Can i fill my scuba tank with nitrogen?

[bgood44]

I am in need of a nitrogen tank that is equipped with a cga 580 valve. I have in my possession a CGA 580 valve, and a scuba tank. The scuba tank has 3/4" female NPSM threading. The cga 580 has 3/4" male NPT threads. I would like to put the cga 580 on the scuba tank and fill it with 2400 psi nitrogen. I have found online that these two thread types are compatible. Do you guys see any reason why this wouldn't work? Thanks in advance for the replies.


Brad

[rode2rouen]

Ain't 2400psi a little stout for a scuba tank?


Rex

[Sandy]

The big question is will any distributor fill a scuba tank with nitrogen? I really doubt it.

[tanglediver]

Originally Posted by rode2rouen

Ain't 2400psi a little stout for a scuba tank?


Rex

Negative.

[MAC702]

Originally Posted by rode2rouen

Ain't 2400psi a little stout for a scuba tank?

The pressure won't be the problem, but as an advanced diver, I don't like ANYTHING else about the idea.

[Mandau]

U need new label on the vessel just in case someone wanted to borrow without yur permission. Nitrogen is used for toy gun refill?

[DSW]

Originally Posted by rode2rouen

Ain't 2400psi a little stout for a scuba tank?


Rex

I have steel scuba tanks rated for 2640psi, 3000psi, 3500psi nad you can get them to 4500psi (not that many get them).

[Craig in Denver]

Well, jumping off the back of a boat, with a regulator in my mouth; hoping for AIR when I SUCK for oxygen.................. OK, I don't really know what the regulations are.

[DSW]

Originally Posted by bgood44

I am in need of a nitrogen tank that is equipped with a cga 580 valve. I have in my possession a CGA 580 valve, and a scuba tank. The scuba tank has 3/4" female NPSM threading. The cga 580 has 3/4" male NPT threads. I would like to put the cga 580 on the scuba tank and fill it with 2400 psi nitrogen. I have found online that these two thread types are compatible. Do you guys see any reason why this wouldn't work? Thanks in advance for the replies.


Brad

While the threads may be compatible I doubt it would work. The scuba tank seals with an O-ring the CGA 580 tapered thread and no o-ring. As said I doubt you would get anyone to fill it and all the fill hardware to fill it from a larger Nitrogen bottle will negate any savings.

What are you trying to fill? A pellet gun? I know some pellet guns from Europe will work off of a scuba tank. (We had one guy who would come into the dive shop to get air fills for his gun/tank.)

[rlitman]

The NPT thread is indeed "compatible" with the NPSM thread, in that it will screw into the tank, BUT, NPT threads will only seal with NPT and NPTF threads.
Inserting an NPT nipple into an NPSM collar will result in the threads binding only at the largest diameter, which will form an extremely weak connection that will not seal, but would also probably give way under pressure. In fact, NPSM threads are not designed to bind, do not seal by themselves (unlike NPT threads), and require some other form of sealing (O-ring, mating cones, etc.)

I'm sure someone on the internet will say that this would work, and I'm sure it will seal for low pressures, BUT forget about it for this kind of pressure.

Don't get totally discouraged by this though. Argon is frequently used in SCUBA dry-suits, and is used with a CGA-580 valve as well, so you might be able to find a CGA-580 valve with the correct NPSM threads and o-ring.

[DSW]

Originally Posted by rlitman

Don't get totally discouraged by this though. Argon is frequently used in SCUBA dry-suits, and is used with a CGA-580 valve as well, so you might be able to find a CGA-580 valve with the correct NPSM threads and o-ring.

Actually Argon used for suit inflation is stored in standard scuba bottles ( 6cf-14 cf primarily) The valves are the same as standard valves (yoke or primarily DIN as argon is typically used in technical diving and these divers prefer din.) The regs are standard scuba regs but with no 2nd stage regulator to breath from. In "theory" argon bottles should be well labeled as to the contents, but unlike standard bottles where the different CGA valves prevents accidental switches of gas, dive tanks for 100% argon, 100% O2, air, Nitrox (air with extra O2 added) and trimix (N, O2, HE blends) all can use the same valves. This has on a number of occasions resulted in the deaths of divers accidentally breathing 100% argon or gases inappropriate to the depth they will dive.

I have worked in the dive industry for years. PM me and let me know just what you are trying to do. There are special fill adapters designed to let shops fill argon, helium and so on, into dive tanks. I build scuba tank fill equipment to do just that and have access to the special scuba adapters. However the basic connector to fill a scuba tank runs about $70+. That's just the part that mates to the tank valve. You will still need a HP line and all the CGA parts. I doubt that it will be economical vs just buying a std. tank with CGA 580 valve.