On 16/11/2014 15:48, Thomas de Groot wrote:
> On 16-11-2014 15:13, Stephen wrote:
>> The heat is taken from the air and the hand that is holding it. You can
>> feel the lighter getting cold and you can hear the butane rushing into
>> the lighter. The sound will stop when the pressure has equalised and the
>> lighter will continue to fill up.
>>
>
> Such a long time since I stopped smoking that I only dimly remember
> these things. The cold comes from the gas expanding, right? Same way as
> a fridge.

Correct.

> Your last sentence seems contradictory to me. With equal
> pressure no further fill up, or am I wrong (probability: 98%)?
>

And the argument is: If it is not a difference in pressure then it must 
be gravity that is making the liquid flow.
And because you do not have the opportunity to do the experiment 
yourself. If when you are filling a lighter and you turn the system 
upside down so that the lighter is above the gas cylinder. A lot of the 
liquid drains into the gas cylinder. Gravity?
Some cigarette lighters have the chamber split into two by a dividing 
weir. If you keep the liquid in the chamber underneath the valve. The 
liquid will rise to the top of the weir and stop rising. No more gas 
will go in. Then if you tip the lighter so that the liquid spills into 
other chamber. The empty part (under the valve) can then be filled.

I first had this discussion 25 years ago and would quite like to know 
the answer.


-- 

Regards
     Stephen

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> And the argument is: If it is not a difference in pressure then it must
> be gravity that is making the liquid flow.

It's sort of both.
Picture instead the ordinary case of filling a vessel with liquid at atmospheric
pressure through a narrow orifice.
At first there may be a rapid flow of liquid until the headspace gets compressed
and builds up pressure.
THEN there needs to be a chance for the gaseous headspace to bubble up and trade
volume with the liquid for there to be a mass transfer.
The problem lies in only one very narrow tube for bidirectional flow.

If there were a two-way filling mechanism, or a way to vent the gaseous
headspace, then you'd get rapid filling.

Another alternative might be to iteratively overfill with liquid by an increase
in pressure, or by chilling and contracting the headspace, and then letting the
back-pressure bubble up back into the fill vessel.

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On 16-11-2014 22:59, Bald Eagle wrote:
>
>> And the argument is: If it is not a difference in pressure then it must
>> be gravity that is making the liquid flow.
>
> It's sort of both.
> Picture instead the ordinary case of filling a vessel with liquid at atmospheric
> pressure through a narrow orifice.
> At first there may be a rapid flow of liquid until the headspace gets compressed
> and builds up pressure.
> THEN there needs to be a chance for the gaseous headspace to bubble up and trade
> volume with the liquid for there to be a mass transfer.
> The problem lies in only one very narrow tube for bidirectional flow.
>
> If there were a two-way filling mechanism, or a way to vent the gaseous
> headspace, then you'd get rapid filling.
>
> Another alternative might be to iteratively overfill with liquid by an increase
> in pressure, or by chilling and contracting the headspace, and then letting the
> back-pressure bubble up back into the fill vessel.
>

I find this explanation neat, although I am not entirely satisfied 
somehow. Imho the problem resides in the fact that the liquid is a 
compressed gas which will want to expand as soon as there is a 
possibility for it. I dimly remember that refilling a lighter often gave 
frustrating results as it was impossible to refill up to the initial 
level... with the exception of the use of a /pressurised/ filling mechanism.

Thomas

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> But it is only liquid because it is under pressure. As soon as some
> liquid is in the lighter it vaporises to fill the chamber and if the
> resultant pressure is less than the pressure in the gas cylinder more
> liquid will go into the lighter until the system will reach stability.
>
>> Yes, adding liquid to the lighter gives back a bit of pressure for the
>> lighter's side, but not enough. The fresh liquid could vaporize to
>> provide more gas but that transformation requires a lot of heat which is
>> not available at the refill time.
>>
> The heat is taken from the air and the hand that is holding it. You can
> feel the lighter getting cold and you can hear the butane rushing into
> the lighter. The sound will stop when the pressure has equalised and the
> lighter will continue to fill up.

