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Posted

If it went off under my saddle I will have something in my pants, but it won't be KOM

I wonder how loud the bang would be?

Many years ago before the days of tubeless I was out riding my MTB. Got a puncture near a garage so changed my tube there. I didn't notice that I actually had a slice in the sidewall. I was busy pumping my tyre with the garage air and hadn't noticed the tube bulging out. Next second there was a massive bang. The poor petrol attendants all dropped and lay on the ground. My toppie and I got such a fright, I honestly thought a bomb had gone off.

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Posted

I wonder how loud the bang would be?

Many years ago before the days of tubeless I was out riding my MTB. Got a puncture near a garage so changed my tube there. I didn't notice that I actually had a slice in the sidewall. I was busy pumping my tyre with the garage air and hadn't noticed the tube bulging out. Next second there was a massive bang. The poor petrol attendants all dropped and lay on the ground. My toppie and I got such a fright, I honestly thought a bomb had gone off.

had a similar thing happen with my wifes mtb. We were still dating at the time and I was changing her mtb tyres to slicks in their lounge.

Busy inflating the tyre with a track pump and didnt notice i had pinched the tube, huge bang and every lose ornament shook.

Posted

Liquid CO2 doesn't exist at normal atmospheric pressure. There is no temperature where it remains liquid - it will always turn into either a solid or a gas.

As you might also remember from chem, the freezing and boiling points of substances changes with pressure.

 

http://upload.wikimedia.org/wikipedia/commons/thumb/1/13/Carbon_dioxide_pressure-temperature_phase_diagram.svg/636px-Carbon_dioxide_pressure-temperature_phase_diagram.svg.png

 

As you increase the pressure on CO2, the boiling point moves away from the freezing point creating a gap for liquid to exist.

Another interesting fact about CO2 (and similar volatile non-polar liquids) is that the pressure in a container, so long as it is not depleted (with no liquid left) or overloaded, is determined entirely by temperature, and not how much CO2 is in it. A CO2 tank at room temperature is at about 850 PSI, no matter if it is full of half empty.

Now, for the scary part, pressure increase is logarithmic with temperature. A 2x increase in the temperature of a CO2 tank results in a 10x increase in pressure, and above about 91F CO2 really doesn't want to be a liquid anymore no matter the pressure (The critical point). It's about this time when a release valve would go off if your tank was big enough to need one. Luckily small CO2 cylinders are incredibly over engineered for what they do, so you're still pretty safe.

 

 

(as you can see from the farhenheit, i swiped this from here - https://www.bikeforums.net/bicycle-mechanics/743958-can-co2-cartridges-explode-3.html)

 

where I also found this

i'm guessing there was some fault with the cartridge, a car cubbyhole should never get that hot

Posted (edited)

had a similar thing happen with my wifes mtb. We were still dating at the time and I was changing her mtb tyres to slicks in their lounge.

Busy inflating the tyre with a track pump and didnt notice i had pinched the tube, huge bang and every lose ornament shook.

 

Sorta related, what happens when a tubeless setup goes wrong: https://www.pinkbike.com/video/509984/

Edited by Jacquers
Posted

I wonder how loud the bang would be?

Many years ago before the days of tubeless I was out riding my MTB. Got a puncture near a garage so changed my tube there. I didn't notice that I actually had a slice in the sidewall. I was busy pumping my tyre with the garage air and hadn't noticed the tube bulging out. Next second there was a massive bang. The poor petrol attendants all dropped and lay on the ground. My toppie and I got such a fright, I honestly thought a bomb had gone off.

We were racing the criterium in Boksburg many years ago. One of my friends had finished racing, so my old man packed her bike into the kombi. It was raining, so my mom was sitting in the kombi, when the tyre exploded (hp clinchers pumped to 100 PSI) the ringing in her ears lasted for a week or 2!
Posted

What makes you think the gas is liquified?

 

Liquid CO2 doesn't exist at normal atmospheric pressure. There is no temperature where it remains liquid - it will always turn into either a solid or a gas.

 

As you might also remember from chem, the freezing and boiling points of substances changes with pressure.

 

http://upload.wikimedia.org/wikipedia/commons/thumb/1/13/Carbon_dioxide_pressure-temperature_phase_diagram.svg/636px-Carbon_dioxide_pressure-temperature_phase_diagram.svg.png

 

As you increase the pressure on CO2, the boiling point moves away from the freezing point creating a gap for liquid to exist.

 

Another interesting fact about CO2 (and similar volatile non-polar liquids) is that the pressure in a container, so long as it is not depleted (with no liquid left) or overloaded, is determined entirely by temperature, and not how much CO2 is in it. A CO2 tank at room temperature is at about 850 PSI, no matter if it is full of half empty.

 

Now, for the scary part, pressure increase is logarithmic with temperature. A 2x increase in the temperature of a CO2 tank results in a 10x increase in pressure, and above about 91F CO2 really doesn't want to be a liquid anymore no matter the pressure (The critical point). It's about this time when a release valve would go off if your tank was big enough to need one. Luckily small CO2 cylinders are incredibly over engineered for what they do, so you're still pretty safe.

 

 

(as you can see from the farhenheit, i swiped this from here - https://www.bikeforums.net/bicycle-mechanics/743958-can-co2-cartridges-explode-3.html)

 

where I also found this

https://youtu.be/pL0n3DbInKY

i'm guessing there was some fault with the cartridge, a car cubbyhole should never get that hot

Posted (edited)

Plot that T and P on the phase chart. Well in the gas zone.

 

Your suggestion would mean your bombed tyres are full of liquid on a summers day...

 

At 32c and below at higher than 76psi co2 is usually A liquid

Edited by Fat Boab
Posted

Plot that T and P on the phase chart. Well in the gas zone.

 

Your suggestion would mean your bombed tyres are full of liquid on a summers day...

 

that assuming ideal conditions , the space in your tyre obviously has a big influence 

post-46013-0-93287900-1578423292_thumb.jpg

Posted

I think main thing here is as mentioned before , there's probably no standard on how these things get made and to what tolerance/resolution ect ect.

 

and that's where i might get hard to distinguish between if heat/poor manufacturing is to blame for these explosions 

 

but id bet it's probably around 1 out of every 100 000 bombs that go boom if that much even 

Posted

I think main thing here is as mentioned before , there's probably no standard on how these things get made and to what tolerance/resolution ect ect.

 

and that's where i might get hard to distinguish between if heat/poor manufacturing is to blame for these explosions 

 

but id bet it's probably around 1 out of every 100 000 bombs that go boom if that much even 

 

 

I think these canisters are used in other domestic and industrial applications so they should be made to an international standard. Ill sift through the IHS library and find it.

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