Nitrox ready or o2 valve?
- Thread starter cythack
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There’s no scuba tank valves fit for 100% oxygen service in the U.S. There could be in Europe but that’s only because of different standards. A valve would have to be Oxygen clean and Oxygen compatible. When scuba tanks were designed it was for air.
Don't you mean not enough turns?
Just to explain the concept behind the comment, Oxygen service valves are designed to minimize rapid changes in gas velocity. This is done by controlling the seat design in combination with the threads on the stem/spindle.
The reason is a rapid pressure increase caused particles to be picked up in the gas stream and heated, more from aerodynamic friction than heat of compression. This is why "needle valve seats" are preferred over flat seats found on Scuba cylinder valves.
Part of my training for US Navy saturation diving certification in the early 1970s included Oxygen fire safety and cleaning. This was only a few years after the chamber fire at NEDU and the Apollo fire. NASA spent millions of dollars researching Oxygen fires.
One of the many contributions to our understanding was a high speed video of what happens to a minute iron particle that is picked up in a gas stream when an HP ball valve is opened. The 16mm film showed the otherwise invisible particle glow cherry red as it accelerated past the speed of sound, as the narration explained it.
An Oxygen fire occurred at the UDT/SEAL base south of Coronado about a year later. They had a large HP Oxygen system for filling the rebreathers that blew up. The culprit was tracked down to 1/4" ball valves used in the system, along with inadequate Oxygen cleaning (based on the new standards). They system operated for years before the fire.
The dive team I was on had a class 100000 clean room. I was not certified as a clean room tech because I was in electronics instead of a "gas king", but was trained in the basics. Literally every piping system was O2 cleaned, including hot water and pure Helium systems. This seemed sort of crazy to me until a Master Diver explained it improves reliability and was simpler to have everything cleaned to the same standard.
As demonstrated by the UDT/SEAL O2 fire, what is good enough is a tough call. They operated years before it blew up.
As a mentor of mine said: "Any moronic practice is safe, until someone dies". This is similar to a saying from the structural engineer I used on my all concrete home: "Everything is strong enough, until it is not"
Akimbo:
Julius SCHMIDT
Contributor
Yes I'm waiting for my concrete to crack, there ain't no pointy seats on my O2 storage bottles
I know some people always want to talk about rebreathers but I don’t believe the OP was asking about a rebreather. He was asking about a valve suitable to attach a scuba regulator too.
True but it requires quite a few turns to fully open. I can slowly crack a ball valve and it will rarely explode on pure Oxygen. It all comes down to what proves to be a safe practice in all conditions over a long time.
There’s a good chance you can get away using axle grease on an Oxygen system too... until it blows up.
But there’s not for use in scuba, there clean and compatible but you can’t use them for 100% oxygen, it’s like I’ll sell you the gear but I won’t say YOU can use it for 100% oxygen.
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