ya have to carry a redundant battery. And the cavers have to send in mules to place batteries along the way... > > So, instead of watching an SPG, you will be watching a battery meter and a > > dissolved 02 meter... > > > ... and, of course, ya have to carry a redundant battery. And > the cavers have to send in mules to place batteries along the way... And don't forget the redundant meters also, as you can't trust just one. > > [quoted text clipped - 8 lines] > > Curtis Draeger patented that back in the late teens or early '20s. >>A mechanical device, with multiple failure modes, so you would have to >>carry [quoted text clipped - 6 lines] > > Curtis There was a liquid air unit about 35 years ago. it worked Very well and was compact. it used 2 bottles about then size of 40 ft3 Al ones and had a duration of a half day or so, the unit failed to be mass produced - trouble AFAICR was getting a fill. I'm sure mike gray remembers these ;) >>> A mechanical device, with multiple failure modes, so you would have >>> to carry [quoted text clipped - 11 lines] > had a duration of a half day or so, the unit failed to be mass produced > - trouble AFAICR was getting a fill. I'm sure mike gray remembers these ;) Liquid air and LOX both go back a long way. Draeger's patent (US# 1,472,117; app 6/9/1921) clearly illustrates the big problem - the pressure available from the tank is the evaporation pressure of the liquid, a function of the ambient temperature and a very small number (someone here will know the numbers...). At depth, that pressure needs to be boosted either by heating the liquid, by a mechanical booster, or both. LOX, used in a rebreather, is actually a simpler solution than liquid air used in open circuit because ya need only a tiny fraction as much volume. And Lee Bell points out the problem of extraction from water: ya got to move a huge amount of water to get enough O2, and you'd need the Hoover Dam to get the diluent (unless yer happy with carbon dioxide). m > And Lee Bell points out the problem of extraction from water: ya > got to move a huge amount of water to get enough O2, and you'd > need the Hoover Dam to get the diluent (unless yer happy with > carbon dioxide). Electrolysis and use the H2 as a dilutent... Minor problem with size of battery and flamability percentages of H2 though... <grin> Apparently there are other options then electrolysis... http://www.isracast.com/tech_news/310505_tech.htm And we don't use all the air we breathe, most of it we breath back out again. So we need lesser O2 then you think... ... >> And Lee Bell points out the problem of extraction from water: ya >> got to move a huge amount of water to get enough O2, and you'd [quoted text clipped - 3 lines] >Electrolysis and use the H2 as a dilutent... Minor problem with size of >battery and flamability percentages of H2 though... <grin> >Apparently there are other options then electrolysis... > >http://www.isracast.com/tech_news/310505_tech.htm Discussed a couple of weeks ago. With most feeling that it was technically infeasible. >And we don't use all the air we breathe, most of it we breath back out >again. So we need lesser O2 then you think... Partial pressure of O2 needs to be fairly close to 2.9 psi at sea level to effectivly perform the needed exchange of CO2 and O2. >... > [quoted text clipped - 5 lines] >>Electrolysis and use the H2 as a dilutent... Minor problem with size of >>battery and flamability percentages of H2 though... <grin>  Signaturedillon Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. > Partial pressure of O2 needs to be fairly close to 2.9 psi at sea > level to effectivly perform the needed exchange of CO2 and O2. What about nitrox? Deco gas? > > >>Partial pressure of O2 needs to be fairly close to 2.9 psi at sea >>level to effectivly perform the needed exchange of CO2 and O2. > > What about nitrox? Deco gas? With Oxygen, it's at least Xpp, but not more than Ypp. With other gases, it's not more than Zpp. You can argue that there is a lower limit to CO2, to trigger the breathing response in case you forget, but since we make our own as we go along it's not a concern. What Ghost misses is that a significant portion of the Oxygen is consumed with each breath. Nitrox and deco gas are unlikely to fall below the at least ppO2 before the not more than ppCO2 is reached, but it does happen. > There was a liquid air unit about 35 years ago. it worked Very well and > was compact. it used 2 bottles about then size of 40 ft3 Al ones and had a > duration of a half day or so, the unit failed to be mass produced - > trouble AFAICR was getting a fill. I'm sure mike gray remembers these ;) Yep...one I saw had about a one day "life" for a fill. Not a problem for the guy who built that particular unit, but for the general public, be hard to find fills. Curtis > http://www.gizmodo.com/gadgets/gadgets/index.php#tankless-underwater-breathi > ng-apparatus-105999 [quoted text clipped - 11 lines] > > I wonder how much noise the centrifuge makes? Who cares about the noise? The best part is that you can centrifuge out the plankton for a quick snack while diving. m > A mechanical device, with multiple failure modes, so you would have to > carry > OC bailout anyway. > > I wonder how much noise the centrifuge makes? I wonder: 1. How you carry a centrifuge large enough to generate enough air to bet a breath. 