Overfilling and life expectancy. (LP Tanks)

[VooDooGasMan]

I got a Bucket!!!!!!!!!!!!!

Seems to me I seen a hydro on youtube awhile back, but at the hydro facility if your talking steel tanks, there are so many steel tanks that hydro daily, not just scuba.

I'm sure it is possible to play with physics and do a bucket hydro, but your math needs to be tested with failure to a commercial hydro tank to have the statistics.

It cost very minimal and a short time for me to take my tanks to fire king, when i show up there is always 20 to 30 scubatanks standing there with a ton of other tanks.

I still find the most dangerous is storing a full tank, or a 100% o2 where it can fall from to high and hit and explode.

 

[SandyRobinson]

Around here ...

Please let us know where "around here" is.

 

[halocline]

Tanks don't rupture during hydro because the difference in pressure from the outside of the tank and the inside of the tank (inside the vat) is very close.

I don't believe this is accurate. The tanks are put in a vessel filled with water, and then the tanks are filled with water and pressurized, just like you mentioned. But the water jacket in the vessel, outside of the tank, must stay at ambient pressure to accurately measure the expansion of the tank. It's that expansion that forces the water in the vessel up into a graduated cylinder. If the water jacket were also under pressure, the net pressure on the tank would be very low and the hydrotest would be useless.

The reason so few tanks rupture during the hydrotest is because tanks are built to withstand far greater pressures than their working pressure before rupturing. If they weren't, i.e. if the margin of safety with pressurized gas cylinders was not large, there would be exploding cylinders fairly frequently, considering the high numbers of pressurized gas cylinders (fire extinguishers, welding equpment, CO2, scuba, SCBA, etc.....) that are found in daily life. This would not be a great thing....and would immediately put the cylinder industry out of business.

But you are correct that the other poster seems to have absolutely no idea of what hydrotesting is.

 

[Rogersea]

Total BS.
At least in the USA where DOT is king.

Dude, you're caught. You haven't a clue what you're talking about. Let it go. I understand the need to try to convince us, but you don't have enough knowledge on the subject to sway us that far. You lose. It's ok. Just walk away.

I am sure your a great guy, but you must remember that not everyone lives in the US, and uses the type of machine you have. I personally have a hydro business and have seen several different set-ups, with and without water jackets. Why dont you check out this link Hydrostatic Test Equipment . Are you sure tanks dont burst during testing?


Cheers,
Roger

 

[halocline]

Are you sure tanks dont burst during testing?

Cheers,
Roger

I've often wondered about this....I'm sure it's not a common occurrence but I bet it does happen from time to time. I've seen the set ups at a couple of hydro shops in the U.S. and the vessels are small bunkers. There's ALOT of energy in an exploding cylinder releasing 5000PSI. The thing is, to burst at 5/3 of service pressure is not a huge safety margin, and if you're talking about thousands and thousands of tanks, I just can't see anyone tolerating that slim a margin.

 

[Leadking]

Tanks don't go "bang" in a hydro because water is not compressable. What happens is the tank will stretch and a crack will form relieving the pressure and the tank cannot return to its' former shape. The difference between no pressure and 5,000psi is measured in cc's not cubic feet.

 

[Superlyte27]

I am sure your a great guy, but you must remember that not everyone lives in the US, and uses the type of machine you have. I personally have a hydro business and have seen several different set-ups, with and without water jackets. Why dont you check out this link Hydrostatic Test Equipment . Are you sure tanks dont burst during testing?



Cheers,
Roger

I'm sorry but I thought Federal DOT requirements were just requirements in the USA..... Oh wait!!! They are requirements IN THE USA.

 

[Scared Silly]

Air is NOT used in any shape or form in a hydro test. Hydrostatic testing is done with water (i.e. the cylinder is filled with water and put in a water bath). Then a cylinder cracks all the way through water will initially come pissing out at at high pressure but it will very quickly drop to a lower pressure because water incompressible, and as Lee said the amount of water needed to create high pressure is very little. There is very little energy being released in a hydro test. Folks should really take some time and visit a hydro shop and see how the test is done.

A gas which is compressible, when it expands releases energy. No compression, no stored energy. QED

If you want to try a home experiment get two balloons that are the same size and shape. Fill one with air and one with water. Fill both to the same volume. Put a pin to the one with air and it goes bang. Put a pin to the one with water and see what happens.

 

[jaycanwk]

I know plenty of guys that fill their lp's to 4500 psi. I wouldn't do it, but I've never heard of a cylinder fail hydro because of overfilling, and I've never heard of a steel explode at less than 11,000 psi. Go for it.

I would love to see The Myth Busters actually do a test like that. Weld the tank shut then just keep pumping air to see how much it would actually take. Is there actually a such thing as compressors that could handle that?

 

[VooDooGasMan]

Jay a booster pump would more than likely do it, they put 10,000 psi in condom's to test, of course like silly say's one pin hole it will leak with out any noise at all.