Closing off your airflow when refilling tanks. ???

[slugster]

Never had a problem myself, I just fill them up

 

[Cliffyboy1962]

I am shamelessly bumping this thread in the hope of more discussion.

 

[speedfreek67]

A caveat here - I'm obviously making this up as I go along, just trying to think it all through.

Firstly would you agree that air can travel freely through the airholes at the bottom, up through the coil and out of the chimney to the drip tip and out to your mouth ? After all, this is how it works.

I'm not sure about the term "freely". Air only does that when you suck through the chimney, creating a negative pressure, and there is some resistance due to the wicking material. Also, there is a viscous liquid in the way.

OK Now why can the pressure not equalise ?

There is still a direct connection betwen this chamber and atmosphere, through the coil and up to the chimney.

The connection is not direct - there is a volume of viscous liquid in the way, and then the wicking material.

Unlikely seeing as equalisation has been occuring all the time up to point of refill.

But does the pressure ever actually equalise before you open the tank? Perhaps the viscosity of the liquid would ensure that the "last bubble" required to equalise the pressure both sides would not come through, as there is not enough difference in air pressure to overcome that viscosity?

Can't see how ?, as surely any increase in pressure here will vent to atmosphere up the chimney.

Perhaps that is why it is recommended to top fill quickly, to seal up the tank again before that happens?

The one thing I can think of that might affect this reasoning is the main variable here. The coil bore dimensions (much thinner on earlier coils and tending to get larger more recently) and coil design. But, no matter how small the hole trough the coil up to the chimney, there has to be an air gap, or the thing wouldn't work.

Still don't get what closing the airflow holes actually does. Is it voodoo ?

Heh, I must admit I'm a little perplexed too. "Micro changes in air density", indeed... (spot the obscure movie reference)

 

[Alstoj79]

Hmmm... got me thinking! There must be some sense in the whole air pressure thing... ever been on an airplane with a half filled tank? Well it doesn't stay half filled for long! And the remedy for this... unscrew the top cap to let air into the tank to equalise the pressure.

 

[Simon G]

For me it's always about when you screw the top back on ..... if you close the airflow off the juice doesn't seem to get pushed through and out the airflow, on some of my tanks if I turn them upside down and then open the airflow they give a little 'sigh' and you can hear the air escaping out of the airflow holes, the pressure was caused by screwing the cap back on.

 

[Simon G]

I'm not sure about the term "freely". Air only does that when you suck through the chimney, creating a negative pressure, and there is some resistance due to the wicking material. Also, there is a viscous liquid in the way.

No mate, you are sucking the air from the bottom of the tank, up though the coil and into the mouth piece, which collects the vapour from the coil on tre way through ... there's no 'viscous liquid' in the way of the airflow... or at least there shouldn't be unless your tank is flooded.

 

[speedfreek67]

@simong err yeah I see what you mean. Dunno what I was thinking there. Perhaps you'd best ignore me.

 

[Simon G]

@simong err yeah I see what you mean. Dunno what I was thinking there. Perhaps you'd best ignore me.

I dunno, you have me thinking now .... maybe you are 'pulling' on the juice in the tank a bit too?

 

[speedfreek67]

I'm sure the term osmosis is gonna get involved somehow.

 

[speedfreek67]

Anyway, apologies to @Cliffyboy1962 , I see what you mean about the freely flowing air now. I'm stumped too, I was leading myself down a blind alley, not thinking of the mechanism of the tank properly at all.