eweingarden
Contributor
Can I use one tank to fill with air on some dives, and Nitrox for other (deeper) dives? Thanks.
One Tank for Air and Nitrox
- Thread starter eweingarden
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Short answer: Yes and no!
Long answer: It depends on how the gas is being produced.
Partial pressure blending requires that your tank is oxygen cleaned, while banked nitrox does not. So in theory, if the nitrox is banked you could use any tank. Although I have run into shops who require that your tank is oxygen cleaned to get a nitrox fill even though they bank nitrox.
Long answer: It depends on how the gas is being produced.
Partial pressure blending requires that your tank is oxygen cleaned, while banked nitrox does not. So in theory, if the nitrox is banked you could use any tank. Although I have run into shops who require that your tank is oxygen cleaned to get a nitrox fill even though they bank nitrox.
as long as the enriched air is banked
and all the rest of the stuff you learned in your class is held to
remember the residual enriched air!
no ox/tox.....
have fun
yaeg
and all the rest of the stuff you learned in your class is held to
remember the residual enriched air!
no ox/tox.....
have fun
yaeg
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The validity of the "oxygen clean status" of a cylinder is always questionable, but that's not what you asked.
Here's an interesting article to ponder on the point:
Oxygen Clean - Is a Myth ADVANCED DIVER MAGAZINE By Bart Bjorkman
Here's an interesting article to ponder on the point:
Oxygen Clean - Is a Myth ADVANCED DIVER MAGAZINE By Bart Bjorkman
Actually, you can have tanks used for both partial pressure blending and air fills, as long as you have the right kind of air. Let's look at how partial pressure blending is done to see why.
Step One: Add the appropriate amount of oxygen to the cylinder.
Step Two: Hook the cylinder up to your compressor and top it off with air.
If you just want to have air put in your oxygen clean cylinder, tell them to skip step one.
This works if the air coming out of the compressor has been adequately filtered. If a shop is giving you nitrox through partial pressure blending, that means they believe the air they are pumping is pure enough for that purpose. If it is pure enough for that purpose when they are blending the nitrox, it is pure enough if they are just filling your cylinder with air.
A lot of shops don't know that, though.
Step One: Add the appropriate amount of oxygen to the cylinder.
Step Two: Hook the cylinder up to your compressor and top it off with air.
If you just want to have air put in your oxygen clean cylinder, tell them to skip step one.
This works if the air coming out of the compressor has been adequately filtered. If a shop is giving you nitrox through partial pressure blending, that means they believe the air they are pumping is pure enough for that purpose. If it is pure enough for that purpose when they are blending the nitrox, it is pure enough if they are just filling your cylinder with air.
A lot of shops don't know that, though.
And, since nobody else reminded you, nitrox is not for deep dives.
An issue with using a single cylinder is variation in blend after a fill.
Example: you start with a cylinder of air. After a dive you fill it with ean32. Unless you completely emptied your cylinder, you now have gas that is somewhere between 21% and 32% O2.
Example: you start with a cylinder of air. After a dive you fill it with ean32. Unless you completely emptied your cylinder, you now have gas that is somewhere between 21% and 32% O2.
He said deepER, which will give you increased NDL within recreational limits
So empty the tank before the fill and analyse after the fill. Or PP fill. Non issue.
packrat12
Contributor
knotical - That is true with any mix change unless you dedicate a tank to a specific mix. You just need to plan for it and determine what mix should be used to get you close to the desired mix. Most of the time, the differences are not that bad anyway and from most of my fills, they vary drastically by up to 1%-5%. It is rare that I am within 1% of what I asked for.
Also, remember that Air is the original Nitrox (21% O2, 79% N2). It is only the partial pressure blenders that matter as they may add pure O2. Label the tank as nitrox and mix/blend as needed. Use hyperpure Air for normal fills to attempt to maintain O2 clean. If you fill with a normal compressor, do not partial pressure blend again until you are O2 cleaned.
Also, remember that Air is the original Nitrox (21% O2, 79% N2). It is only the partial pressure blenders that matter as they may add pure O2. Label the tank as nitrox and mix/blend as needed. Use hyperpure Air for normal fills to attempt to maintain O2 clean. If you fill with a normal compressor, do not partial pressure blend again until you are O2 cleaned.
You should change your filling provider, it's not that hard. 5% variance? That's ridiculous for recreational nitrox fills, should be <1% or make them redo it.
How do you define O2 cleaning?
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