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From: Stephen
Subject: A question for big brains.
Date: 16 Nov 2014 06:17:15
Message: <546887bb$1@news.povray.org>
What causes cigarette lighter gas to flow from the refill into the 
lighter? Is it gravity or pressure?

Just because, Andrew is AWOL

-- 

Regards
     Stephen


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From: Thomas de Groot
Subject: Re: A question for big brains.
Date: 16 Nov 2014 06:54:32
Message: <54689078$1@news.povray.org>
On 16-11-2014 12:17, Stephen wrote:
> What causes cigarette lighter gas to flow from the refill into the
> lighter? Is it gravity or pressure?
>
> Just because, Andrew is AWOL
>

Pressure, My guess.

Thomas


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From: Le Forgeron
Subject: Re: A question for big brains.
Date: 16 Nov 2014 07:22:35
Message: <5468970b$1@news.povray.org>
On 16/11/2014 12:54, Thomas de Groot wrote:
> On 16-11-2014 12:17, Stephen wrote:
>> What causes cigarette lighter gas to flow from the refill into the
>> lighter? Is it gravity or pressure?
>>
>> Just because, Andrew is AWOL
>>
> 
> Pressure, My guess.
> 
> Thomas
> 
It's a liquid... pushed by its own vaporized gas on the free surface
(inside the refiller can).

To refill (quite an old practice, nowadays with no-refill lighters), the
difference of pressure (from empty lighter with nearly no more gas vs
the refill at whole pressure due to the big amount of liquid providing
enough gas on the free part) found on its way the liquid and push it to
the weakest part (the empty lighter)

That is for the butane lighters.

Now, if you are using an old Zippo, the refill is with nafta and there
is no pressure, just gravity, like when you pour a drink.

-- 
IQ of crossposters with FU: 100 / (number of groups)
IQ of crossposters without FU: 100 / (1 + number of groups)
IQ of multiposters: 100 / ( (number of groups) * (number of groups))


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From: Stephen
Subject: Re: A question for big brains.
Date: 16 Nov 2014 07:48:36
Message: <54689d24$1@news.povray.org>
On 16/11/2014 12:22, Le_Forgeron wrote:
> On 16/11/2014 12:54, Thomas de Groot wrote:
>> On 16-11-2014 12:17, Stephen wrote:
>>> What causes cigarette lighter gas to flow from the refill into the
>>> lighter? Is it gravity or pressure?
>>>
>>> Just because, Andrew is AWOL
>>>
>>
>> Pressure, My guess.
>>
>> Thomas
>>
> It's a liquid... pushed by its own vaporized gas on the free surface
> (inside the refiller can).
>
> To refill (quite an old practice, nowadays with no-refill lighters), the
> difference of pressure (from empty lighter with nearly no more gas vs
> the refill at whole pressure due to the big amount of liquid providing
> enough gas on the free part) found on its way the liquid and push it to
> the weakest part (the empty lighter)
>
> That is for the butane lighters.
>
> Now, if you are using an old Zippo, the refill is with nafta and there
> is no pressure, just gravity, like when you pour a drink.
>
You are both saying pressure and yes I am talking about butane lighters.
Consider this, the pressure differential between the gas cylinder and 
the lighter is equalised within a fraction of a second. Yet still the 
liquid flows after that.


-- 

Regards
     Stephen


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From: Le Forgeron
Subject: Re: A question for big brains.
Date: 16 Nov 2014 07:56:24
Message: <54689ef8$1@news.povray.org>
On 16/11/2014 13:48, Stephen wrote:

> You are both saying pressure and yes I am talking about butane lighters.
> Consider this, the pressure differential between the gas cylinder and
> the lighter is equalised within a fraction of a second.

How ? the lighter has a depleted pressure chamber, and only liquid is
flowing from the refiller.

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.

> Yet still the
> liquid flows after that.
> 
> 


-- 
IQ of crossposters with FU: 100 / (number of groups)
IQ of crossposters without FU: 100 / (1 + number of groups)
IQ of multiposters: 100 / ( (number of groups) * (number of groups))


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From: Stephen
Subject: Re: A question for big brains.
Date: 16 Nov 2014 09:13:32
Message: <5468b10c$1@news.povray.org>
On 16/11/2014 12:56, Le_Forgeron wrote:
> On 16/11/2014 13:48, Stephen wrote:
>
>> You are both saying pressure and yes I am talking about butane lighters.
>> Consider this, the pressure differential between the gas cylinder and
>> the lighter is equalised within a fraction of a second.
>
> How ? the lighter has a depleted pressure chamber, and only liquid is
> flowing from the refiller.
>

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.

>> Yet still the
>> liquid flows after that.
>>
>>
>
>


-- 

Regards
     Stephen


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From: Thomas de Groot
Subject: Re: A question for big brains.
Date: 16 Nov 2014 10:48:10
Message: <5468c73a$1@news.povray.org>
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. Your last sentence seems contradictory to me. With equal 
pressure no further fill up, or am I wrong (probability: 98%)?

Thomas


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From: Stephen
Subject: Re: A question for big brains.
Date: 16 Nov 2014 11:42:39
Message: <5468d3ff$1@news.povray.org>
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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From: Bald Eagle
Subject: Re: A question for big brains.
Date: 16 Nov 2014 17:00:01
Message: <web.54691e59d7fb850d5e7df57c0@news.povray.org>
> 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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From: Thomas de Groot
Subject: Re: A question for big brains.
Date: 17 Nov 2014 03:27:51
Message: <5469b187$1@news.povray.org>
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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