Lighters: Convential vs jet-style

Octavo · 30th January 2014, 05:13 AM

I recently purchased one of these lighters.

It is refillable with the same lighter fluid that ordinary lighters are filled with and the ignition system is a simple electric spark (identical to those found in conventional lighters)

However, the properties of the emitted flame are vastly different. A convential lighter emits a yellow-orange flame that is easily disturbed by wind-currents, provides a fairly significant amount of light and a relatively low heat.

The jet-style lighter emits a blue flame that is not disturbed by wind currents at all and retains its shape. The amount of light emitted is significantly lower, while the heat produced is significantly higher.

I can only deduce that the differences between the flames must be down to the size/placement/shape/number of nozzles.

Can anyone please explain to me, how it is that a flame with such vastly different properties can be produced from the same materials, by simply changing the shape/placement/size/number of nozzles?

Further can anyone explain to me, specifically, why the blue flame retains its shape, how much lower light output and higher heat output?

pics of lighter in operation to follow (if I can get my phone to play along)
ETA:

Octavo · 30th January 2014, 05:28 AM

Pro-tip: While the Jet-Style lighter is great for windy days outside, it sucks for lighting pipes or bongs as all it does is instantly incinerate whatever you were trying to ignite, and getting the lighter positioned correctly so that you don't get the flame blade anywhere near your hands is nearly impossible.

Horatius · 30th January 2014, 05:38 AM

Quote:

Specialized "windproof" butane lighters are manufactured for demanding conditions such as shipboard, high altitude, and wet climates. Some dedicated models double as synthetic rope cutters. Such lighters are often far hotter than normal lighters (those that use a "soft flame") and can burn in excess of 1100 °C. Contrary to common misconception, the windproof capabilities are not achieved from "higher pressure" fuel. Windproof lighters use the same fuel (butane) as standard lighters, and therefore develop the same vapour pressure. The difference is that windproof lighters mix the fuel with air, and pass the butane/air mixture through a catalytic coil. An electric spark starts the initial flame, and soon after the coil is hot enough to sustain a catalytic reaction and cause the fuel/air mixture to burn on contact. In essence, the flame is constantly reignited by the coil.

http://en.wikipedia.org/wiki/Lighter#Operation

Rat · 30th January 2014, 07:03 AM

Same principle as a bunsen burner, I guess, which goes from slow yellow flame to tight blue flame when you add air. Or an oxy-acetylene welding torch, in fact. Still doesn't beat a Zippo.

Octavo · 30th January 2014, 07:18 AM

Originally Posted by Rat

Same principle as a bunsen burner, I guess, which goes from slow yellow flame to tight blue flame when you add air. Or an oxy-acetylene welding torch, in fact. Still doesn't beat a Zippo.

I find Zippo's give the first drag an unmistakable lighter-fluid taste, which I don't like - they are aesthetically pleasing though

Ok, so I understand now that it's not to much the actual nozzle/valve, but the fact that the lighter pre-mixes the butane with air.

What I'd like to know now (from a physics pov) is how does that change the reaction, such that the resultant flame is both windproof, less luminous and has a higher temperature? I suppose the oxygen causes a faster reaction, but why does that result in less light and a more coherent flame?

casebro · 30th January 2014, 07:27 AM

It's a pressurized gas, not old fashioned lighter fluid like Zippos. Beyond that is IS the nozzle design. I suspect disposables will be along shortly that use the same jet-system.

HighRiser · 30th January 2014, 07:38 AM

The difference is the Venturi effect of the combustion chamber. A regular cigarette lighter, like a Bic, burns with a simple open-air flame; similar to a candle. What you are calling a jet lighter accelerates the air in an hourglass-shaped chamber; as the fuel burns, the volume of the combustion products is greatly increased due to heating, and the Venturi chamber is shaped to take advantage of the resulting pressure differential to accelerate the incoming air.

Rat · 30th January 2014, 07:51 AM

Originally Posted by casebro

It's a pressurized gas, not old fashioned lighter fluid like Zippos. Beyond that is IS the nozzle design. I suspect disposables will be along shortly that use the same jet-system.