2. How you replenish the water in the centrifuge with fresh, fully oxygenated water while it's still spinning. 3. Why any of us, who should know better, would take this article seriously. > 3. Why any of us, who should know better, would take this article > seriously. Same reason we listen to Greg, suds and the like.......for amusement, not to be taken seriously. :-) Curtis You get mail Lee? > This is either the scam of the century or a pretty ground-breaking piece > of news. An Israeli company has patented and prototyped a tankless > underwater breathing apparatus that separates absorbed gas in water. Hey Mike. If for real, wonder how it would work in water with lowered amounts of dissolved gas in it, like our playgrounds. Curtis > > This is either the scam of the century or a pretty ground-breaking piece > > of news. An Israeli company has patented and prototyped a tankless [quoted text clipped - 4 lines] > If for real, wonder how it would work in water with lowered amounts of > dissolved gas in it, like our playgrounds. Getting gas out of a liquid is hardly revolutionary. There are several things I don't see addressed which would be far more complex than reclaiming disolved oxygen from water. For instance, once one has the oxygen, how does one get it pressurized to the point at which one could actually breath it under hyperbaric conditions? Further, the article states it reclaims dissolved oxygen to 200 metres but how does one now regulate the partial pressure of oxygen; what does it get diluted with and where does the dilutent come from; and again, how does one regulate the gas pressure with ambient in order to actually have respiratory function? And so on and so on etc. -- Randy F. Milak ~I'm just working here until a good fast-food job opens up!~ > > > This is either the scam of the century or a pretty ground-breaking piece > > > of news. An Israeli company has patented and prototyped a tankless [quoted text clipped - 18 lines] > regulate the gas pressure with ambient in order to actually have respiratory > function? And so on and so on etc. Although the article mentioned oxygen, I suspect they really mean dissolved gas in general (the article also mentions "oxygen tanks," which is usually a tip off that the writer isn't too involved with diving). I wonder how well this would work around volcanic vents and other areas where the dissolved gas might not be breatheable. > Getting gas out of a liquid is hardly revolutionary. There are several > things I [quoted text clipped - 13 lines] > respiratory > function? And so on and so on etc. Which is why I'd think that a different packaging (cryogenics) will come well before a different refinery (separating gasses then recombining in proper mixes). Think I'll plan on sticking with standard OC for my diving years. Curtis > Which is why I'd think that a different packaging (cryogenics) will come > well before a different refinery (separating gasses then recombining in > proper mixes). Will come? It's all along there. The russians built an OC as well as a rebreather based on cryogneic gas/oxygen. Matthias PS: Someone some may know, in New Jersey, seems to own one. > Will come? > It's all along there. > The russians built an OC as well as a rebreather based on cryogneic > gas/oxygen. OK, will come in a safe, practical, mass produced format affordable to the average person. :-) We're not there yet. > PS: > Someone some may know, in New Jersey, seems to own one. News to me.......but really, these are just trivia items to me at this time. I found the unit I saw quite interesting, but shy of general usage status. Curtis > ... once one has the oxygen, how does one get it >pressurized to the point at which one could actually breath it under hyperbaric >conditions? Seems like if it is seperated from the water at the ambient pressuer, it would already be at ambient pressure. > ... how does one regulate the partial pressure of oxygen; what does it >get diluted with and where does the dilutent come from; I assume this is a re-breather, so the re-used gase is refreshed with the O2. But you are correct that getting the right PP O2 is an issue. Seems like some electronics are required. I'd guess you also need a small amount of gas to make-up volume as you descend. This thing may be technically intersting, but, as a practical matter I'm not at all sure. Existing, prooven re-breather technology seems to have it beat hands down. SignatureCharlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA (hammond@not@peek.ssr.hp.com -- remove "@not" when replying) All opinions expressed are my own and not necessarily my employer's. > I assume this is a re-breather, so the re-used gase is refreshed with > the O2. But you are correct that getting the right PP O2 is an issue. > Seems like some electronics are required. I'd guess you also need a > small amount of gas to make-up volume as you descend. I assume you stopped thinking before you said this. You don't get oxygen out of water by centrifuging it. I'm not even sure you can get air, but if you can, you'll get whatever other gasses