Good point! But I still won't try to pass a chem test by claiming nitrogen is one of the "inert gases". And I won't try to define "vacuum" without specifying (somehow) the pressure or density or parts per (insert volume measurement here). And when someone calls me a "troll" I will take that as an absurd statement that nowadays just means "This is MY internet, and I don't want you using it!". AND (in conclusion)(finally) when someone resorts to babbling made up words (like "f****it") I WILL decide that they have nothing to say, and I will go on to more profitable interchanges.
Usually a mixture of argon and nitrogen, more argon than nitrogen. I have seen a cite or two indicating a common mixture to be 93% argon 7% nitrogen. Argon is preferable due to lower heat conductivity, while nitrogen impairs formation of destructive arcs across the filament.
In air, the filament will oxidize very rapidly, to the point of complete failure in usually a few to several seconds.
In a vacuum, the filament evaporates more quickly, although heat conduction from a gas is eliminated. A gas slows down evaporation of the filament because gas atoms bounce most evaporated tungsten atoms back towards the filament. A gas permits a higher filament temperature by slowing evaporation. A higher filament temperature achieves a higher percentage (although still a minority) of the filament's radiation being visible rather than infrared.
Some filament designs have higher energy efficiency when operated at reduced temperature in a vacuum. If the filament is a low current design dissipating less than *roughly* 10 watts per centimeter of apparently visible filament length (as a "rough rule" as far as I have seen), then you get better "overall luminous efficacy" (lumens of light out per watt in) with a vacuum and lower filament temperature than with argon-nitrogen mixture and higher temperature.
I have seen pure argon in a very few low voltage lamps. Even in low voltage lamps where nitrogen is not necessary to block arc formation, it appears to me that the compromise of 93% argon 7% nitrogen compared to pure argon makes a difference small enough for many or most manufacturers to prefer to not have to use two different gas formulations.
There are premium fill gases, mainly ones with argon or krypton. The larger atoms of these heavier fill gases make them more effective than argon at slowing filament evaporation. The heavier molecular weight reduces heat conduction losses. These premium gases are widely mentioned to be used in flashlight lamps, whose small size reduces the expense of these premium gases.
I have seen 120V lamps (mostly some traffic signal ones) and some automotive ones having a krypton-nitrogen mixture. Older GE "miser"
120V incandescents 60-100 watts made close to 1980 achieved a power consumption decrease of 5 watts with essentially no compromise in life expectancy or light output. (More recent GE "Misers" did not have krypton and had compromised light output.) Some automotive lamps have life claimed to be doubled with no significant compromise in light output nor significant increase in power cosnumption as an achievement of using krypton.
Flashlight lamps with premium fill gases producing 2.5-3 times the light of "ordinary" ones also consume 1.5-1.75 times as much power, and in addition benefit from a couple "economies of scale":
a) The thicker higher power filament takes longer to be destroyed by evaportion and can be operated at a higher temperature.
b) Percentage of input power being heat conduction loss by fill gas decreases with thicker filaments. Reason: As filament diameter increases, the "boundary layer" of hot gas between the filament and the surrounding cooler gas gets thicker and its temperature gradient decreases. As a result, heat conduction loss per unit length of visibly apparent filament increases less than proportionately (often hardly at all) as filament diameter is increased.
Use of a premium fill gas usually achieves a 5-25% increase in energy efficiency if wattage, voltage and life expectancy are unchanged, with the gains being bigger in lower wattage / lower current designs where the efficiency of a given combination of voltage, wattage and design life expectancy is less no matter what. (Ever notice the design life expectancy of incandescent flashlight lamps - usually 10-30 hours?)
Halogen lamps have an inert gas (argon, krypton or xenon) plus a trace of a halogen - traditionally iodine - but maybe in some cases a halide.
The main benefit of halogen is keeping the inside surface of the bulb clean. Life extension from returning of evaporated tungsten to the filament is disappointingly small because the "halogen cycle" is not good at depositing returned tungsten to where it is most needed.