I used to have one that was about 30 or 40 years old (that is to say would be that old if I still had it), so they are already here.

Bikewer · 30th January 2014, 07:53 AM

I'm old enough to remember when the standard was a Zippo.... Filled with liquid naptha and stinking of same.
I worked for Chrysler for about a year prior to going into police work, about 1967. Everybody smoked in the factory, and there were big open 55-gallon drums of naptha that the guys just outside the welding shop used to clean excess sealer from the newly-welded bodies.
They would just dunk their Zippos in the barrel, and smoke while they were doing it! A miracle we were not incinerated....

And pipe and cigar conneiseurs know that to light one's smoke with such a thing is anathema, nasty fumes and all.

TjW · 30th January 2014, 08:03 AM

The bit about the catalytic coil doesn't make much sense to me. What chemical process is the catalyst facilitating?
All flames are continually reigniting themselves.
The idea of the nozzle working as a sort of carburetor, getting the fuel-air mixture up closer to a stoichometric ratio and burning more efficiently makes sense.

Olowkow · 30th January 2014, 09:42 AM

Originally Posted by TjW

The bit about the catalytic coil doesn't make much sense to me. What chemical process is the catalyst facilitating?
All flames are continually reigniting themselves.
The idea of the nozzle working as a sort of carburetor, getting the fuel-air mixture up closer to a stoichometric ratio and burning more efficiently makes sense.

These are lit by using a piezo-electronic device. When a piece of quartz crystal is struck with a hammer, it emits a small current at right angles to the force, and conversely, if you put a current into it, the crystal will deform.

This small current pulse is converted, using a transformer, to a high voltage, and a spark is created which ignites the fuel. The same system is used on propane barbeque stoves.

Though it looks pretty, I think a blue flame is a bit of overkill for cigarette lighting. Blue flame, like a gas stove, is much hotter than yellow.

You mentioned a catalytic coil. This is a different type of fuel and ignition system. I remember buying one of these lighters quite a few years ago out of curiosity, and it worked for about a week.

I think there is something like a small piece of platinum (an excellent catalyst) is in the flow path of the evaporating highly volatile fuel, which catalyzes the combination of these fumes with oxygen and causes production of a flame. I don't see these any more, and I suspect they may have been kind of dangerous. It used a special liquid fuel, not like Zippo. Not being a chemist, that is the best I can do.

Horatius · 30th January 2014, 10:46 AM

Originally Posted by Olowkow

Though it looks pretty, I think a blue flame is a bit of overkill for cigarette lighting. Blue flame, like a gas stove, is much hotter than yellow.

The big issue with these lighters isn't the temperature or appearance of the flame, it's that they are "wind proof" lighters. I can't say as I've ever tested that, but it is this feature which is desired over standard butane lighters.

MostlyHarmless · 30th January 2014, 11:18 AM

I had several of these in the 20+ years I smoked. They worked great in the wind, even on the deck of a moving boat. I didn't have one that worked for more than one refill.

catsmate · 30th January 2014, 01:21 PM

Originally Posted by Rat

Same principle as a bunsen burner, I guess, which goes from slow yellow flame to tight blue flame when you add air. Or an oxy-acetylene welding torch, in fact. Still doesn't beat a Zippo.

The orange flame is the region of partial combustion where the fuel is starved of oxygen, the blue flame is hotter because the mix has sufficient oxygen.

Personally I prefer an electric lighter, USB recharged, with LED torch.

tyr_13 · 30th January 2014, 01:31 PM

I've used small torches and lighters that work like that for craft purposes. Believe it or not, lighting pipes/bongs/cigarets is not the only use for small flames.

ben m · 30th January 2014, 02:04 PM

Originally Posted by Octavo

Ok, so I understand now that it's not to much the actual nozzle/valve, but the fact that the lighter pre-mixes the butane with air.

What I'd like to know now (from a physics pov) is how does that change the reaction, such that the resultant flame is both windproof, less luminous and has a higher temperature? I suppose the oxygen causes a faster reaction, but why does that result in less light and a more coherent flame?

In a conventional flame, you put gas in the center, air on the outside, and the reaction only proceeds to the extent that diffusion/turbulence brings the two species into contact.