I haven't had chance to think in detail what is happening (nor do I have 
much experience with refilling lighters), but I suspect a good 
understanding of vapour pressure and how it changes with temperature is 
required:

http://en.wikipedia.org/wiki/Vapor_pressure
http://en.wikipedia.org/wiki/Butane_(data_page)#Vapor_pressure_of_liquid

Also bear in mind that it might not be 100% pure butane in the refill 
(or there might be some air in the lighter), so you better also know 
about partial pressure :-)

http://en.wikipedia.org/wiki/Partial_pressure

It sounds to me from what you describe that it's got something to do 
with things heating up or cooling down, causing the vapour pressure to 
change. An interesting experiment would be to prepare the lighter to be 
cooler or warmer than the refill canister and note any difference in 
behaviour when it is refilled.

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> The heat is taken from the air and the hand that is holding it. You can
> feel the lighter getting cold and you can hear the butane rushing into
> the lighter. The sound will stop when the pressure has equalised and the
> lighter will continue to fill up.

One possibility is that the sound you hear is actually a small amount of 
gas flowing rapidly into the lighter (or liquid that instantly 
evaporates as it hits the low pressure in the empty lighter) before the 
liquid starts to flow through the opening. When the sound stops that 
isn't because the pressure has equalised, just that it is liquid flowing 
much slower then rather than gas flowing quickly.

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On 11/16/2014 10:42 AM, Stephen wrote:
> On 16/11/2014 15:48, Thomas de Groot wrote:
>> On 16-11-2014 15:13, Stephen wrote:
>>> The heat is taken from the air and the hand that is holding it. You can
>>> feel the lighter getting cold and you can hear the butane rushing into
>>> the lighter. The sound will stop when the pressure has equalised and the
>>> lighter will continue to fill up.
>>>
>>
>> Such a long time since I stopped smoking that I only dimly remember
>> these things. The cold comes from the gas expanding, right? Same way as
>> a fridge.
>
> Correct.
>


Almost, but not fully.

The cold comes from the phase change from liquid to gas (It takes energy 
to evaporate the liquid, and the liquid will happily do so, because the 
equilibrium favors the gas phase (lower pressure on the cold side) If 
there is not enough pressure on the hot side (i.e. not enough coolant) 
to condense the gas to a liquid, the refrigeration is minimal to 
nonexistent.


... As for the rest of the conversation, it's fascinating; I think it's 
pressure difference that fills the lighter.

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On 17-11-2014 15:09, Raiford, Michael wrote:
> On 11/16/2014 10:42 AM, Stephen wrote:
>> On 16/11/2014 15:48, Thomas de Groot wrote:
>>> On 16-11-2014 15:13, Stephen wrote:
>>>> The heat is taken from the air and the hand that is holding it. You can
>>>> feel the lighter getting cold and you can hear the butane rushing into
>>>> the lighter. The sound will stop when the pressure has equalised and
>>>> the
>>>> lighter will continue to fill up.
>>>>
>>>
>>> Such a long time since I stopped smoking that I only dimly remember
>>> these things. The cold comes from the gas expanding, right? Same way as
>>> a fridge.
>>
>> Correct.
>>
>
>
> Almost, but not fully.
>
> The cold comes from the phase change from liquid to gas (It takes energy
> to evaporate the liquid, and the liquid will happily do so, because the
> equilibrium favors the gas phase (lower pressure on the cold side) If
> there is not enough pressure on the hot side (i.e. not enough coolant)
> to condense the gas to a liquid, the refrigeration is minimal to
> nonexistent.

Ah! Thank you for that correction. Phase change indeed.

>
>
> ... As for the rest of the conversation, it's fascinating; I think it's
> pressure difference that fills the lighter.
>

That's my best guess too.

Thomas

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Cooling in refrigeration is accomplished by adiabatic expansion of the
refrigerant gas - a rapid increase in the entropy due to the phase change from
liquid to gas.  From the ideal gas laws, P1V1/T1 = P2V2/T2   Change the pressure
and volume, and the temperature changes as a consequence.  See "Carnot cycle".

> I find this explanation neat, although I am not entirely satisfied
> somehow. Imho the problem resides in the fact that the liquid is a
> compressed gas which will want to expand as soon as there is a
> possibility for it.