are there as well. Notice that the article says nothing about decompression issues. Lee >> I assume this is a re-breather, so the re-used gase is refreshed with >> the O2. But you are correct that getting the right PP O2 is an issue. [quoted text clipped - 4 lines] >out of water by centrifuging it. I'm not even sure you can get air, but if >you can, you'll get whatever other gasses are there as well. You take gaseous uranium and spin out the U238 to enrich it. Why not do the same thing here? Those centrifuges only cost $100 million or so. >Notice that the article says nothing about decompression issues. Not to worry. The ox tox will eliminate that problem. >Lee Signaturedillon Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. >>>This is either the scam of the century or a pretty ground-breaking piece >>>of news. An Israeli company has patented and prototyped a tankless [quoted text clipped - 14 lines] > regulate the gas pressure with ambient in order to actually have respiratory > function? And so on and so on etc. Geez, dummy, ya just carry doubles filled with Helium. > >>>This is either the scam of the century or a pretty ground-breaking piece > >>>of news. An Israeli company has patented and prototyped a tankless [quoted text clipped - 6 lines] > > > > Getting gas out of a liquid is hardly revolutionary. There are several things I > > don't see addressed which would be far more complex than reclaiming disolved > > oxygen from water. For instance, once one has the oxygen, how does one get it [quoted text clipped - 6 lines] > > Geez, dummy, ya just carry doubles filled with Helium. Tankless underwater breathing apparatus... I can see it now... "Honey, hand me my tuba unit. I want to go look at the coral." > Tankless underwater breathing apparatus... I can see it now... "Honey, > hand > me my tuba unit. I want to go look at the coral." Chris, will you please pass the Windex.....got a monitor full of Oreos...... Curtis >> Tankless underwater breathing apparatus... I can see it now... "Honey, >> hand [quoted text clipped - 4 lines] > >Curtis At least I have the sense to put down the beer when I read this NG. Signaturedillon Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. > http://www.gizmodo.com/gadgets/gadgets/index.php#tankless-underwater-breathing-a pparatus-105999 > [quoted text clipped - 7 lines] > > Mike B Mike: Warning signs of bogus science: http://www.quackwatch.org/01QuackeryRelatedTopics/signs.html 1. The discoverer pitches the claim directly to the media. 4. Evidence for a discovery is anecdotal. 6. The discoverer has worked in isolation. 3/7. That's not good. Where is the peer-reviewed journal? Where are the actual results of the experiment? Saying "It was in a movie, and fish do it" with a picture of a few tubes in an aquarium is not scientific proof. Are the experiments independently verified? Until there's some science backing this up, this isn't believable. This is my first post on rec.scuba. Please don't ask me about my gear. You won't like the answer. :) SignatureMagnus McElroy Electrical Engineer (EIT) HABIT Research (250) 381-9425 > <snipity do da, snipity day...> > > This is my first post on rec.scuba. Welcome, glad to have. > Please don't ask me about my gear. > You won't like the answer. :) Ok, fess up... and don't make it short. Besides, as long as you're into force fins and spare airs, you'll fit right in around here. -- Randy F. Milak ~This message is brought to you by the committee to use professional politicians as lab animals!~ >><snipity do da, snipity day...> >> >>This is my first post on rec.scuba. > > Welcome, glad to have. Thanks. I'm from Victoria, BC, Canada. There are a lot of nice sites here, but it's cold enough to have to bundle up all year. >>Please don't ask me about my gear. >>You won't like the answer. :) > > Ok, fess up... and don't make it short. Besides, as long as you're into force > fins and spare airs, you'll fit right in around here. Okay, you asked. Integrated weight BC that I bought used for $40 because it leaked. The previous owner replaced it with a custom setup designed for a dual tank. Made the weights (34 pounds) myself out of an old shot belt. Force Fins from eBay. I figured that since it's all psuedoscience anyway, any fin was as good as any other. They were $130 CDN with shipping. Poseidon Cyklon 5000 bought used from a guy in the paper. An Air2 came with the Cyklon. $550 CDN with a computer. (Suunto Solution) Leaky 2nd-hand drysuit. It had been custom-made for a guy with my build. It fits great. I think I prefer arm leaks to leg leaks. (My previous suit has a really stubborn leak on one elbow.) Gloves / Hood are Gold Core. This might be the best $200 I've spent. I haven't got the Spare Air, but it's a planned purchase. I'll go sit in the corner. ;) SignatureMagnus McElroy Electrical Engineer (EIT) HABIT Research (250) 381-9425 > >><snipity do da, snipity day...