The thing we call a "flame" requires several things to come together. (a) you have to have fuel and air mixed together, (b) the temperature has to get high enough for fuel/air reactions to occur, and importantly (c) the resulting reactions have to heat the next incoming bit of fuel/air to get them to the temperature appropriate for (b).

Notice that (b) and (c) depend on (a). Poorly-mixed fuel/air won't get to high temperature quickly, it has to wait for diffusion (which gives it more time to cool). A flame that's heating up slowly is also rising away from the lighter, which means the heat-generation is farther away from the incoming fuel that needs pre-heating. So, yeah, the flame is cooler.

Then, let's talk about incomplete combustion. If you have fuel (C4H10) mixed with plenty of oxygen, at a good high temperature, your reaction products are all maximally-oxygenated. H all goes into H2O. C all goes into CO2. It just so happens (and no this is not obvious from first principles) that the H2O and CO2 molecules, and the related radicals, do NOT have many excitations that emit visible light. You get some UV, leaking into the blue, and some IR. There's a gap in the visible. By contrast: when you have incomplete combustion, rather than getting pure CO2 and H2O, your fuel molecules end up making a bunch of C2, C3, CH, various floppy hydrocarbons, etc., and those molecules do have lots of emission line features in the visible. So, all else being equal, incomplete/cool combustion tends to produce a more-visible flame. A corollary is that the red-orange-emitting molecules, if they're not quickly mixed with oxygen and allowed to burn, will condense into soot. You don't get soot from that hot blue jet-flame thing.

To see a dramatic demonstration of this, watch rocket launch, or video thereof. Compare the flight of (a) a hydrogen-fueled rocket (where the exhaust is nearly pure H2O) vs. (b) a solid-fueled rocket (where the exhaust is full of chlorine and aluminum molecules). The former is hot but nearly invisible. The latter is also hot, but bright white/yellow/red depending on temperature.

DavidS · 30th January 2014, 02:06 PM

Originally Posted by Octavo

What I'd like to know now (from a physics pov) is how does that change the reaction, such that the resultant flame is both windproof, less luminous and has a higher temperature? I suppose the oxygen causes a faster reaction, but why does that result in less light and a more coherent flame?

A semi-educated estimate without consulting references:

Premixing the fuel with air allows more direct combustion of the hydrocarbon molecules throughout the flame volume, limited by the reaction rate.

Withough the premix, combustion occurs mostly at the air:hydrocarbon interface, limited by the "diffusion" rate. Heat from the interface pyrolizes nearby but still oxygen-starved hydrocarbons into minute particles of carbon, which glow a cooler yellow as their combustion rate is limited by transport of oxygen to their surfaces.

I think (to use the term loosely).

Iamme · 30th January 2014, 10:05 PM

In case you ever run out of matches or lighter fluid/butane...you can always light your cigarette off an electic stove burner.
.
Here`s another tidbit; if you ever show off how you can light a farmer match with one fingernail using one hand...you run the risk of having burning matchhead material stuck under your fingernail. Not pleasant. Lol

Octavo · 30th January 2014, 10:51 PM

Originally Posted by Horatius

The big issue with these lighters isn't the temperature or appearance of the flame, it's that they are "wind proof" lighters. I can't say as I've ever tested that, but it is this feature which is desired over standard butane lighters.

They are definitely completely wind-proof. Lighting them in high winds does sometimes take a few clicks of the trigger, but once lit, they don't go out.

Originally Posted by MostlyHarmless

I had several of these in the 20+ years I smoked. They worked great in the wind, even on the deck of a moving boat. I didn't have one that worked for more than one refill.

I've refilled mince twice for far, so here's hoping!

Originally Posted by ben m

In a conventional flame, you put gas in the center, air on the outside, and the reaction only proceeds to the extent that diffusion/turbulence brings the two species into contact.

The thing we call a "flame" requires several things to come together. (a) you have to have fuel and air mixed together, (b) the temperature has to get high enough for fuel/air reactions to occur, and importantly (c) the resulting reactions have to heat the next incoming bit of fuel/air to get them to the temperature appropriate for (b).

