Hi all, Greatly appreciate all the posts here. They have helped me get two “Petromax” kerosene single mantle lamps going very nicely. Now for my topic: Recall if you will chemistry class where the gas fired Bunsen burner was displayed. The copper gauze atop which the beaker to heat (whatever) was placed between flame and beaker. The flame from burner would either burn above gauze (but not below) or, below gauze (impinging often on gauze), but not above. Either flame arrangement was possible hit in now wise did flame pass through gauze. Now, by contrast the mantle: Why is there no impingement? Flame easily passes through whilst burning inside (blue) the mantle! I would love to know why! Is it because the mantle is so nearly massless? Temperatures are so high the flame never “sees” it? Thanks in advance for all comments, And thanks again for such a helpful site!
Rod, in some way you already described the answer to your question yourself: As the mantle is nearly massless, it just doesn't have the thermal capacity to prevent the flame from burning inside it, even when ignited from the outside (as usual). That's unlike e. g. the burner nozzle under normal conditions: If all runs well, the tiny holes in the burner head will prevent the flamelets from creeping inside the burner, and thus burning the (stoichiometric) fuel/air mixture already inside the mixing tube. There are other burners e. g. at the Coleman lamps & lanterns, where a simple metal mesh is doing the same job: because its thermal capacity is still high enough (or better: its thermal resistance is low enough), the flamelets will well stay outside the burner, but within the mantle. The mantle is not as hot as the visible colour would suggest, because due to various chemical processes inside the flame plasma, a sufficient amount of energy is transferred to the mantle's ashes that will induce the light emission, which isn't in fact the spectrum of a black body, but has a very distorted spectrum that only looks like white light to the human eye. Hope that answers your question, Martin ***edit: The metal mesh inside the Coleman burners is often referred to as the "burner screen".***
Humphry Davy's miners' safety lamp. Davy lamp - Wikipedia If you get a hole in your mantle flame will indeed pass through and can damage the globe by creating a hot spot in a localized area.
@Reese Williams That's more a problem of the unevenly distributed flame when the mantle has got a hole: An intact mantle will almost evenly distribute the combustion gases or flame plasma flowing around it, whereas a hole will cause combustion gases to erupt in the appropriate direction. This will eventually create a hotspot that can damage the glass or other parts inside the lamp / lantern.
Another interesting aspect: the miner's safety lamps, with the help of the metal mesh, reliably prevent the ignition of an explosive atmosphere outside the combustion chamber, even if explosive gas mixtures enter the lamp. But this can be seen as an effect on the flame, which actually indicates that the atmosphere is indeed dangerous.
Replies appreciated! Ironically, a hole developed that pointed hot gases right at the vaporizer tube! Boy it runs great! Lol… After replacing the fuel jet ye olde 500 is running very nicely. Mantle comments most excellent thanks