> > >> [quoted text clipped - 14 lines] > > Integrated weight BC that I bought used for $40 because it leaked. Leaky BCD... Check. > The previous owner replaced it with a custom setup designed for a dual > tank. Previous owner saw the light... Check. > Made the weights (34 pounds) myself out of an old shot belt. Potential future lead poisoning problems... Check. > Force Fins from eBay. You're kidding? I was joking 'bout the Force fins but since you have a pair, from eBay no less... Check. > I figured that since it's all psuedoscience anyway, any fin was as good > as any other. Propulsion through water is a psuedoscience?... Check. > They were $130 CDN with shipping. Potential 'lollipop written across the forehead' tendencies... Check. > Poseidon Cyklon 5000 bought used from a guy in the paper. Life support equipment that didn't sell at a yard sale... check. > An Air2 came with the Cyklon. $550 CDN with a computer. (Suunto Solution) Cyklons and AIR2s utilize significantly different intermediate pressures. The latter is not exactly a wise combination to say the least. > Leaky 2nd-hand drysuit. Semi-dry drysuit... Check. > It had been custom-made for a guy with my build. > It fits great. I think I prefer arm leaks to leg leaks. (My previous > suit has a really stubborn leak on one elbow.) Experienced leaky diver... check. > Gloves / Hood are Gold Core. This might be the best $200 I've spent. Finally... Ever try dry gloves? Although, seems kinda pointless if the rest of your suit keeps leaking I suppose. > I haven't got the Spare Air, but it's a planned purchase. Surely you jest? > I'll go sit in the corner. ;) What for, we're haven' fun... unfortunately most of it may be at your expense, what with your gear selection criteria and so forth. :) -- Randy F. Milak ~Never question your wife's judgement...look who she married!~ > What for, we're haven' fun... unfortunately most of it may be at your > expense, > what with your gear selection criteria and so forth. :) What are you, some kind of DIR nut? Individual preference is the key to fruitful diving. > Individual preference is the key to fruitful diving. Nope West is the Key for fruitful diving. Curtis >> Individual preference is the key to fruitful diving. > > Nope > > West is the Key for fruitful diving. Oh my god. > > [quoted text clipped - 5 lines] > > Oh my god. That was pretty good, coming from a lawyer. > >>> Individual preference is the key to fruitful diving. > >> [quoted text clipped - 5 lines] > > > That was pretty good, coming from a lawyer. since a lawyer is an officer of the court, and thus part of the government, I don't think he can say that. > since a lawyer is an officer of the court, > and thus part of the government, > > I don't think he can say that. If I'm really part of the government, why don't I get the cushy work hours and the pension? >> since a lawyer is an officer of the court, >> and thus part of the government, [quoted text clipped - 3 lines] > If I'm really part of the government, why don't I get the cushy work hours > and the pension? 1. You're not part of the government unless, of course, you're a prosecuting, state's or district attorney. 2. The government doesn't get cushy work hours. Most government employees are paid on an hourly basis and are expected to work 80 hours, or more, every two weeks. Many, including me, don't get a dime for working more than 80 hours in a two week period. You, unless I'm mistaken, have work hours as cushy as you chose to make them. 3. You do get a pension. Yours is made up of Social Security, payments you made into a separate pension plan and any contributions made by your employer, including yourself if you are self employed. The current government retirement plan is made up of Social Security, payments the employee made into a separate pension plan and any contributions made by his employer. The old government retirement plan, which I'm under, is made up of contributions I made into a separate pension plan and any contributions made by my employer. Lee >>>> Individual preference is the key to fruitful diving. >>>> Nope >>>> West is the Key for fruitful diving. >>>> That was pretty good, coming from a lawyer. OK, first, it was not the lawyer that came up with the great line. It was Curtis. > since a lawyer is an officer of the court, > and thus part of the government, > I don't think he can say that. Second, the prosecutor in a criminal case is a part of the government. He represents the state. The defense attorney, even a public defender, is not a part of the government for the duration of the trial. Third, Attorneys seem to be able to say whatever they like. The whole truth does not appear to be part of their responsibilities. Lee > >>>> Individual preference is the key to fruitful diving. > [quoted text clipped - 17 lines] > Third, Attorneys seem to be able to say whatever they like. > The whole truth does not appear to be part of their responsibilities. and thus you win "The Laugh of the Day Award" !! (even more, truth is an alien concept to them.) > Lee > > Individual preference is the key to fruitful diving. > > Nope > > West is the Key for fruitful diving. and thus you win "The Laugh of the Day Award" !! > Curtis snip >>>>Please don't ask me about my gear. >>>>You won't like the answer. :) [quoted text clipped - 6 lines] >>Integrated weight BC that I bought used for $40 because it leaked. > Leaky BCD... Check. It was a really tiny leak. I fixed it with some Cotol-240 and Aquaseal. >>The previous owner replaced it with a custom setup designed