Notice that (b) and (c) depend on (a). Poorly-mixed fuel/air won't get to high temperature quickly, it has to wait for diffusion (which gives it more time to cool). A flame that's heating up slowly is also rising away from the lighter, which means the heat-generation is farther away from the incoming fuel that needs pre-heating. So, yeah, the flame is cooler.

Then, let's talk about incomplete combustion. If you have fuel (C4H10) mixed with plenty of oxygen, at a good high temperature, your reaction products are all maximally-oxygenated. H all goes into H2O. C all goes into CO2. It just so happens (and no this is not obvious from first principles) that the H2O and CO2 molecules, and the related radicals, do NOT have many excitations that emit visible light. You get some UV, leaking into the blue, and some IR. There's a gap in the visible. By contrast: when you have incomplete combustion, rather than getting pure CO2 and H2O, your fuel molecules end up making a bunch of C2, C3, CH, various floppy hydrocarbons, etc., and those molecules do have lots of emission line features in the visible. So, all else being equal, incomplete/cool combustion tends to produce a more-visible flame. A corollary is that the red-orange-emitting molecules, if they're not quickly mixed with oxygen and allowed to burn, will condense into soot. You don't get soot from that hot blue jet-flame thing.

To see a dramatic demonstration of this, watch rocket launch, or video thereof. Compare the flight of (a) a hydrogen-fueled rocket (where the exhaust is nearly pure H2O) vs. (b) a solid-fueled rocket (where the exhaust is full of chlorine and aluminum molecules). The former is hot but nearly invisible. The latter is also hot, but bright white/yellow/red depending on temperature.

That is exactly the kind of explanation I was hoping for! Thanks ben m

Cuddles · 31st January 2014, 07:55 AM

Originally Posted by Horatius

The big issue with these lighters isn't the temperature or appearance of the flame, it's that they are "wind proof" lighters. I can't say as I've ever tested that, but it is this feature which is desired over standard butane lighters.

The temperature can be very useful as well. They're very handy for welding plastic kayaks and the like. There are better methods available, but none quite as small and light that can be easily packed in an emergency kit.

30th January 2014, 05:13 AM	#1
Octavo Illuminator Join Date: Jun 2007 Location: South Africa Posts: 3,485	Lighters: Convential vs jet-style I recently purchased one of these lighters. It is refillable with the same lighter fluid that ordinary lighters are filled with and the ignition system is a simple electric spark (identical to those found in conventional lighters) However, the properties of the emitted flame are vastly different. A convential lighter emits a yellow-orange flame that is easily disturbed by wind-currents, provides a fairly significant amount of light and a relatively low heat. The jet-style lighter emits a blue flame that is not disturbed by wind currents at all and retains its shape. The amount of light emitted is significantly lower, while the heat produced is significantly higher. I can only deduce that the differences between the flames must be down to the size/placement/shape/number of nozzles. Can anyone please explain to me, how it is that a flame with such vastly different properties can be produced from the same materials, by simply changing the shape/placement/size/number of nozzles? Further can anyone explain to me, specifically, why the blue flame retains its shape, how much lower light output and higher heat output? pics of lighter in operation to follow (if I can get my phone to play along) ETA:
	Last edited by Octavo; 30th January 2014 at 05:24 AM. Reason: Adding pic

30th January 2014, 05:38 AM	#3
Horatius NWO Kitty Wrangler Join Date: May 2006 Posts: 27,374	Quote: Specialized "windproof" butane lighters are manufactured for demanding conditions such as shipboard, high altitude, and wet climates. Some dedicated models double as synthetic rope cutters. Such lighters are often far hotter than normal lighters (those that use a "soft flame") and can burn in excess of 1100 °C. Contrary to common misconception, the windproof capabilities are not achieved from "higher pressure" fuel. Windproof lighters use the same fuel (butane) as standard lighters, and therefore develop the same vapour pressure. The difference is that windproof lighters mix the fuel with air, and pass the butane/air mixture through a catalytic coil. An electric spark starts the initial flame, and soon after the coil is hot enough to sustain a catalytic reaction and cause the fuel/air mixture to burn on contact. In essence, the flame is constantly reignited by the coil. http://en.wikipedia.org/wiki/Lighter#Operation
	__________________ Obviously, that means cats are indeed evil and that ownership or display of a feline is an overt declaration of one's affiliation with dark forces. - Cl1mh4224rd