However, halogen lamps often have significant improvement in efficiency and/or life expectancy over non-halogen ones for a couple other reasons:
The bulb or its "inner capsule" (in the case of ones with inner and outer bulbs) is small and is usually made of a higher strength material and has material thickness usually greater than usual for non-halogen bulbs of similar size. That permits much higher fill gas pressure, which reduces filament evaporation more.
The small size of this bulb or "inner capsule" increases the economic feasibility of use of premium inert main ingredient of the fill gas.
You got the room temperature pressure correct, but the usual mixture is one of argon and nitrogen with more argon.
Keep in mind that depending on filament/lamp design (especially in terms of power input per unit length of apparently visible filament) it can be preferable to use a vacuum and operate the filament at a lower temperature.
Among 120V lamps, a very few specialized 60-watters, some but not most common 40-watters, some 25-watters and most to all 25 watts or less have a vacuum and are supposed to have one.
Also, many low voltage lamps designed for .3 amps or less and most designed for less than .2-.25 amp have a vacuum.
There are some non-defective ones with a vacuum and that last thousands of hours - although energy efficiency is low (and not improved by gas fill due to heat conduction loss) and the color is more orangish-yellowish, with color temperature being around or a little under 2500 Kelvin. Lower current (60 mA or less) lower power indicator lamps designed to last
15,000 - 50,000 hour may have color close to that of a candle flame and overall luminous efficacy 2-5 lumens per watt but they have a vacuum! Example - every 120V lightbulb 15 watts or less that I have ever seen! Go ahead and crush a 5,000 hour 4 watt 120V nightlight bulb under water and see how much gas comes out!
I do want to mention that helium and neon and maybe argon have yet to be known to undergo any chemical reaction. Although noble gases with electronegativity less than that of fluorine have formed fluorides and ones with electronegativity less than that of oxygen have formed oxides.
There are plenty of compounds of xenon, while neon has at best formed claptrates (not chemical compounds so much as making neon atoms fit into spaces in molecular or crystal structure).
Usual 120V household lightbulbs 60 watts or more have a gas fill. Most lower voltage lamps of wattage at least 2.25 watts and current at least .48 amp have a gas fill. Most incandescent lamps designed for less than .2 amp have a vacuum.
120V tubular "showcase" and "refrigerator" bulbs up to 40 watts with a filament of length near or over 7 cm (close to 3 inches) have a vacuum. So do 60 watt showcase lamps with filament length around/over 15 cm (6 inches).
120V lightbulbs 15 watts or less mainly to close to entirely contain a vacuum, even if made by "Big 3" manufacturers in first world countries in the 1970's or 1980's.
Whadda you mean "works". Your schematic was a HIGHLY specialized little gimmick, that even if it did "work" would only fit your needs (and only at the present moment). No one but you would ever know if it was "working". And what was that thing (named schematic) I posted supposed to do, that it didn't do? And who is doing the supposing? I didn't make any claims for it.
If you insist that a vacuum must contain no atoms (or other particles) whatsoever, then vacuums do not exist ANYWHERE in the universe. Not even in intergalactic space.
If you insist that an "inert" substance not react with
**anything**, then there are no inert substances.
If you want to talk about practical uses of vacuums and inert substances, then you have to accept that a vacuum can contain some atoms. And an "inert" substance can still react under the right circumstances.
Mark
Oh, and one more thing. If you refer to things like nitrogen, without specifying whether you mean single-atoms or N2 molecules, you shouldn't expect others to read your mind and know which one you meant to say.
--- From my POV, the vacuum exists everywhere _except_ where there is matter, which means that the huge majority of the volume of our universe is The Vacuum. Kind of like a huge lacy Swiss cheese in reverse, where the holes represent particles of matter and the cheese represents the space between them.