for a dual >>tank. > Previous owner saw the light... Check. He's a tech diver. I've heard that they're picky. >>Made the weights (34 pounds) myself out of an old shot belt. > Potential future lead poisoning problems... Check. No, my irratibilty is from the stress of buying a house and moving. The hyperactivity is from too much sugar. The weight loss is from walking / biking to work. At least I hope it is. By the way, why is this old paint so tasty? >>Force Fins from eBay. > You're kidding? I was joking 'bout the Force fins but since you have a pair, > from eBay no less... Check. I'm not a Force Fin zealot or anything. They're all right underwater. They're kind of useless on the surface. >>I figured that since it's all psuedoscience anyway, any fin was as good >>as any other. > Propulsion through water is a psuedoscience?... Check. Oh no, hydrodynamics is a real science. Drawing arrows next to a picture of the fin and saying "It's more awesome" is psuedoscience. Everyone says that their fins are more efficient or more powerful or something else. Odds are it's all marketing. >>They were $130 CDN with shipping. > Potential 'lollipop written across the forehead' tendencies... Check. I'm sorry, I don't understand this reference. On a related note: don't google for "lollipop and forehead" at work. >>Poseidon Cyklon 5000 bought used from a guy in the paper. > Life support equipment that didn't sell at a yard sale... check. I got it checked out and serviced before I bought it. The Cyklon repair kit bascially replaces everything inside, so it's like new once it's been taken care of. The problem was that the previous owner didn't rinse it well enough. The dealer taught me how to rinse correctly and I've had no problems with it. Uh, except the Air2, but I get the feeling that you guessed that. >>An Air2 came with the Cyklon. $550 CDN with a computer. (Suunto Solution) > Cyklons and AIR2s utilize significantly different intermediate pressures. The > latter is not exactly a wise combination to say the least. Yeah, it's a little... finicky. I'd provide a more detailed description, but I'm not sure exactly how to combine the words "boneheads" and "scubapro" into one word. (I've got a 16-month old so I have to watch my language.) >>Leaky 2nd-hand drysuit. > Semi-dry drysuit... Check. I prefer "hybrid". The last one was so bad I had to wear a wetsuit under the drysuit. >>Gloves / Hood are Gold Core. This might be the best $200 I've spent. > Finally... Ever try dry gloves? Although, seems kinda pointless if the rest of > your suit keeps leaking I suppose. As you said, there's not much point. I might as well keep my hands warm. >>I haven't got the Spare Air, but it's a planned purchase. > Surely you jest? Am I joking? It's hard to tell, isn't it? You should see me in real life. What's the problem with them? I can't find any unbiased information on them. You know, like the unbiased info I was able to find on the fins, regs, Air2, etc. >>I'll go sit in the corner. ;) > What for, we're haven' fun... unfortunately most of it may be at your expense, > what with your gear selection criteria and so forth. :) Hey, no problem. If I can't laugh at myself (or more importantly, my gear) then what the hell am I doing here? I knew that I'd manage to offend just about everyone with my gear. Right now I'm sure there's someone composing a well-thought and articulate response out response begging me to "reconsider my kit or at least get life insurance". More likely, nobody cares. It's my first set of gear. I've managed to get everything for under $2000. That's pretty good. There are things that I want to replace, but I simply can't afford to...yet. > -- > Randy F. Milak > ~Never question your wife's judgement...look who she married!~ SignatureMagnus McElroy Electrical Engineer (EIT) HABIT Research (250) 381-9425 <snip> >>> I haven't got the Spare Air, but it's a planned purchase. >> [quoted text clipped - 5 lines] > them. You know, like the unbiased info I was able to find on the fins, > regs, Air2, etc. Just do the calculations the numbers won't lie. John > <snip> > > [quoted text clipped - 9 lines] > > Just do the calculations the numbers won't lie. Here's Dave Waller's venerable summary from the FAQ: http://scifi.squawk.com/scuba.html#PONY_HOWMUCH Since accepted ascent rates are now 30ft/min instead of 60ft/min, this adjustment needs to be made to Dave's numbers...simplistically, it would cause them all to not quite double vs what is listed. Have fun, Magnus...let us know what your numbers reveal. -hh > > > What's the problem with them? I can't find any unbiased information on > > > them. You know, like the unbiased info I was able to find on the fins, [quoted text clipped - 11 lines] > > Have fun, Magnus...let us know what your numbers reveal. I've taken a stab at reproducing Dave Waller's original calculations in a similar format, with the ability to modify the inputs to whatever the Contingency Planning diver wants to use. Here's an example with a 30ft/min ascent rate, and IMO very liberal assumptions on the diver's stressed SAC rates: http://www.huntzinger.com/dive/spare_air_bailout.html The spreadsheet that allows data entry is at: http://www.huntzinger.com/dive/spare_air_bailout.xls