30th January 2014, 07:03 AM	#4
Rat Not bored. Never bored. Moderator Join Date: May 2003 Location: Leicester, UK Posts: 10,624	Same principle as a bunsen burner, I guess, which goes from slow yellow flame to tight blue flame when you add air. Or an oxy-acetylene welding torch, in fact. Still doesn't beat a Zippo.
	__________________ "Man muß den Menschen vor allem nach seinen Lastern beurteilen. Tugenden können vorgetäuscht sein. Laster sind echt." - Klaus Kinski UKLS 1988- Sitting on the fence throwing stones at both sides.

30th January 2014, 07:27 AM	#6
casebro Penultimate Amazing Join Date: Jun 2005 Posts: 16,973	It's a pressurized gas, not old fashioned lighter fluid like Zippos. Beyond that is IS the nozzle design. I suspect disposables will be along shortly that use the same jet-system.
	__________________ Great minds discuss ideas. Medium minds discuss events. Small minds spend all their time on U-Tube and Facebook.

30th January 2014, 07:38 AM	#7
HighRiser Graduate Poster Join Date: Nov 2005 Location: High above Indianapolis Posts: 1,858	The difference is the Venturi effect of the combustion chamber. A regular cigarette lighter, like a Bic, burns with a simple open-air flame; similar to a candle. What you are calling a jet lighter accelerates the air in an hourglass-shaped chamber; as the fuel burns, the volume of the combustion products is greatly increased due to heating, and the Venturi chamber is shaped to take advantage of the resulting pressure differential to accelerate the incoming air.
	__________________ Congratulations, you have successfully failed to model something that you assert "isn't noticeable". -The Man Science is not hopelessly hobbled just because it knows the difference between fact and imagination. -JayUtah

30th January 2014, 05:28 AM	#2
Octavo Illuminator Join Date: Jun 2007 Location: South Africa Posts: 3,485	Pro-tip: While the Jet-Style lighter is great for windy days outside, it sucks for lighting pipes or bongs as all it does is instantly incinerate whatever you were trying to ignite, and getting the lighter positioned correctly so that you don't get the flame blade anywhere near your hands is nearly impossible.

30th January 2014, 07:18 AM	#5
Octavo Illuminator Join Date: Jun 2007 Location: South Africa Posts: 3,485	Originally Posted by Rat Same principle as a bunsen burner, I guess, which goes from slow yellow flame to tight blue flame when you add air. Or an oxy-acetylene welding torch, in fact. Still doesn't beat a Zippo. I find Zippo's give the first drag an unmistakable lighter-fluid taste, which I don't like - they are aesthetically pleasing though Ok, so I understand now that it's not to much the actual nozzle/valve, but the fact that the lighter pre-mixes the butane with air. What I'd like to know now (from a physics pov) is how does that change the reaction, such that the resultant flame is both windproof, less luminous and has a higher temperature? I suppose the oxygen causes a faster reaction, but why does that result in less light and a more coherent flame?

30th January 2014, 07:51 AM	#8
Rat Not bored. Never bored. Moderator Join Date: May 2003 Location: Leicester, UK Posts: 10,624	Originally Posted by casebro It's a pressurized gas, not old fashioned lighter fluid like Zippos. Beyond that is IS the nozzle design. I suspect disposables will be along shortly that use the same jet-system. I used to have one that was about 30 or 40 years old (that is to say would be that old if I still had it), so they are already here.
	__________________ "Man muß den Menschen vor allem nach seinen Lastern beurteilen. Tugenden können vorgetäuscht sein. Laster sind echt." - Klaus Kinski UKLS 1988- Sitting on the fence throwing stones at both sides.

