Nitrox questions

Hi
I know that the subject hasn’t been talked about for a while, like the saying “out of sight out of mind” I forgot.
The subject is EANx
The questions are:
1) What is the preferred method of mixing/blending air?
2) How often do you need to O2 clean your tank?
3) Can you mix dive your tank without O2cleaning? Meaning dive a Nitrox say 32% then empty the tank and get it filled with 21%?

But, hey, I ain't shy and will step way out on the thin part of the limb on this one. "No guts, no glory"

Just a second while I put on my asbestos underwear.

OK, they're on, a little chard, but they still work.

Originally posted by Fishkiller
Hi
I know that the subject hasn’t been talked about for a while, like the saying “out of sight out of mind” I forgot.
The subject is EANx
The questions are:
1) What is the preferred method of mixing/blending air?
2) How often do you need to O2 clean your tank?
3) Can you mix dive your tank without O2cleaning? Meaning dive a Nitrox say 32% then empty the tank and get it filled with 21%?

Click to expand...

1) In my part of the country, (The Diving Mecca of the Free World), partial pressure blending is the norm. None of the gas suppliers that I am aware of sell premix.

2) Probably need to see if we can get Rainreg to answer this one.

3) Yes and No, Yes you can if you get it filled from a Nitrox station and have it filled from the same whip as the air (21%) that they use to fill the Nitrox tanks.
No if you fill it out of the same whip as they use to fill regular air (21%) tanks.

Hope this helps, I will see If I can raise Rainreg from the dead and get him to reply to #2.

ID

1)partial pressure blending, serious I forgot that.

2) waiting

3) so if the whip off the 32% is used on the 21% it would be ok? could the reverse remain true?

1. My preference is to get nitrox from a source that "banks" it at less than 40% and blends to get the desired mix. That way I just need to have a Nitrox prepped tank, not fully O2 cleaned.

2. Never(you can have it nitrox prepped as long as nothing over 40% goes in your tank), or once per year, or after it is contaminated. Some shops will argue this with you & use it as a way to get a few more $$ out of your pocket for O2 cleaning.

3. Yes, as long as you get hydrocarbon-free air. (even that is debatable - some say that if the air from a regular compressor is clean enough (grade E???) you can use that too.)

Are you Nitrox certified Fishkiller?

-kate

-Kate no I'm not Nitrox yet, but wish to be.

So grade E air can be used in my yet to be Nitrox cyclinder?

1. The LDS I use has a compressor which mixes 100% oxygen with air inside the compressor so only the compressor needs to be oxygen clean. This method works up to 40% O2. The LDS does not require you to O2 clean your tank and is very quick in delivering odd blends unlike pre mixed fill stations. If you want more that 40% O2 they use partial pressure blending and an O2 clean tank is required.

2. If you are using partial pressure blending you should probably O2 clean your tank every year, consider having it done when you get your visual inspection.

3. As long as the compressor that gives you air is O2 clean then you are okay, otherwise you will have to reclean your tanks. Most LDS will be able to tell you if thier fills will negate your O2 cleaning.

In answer to question #2 how often do you need to o2 clean your tanks?

the answer is this:

1. clean your tanks yearly along with the visual inspection.

2. If the fascility that does the visual inspection of your tanks also cleans your tanks. they should have the ability to verify particulate contamination by conducting swipes and verification of cleanliness. This process negates having to reclean your tanks every time. The process verifies that cleanliness has been maintained and the particulate count is at or below recommended levels. therfore to reclean every time is not always a necessity.

3. If the tank is suspect, Meaning that air or other contaminats have been or thought to have been exposed to the inside of the valve or tank. If this is the case follow step 2 before a full reclean is required.

the recommended particulate level is at 5 Parts per Million or less this is verified by the use of an IR machine (Perkin Elmer) this can also be completed useing another process as well.

I hope this answered your question. for further info feel free to contact me via phone 850-913-0888 after 930pm Central Time is best (I am up till @1am daily so call if you have questions)

rainreg