what is in a scuba divers tank is it pure oxgen?

Question

if a mix then what is the mix

Answer 1

Lol, lachicadecafe. Ok..I will.
The only pure O2 a diver inhales is on the deck, in trouble. It's only use in an actual dive is to keep a diver alive that's taken a DCS hit and he's lying at your feet.
Other than that, it IS used in other concentrations as a breathing mix.
The most common mix is exactly what you're breathing now, 21% O2, 78% N and 1% trace gasses. It only differs in that it's stored and delivered to the diver under pressure. Typically an 80 cuft Aluminum recreational tank is charged with normal air to 3000 PSI ( nice little bomb). That amount of air is about equivalent to the amount of air in a typical closet. If the fill station attendant knows what he's doing, sometimes you can get what we call a hot fill, and get up to 4200 PSI (more air), but it's a dangerous practice. More than one dive shop has blown up this way. Some twice.
The next most common mix is called Nitrox or enriched air. It's O2 content is higher than what you are breathing now. A typical, all round mix, diving Nitrox is a 32%. That's 32% of that tank being O2. A nitrox mix can go up to 40%, but usually people don't go for more than 36%. Nitrox is more expensive than air, it has some good points and some bad ones. It is a good gas, if you are diving shallower depths. Yup, shallower. The higher the % of O2, the shallower the dive has to be. A 32 mix, for example, can't be dived deeper than 120 ft. Go to 125 ft and you're dead. Just like that. It's called oxygen toxicity and sends you into convulsions as your central nervous system crashes.
Nitrox is used instead of compressed air, when you want to extend your allowable bottom time before sliding into no decompression limits, placed on recreational divers. It lessens the nitrogen load your body is absorbing to let this happen. It can really only be used cost effectively at between 100 ft up to 70 feet or so. If the dive is either above or below this, it's gonna hurt someone or just cost more than it needs to money wise.
Tri mix (my fav) is used by technical divers only. It's a gas mix that's hypoxic. It has a lot less O2 in it than normal air. It can actually be as low as 6%. The other gasses it contains are helium and a little nitrogen. If you breathed it with a full face mask, on a boat deck, you'd be out cold in a minute. At depth, it's fine. It has to do with the behaviour of gasses when breathed under partial pressures. A typical mix, I'd use for a dive to 300 feet is 10% O2, 70% helium, and 20% nitrogen. This mix allows for a max out to around 340 feet and breathability back into the compressed air zone of 160 feet for me. I get really silly deeper than that. It's all that nitrogen talking.
A diver can actually employ all three types of gas mixes on a dive. He can use compressed air as a travel gas to get to 150 ft ( we don't tend to get narc'd to the point we're useless), then go to trimix for the bottom portion of the dive. Watch the clock and start our ascent doing our mandatory deco stops until we get back to 150, swap over to normal compressed air for our travel to the next deco, which if we planned it right, ought to be above 120 ft then swap gasses again to Nitrox this time, continue the ascent and our decos. We tend to like using nitrox last, because it's in it's safe use zone then and it's higher O2 content helps get the nitrogen load we've taken on, gone faster. If we really want to cut down on deco, we can employ a pony bottle of 40% -50% O2 on our next to last stop to speed up the deco even more.There's only so much scissors, rock, paper , hangman or X's and O's you can play hanging on a line for 2 hours. All of this takes extensive planning before the dive, diving the plan and ocassionally some calculations on the fly. It's not something to try unless you have been properly trained. There, had to get that in or someone would try this ,kill themselves and I'd get sued.

Edit: Lachic, yup, I have that book on my shelf. Had the pleasure of meeting John Chatterton who was on the boat that day a few years back at a lecture. He's a God in the tech community. Tech diving isn't dangerous per se, there are just a lot more rules to follow and equipment to own. It's all about managable risk. The Chris' were doing their dives before any techniques were really taught. They didn't use trimix on that occasion, they deemed it too expensive and paid the price in the worst way.

Answer 2

It's compressed air. Same air as you breathe on the surface, just compressed so it can fit in that little tank. The diver's regulator de-compresses the air on demand.

There are special helium mixes for deep prolonged diving, but that is for very unusual situations.

Fish (the scuba diver)

Answer 3

Most recreational divers use compressed air in their tanks, but there are also divers who use nitrox or trimix, which are gases. I don't know that much about them, but I bet sooner or later scubabob will come along and tell you!

See, I knew he would be!

Thanks for the info, scubabob! This little OWD always learns a lot from you. I think you're awfully brave to do the kind of diving that you do, although I know you've been trained for it. I've read stories about divers who have not used trimix for deep, deep dives and have gotten narced out of their minds, that's scary stuff! (The Last Dive, about Chris and Chrissy Rouse... sad story, I'm sure you know what I'm talking about.)

Answer 4

Because left-handed, colorblind. lesbian scuba divers never get sick. Those that seem to aren't really colorblind, they just cheat on the test. Prove me wrong. The real question is why there are any christian hospitals. If you believe what Jesus taught, if you believe the bible, prayer can cure all things. Medicine is just scientific clap trap on the level of evolution.

Answer 5

no it is normal air only that is compress so ypu can have big volumen of air in a small container pure oxigen cannot be use to dive cause it will be poison from 12 feet down . in some cases you can put some mix of gas but never pure oxigen

Answer 6

It varies, but it's usually 21% oxygen (same as the atmosphere). The rest is usually nitrogen. Pure oxygen can be poisonous.

Answer 7

no its not pure we would die the mix is 78% nitrogen 21% oxygen and 1% other just like our air

Answer 8

Unless it is a deep dive suit it will usually be what we breathe. 78 % Nitrogen, 21 % Oxygen, and 1% other gases.

Answer 9

just regular air, just like we breathe