Understanding how much gas is in a bottle?

[pacificchance]

Does anyone know how to tell what gas is in a bottle. If I buy a 9L bottle of Nitrogen how much gas is in it to last me? It is at 137 bar I think but I don't know how to figure it out. Also there is a 2 litre bottle at 200 bar I believe. Has anyone got any ideas?

 

[Nitromask]

Math isn't my strongest point, but I think a 9l cu tank lasts 48 mins at 15lpm

edit: actually ignore me, I think that's completely wrong. Here in the US the tanks are measured in cu ft so I was using the same logic for L, but I don't think it works like that

second edit: my updated answer is 54 minutes based on this link. I still might be wrong haha
https://industry.airliquide.us/volume-compressed-gas-cylinder

 

[frees]

Does anyone know how to tell what gas is in a bottle. If I buy a 9L bottle of Nitrogen how much gas is in it to last me? It is at 137 bar I think but I don't know how to figure it out. Also there is a 2 litre bottle at 200 bar I believe. Has anyone got any ideas?

The math is simple: you multiply the volume with the pressure. 9 L * 137 bar = 1233 liters

1233 liters divided by 15 liters per minute is 82,2 minutes.

Thats plenty for an exit bag. The small bottle would be good for 2 L * 200 bar / 15 L = 26,6 minutes, which might work, but is too short for comfort.


Tocheck the bottle pressure:
-close the valve on the regulator
-attach the regulator the the bottle. tighten firmly
-open the bottle valve
-read pressure
-close bottle valve

 

[pacificchance]

The math is simple: you multiply the volume with the pressure. 9 L * 137 bar = 1233 liters

1233 liters divided by 15 liters per minute is 82,2 minutes.

Thats plenty for an exit bag. The small bottle would be good for 2 L * 200 bar / 15 L = 26,6 minutes, which might work, but is too short for comfort.


Tocheck the bottle pressure:
-close the valve on the regulator
-attach the regulator the the bottle. tighten firmly
-open the bottle valve
-read pressure
-close bottle valve

This was all extremely helpful. Thank you very much!!! :)

 

[Stan]

Be careful that new bottles have the amount advertised on the label. Some refilled bottles have been know to have less and sometimes the purity isn't as expected.

 

[account676]

The math is simple: you multiply the volume with the pressure. 9 L * 137 bar = 1233 liters

1233 liters divided by 15 liters per minute is 82,2 minutes.

Thats plenty for an exit bag. The small bottle would be good for 2 L * 200 bar / 15 L = 26,6 minutes, which might work, but is too short for comfort.


Tocheck the bottle pressure:
-close the valve on the regulator
-attach the regulator the the bottle. tighten firmly
-open the bottle valve
-read pressure
-close bottle valve

Wow that is some expertise!

 

[Wiltshire]

Is this thread still being viewed. I know where the supplier is whom the original question was about. They sell 9l and 2L I have just received the 2 L times 200 bar tank. This was after reading the PPH handbook which suggests that 400 L of nitrogen is 'plenty for a peaceful death' and it seems to be similar to what is used by Max dog. There was also a comment in the PPH handbook that another supplier sold a 9 L tank and that that was too much and not necessary.Now I'm a bit worried that the 2L one might not actually be long enough. I haven't done a test yet but presumably I will use about two minutes with testing just whilst waiting for the bag to fill up. I am now thinking I might have to order a 9 litre tank.

 

[notuntilperfection]

This thread saved my life, i was so confused

 

[WearyOfStruggling]

Does anyone know how to tell what gas is in a bottle. If I buy a 9L bottle of Nitrogen how much gas is in it to last me? It is at 137 bar I think but I don't know how to figure it out. Also there is a 2 litre bottle at 200 bar I believe. Has anyone got any ideas?

Frees answer isn't exactly correct in my opinion, so I will give you my answer.

There is an easy way to calculate the uncompressed volume of gas that is stored in a given volume at a given pressure called Boyle's Law. I suggest reading about it online, but the basic equation is P1*V1 = P2*V2. So if you solve for V2, V2 = P1*V1/P2. Make sure units are consistent. If pressures are in bar, atmospheric pressure, P2, is 1.013 bar, so V2 it is very close to P1*V1 as @frees said. But for any other units, that won't be the case.

Then when you have the total volume of uncompressed gas, divide by the flow rate, such as 15 lpm, to get how long the gas will last.

 

[FreddieQuell]

To calculate the total amount of liters and flow rate I think @frees method suffices for users of SS.

If you want to be absolutely mathematically correct you could use this tool: https://www.omnicalculator.com/physics/boyles-law.
As an example, I will calculate the uncompressed volume of a 5 liter cylinder of nitrogen at 300 bar.

Calculating the uncompressed volume of gas this cylinder contains I am using the following as initial parameters:
- Initial pressure: 300 bar
- Initial volume: 5 liter
- Temperature: 20 degrees celcius

Final parameters:
- Final pressure: 1 bar

This gives you an uncompressed total of 1500 liters. Using @frees method we'd get exactly the same answer, 300 * 5 = 1500. In short, let's not overcomplicate.

 

[WearyOfStruggling]

To calculate the total amount of liters and flow rate I think @frees method suffices for users of SS.

If you want to be absolutely mathematically correct you could use this tool: https://www.omnicalculator.com/physics/boyles-law.
As an example, I will calculate the uncompressed volume of a 5 liter cylinder of nitrogen at 300 bar.

Calculating the uncompressed volume of gas this cylinder contains I am using the following as initial parameters:
- Initial pressure: 300 bar
- Initial volume: 5 liter
- Temperature: 20 degrees celcius

Final parameters:
- Final pressure: 1 bar

This gives you an uncompressed total of 1500 liters. Using @frees method we'd get exactly the same answer, 300 * 5 = 1500. In short, let's not overcomplicate.

I edited my post above to state that if pressure is in bar, final pressure, atmospheric pressure, is 1.013 bar, so @frees is close enough, but if any other units are used, it won't be. I'm in the US, so we still commonly use psi. Atmospheric pressure is 14.7 psi