30th January 2014, 07:53 AM	#9
Bikewer Penultimate Amazing Join Date: Sep 2003 Location: St. Louis, Mo. Posts: 12,579	I'm old enough to remember when the standard was a Zippo.... Filled with liquid naptha and stinking of same. I worked for Chrysler for about a year prior to going into police work, about 1967. Everybody smoked in the factory, and there were big open 55-gallon drums of naptha that the guys just outside the welding shop used to clean excess sealer from the newly-welded bodies. They would just dunk their Zippos in the barrel, and smoke while they were doing it! A miracle we were not incinerated.... And pipe and cigar conneiseurs know that to light one's smoke with such a thing is anathema, nasty fumes and all.

30th January 2014, 08:03 AM	#10
TjW Penultimate Amazing Join Date: Mar 2005 Posts: 11,097	The bit about the catalytic coil doesn't make much sense to me. What chemical process is the catalyst facilitating? All flames are continually reigniting themselves. The idea of the nozzle working as a sort of carburetor, getting the fuel-air mixture up closer to a stoichometric ratio and burning more efficiently makes sense.

30th January 2014, 09:42 AM	#11
Olowkow Philosopher Join Date: Oct 2007 Posts: 8,230	Originally Posted by TjW The bit about the catalytic coil doesn't make much sense to me. What chemical process is the catalyst facilitating? All flames are continually reigniting themselves. The idea of the nozzle working as a sort of carburetor, getting the fuel-air mixture up closer to a stoichometric ratio and burning more efficiently makes sense. These are lit by using a piezo-electronic device. When a piece of quartz crystal is struck with a hammer, it emits a small current at right angles to the force, and conversely, if you put a current into it, the crystal will deform. This small current pulse is converted, using a transformer, to a high voltage, and a spark is created which ignites the fuel. The same system is used on propane barbeque stoves. Though it looks pretty, I think a blue flame is a bit of overkill for cigarette lighting. Blue flame, like a gas stove, is much hotter than yellow. You mentioned a catalytic coil. This is a different type of fuel and ignition system. I remember buying one of these lighters quite a few years ago out of curiosity, and it worked for about a week. I think there is something like a small piece of platinum (an excellent catalyst) is in the flow path of the evaporating highly volatile fuel, which catalyzes the combination of these fumes with oxygen and causes production of a flame. I don't see these any more, and I suspect they may have been kind of dangerous. It used a special liquid fuel, not like Zippo. Not being a chemist, that is the best I can do.
Olowkow Philosopher Join Date: Oct 2007 Posts: 8,230

30th January 2014, 10:46 AM	#12
Horatius NWO Kitty Wrangler Join Date: May 2006 Posts: 27,374	Originally Posted by Olowkow Though it looks pretty, I think a blue flame is a bit of overkill for cigarette lighting. Blue flame, like a gas stove, is much hotter than yellow. The big issue with these lighters isn't the temperature or appearance of the flame, it's that they are "wind proof" lighters. I can't say as I've ever tested that, but it is this feature which is desired over standard butane lighters.
	__________________ Obviously, that means cats are indeed evil and that ownership or display of a feline is an overt declaration of one's affiliation with dark forces. - Cl1mh4224rd

30th January 2014, 11:18 AM	#13
MostlyHarmless Thinker Join Date: Mar 2004 Posts: 213	I had several of these in the 20+ years I smoked. They worked great in the wind, even on the deck of a moving boat. I didn't have one that worked for more than one refill.
MostlyHarmless Thinker Join Date: Mar 2004 Posts: 213	__________________ Theology is never any help; it is searching in a dark cellar at midnight for a black cat that isn't there. [Robert A. Heinlein, JOB: A Comedy of Justice]

30th January 2014, 01:21 PM	#14
catsmate No longer the 1 Join Date: Apr 2007 Posts: 21,216	Originally Posted by Rat Same principle as a bunsen burner, I guess, which goes from slow yellow flame to tight blue flame when you add air. Or an oxy-acetylene welding torch, in fact. Still doesn't beat a Zippo. The orange flame is the region of partial combustion where the fuel is starved of oxygen, the blue flame is hotter because the mix has sufficient oxygen. Personally I prefer an electric lighter, USB recharged, with LED torch.
	__________________ As human right is always something given, it always in reality reduces to the right which men give, "concede," to each other. If the right to existence is conceded to new-born children, then they have the right; if it is not conceded to them, as was the case among the Spartans and ancient Romans, then they do not have it. For only society can give or concede it to them; they themselves cannot take it, or give it to themselves.

