How does butane gas flow from a canister to refill a lighter?

[M.Kalai vanan]

when butane lighters are refilled by external canister, HOW and WHY butane gas flows from canister to lighter
Is it due to GRAVITY or VAPOR PRESSURE?
If GRAVITY is the reason I have posted a link where torch is held above the canister?
If it is vapor pressure, it is going to be same is both the tanks ?
Some one please explain HOW this actual transfer is happening ?

 

[Lord Jestocost]

Have a look at https://www.physicsforums.com/threads/refilling-butane-lighter-the-physics-way.900000/

 

[anorlunda]

Have a look at https://www.physicsforums.com/threads/refilling-butane-lighter-the-physics-way.900000/

Thanks. That was a very interesting thread.

 

[M.Kalai vanan]

Thanks
But I still don't have a clear picture
If the lighter tank is vented to atmosphere causing a pressure drop between canister and tank,
Will then the
volume of fuel exiting the tank= volume of fuel entering the tank from canister
Then how does it gets filled