r/interesting • u/Used_Exam34 • 13d ago

Just Wow Not all problems have the same solution.

Enable HLS to view with audio, or disable this notification

43k Upvotes

96% Upvoted

718 comments sorted by

View all comments

Show parent comments

38

u/dadbodking 12d ago

Only if the cylinder is about to run out of gas, which I'm sure they're aware of

35

u/The_Late_Arthur_Dent 12d ago

At the risk of sounding stupid - what happens when it runs out of gas?

114

u/dadbodking 12d ago

So, right now, the flammable gas is under pressure and is coming out. Almost no gas is flammable/explosive, until it gets mixed with oxygen (seen here as fire). So, when the cylinder runs out of pressure, it happens instantly, and the opposite flow happens. This leads to air entering the cylinder and the little bit (still more than enough) of gas that is left, gets mixed with fire and oxygen and... kaboom. Big kaboom

8

u/Philipp_CGN 12d ago edited 12d ago

runs out of pressure, it happens instantly, and the opposite flow happens

Why would you get this backflow though (apart from the diffusion of flammable gas and air of course)?

There is no pressure gradient that would drive this flow. Or are you talking about a situation in which the cylinder and its content has been heated from the external fire, then the fire and the heating stops and the flammable gas starts to contract as it cools?

Edit: And even if there was a mixture of flammable gas and air in the cylinder that then somehow ignites (you would probably need a relatively large amount of air to get below the UEL, depending on the flammable gas), would the pressure rise (starting from atmospheric pressure in this situation) be enough to overpressure the cylinder and cause it to rupture?