30th January 2014, 01:31 PM	#15
tyr_13 Penultimate Amazing Join Date: Aug 2008 Posts: 16,034	I've used small torches and lighters that work like that for craft purposes. Believe it or not, lighting pipes/bongs/cigarets is not the only use for small flames.
	__________________ Circled nothing is still nothing. "Nothing will stop the U.S. from being a world leader, not even a handful of adults who want their kids to take science lessons from a book that mentions unicorns six times." -UNLoVedRebel Mumpsimus: a stubborn person who insists on making an error in spite of being shown that it is wrong

30th January 2014, 02:04 PM	#16
ben m Guest Join Date: Jul 2006 Posts: 6,387	Originally Posted by Octavo Ok, so I understand now that it's not to much the actual nozzle/valve, but the fact that the lighter pre-mixes the butane with air. What I'd like to know now (from a physics pov) is how does that change the reaction, such that the resultant flame is both windproof, less luminous and has a higher temperature? I suppose the oxygen causes a faster reaction, but why does that result in less light and a more coherent flame? In a conventional flame, you put gas in the center, air on the outside, and the reaction only proceeds to the extent that diffusion/turbulence brings the two species into contact. The thing we call a "flame" requires several things to come together. (a) you have to have fuel and air mixed together, (b) the temperature has to get high enough for fuel/air reactions to occur, and importantly (c) the resulting reactions have to heat the next incoming bit of fuel/air to get them to the temperature appropriate for (b). Notice that (b) and (c) depend on (a). Poorly-mixed fuel/air won't get to high temperature quickly, it has to wait for diffusion (which gives it more time to cool). A flame that's heating up slowly is also rising away from the lighter, which means the heat-generation is farther away from the incoming fuel that needs pre-heating. So, yeah, the flame is cooler. Then, let's talk about incomplete combustion. If you have fuel (C4H10) mixed with plenty of oxygen, at a good high temperature, your reaction products are all maximally-oxygenated. H all goes into H2O. C all goes into CO2. It just so happens (and no this is not obvious from first principles) that the H2O and CO2 molecules, and the related radicals, do NOT have many excitations that emit visible light. You get some UV, leaking into the blue, and some IR. There's a gap in the visible. By contrast: when you have incomplete combustion, rather than getting pure CO2 and H2O, your fuel molecules end up making a bunch of C2, C3, CH, various floppy hydrocarbons, etc., and those molecules do have lots of emission line features in the visible. So, all else being equal, incomplete/cool combustion tends to produce a more-visible flame. A corollary is that the red-orange-emitting molecules, if they're not quickly mixed with oxygen and allowed to burn, will condense into soot. You don't get soot from that hot blue jet-flame thing. To see a dramatic demonstration of this, watch rocket launch, or video thereof. Compare the flight of (a) a hydrogen-fueled rocket (where the exhaust is nearly pure H2O) vs. (b) a solid-fueled rocket (where the exhaust is full of chlorine and aluminum molecules). The former is hot but nearly invisible. The latter is also hot, but bright white/yellow/red depending on temperature.
ben m Guest Join Date: Jul 2006 Posts: 6,387

30th January 2014, 02:06 PM	#17
DavidS Muse Join Date: Dec 2006 Posts: 623	Originally Posted by Octavo What I'd like to know now (from a physics pov) is how does that change the reaction, such that the resultant flame is both windproof, less luminous and has a higher temperature? I suppose the oxygen causes a faster reaction, but why does that result in less light and a more coherent flame? A semi-educated estimate without consulting references: Premixing the fuel with air allows more direct combustion of the hydrocarbon molecules throughout the flame volume, limited by the reaction rate. Withough the premix, combustion occurs mostly at the air:hydrocarbon interface, limited by the "diffusion" rate. Heat from the interface pyrolizes nearby but still oxygen-starved hydrocarbons into minute particles of carbon, which glow a cooler yellow as their combustion rate is limited by transport of oxygen to their surfaces. I think (to use the term loosely).
DavidS Muse Join Date: Dec 2006 Posts: 623

