How is this possible?
And why isn’t it reproducible?
Yah, my Mom had a two pairs of light bulbs on her vanity that had been going for at least 20 years, and she used them quite often. I assume they’re still going, however we sold the vanity about 5 years ago.
I don’t know squat about light bulbs, so this is a wild guess, but I think you could come up with a metal that didn’t burn up so easily from the heat. As long as the metal is in tact it will keep going.
I suspect we don’t have these because the light bulb companies would rather you buy more cheap light bulbs than one expensive one (and I would think not that expensive).
It’s only a 4 watt bulb; that filament can’t be getting all that hot.
The bulb is likely one of Edison’s, with a carbonized bamboo filament. Did you notice how yellow it’s light is in the pictures? That’s because it runs at a lower temperature than modern tungsten bulbs. The lower temperature slows the evaporation of filament material, and subsequent breakage. You could probably get the same longevity out of a modern bulb, if you were willing to run it off of a 50 volt circuit.
Also, these long lasting light bulbs are always left on so they don’t suffer fatigue from heating up and cooling down.
Haj
Or those evil bastards at GE could put a filament inside the bulb that’s actually intended to last a decent amount of time, and construct the rest of the bulb so that it would hold vacuum better. And if I ever find out who’s got the nerve to actually write long lasting on their boxes I’m gonna smack him right upside the head.
It’s not that they are incapable of making better bulbs, it’s that they are unwilling. The bulbs are carefully engineered to die when they do. It’s all about profit, and profits come from selling more bulbs.
You can actually buy decent bulbs. There’s a charity organization that we’ve bought some from before, but I can’t recall the name off the top of my head.
[nitpick]
They fill bulbs with nitrogen or argon these days.
[/nitpick]
Here’s more than I wanted to know about lightbulb technology. There’s a discussion of fill gases.
Actually, lightbulb filaments are little miracles of materials technology. You try processing a tiny coiled coil from tungsten powder, with thorium oxide dispersions to improve the light emissivity and potassium bubbles for creep resistance, and see how far you get.
You want your lightbulbs to run for longer, you run them colder, which makes them less efficient and more yellow. If you make an improvement that means that a 1000 hour bulb will now last 2000 hours, generally you would make the bulb run hotter, reducing the life back to 1000 hours but getting more and whiter light for the power.
Long life bulbs aren’t made better, they are just built to run slightly cooler, e.g. they would have the standard 1000 hour life if run off a 130V supply, but they last a lot longer on 110V. A British 240V lightbulb running on 110 V will probably run for centuries, but a little red glow worm isn’t very useful as a light.
Nobody has yet mentioned the phenomenon of inrush current, or the fatigue induced during repeated heating/cooling cycles. As you may have noticed, light bulbs tend to burn out when power is first applied - if you leave a light bulb on continuously, it will last much longer than if put into normal service where it is switched frequently.
hajario did:
I’m kind of surprised that someone of your technical sophistication believes this. It’s not a conspriacy, it’s a trade off.
See
Lightbulbs Can Last Centuries
And Why They Don’t Make Them That Way
Of course if you want a bright, but long lasting light, do what I did, replace all your lights with compact fluorescents.
Don’t work with regular X10 controllers, and certainly don’t dim!
You kind of answered a question I was wondering about. I have a touch lamp with three setting, four if you count touching it to turn it off. Anyway, I wondered if they made adjustable compact fluorescent bulbs, but I guess not.
Most multi-level bulbs are actually two different filaments. One setting turns on the weak one, one turns on the strong, and one turns both on. There’s no reason I see you couldn’t make a multi-level compact fluorescent the same way.
I got one through a promotion that I’m trying in my living room lamp. Sorry, I find it vaguely annoying - there isn’t a real LONG lag time, but long enough that I flick the switch and think the bulb’s burnt out before I simultaneously remember it’s got the flourescent in it and the light comes on. The light’s wrong, too.
-
-
- What normally causes lightbulb failures is that the heat of the filament causes the glass to expand, and that allows oxygen to leak in and react with the filament metal, slowly burning/breaking it. So if you run a cooler filament, you get much less glass expansion, and much longer life… but much less light output as well. A lightbulb that is operated in a cool draft of air can last super-long times as well, for the same “glass-cooling” reason.
-
- Also consider that back then the processes for manufacturing filaments wasn’t very good, and so the filaments used were comparatively thick and simple. Not the super-thin tiny coils you see in modern examples.
~
Thanks,Q.E.D. Very attractive site,and I had never heard about that technology.Do you have any of them?
yabob:
What did you mean when you said,“The lights wrong,too”?
While this may happen from time to time, it is not the normal failure mode for tungsten incandescent bulbs. Filaments in conventional light bulbs fail due to tunsgten evaporating from hot spots on the filament, creating even hotter spots due to resistive heating. Halogen bulbs last longer because the halogen gas helps redeposit the evaporated tungsten back onto the hot spots, effectively maintaining the filament integrity. If air leakage were the primary failure mode, then halogens would last no longer than convetional bulbs, since the glass envelope construction is identical for both.