That's irrelevant once the pressure differential between the two containers is
equilibrated.  What evaporated into gas can be recompressed back into liquid.

> I dimly remember that refilling a lighter often gave
> frustrating results as it was impossible to refill up to the initial
> level... with the exception of the use of a /pressurised/ filling mechanism.
>
> Thomas

Yes, when refilling with butane the filling container is obviously pressurized.

I believe that there are several interrelated issues here.

First, most people hold the butane refiller to the refilling valve, depress, and
then it's over and done with.  The system has not been given a chance to attain
equilibrium.

Second, there is likely to be a mixture of gases at play -

From http://lighterreviews.com/butane/  :

"Butane, is either of two isomeric flammable gaseous alkanes C4H10 usually
obtained from petroleum or natural gas and used as a fuel. Most butane for cigar
lighters is a mixture of of butane as noted above, isobutene , propane and a
small amount of air (yup the stuff we breath everyday). "

When you use the lighter, the butane flows from the bottom, through a "dip
tube".
http://www.inpharmix.com/jps/_images/exploded%20lighter%20labeled.jpg

Which means that the less volatile components, the ones that tend to remain
liquid as the lighter gets used, are pushed out by the headspace gas - composed
of the comparatively less liquifiable components.  After several
discharge/refill cycles, the lighter becomes filled with a higher proportion of
less liquifiable compounds, and so requires either more pressure to complete the
same fuel transfer, or venting of the more volatile components.

You could hold down the fuel lever to vent these gases before refilling, or more
effectively, hold the partially full lighter upside down while doing so -
causing the expansion of the less volatile components to push the more volatile
ones out the dip tube (which is now at the top).
You could then refill the lighter which has been depleted of those other
components.

To enhance filling, you could heat the butane refiller while filling with warm
water or a towel soaked in hot water.  Alternatively, you could chill the
lighter in the freezer before filling.

And, you could just wait and keep the filler depressed against the lighter for
far longer than most people do so that equilibrium can be more closely achieved.

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On 17/11/2014 17:04, Bald Eagle wrote:
> That's irrelevant once the pressure differential between the two containers is
> equilibrated.  What evaporated into gas can be recompressed back into liquid.
>

Yes, if we ignore heat transfer from the outside it is a closed system.

>> >I dimly remember that refilling a lighter often gave
>> >frustrating results as it was impossible to refill up to the initial
>> >level... with the exception of the use of a/pressurised/  filling mechanism.
>> >
>> >Thomas
> Yes, when refilling with butane the filling container is obviously pressurized.
>
> I believe that there are several interrelated issues here.
>

Nicely observed and the image is handy too.

 > http://www.inpharmix.com/jps/_images/exploded%20lighter%20labeled.jpg

I think that there is an additional factor. As Scott pointed out vapour 
pressure might have something to do with it as well. I did mention but 
it was probably overlooked.
When you fill the lighter the liquid fills the part of the chamber below 
the valve then stops. (Using the image you posted. The central divider 
in the lighter body, is the other way around and the gap is at the valve 
end.) At this point the system is in equilibrium. If you then pour some 
of the liquid into the empty part. You can fill the lighter to a similar 
level in the first chamber.
So I am guessing that it has to do with a function of vapour pressure 
and the distance from the top of the liquid to the inlet valve.


-- 

Regards
     Stephen

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On 17/11/2014 12:25, scott wrote:
>> The heat is taken from the air and the hand that is holding it. You can
>> feel the lighter getting cold and you can hear the butane rushing into
>> the lighter. The sound will stop when the pressure has equalised and the
>> lighter will continue to fill up.
>
> One possibility is that the sound you hear is actually a small amount of
> gas flowing rapidly into the lighter (or liquid that instantly
> evaporates as it hits the low pressure in the empty lighter) before the
> liquid starts to flow through the opening. When the sound stops that
> isn't because the pressure has equalised, just that it is liquid flowing
> much slower then rather than gas flowing quickly.
>

You could very well be right. I did not think of that.
Someone needs to do a doctoral theses on the subject. :-)

-- 

Regards
     Stephen

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