This is version 1.0, so if anyone finds a mathematical error in it, or wants to suggest a different method of modeling calculation, please let me know. -hh > Drawing arrows next to a picture of the fin and saying "It's more awesome" > is psuedoscience. Everyone says that their fins are more efficient or more > powerful or something else. Odds are it's all marketing. More powerful has no meaning since it is the diver that provides all of the power. More efficient, however, has considerable meaning. What the advertising says may be all hype, but there are differences. My wife's Mares Avanti fins are more efficient than the Cressi Rondines I had prior to switching. My Mares TRE fins are slightly more efficient than her Avanti's. The difference is not enough that she'll upgrade until she wears her Avantis out. My Quatro Power fins require more power from me to work effectively. The net result is more power out, but it may or may not be more efficient. > Uh, except the Air2, but I get the feeling that you guessed that. > Am I joking? It's hard to tell, isn't it? You should see me in real life. > > What's the problem with them? I can't find any unbiased information on > them. You know, like the unbiased info I was able to find on the fins, > regs, Air2, etc. The cost is too high for the minimal benefit. They cost darned near as much as a much larger tank and a better quality regulator. > It's my first set of gear. I've managed to get everything for under $2000. > That's pretty good. There are things that I want to replace, but I simply > can't afford to...yet. My first tank, backpack and single hose regulator cost me $89, brand spanking new. Lee >>><snipity do da, snipity day...> >>> [quoted text clipped - 33 lines] > >I'll go sit in the corner. ;) You're going to fit right in. Welcome to rec.scuba! Rick Simms ************************************************* Shortest fairy tale ever................ Once upon a time a guy asked a girl "will you marry me" She said" no" And the guy lived happily ever after. >http://www.gizmodo.com/gadgets/gadgets/index.php#tankless-underwater-breathing-a pparatus-105999 > [quoted text clipped - 7 lines] > >Mike B Rapidly spinning centrifuge? That's exactly what I want underwater, a gyroscope. It's pretty early in this century to call something the scam of the century, but right now I'm sure it's scam of the year and might make scam of the decade. Last century's scam was the Moeller Air Car. "I want my flying car" Signaturedillon Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. > http://www.gizmodo.com/gadgets/gadgets/index.php#tankless-underwater-breathing > -apparatus-105999 > > This is either the scam of the century or a pretty ground-breaking piece > of news. O2 extraction from seawater isn't hard...its just an Osmosis transfer. But what is hard is having enough water surface transfer area with a flow rate that will let you extract enough O2 per minute to allow a 200lb mammal to survive on. Oh, and have it in a package that's small enough to allow it to still be swimmable by its user. Back when Popular Science magazine published in a 3/4 size magazine format (yeah, around 30 years ago), they published an article on a "artificial gill" that the US Navy had been experimenting with. Remember the cartoon that Steam Machines used for their rebreather? The one where the device was as big as the diver? Here it is: http://www.steammachines.com/images/smallguy.jpg Yeah, that's about the order of magnitude that USN's "gill" system from 30 years ago looked like...only fewer rounded corners, since they didn't really have injection-molded plastic technology yet :-). Pragmatically, most of what you're doing here is trading-off one medium of stored prime power for another. Here, its an onboard electrical battery to run the gill to generate O2, versus a compressor back on shore that packaged your O2 for you, pre-dive. Both technologies have unavoidable failure modes, additional complexities (such as makeup volume for depth changes) and so forth, and to maximize their efficiencies, both would be inclined to use a closed circuit. What it really comes down to is that there needs to be a better packaging efficiency for an osmosis system and maybe this approach does address this, through their centrifuge concept, but Dillon's comment that you're now wearing a gyroscope is quite astute. Overall to me, this looks like YA example of a "It works, but is it really worth anything?" science project. -hh >> http://www.gizmodo.com/gadgets/gadgets/index.php#tankless-underwater-breathing >> -apparatus-105999 [quoted text clipped - 7 lines] > flow rate that will let you extract enough O2 per minute to allow a > 200lb mammal Speak for yourself :-) >to survive on. >> But what is hard is having enough water surface transfer area with a >> flow rate that will let you extract enough O2 per minute to allow a [quoted text clipped - 3 lines] > >>to survive on. OK, a 320 lb mammal. Curtis > http://www.gizmodo.com/gadgets/gadgets/index.php#tankless-underwater-breathing-a pparatus-105999 > [quoted text clipped - 7 lines] > > Mike B Lugging the weight of the scuba tank is one of the worst things about diving. It would be great if it works