High pressure air fills

[Teamcasa]

I was asked this question the other day and have been searching for a suitable answer.
Could you use high pressure tanks to mix nitrogen (79%) and oxygen (21%) to fill SCUBA tanks.
Or, could a gas company, like AIRGAS premix a single high pressure tank with SCUBA air.
This question came up by a guy that is interested in diving, works for AIRGAS (he has access to the tanks), has his own boat but does not want to buy a compressor.

I think it would be possible for a few fills albeit expensive. Would there be any medical dangers (besides dealing with the high pressure tanks)?

Dave

 

[Bob3]

The commercial diving industry uses premix bottles manifolded together all the time, as does the USN.
Being cost effective is another matter entirely. You're probably looking at a bank of at least a half-dozen 300 cu ft bottles for starters.
All gas needs to be of breathing grade, of course.

 

[oxyhacker]

One of our readers emailed us that he had been able to find 6000 psi tanks of nitrogen very cheaply from his local gas supplier, and was PP mixing all his gas from scratch, even air! Per tank it worked out to about the same as getting air fills from an LDS, and much less for nitrox. Oh, and a lot cheaper that setting up a compressor!

I called up a couple local gas suppliers and their price on nitrogen was prohibitively high. And they couldn't supply that kind of pressure.

So it does work, it all just boils down (like most of these things) to price.

I was asked this question the other day and have been searching for a suitable answer.
Could you use high pressure tanks to mix nitrogen (79%) and oxygen (21%) to fill SCUBA tanks.
Or, could a gas company, like AIRGAS premix a single high pressure tank with SCUBA air.
This question came up by a guy that is interested in diving, works for AIRGAS (he has access to the tanks), has his own boat but does not want to buy a compressor.

I think it would be possible for a few fills albeit expensive. Would there be any medical dangers (besides dealing with the high pressure tanks)?

Dave

 

[cummings66]

I checked on something like that myself and the biggest issue is cost. It's not cost effective for me. Now an employee working there probably can get it for free. The gas supplier told me that they make their own Nitrogen, they have this filter that separates it out and puts it in a tank, it's very pure and clean. They even supply it to hospitals. It's pretty cheap but you need many tanks and that's where the cost gets you. Add it all up and a compressor is a better deal. Same deal on the O2, a single tank is cheap enough but you won't get many fills out of it.

There is no reason it can't be done.

 

[Surface Tension]

Maybe something being overlooked is convenience. The reason I got a compressor was to avoid having to lug tanks all over creation. My dive tanks go from the boat to my garage and back again when it's time to dive. My back and hands thank me.

 

[Dive-aholic]

But if you have a cascade system set up in your garage, it's really no different. The Airgas guy is the one who lugs around the big tanks, not you.

 

[Surface Tension]

I see. I thought you meant hauling them to get them filled.

 

[rakkis]

If he works for AIRGAS and has access to N2 and O2 why even bother mixing it? He can certainly get his hands on grade E breathing air.

 

[Cheekymonkey]

Well he mixxing for Nitrox