30th January 2014, 10:05 PM	#18
Iamme Philosopher Join Date: Aug 2003 Posts: 6,214	In case you ever run out of matches or lighter fluid/butane...you can always light your cigarette off an electic stove burner. . Here`s another tidbit; if you ever show off how you can light a farmer match with one fingernail using one hand...you run the risk of having burning matchhead material stuck under your fingernail. Not pleasant. Lol
Iamme Philosopher Join Date: Aug 2003 Posts: 6,214	__________________ I lost my mind many years ago and it hasn't affected me a bit...a bit..a bit..a bit. Last edited by Iamme; 30th January 2014 at 10:07 PM. Reason: Wrong word mysteriously appeared!

30th January 2014, 10:51 PM	#19
Octavo Illuminator Join Date: Jun 2007 Location: South Africa Posts: 3,485	Originally Posted by Horatius The big issue with these lighters isn't the temperature or appearance of the flame, it's that they are "wind proof" lighters. I can't say as I've ever tested that, but it is this feature which is desired over standard butane lighters. They are definitely completely wind-proof. Lighting them in high winds does sometimes take a few clicks of the trigger, but once lit, they don't go out. Originally Posted by MostlyHarmless I had several of these in the 20+ years I smoked. They worked great in the wind, even on the deck of a moving boat. I didn't have one that worked for more than one refill. I've refilled mince twice for far, so here's hoping! Originally Posted by ben m In a conventional flame, you put gas in the center, air on the outside, and the reaction only proceeds to the extent that diffusion/turbulence brings the two species into contact. The thing we call a "flame" requires several things to come together. (a) you have to have fuel and air mixed together, (b) the temperature has to get high enough for fuel/air reactions to occur, and importantly (c) the resulting reactions have to heat the next incoming bit of fuel/air to get them to the temperature appropriate for (b). Notice that (b) and (c) depend on (a). Poorly-mixed fuel/air won't get to high temperature quickly, it has to wait for diffusion (which gives it more time to cool). A flame that's heating up slowly is also rising away from the lighter, which means the heat-generation is farther away from the incoming fuel that needs pre-heating. So, yeah, the flame is cooler. Then, let's talk about incomplete combustion. If you have fuel (C4H10) mixed with plenty of oxygen, at a good high temperature, your reaction products are all maximally-oxygenated. H all goes into H2O. C all goes into CO2. It just so happens (and no this is not obvious from first principles) that the H2O and CO2 molecules, and the related radicals, do NOT have many excitations that emit visible light. You get some UV, leaking into the blue, and some IR. There's a gap in the visible. By contrast: when you have incomplete combustion, rather than getting pure CO2 and H2O, your fuel molecules end up making a bunch of C2, C3, CH, various floppy hydrocarbons, etc., and those molecules do have lots of emission line features in the visible. So, all else being equal, incomplete/cool combustion tends to produce a more-visible flame. A corollary is that the red-orange-emitting molecules, if they're not quickly mixed with oxygen and allowed to burn, will condense into soot. You don't get soot from that hot blue jet-flame thing. To see a dramatic demonstration of this, watch rocket launch, or video thereof. Compare the flight of (a) a hydrogen-fueled rocket (where the exhaust is nearly pure H2O) vs. (b) a solid-fueled rocket (where the exhaust is full of chlorine and aluminum molecules). The former is hot but nearly invisible. The latter is also hot, but bright white/yellow/red depending on temperature. That is exactly the kind of explanation I was hoping for! Thanks ben m

31st January 2014, 07:55 AM	#20
Cuddles Penultimate Amazing Join Date: Jul 2006 Posts: 18,575	Originally Posted by Horatius The big issue with these lighters isn't the temperature or appearance of the flame, it's that they are "wind proof" lighters. I can't say as I've ever tested that, but it is this feature which is desired over standard butane lighters. The temperature can be very useful as well. They're very handy for welding plastic kayaks and the like. There are better methods available, but none quite as small and light that can be easily packed in an emergency kit.