Testing oxygen and other high pressure cylinders.

[moonlight machine]

Yesterday I saw a full 337 cu ft oxygen cylinder fall about 5', landed on a concrete floor with a hell of a crash and ringing sounds. Nothing happened. Anyone know how they were tested for safety? I know they are pressure tested about every 10 years or so. Just what sort of abuse will a high pressure cylinders take?

 

[reggie_obe]

Sounds like the premise for another Mythbusters episode.

 

[guythatbrews]

Don't know how much abuse they will take but we've all heard the stories about a valve getting knocked off and the tank going
through a cinderblock wall.

Ouch! Keep 'em chained up!

 

[atex57]

Don't know how much abuse they will take but we've all heard the stories about a valve getting knocked off and the tank going
through a cinderblock wall.

Ouch! Keep 'em chained up!

Depends on how much of a running start it has. We had a tank fall over and do the same thing but it only had 5ft till it hit a shelving unit. Put a dent in the shelving and exhausted it contents and my pocket book. They get strapped tight BEFORE the cap comes off.

Ed.

 

[memphisjed]

They can fall off trucks at 55 mph and not explode. They are meant to be safe enough to not explode in a car crash.
Not that I want to test either limit....

 

[Bill D]

Helium tanks made by nazi germany for derigbles are still being used today. So no expiration date on top of hydro tests. Propane tanks have expiration dates.
Bill D

 

[eKretz]

Mainly the valve breaking off at the threads is the concern. Just like a rocket under thrust in that case. 1" NPT I think for the valve thread, so at 2200 psi a full cylinder would have around 750 pounds of thrust. A little less from the remnants of the male fitting still in place.

 

[Tyrone Shoelaces]

When I was at engineering day school I remember the class being shown an old film of a cylinder being pressured up with water and then shot with an armour piercing bullet. It was in a railway sleeper lined room. At normal speed all you saw was a white explosion of vapour. Played back frame by frame it was very scary.

Regards Tyrone

 

[sfriedberg]

being pressured up with water

And that's the nice version of the demo! Nearly-incompressible water loses its "oomph" (outward force on the tank) almost instantly as the tank ruptures. If it had been pressurized gas, they'd probably still be picking pieces of tank shell out of the lining of the room, because the highly-compressible spring-like contents would still be accelerating the tank shards for some appreciable time.

 

[moonlight machine]

Helium tanks made by nazi germany for derigbles are still being used today. So no expiration date on top of hydro tests. Propane tanks have expiration dates.
Bill D

The oldest bottle in my shop right now is 8-28, I have seen one from '09

 

[ratbldr427]

We had a fl propane tank blow recently due to the truck catching on fire. Caught every thing on the security camera. The fireball was pretty spetacular. The strangest part was the escape hole in the tank was splayed out like it was shot from inside with a 50cal. Had to check and see if something penetrated from the other side. Nope.
I have seen a few tanks that ruptured from fire and overpressure and all of them were ripped apart , split open.

 

[rke[pler]

Propane tanks have to be retested after 10 years and are certified for 5 more (test doesn't seem to involve more than wiping welds down with soapy water and looking for bubbles).

There are a few videos of oxygen tanks being shot with 50 BMG API. Turns out the steel in the tank is happy to burn so you get a much bigger hole than anticipated.

 

[reggie_obe]

Depends on how much of a running start it has. We had a tank fall over and do the same thing but it only had 5ft till it hit a shelving unit. Put a dent in the shelving and exhausted it contents and my pocket book. They get strapped tight BEFORE the cap comes off.

Ed.

So it cracked the valve, but didn't shear it off.
As Mythbusters showed it's a lot harder than you might think to completley shear the valve off and produce a rocket.

 

[boslab]

I’ve seen quite a few cylinders explode when they got in the scrap for the converter in work, a full ( I’d guess) propane tank went off like a bloody bomb, think the fireman called it a blevy , boiling liquid explosion, that shook the dust off the steelwork, it was raining carbon dust then that eploded too, gas cylinders are underestimated things, a family of 4 were wiped out when the propane tank exploded not far from where I lived, tragic so I’m generally shy of the things, I’d send it back for a retest myself, just in case
Mark

 

[William Lynn]

I worked with a welder that was ex Air Force. He told me he witnessed a total oxygen valve separation inside a hangar. Killed one airman then the tank went through the roof.

 

[L Vanice]

Helium tanks made by nazi germany for derigbles are still being used today. So no expiration date on top of hydro tests. Propane tanks have expiration dates.
Bill D

The Germans used hydrogen in their Zeppelins, not helium. Remember the blazing end of the Hindenburg in 1937, which made Zeppelins very unpopular for civil aviation.

https://www.globalsecurity.org/military/world/airship-helium.htm This is a very good history of helium and its use in airships and the use of airships in war. The Germans used Zeppelins to bomb England from 1915 to 1917, but lost most of them to defensive ground and airplane fire. The US and Canada had plenty of helium by 1918, just a little too late to use in Allied airships to bomb Germany before the end of WW1 on November 11, 1918. It was too vital as a war material to sell it to Germany after WW1, so Germany had to continue to use hydrogen in their airships.

Larry

 

[Joe Gwinn]

For the biggest bang, fill the tank with plain water, plug it with a metal plug screwed tight, and heat till it bursts. The water cannot boil because of the pressure, until something gives. Then the water all flashes into super-heated steam. This is the classic boiler explosion scenario:

https://abcnews.go.com/GMA/video/killed-boiler-explosion-caught-camera-46562554

 

[garyhlucas]

Hydrotest is done with water and a pressure much higher than the tanks rating. The tank is placed in a sealed water filled tank that is free of air and has a graduated cylinder attached. You pressurize the tank under test and it displaces the water in the outer tank up the graduated cylinder. There is an allowable percentage volume expansion for every size and type of tank.

I built a hydraulic machine with a self centering clamp that could hold a 4" cylinder to a 100lb propane cylinder. A hydraulic wrench then unscrewed the valve and the tank was power tipped at an angle for interior inspection with a scope looking for corrosion. It was then uprighted, filled and a test connection with the test tank lid was screwed in by the powered wrench. The wrench was also a lifting mechanism. You raised a door under the tank to reach the test tank and lowered the cylinder straight down, clamped the cover, and tested. Then reversed the process with the clamp tilting the tank over to dump out the water. A hot air lance could be used to dry the tank quicker. That company was bought by Airco, I always wondered what happened to the machine I built, as it replaced a whole raft of equipment that was sold to gas dealers.

 

[boslab]

I’ve seen quite a few cylinders explode when they got in the scrap for the converter in work, a full ( I’d guess) propane tank went off like a bloody bomb, think the fireman called it a blevy , boiling liquid explosion, that shook the dust off the steelwork, it was raining carbon dust then that eploded too, gas cylinders are underestimated things, a family of 4 were wiped out when the propane tank exploded not far from where I lived, tragic so I’m generally shy of the things, I’d send it back for a retest myself, just in case
Mark

 

[guythatbrews]

I don't know why stuff blowing up is so fascinating but it sure is.

Everybody knows how much damage you can do to a shark with a HP bottle and a HP rifle.