O2 tanks of divers

Divers usually use normal atmospheric air accept in some cases when oxygen enriched air is used (upto 36% oxygen). So most of the time divers have 21% oxygen, 78% nitrogen, and 1% "other" a small part of "other" does contain helium in normal atmospheric air.

Oxygen mixtures above 50% oxygen are toxic at sea level and become more toxic the deeper underwater you go (pressure related)

It's odd how the very things we rely on to keep us alive can so easily kill us if they just get the chance. O2 and H2 O.

But astronauts in the Apollo program, didn't they using 100% oxygen?, and what about fighter pilots? I think they use pure oxygen as well?

Astronauts do use 100% oxygen, but like I said its a pressure related thing. How much pressure is there in space???

http://history.nasa.gov/Apollo204/

The link gives a good reason to never use 100% O2 in a confined space.

Current atmosphere profile is 14.7 PSI, with 79% nitrogen and 21% oxygen mix.

I love Wiki. Here is some good information about Breathing Gases. I hold my open water certification but have never trained for mixed air dives so Wiki and the books is my source of info.

Yes, deep divers use heli-ox. At the depths that oil well divers work they not only use heli-ox, but also have to enter a diving bell to make long off gasing stops on the way up. Then enter a re-compression chamber to prevent the bends.

The reason they use helium is that it off gases nitrigon quicker then oxegon.

I guess you mean de-compression chamber.

Nitrogen in the compressed air tank gets absorbed in the blood. You need decompression to prevent this nitrogen to get un-absorbed at a very low rate and that too in normal breathing process nit in blood streams to prevent blood clots around the nitrogen bubbles, which can kill you.

I thought helium replaced most of the nitrogen because it came out of solution in the blood much easier than nitrogen?

No I mean a re-compression chamber, you have been watching too many movies.

They need to re-compress your body in order to shrink the gas bubbles that may block an artery, or cause a Brain hemorrhage, or even an air embolism that could kill you.

When a diver breaths compressed air at a given depth, then ascends to a shallower depth, the air that was breathed at a higher compression rate has less outside pressure, thus allowing that air to expand in your blood stream, and causing the bends. This is why they re-compress you, thus making the bubbles shrink until you can off gas them. Well it's been awhile since a gave a dive class. This one is free.

Current bell diving practice is that divers do not make long off gassing stops on the way up, the bell is locked off and brought up asap and docked with the decomp chamber where the divers are safely decompressed

For pilots, they usually require 100% oxygen over 10,000 feet - that is usually sent at atmospheric pressure. They can go higher, but only for limited amounts of time. For emergencies, at least for military types, the oxygen is forced into the lungs at high pressure - easy to fill the lungs, then the pilot must forcefully exhale to complete the exchange - not too difficult, but has to be learned (paradoxical breathing). At very high altitudes, the gas exchange will not work even with the oxygen being pressurized - it just tears up the lings. The pilot must then be in a pressure suit or suffer hypoxia and worse. Usually pressure suits are worn when going above 50,000 feet. Pressure suits (think spacesuit) pressurize the entire body and allow oxygen exchange to occur, and should not be confused with the pressure pants worn by fighter pilots - they are used to force the blood out of the legs and up into the critical organs during certain flying maneuvers to prevent blacking out.

Now think back to the Challenger disaster - the launches had become so mundane that the crew were in jump suits as opposed to pressure suits. When the orbiter suffered it's catastrophic failure, they wouldn't have been able to breath even if they were able to get their bailout bottles and masks on because they were over 70,000 feet when they lost their atmosphere. One crew member did in fact manage to get a bailout bottle mask over his head before becoming too hypoxic but it was to no avail. When they descended below 50,000 feet, they likely would have starting regaining consciousness (depending on the person, likely somewhere between 35,000 and 50,000 feet) but would probably have been suffering from hypoxia so bad they would not have been able to function. Tragically NASA has learned a hard lesson and now you will see the astronauts will always be in pressure suits when boarding the orbiter. They have their visors down and are on 100% oxygen before the launch.

