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UP 1L co2 bottle failure (safety valve venting)

X3NiTH

X3NiTH

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Joined
13 Apr 2014
Messages
1,669
Hi, not sure what to make of this to be honest, ambient air temperature was less than 25c when my spare full bottle (filled and stored in its box) popped at the safety valve, I was sitting next to it when it went bang!

16172246037_bf585b017e_k.jpg

16356378501_9c3440b85a_k.jpg

Is this due to overfilling by gas vendor (Forth Fire Protection, on your refill vendor list) or due to a faulty safety valve, it shouldn't have gone at the temperature it was stored at, I had it filled the day I received it from you and it's been sitting in the same location with the ambient temperature never more than 25c.

There are two pressure numbers on the label with Chinese writing next to it, 1800psi and 1000psi, can you tell me what the bottle max fill pressure should be and the likelyhood that it could have been overfilled to an incorrect pressure?

Thanks
 
Good afternoon,

Firstly I am really sorry to hear that you have problem with one of our cylinders.

Regarding your question we had look on the pictures and this is something new for us. We really do not think that this happened due to the overfilling of the cylinder.

What we think that the safety valve got damaged somehow during the refilling (possible by doping the cylinder).

So could you be so kind and advice if you were there when they refilled your cylinder or you left it there and came back.
 
Hi Miroslav

I was not present when the cylinders were filled, so no idea if it was dropped by the filling operator. Even if I was present I wouldn't have seen the cylinders being filled because this is done in a separate area out of eyesight to the customer area.

The bottle is pristine and there are no marks anywhere on it to suggest that if it was dropped that it landed on a hard surface (I would expect to see scratches or some sort of impact mark if it had). There is a mark on the other bottle currently in use that appears to look like It's been gripped too tightly in a vice.

If you notice on the full length pictures I have taken of the bottle, there is a dab of white paint between the bottle and stem join, presumably so that if the bottle is dismantled It can be tightened back up so that the lines match ensuring the tight fit of the join, or indicate movement in the join.

16039155659_7fced66a2c_b.jpg

I don't know if this mark was present before I took them to get filled, (I didn't take any pre-fill pictures) If this mark is not present on your other bottles then I would think my filling vendor has added the paint and appears to suggest they have serviced the bottle before filling. No idea, I just paid for the Gas, the reason I wasn't there for the filling was I had to go and get cash from the cashpoint so I could pay the man.

Obviously it's going to need a safety valve change. Do you need the bottle back yourselves to inspect it or should I take the bottle back to the gas vendor and have them inspect it.
 
The only reason (other than obvious safety valve tampering) for a CO2 to vent is overpressure due over filling, very common in paint balling world where they wish to have as much CO2 in their tank as possible and end up discharging their cylinders even before they get to play.

As its only one litre, I bet they over filled it based on standard increase in weight for a 2Kg FE as unlike FE's this cylinder hasn't got its fill weight on it. The FE next to me at work has 4.82KG on it, the filler attaches its to his fill machine, dials in 4.82Kg and presses go. The machine fills the FE until it weighs 4.82Kg, which gives it 2Kg and CO2.
 
Empty bottle weight is 1.17Kg, after filling the bottles weighed 2.08Kg and 2.1Kg. So both bottles were filled with under a Kilo of co2 each, which is what I was expecting (or thereabouts). Can't tell if it's the heavier bottle that was the one that blew, I did write the weights on the bags used to protect the shiny surface of the bottle when stored in the box, but I might have got them switched round when I put them back in the boxes after photographing them, hence not sure if it's the heavier filled one.
 
Good afternoon,

Thank you very much for the pictures and additional informations.

Regarding your question about the cylinder mark yes the white line is supposed to be there and it is on all our cylinders.

Also if I am correct you purchased two of those cylinders so could you be so kind and advice if the second cylinder is ok please?

Regarding your issue we would like to see the cylinder if possible that we can investigate what happened to it. Please note that we will sent you new cylinder and I will include the return form as well.

Lastly could you be so kind and drop me a message with the order number that I can find you in system and sent you the new cylinder as soon as possible please?
 
Hi Miroslav

Happy to send it back so you can have a look.

The other cylinder appears to be fine, but it was at lower pressure and in operation when the other bottle vented. The bottles were located within inches of each other so subject to the same environment, the running one in the cabinet and the one that vented was next to the cabinet.

The bottle I'm running on (started use an hour or so after filling) at the beginning read 1800psi and dropped over the space of a week to 500psi where it remains currently.

The bottles were ordered in two separate orders, the numbers are #S3719 and #S3728.

Thanks
 
I have the same up cylinder here. At our local LFS, they don't fill up by weight, I.e.1kg. But rather like 66% or something of that 1L. Will dig it out later. All our co2 cylinder are sold by litres in Singapore.
 
The graph below shows why you should only fill a CO2 cylinder to 68% of its volume (also 1Kg in your case). If you fill to 100% (no gas space) and cylinder warms up, in house, in car etc, you can see the pressure rises very quickly ie nearly 2000psi at 120F and much higher will rupture the blowout valve at 2220psi. At 68% fill you have to warm up the cylinder a lot ie fire ? before the pressure will rise sufficiently to burst the blowout.
co2pv.gif
Just trying to find the Mythbusters episodes where they place CO2 extinguishers in a fire, testing the myth that an exploding fire extinguisher will put out the fire. Myth is a failures as fire extinguisher just vent safely via safety valve and fire is completely unaffected. However putting a CO2 extinguisher into a fire with safety valve plugged up does put out the fire by blowing up and scattering the fire all over the place, very impressive explosion.

Here it is starts about 7 minutes in and detonates at 8:40...
 
68% volume = 1KG? how does this work out?

I thought it has always been 68% of 1L and in weight(mass) grams.
 
Last edited:
ltsai said:
68% volume = 1KG? how does this work out?
Click to expand...
The actual tank volume has enough volume to hold 1.47Kg of gas to the top, so 68% = 1Kg. So you put in 1Kg of liquid CO2 (at 55bar) and have space above the liquid acting as a "pressure buffer".
 
Sorry, still abit lost. 1L tank can hold 1KG of gas? I thought there is a difference between volume vs mass and between say a 2L CO2 tank vs a 2KG FE?

Because it looks like I am definitely short changed because my local LFS is assuming 68% of 1L. The tank itself weigh about 1kg, after filling is only about 1.5-1.7kg.
 
I always thought a 2Kg FE was filled to 2Kg weight of CO2 but this is only 68% the amount you could get in.

Relevant bit from link below here.
" The weight of gas/liquid that the bottle should hold will be stamped on the bottle....NEVER exceed it.
A 2 kg tank is designed to carry safely a maximum of 2 kg of liquid C02. "

http://www.teamonslaught.fsnet.co.uk/co2_info.htm
 
Yeah, that I understood for a 2KG FE. But if the tank is in litres, which is quite common in Asia.

Thought litre is a volumetric measurement and not weight, which is mass, thus my confusion.

Maybe Zak / flygja can chime in 🙂
 
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