and would open up the sport to a lot more people. Adam > > http://www.gizmodo.com/gadgets/gadgets/index.php#tankless-underwater-breathi > > ng-apparatus-105999 [quoted text clipped - 18 lines] > > Adam Issues of physics aside, what makes you think this is going to weigh any less than a tank? > ? "Michael Blitch" <@oasisofficepark.com> wrote in message > ? news:boEne.90955$w15.18831@tornado.tampabay.rr.com... [quoted text clipped - 26 lines] > Issues of physics aside, what makes you think this is going to weigh > any less than a tank? The reason for the weight is to contain all the high pressure gas. This is a physics limitation and cannot be overcome as long as you have to carry all the gas in one bottle. A tankless system does not have to face this. Adam >> ? "Michael Blitch" <@oasisofficepark.com> wrote in message >> ? news:boEne.90955$w15.18831@tornado.tampabay.rr.com... [quoted text clipped - 32 lines] > >Adam But where do you get the juice to spin the centrifuge? A 12 volt battery is pretty heavy. The DMs for Severns carry some pretty huge lights and the batteries are strapped to the tank. And they wear no weights. Signaturedillon Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. >>> ? "Michael Blitch" <@oasisofficepark.com> wrote in message >>> ? news:boEne.90955$w15.18831@tornado.tampabay.rr.com... [quoted text clipped - 38 lines] > lights and the batteries are strapped to the tank. And they wear no > weights. It's a good thought. The article mentions that a one kilo lithium battery should provide the power for one hour of diving, which may be far fetched, who knows. Also a battery is heavy but small and does not change buoyancy like a tank. It can take the place of a diving weight. Adam > It's a good thought. The article mentions that a one kilo lithium battery > should provide the power for one hour of diving, which may be far fetched, > who knows. You know. You've been around long enough to be able to figure this one out. Just how much air do you suppose is in a given volume of water? The gills that, according to science magazines of my youth, should have been available many years ago, simply did not work because there were not enough gas in the water that could be processed, to sustain life in a human. That hasn't changed. Lee > You know. You've been around long enough to be able to figure this one > out. Just how much air do you suppose is in a given volume of water? The > gills that, according to science magazines of my youth, should have been > available many years ago, simply did not work because there were not > enough gas in the water that could be processed, to sustain life in a > human. That hasn't changed. I thought you're so hot about your low air consumption. Maybe it's just not low enough. > I thought you're so hot about your low air consumption. Maybe it's just > not low enough. Others seem to worry about my air consumption a lot more than I do. I just do it. You're right. My consumption is not low enough to survive on what I can get out of the water. I have to tell you, I'm quite disappointed. I've been waiting for human gills for a long time. Looks like I'll have to wait a while longer. Lee >> I thought you're so hot about your low air consumption. Maybe it's just >> not low enough. [quoted text clipped - 8 lines] > >Lee They'll be along about the same time as your flying car. Signaturedillon Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. > They'll be along about the same time as your flying car. Interestingly, I clearly recall a Mechanics Illustrated or perhaps a Popular Science article that led me to believe that a flying car already existed. Perhaps my mind is playing tricks on me, but I just assumed that traffic control was the primary reason we don't have them already. Lee > > They'll be along about the same time as your flying car. > [quoted text clipped - 4 lines] > > Lee Yeah, so many people can't even handle 2 dimensional driving. (with or without a cellphone or other distractions). SignatureMy diesel truck has been modified to run on an environmentally friendly mixture of clean burning Caribou fat and whale oil. "Tolerance is the virtue of a man without convictions" G.K. Chesterton >> > They'll be along about the same time as your flying car. >> [quoted text clipped - 7 lines] >Yeah, so many people can't even handle 2 dimensional driving. >(with or without a cellphone or other distractions). A couple of years ago we rented a Volvo S80 from Hertz and got NeverLost. The guy at the counter told us about one customer who drove through the wrong part of a T intersection while he was head down looking at the display to see where he was. Something about a mirror and a flashlight. Signaturedillon Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. > > They'll be along about the same time as your flying car. > [quoted text clipped - 4 lines] > >Lee Look up Moeller Flying Car. And while you're at it, look up SEC Complaints Against Moeller Flying Car. They've been promising the thing for 6 years now, don't even have a flying prototype. Go to any of the rec.aviation NG and ask. But be ready for the laughter. Ask at rec.aviation.homebuilt. Those guys are great fun. In addition to building their own