Oxygen compatibility, materials and explosions

[rddvet]

Actually there’s a very simple reason for sending it through the compressor, when the pressure in the j bottle drops to low to decant you can use all of the remaining gas and I don’t have the budget of the military or industry, Alao oil can’t ignite til it reaches a flash point and compressors are designed to run at less than a third of that.

It looks like I was wrong in my options of 1, 2, and 3. Its option 4: you're stupid and cheap, and apparently very pig headed because you are going to continue to argue a losing battle. I officially give up. I hope you dont blow yourself up. I also hope somebody will get through to you before you do. It aint gonna be me.

 

[TrimixToo]

But that’s the beauty of sending it through the compressor, unlike decanting, it’s not going at high speed , you simply trickle oxygen with a needle valve from the j bottle Into the air intake,no sudden rise in heat and it mixes in the compressor, what could be simpler.

No sudden rise in heat? In a *compressor*? Really?

When gas is compressed, its temperature rises in direct proportion to the amount it is compressed. (That whole PV=nRT thing. Note that P and T are on opposite sides of the equation.) Then, the hot compressed gas goes past the restriction represented by the exhaust valve. Then, it goes through an air cooling coil (usually), but then, still much warmer than ambient, it gets to the next stage, through an inlet valve restriction, and the rest of the process repeats. And again. And, in a 4-stage compressor, once more. Then, it goes through the coalescer and through the restriction represented by the pressure maintaining valve.

For premixed Nitrox (Google "nitrox stick") up to 40% this is safe for some compressors (not mine) when high-temperature flashpoint synthetic oils are used. In no way is it safe to bleed O2 into the intake or exceed 40%.

Further, "decanting" is properly done through a needle valve that controls the O2 flow rate so that the receiving tank's pressure rises at 60 PSI/minute or less. Waiting for O2 fills is sort of like watching gas grow when done right.

I have advanced gas blender cards from both PADI and TDI. Anyone who wants to blend with O2 should learn to do it the right way.

I repeat for anyone else misguided enough to believe you: What you are doing is NOT a safe practice.

 

[broncobowsher]

I've had a little accidental O2 fire. It was a medical O2 fire. Uncle's mother in law was on O2. Christmas day, out in the boonies (little ranch miles from anywhere). Bottle change. Had an O-ring issue, needed a new one. We had nothing close to an O-ring. But there was an old truck innertube. So we made a square ring. Given the location and timing it was the best that we were going to get. Opened the valve, the rubber was way too soft and flew out. Little puff of smoke and the smell of a drag strip. Took it apart and the innertube was charred. We got lucky.

After all that, she decided that she really didn't need oxygen and we finished Christmas without it. I knew how bad it could have been, no one else realized how bad things could have been. I have a healthy respect for high pressure O2 after that. And that doesn't include what I already knew and have played with on an Oxy-fuel torch. Little things like cutting steel plate with O2 and turning the fuel off.

 

[KevinNM]

Oxygen is neither combustible or explosive, you must add fuel and heat. I’ve pumped 80% deco. stage bottles straight through a standard Bauer compressor from cutting oxygen j bottles.

Are you putting it in aluminum cylinders? The cylinder will burn just fine at 100 bar of 100% or 80%. From the inside out, then the tank wall fails in a very noisy way. It's your life, so do what you want, but I sure hope you have a lot of life insurance if you have small kids.

 

[grf88]

Alao oil can’t ignite til it reaches a flash point and compressors are designed to run at less than a third of that.

You may want to review this:
https://www.dekra-process-safety.co...under-process-safety-conditions-datasheet.pdf

 

[northernone]

I have a hearty respect for o2, both from personal experience and reading on the very clear scientific research which explains the how's and the why's of when things go boom.

I'm concerned by the unnecessary risk of pumping high fo2 mixes through a dirty compressor. Rolling the weighted dice. It's bitten dozens of smart people, please reconsider adding yourself to the list.

Oh, I also have a scorched reg that was o2 cleaned at one time but had enough contaminates to form a fuel. It's unpredictably predictable. If 1 in 2000 fills results in a fatal explosion (made up stat) one could easily done it 1,000 times "safely" but it doesn't mean it's safe.

Regards,
Cameron

 

[Akimbo]

I'm concerned by the unnecessary risk of pumping high fo2 mixes through a dirty compressor.

You are not alone. All the industrial gas plants that produce bulk cryogenic and HP Oxygen I have ever seen use 25-120HP high-purity stainless steel diaphragm compressors. Basically, fluid from a piston pump deflects a stainless diaphragm with the gas on the other side.

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[Celt]

Are you putting it in aluminum cylinders? The cylinder will burn just fine at 100 bar of 100% or 80%. From the inside out, then the tank wall fails in a very noisy way. It's your life, so do what you want, but I sure hope you have a lot of life insurance if you have small kids.

Aluminum dust is very explosive, that would be silly.

 

[Celt]

It looks like I was wrong in my options of 1, 2, and 3. Its option 4: you're stupid and cheap, and apparently very pig headed because you are going to continue to argue a losing battle. I officially give up. I hope you dont blow yourself up. I also hope somebody will get through to you before you do. It aint gonna be me.

Well you don’t know me and your attempt at labeling me as “ stupid and cheap “ is pathetic. But then the label suits the imbecile they only have to read it.

 

[Celt]

I have a hearty respect for o2, both from personal experience and reading on the very clear scientific research which explains the how's and the why's of when things go boom.

I'm concerned by the unnecessary risk of pumping high fo2 mixes through a dirty compressor. Rolling the weighted dice. It's bitten dozens of smart people, please reconsider adding yourself to the list.

Oh, I also have a scorched reg that was o2 cleaned at one time but had enough contaminates to form a fuel. It's unpredictably predictable. If 1 in 2000 fills results in a fatal explosion (made up stat) one could easily done it 1,000 times "safely" but it doesn't mean it's safe.

Regards,
Cameron

Thing can go wrong but there’s risk with everything