When I was in the military we used to "pre-breathe" before going over 18,000 feet - a pre-detirmined length of time breathing 100% oxygen to allow the body time to off-gas a large percentage of absorbed nitrogen so we wouldn't get "bent" - the same as can happen with SCUBA and working divers. Same physics, same gas laws.

Very well put. Being a dive control specialist I also had to learn these gas, and atmosphere laws in my basic lessons. If you use them wisely they will save your life, if not they will take it.

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In reply to your question NO oxygen tanks do not contain any other gasses except oxygen.

Air tanks contain air

Mixed gas tanks contain specified mixtures very carefully checked.

Years ago when I took a diving course, I remember them explaining that helium is used in deeper dives because it suitably replaces nitrogen as a dilutant of oxygen. It's necessary because of a medical problem called nitrgen narcosis which affects thinking, making one giddy and reduce one's good judgement.

What i get from ur post, is that previously N2 was used but nowadays it's being replaced by He, bcoz of He can prevent bends, as well as is inert n thus, most appropriate to mix with O2 in the divers' tanks.

I hope I get you correct.

well I guess I'll have to clarify that there are two main illnesses that nitrogen causes.

1. The first problem that a diver faces is nitrogen narcosis. This is basically underwater drunkenness. Divers have been known to remove their regulator from their mouth thinking that they can breath without it. they have also been known to chase immaginary mermaids into dangerous depths, and die from running out of air, or being crushed from the pressure.
2. Not being able to out gas the nitrogen that has built up in the blood, and organs is just as bad if not worse. the best way to describe this is it's like shaking a warm beer, and then opening it. this is what nitrogen does in your blood under pressure, when you come up to fast, or stay at a deep depth to long letting the nitrogen build up to long. unless you have a bunch of extra tanks waiting for you at the proper depth stops, that allows you to off gas the nitrogen safely. you will need to be put in a re-compression chamber a.s.a.p. if you don't die first.~

I think the question people are asking is: TV talks about using a mixture of helium with oxygen. TV says it's because helium comes out of solution from within the blood much easier and faster without causing the formation of bubbles. So, diving with this mix is safer because nitrogen narcosis occurs at lower depths, and a somewhat faster recovery in decompression. True? If yes, then that's why deep divers on TV talk like the Chipmunks?

Also, what about that oxygen-holding liquid thing? Where it let you dive really deep. Just Sci Fi?

And, of course, "Party on Wayne! Party on Garth!"

About the 1st problem:

Is it somethind like the 'anoxia', climbers suffer from, due to less O2?

I can answer this one... No. Climbers suffer from lack of oxygen in the rarefied atmosphere on high mountains. Kind of creepy, but they've done studies of the brains of climbers who go to places like Everest and K2. When CAT scanned, they show a measurable lose of brain size caused by their climbs killing off brain cells! Woof!!!

thats crazy, the thing they love the most is killing them in more ways then one.

a great movie to watch thats is based on this illness, yet great on action, and special effects is "vertical limit"

Did you ever see the film about the two guys that successfully climbed Mt. Everest without oxygen? They practiced for several years (I think) before making their assent to the top.

The really bizarre part about this movie is when the group is in the tent in the last camp before the summit, one of the two guys whips out a pack of Marlboros and lights up! I swear to God!!! I wonder how much Philip Morris had to pay for that bit.

That's OK, but what I was talking about, was the thing about losing consciousness, ... chasing mermaids (not in here!!), ... n stuff.

But, well this info is new n quite interesting, too, though it's beyond my comprehension that why wasn't this heard of, before. I mean, that if this is the case, not many, "life-philic" people wud opt for this profession or whatever!!!

your point is not well received. what are you babbling about. you don't have a subject, or a complete sentence here. what???????????????

Sorry! Actually, I was in a hurry n just scrambled whatever raced in my mind!!

Anyways, perhaps vermin got it. But I was talking about the similarity b/w loosing consciousness at higher n lower altitudes.

I hope you get it, now!

thank you for clearing that up, I wasn't sure what you was talking about.

have a great day.