Thank you, I was indeed deliberately avoiding the difference between atomic nitrogen and molecular nitrogen. Molecular nitrogen NEVER reacts with ANYTHING! Now I will go out on the front porch, and NOT breathe the nitrogen compounds that are NEVER put out by the vehicles that NEVER pass my porch. I humbly stand corrected. Or I could get with the times and realize that technology is now routinely creating temperatures and/or pressures sufficient to react molecular nitrogen. Beer ain't just for breakfast anymore, and ammonia ain't just for microbes anymore.
I still won't try to pass a chem test by calling nitrogen an "inert gas" but I would be willing to say that "nitrogen is relatively inert compared to oxygen" (if I was allowed to use the whole phrase before someone jumped on me).
------------------- You're an ass!! Nitrogen is used in light bulbs for that reason, asswipe.
It is an inert gas at most temperatures, and so called noble gases are NOT, and can and do form compounds!
-Steve
--
-Steve Walz rstevew@armory.com ftp://ftp.armory.com/pub/user/rstevew
Electronics Site!! 1000\'s of Files and Dirs!! With Schematics Galore!!
http://www.armory.com/~rstevew or http://www.armory.com/~rstevew/Public
Nitrogen is not an inert gas to chemists. Nitrogen is not an inert gas to the EPA and the environmental activists Nitrogen is not an inert gas to MIG and TIG welders. I'm not going to post a complete list. "Noble gas" compounds are rare, nitrogen compounds are common. It gets hot inside a light bulb. Yes I am an "asswipe", every morning I have to wipe you off my ass.
You're a goddamned idiot. You're a goddaamned total retard. You starred in that movie "Total Retard", I just know it. You're a goddamned idiot. You could be a bit more retarded, but not today. You're a goddamned retard, Hey, you brainless fucktard... MOOOOooOOoOoOooooo! Alas, the stupid bastards I think an ass boot rail gun is better than merely being the projectile in a rail gun. Makes for better video. You are full of shit, fucktard. You can't have it both ways, dipshit. You're a goddamned idiot. Even your country with apparently at least one pathetic fucktard... You pathetic, biased little pussy. You don't get it. We
are NOT playing, dumbass. We are a peaceful nation. You attack us, you die. So f*ck you, retard boy. You're so full of shit, your eyes are brown, and there is
a foul stench emanating from your ears. Yes, you do have the right, you stupid bastard, You're so full of shit. you stupid, retarded f*ck! You're soooo full of shit, boy.You're a goddamned loony tunes idiot., you stupid f*ck. You're an idiot. Like you with your bullshit retarded pseudonym posts? Oooops... BUSTED! You're an idiot. Put that in your memo box. You're an idiot. Damn! You got one right. You're both idiots. You don' know shit, boy. You are truly a clueless bastard. I never said it was, you f****ng retard. Like I give a shit whether you read my posts or not. You self impotent twit. It is not a funny shape. Your brain has a funny shape.
Your keyboard and monitor must be taking quite a pounding. Your anger and frustration is caused by your inability to live in the larger "real" world. Perhaps you might be happier if you went back to sitting around the campfire and chipping arrowheads with the rest of the JUNGLE BUNNIES! You won't have any worries about nitrogen if you stay in your milieu.
That is news to me, with me having yet to hear of environmental activists complaining about the roughly 78-79% of the atmosphere that is nitrogen.
How severely? How badly? How does nitrogen fare in welding? Is argon preferred for corrosion issues or issues of heat conduction (lower?) or greater ease of striking and maintaining an arc which it surely has? Ease of having an arc is a downside in lightbulbs, and appears to me the main reason lightbulbs usually have a mixture of mostly argon with some nitrogen instead of the otherwise-better only argon.
That is true! Also, some noble gases have never been known to form any compunds - helium and neon. Argon only forms compounds under extreme conditions and also only when fluorine is involved and then first achieved in 2000. (I am excluding claptrates, where atoms of the element in question get fitted into a molecular structure, without any covalent or ionic bonding.)
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