Tank won't fill?...question

[plaamook]

Years back I had a 12L that would only fill to 180bar. Everyone scratching theirs heads.
A gal at the dive shop said she wasn't totally sure what caused it but she'd seen it before and had a fix. She blasted O2 into it because the O2 storage was capable of giving a higher pressure blast.
Sure enough, it went on filling to 230 and continued to do so until it was tested and there was never a fault found.
So how does this work?
At the time I thought...if something was stuck on the way in...and you blow it IN!...can't it then get stuck on the way OUT and potentially cause a really bad day sort of situation?
I was diving twin Indi's at the time so I was happy enough to see how it went for the rest of the season, and it was all fine as I said...but I never really settled my mind on what happened or got an answer or solved the mystery of it.
Now that I've found this place I thought maybe someone around here might be familiar with this.

Thanks

 

[broncobowsher]

There can't be anything wrong with the cylinder. Swap out the valve, maybe something strange inside of it. I've seen odd things with seats get loose, act as check valves, etc.

 

[rhwestfall]

She blasted O2 into it because the O2 storage was capable of giving a higher pressure blast.

 

[jborg]

None of that makes any kind of sense…

 

[plaamook]

None of that makes any kind of sense…

To me neither. That’s why I posted it. Strange.
I don’t have the cylinder any longer so there’s nothing to fix. But I still think about it now n again.

 

[Curtis Hopper]

Years back I had a 12L that would only fill to 180bar. Everyone scratching theirs heads.
A gal at the dive shop said she wasn't totally sure what caused it but she'd seen it before and had a fix. She blasted O2 into it because the O2 storage was capable of giving a higher pressure blast.
Sure enough, it went on filling to 230 and continued to do so until it was tested and there was never a fault found.
So how does this work?
At the time I thought...if something was stuck on the way in...and you blow it IN!...can't it then get stuck on the way OUT and potentially cause a really bad day sort of situation?
I was diving twin Indi's at the time so I was happy enough to see how it went for the rest of the season, and it was all fine as I said...but I never really settled my mind on what happened or got an answer or solved the mystery of it.
Now that I've found this place I thought maybe someone around here might be familiar with this.

Thanks

Isn’t o2 highly explosive under pressure? Everything has to be o2 clean. That’s what I learned in Nitrox class (probably not the correct name of the cert. but that’s off the top of my head). Not advanced Nitrox. Goes well with my Underwater Pumpkin Carving Specialty. Lol

 

[broncobowsher]

Isn’t o2 highly explosive under pressure? Everything has to be o2 clean. That’s what I learned in Nitrox class (probably not the correct name of the cert. but that’s off the top of my head). Not advanced Nitrox. Goes well with my Underwater Pumpkin Carving Specialty. Lol

No, O2 is not explosive. Even under extreme pressures.
It can be reactive, but by itself not a problem. Stuff that it reacts with (fuel), and an ignition source, can make for an energetic release of energy. The high pressures can make for a source of ignition. Think diesel engine. As gasses are compressed rapidly to high pressures, it can create high enough tempertures to start ignition. It isn't the already compressed gas, but the little bit of normal pressure gas getting hammered with a sudden blast of high pressure gas that gets hot.
The oxygen clean is simply removing (or not using) materials that may oxidize in an O2 enviroment. If you have Oxygen, and heat, but no fuel, there is no fire. That is oxygen clean. Being safe is trying to eliminate both the ignition and fuel points from the fire triangle. You can't remove the oxygen corner, that is what you are working with. Take out the other two and if one accidently happens, still nothing happens.

 

[Bob DBF]

I'd like to take that valve apart, which should have been done in the first place. Trying to burn the problem out is not one of my go to fixes.

 

[Gone for diving]

On my storage bank, I have had the rubber seat come free from the threaded part,
Air will come out, but when filling if there was pressure higher than the tank when you opened it, it would not fill,

But doesn't explain your problem

 

[plaamook]

On my storage bank, I have had the rubber seat come free from the threaded part,
Air will come out, but when filling if there was pressure higher than the tank when you opened it, it would not fill,

But doesn't explain your problem

It might in some way. It was exactly that sort of problem.
I don’t know the anatomy of a tank valve beyond some common sense extrapolation