I think that even on pure oxygen on the side of Everest, there's no frolicking around. At best, you're thinking "What the hell am I doing here!!!" And about all you want to do is lay down and die!

What the heck! You're in India, go North and climb a mountain. See for yourself how high you can get (even with O²) before suffering from altitude sickness.

Yeah, I did go north 2 months back n perhaps I did suffer from the alt sickness!

But, I wasn't grasping for air, coz the place wasn't at very high altitude!!

{It's O₂ and not O².}

I was using the Empirical form of the noun.

One of the reasons that you have to go to dive school.

If a tank is marked oxygen it contains oxygen and is used for a 'rebreather` rig.
(They're kinda rare these days)

If a tank is marked air it contains compressed air, (normal ratios), and is
used for standard pressure regulator systems, (aqua lungs).

There are tanks filled with oxygen-helium mixtures for deep use of aqua lung
type gear to avoid nitrogen poisoning, (narcosis), below about 100' or so.
These should be specially marked. The ratios vary with the intended depth.
(Caution - this is 'pro` country.)

Thank you!

The only mistake a few people are still making is to say de-compression, When in order to save a diver that suffers from nitrogen poisonings life, is to put him in a re-compression chamber. This as stated above will shrink the out gassing bubbles allowing the bubbles to pass threw the blood vessels, rather then blocking them, thus saving your life instead of allowing you to die. Also The reason for heli-ox is by the time you reach 100' with a normal aqua-lung you would have to turn around and start back up shortly to prevent the very illness we just talked about.

You've got the process right, but ignore that the final object of treatment
is to get the diver back to normal atmosphere without the bubbles.
After he is 'recompressed`, he is then 'decompressed` under control.

I think 'decompress` expresses that well enough.

Dear dummy,

call the hospital and ask a tech. the machine is call a re-compression chamber no matter what your finite brian wants to tell you it's wrong!

The terms are mutually interchangeable but divers normally refer to them as a deck decompression chamber DDC.

I am a dive control specialist with 25 yrs of diving, and we laugh at nubees that call it a de-compression chamber, so don't try to tell me what divers call it.

We call it what it is. thats like calling a car a motor box.

Mate you should do a bit more studying. 36 years ago I was helping design the worlds first commercial saturation diving complex and we and most other people called it a deck decompression chamber. But like I said the terms are interchangeable depending on the particullar function at the time

As far as hospitals are concerned they are Hyperbaric Chambers to do with as they wish.

hay matie

what does it do? it's first function is to re-compress, hospitals use it mainly for people who are suffering from co2 poisoning. it allows them to shrink the air bubbles that are carrying co2 in large amounts threw the body, thus introducing pure pressurized oxygen to offset the co2!!!!!!!!!!!! Hyperbaric Chambers is also a correct term, but de-compression is it's last function in the process.

another way to put it is we drive our cars but the last thing we do is get out, we don't call it a get out vehical.

And what about that liquid stuff that you're supposed to be able to breath? Purely Sci-Fi???

Experiments have been done with mice breathing oxygenated liquid, they have survived this process but for how long after I am not sure.

The theory is that the liquid replaces the inert carrier gas hence no decompression problems.

To date I do not know of any diver volunteering [ understandably] for this process, the mechanical effort of breathing this liquid would be to great and the possibility of infections etc to risky, the body is not designed for this otherwise we would have had gills

Point taken!

this is a promising research. the basis for this research is the way a baby receives o2 from it mothers embryonic fluids. it's lungs are filled with it.

Point of information:

A fetus receives its oxygen, direct to the bloodstream via the placenta
and umbilical cord. Its lungs are collapsed and don't work untill after birth.

Thanks I was growing weary!!

"Party on, Garth!!!"

I do know that the Navy was doing something in regard to diving and a breathable liquid. Not like on the movie, "The Deep," but something like it.

Also, the Navy was working on a pressurized diving suit, much like wearing a metal can that had possibly unlimited depth capabilities? Of course, not on Venus (even at sea level).