planes, they make their own guns and brew their own beer. Or other beverages made from fermented grains, heated and passed through a condenser. One running joke is about drinking and smoking while shooting guns. Seems they even have a federal agency for that. Signaturedillon Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. > > ? "Michael Blitch" <@oasisofficepark.com> wrote in message > > ? news:boEne.90955$w15.18831@tornado.tampabay.rr.com... > > ? > > > ? > http://www.gizmodo.com/gadgets/gadgets/index.php#tankless-underwater-breathi > > ? > ng-apparatus-105999 > > ? > [quoted text clipped - 26 lines] > limitation and cannot be overcome as long as you have to carry all the gas in one > bottle. A tankless system does not have to face this. Let see, centrifuge, batteries, emergency air supply weigh.....how much? :-) lets see what the full-scale mockup will look like.m Dennis > Adam > > Issues of physics aside, what makes you think this is going to weigh > > any less than a tank? > > The reason for the weight is to contain all the high pressure gas. > This is a physics limitation and cannot be overcome as long as > you have to carry all the gas in one bottle. Actually, the "problem" in regards to an aluminum or steel tank weighing 30+lbs has been overcome with composite tanks...however, it introduces another little nasty physics limitation in that since the tank displaces water, the weight savings from a composite tank had to be made up with a commensurate increase in the diver's weightbelt. > A tankless system does not have to face this. Actually, it does, for no matter how you get your breathing media, you have to have some sort of holding vessel for at least "one full lung's worth", plus you have to figure out how to supply additional makeup volume from 1 ATM to at least 6 ATM for rec diving, and to 20+ ATM for their 200m depth claim. The implication is that if you're not carrying a compressed gas tank for makeup gas, then you're going to very strongly limit the diver's maximum descent rate. In any event, at a steady-state depth, a diver's still gotta breathe, so you're going to have to "rebreather" his exhaust and then reconstitute it with your gill to be the scrubber. As such, you're going to need a counterlung like system, and because this is all going to work by the diver's exhaust pressure and the gill by Osmosis, it *has to be* operated at ambient pressure, unless we're going to add a tiny compressor system and eve more battery power to our rig to run it. Since its not a high pressure source like an OC tank's supply, it will occupy more volume (and displace more water) than we would otherwise expect based on our OC experiences. Insofar as how much media this working loop needs, its total volume is going to be greater than a simple lungfull, since there's lots of plumbing and surface area involved with the Osmosis process...simplistically, if we just KISS and SWAG it and say "one average Vital Capacity from a human", then we'll have ~5 liters of air/gas and since it is at ambient pressure, this means that it will be displacing roughly 10lbs of seawater...the 2.2 lbs of negative bouyancy from our 1kg battery is easily floated, plus more. -hh >>Issues of physics aside, what makes you think this is going to weigh >>any less than a tank? > > The reason for the weight is to contain all the high pressure gas. This is a physics > limitation and cannot be overcome as long as you have to carry all the gas in one > bottle. A tankless system does not have to face this. Nope. The reason for the weight is to offset the buoyancy, which is a function of volume. If the tankless system requires the same volume as, say, an Al 80, it will have to weigh the same. >>>Issues of physics aside, what makes you think this is going to weigh >>>any less than a tank? [quoted text clipped - 8 lines] > If the tankless system requires the same volume as, say, an Al 80, it will have to > weigh the same. That's an interesting way of looking at it. I believe the weight of the tank is due to material strength considerations, but you have a point, for even if there was a light-weight strong material for the tank you would have to take extra weight to make up for the difference. You would have a balloon on your back. So hopefully the volume of the tankless system can be made small. Adam > Lugging the weight of the scuba tank is one of the worst things about > diving. It would be great if it works and would open up the sport to a lot > more people. Why do you lug your own tank? Get some sucker to do it for you. You think smart golfers lug their clubs around the course? > Why do you lug your own tank? Get some sucker to do it for you. You > think smart golfers lug their clubs around the course? Hmmm, glad nobody I know ever thought about that....... Curtis > Lugging the weight of the scuba tank is one of the worst things about > diving. It would be great if it works and would open up the sport to a lot > more people. Yeah, that's why I use my little dub 80s, cuts down on weight, easier to overhead don. ;-) Curtis > Yeah, that's why I use my little dub 80s, cuts down on weight, easier to > overhead don. ;-) Sidemount 72s... |
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