BY adding any contamination to the bulb you create a temp difference and differing rates of this stuff gets deposited, which would tend to exagerate the temp difference. Halogen lamps used in television lighting definitely do not like fingerprints. I have replaced burnt out lamps with fingerprint shaped bubbles.
The lamps we usually used came wrapped in little slips of paper slightly shorter than the lamp, so you could re-lamp without touching the bulb. I used to tech for a small local cable TV station. Wakes you up, for damn sure. I replace a wide variety of light bulbs in my job and the most common type to fail are the halogen bulbs. We have found that bulbs touched with the bare hand will get hot enough to melt the solder in the base of the bulb. Map and chart lights in the flight deck and the emergency slide lights on the exterior fuselage are other common places for halogen bulbs.
When defective bulbs are replaced, I wear white cotton gloves and clean the bulb with isopropyl alcohol after it is installed. I do the same during the rare chances I come across halogen bulbs away from work. This contamination causes a hot spot when the bulb is operated, which can result in cracks or bubbles that will allow halogen gas to leak out, resulting in early failure.
The easiest way to avoid contaminating a quartz halogen bulb is to never touch it with bare skin. Handle the bulb using a rubber glove if possible, a sandwich bag will work if a glove isn't available.
If you do touch the bulb accidentally, it's best to clean it thoroughly with rubbing alcohol, as water alone will not remove all of the oils. I hope this simple tip will help you keep your quartz halogen bulbs burning bright. If you've installed your bulb properly and you're still experiencing early failure, get in touch with a Bulbs.
There may be a better bulb for the job, and we'll help you find it! Tags: tips , halogen , quartz , installation , troubleshooting , early failure. Account Sign In. I also have the experience with the tube type halogen bulbs that they should work in a horizontal position, otherwise you shorten the lifetime. This may be due to uneven temperature distribution if the bulb is not working in a horizontal position -unless someone comes up with a better explanation. I too recollect that the glass is indeed high temperature quartz hence why they are sometimes referred to as quartz-iodine bulbs , but I have never come across a case where there has been a failure of the outer envelope.
The idea is halogen bulbs again, from memory , is that ordinary tungsten bulbs, the hot filament will evaporate and then condense on the inner surface of the glass envelope. As the filament evaporates, it shortens the life of the bulb, and in order to extend the life of the bulb, the temperature of the filament is limited.
With halogen bulbs, a small amount of halide is introduced into the bulb, and this reacts with the tungsten that has condensed on the inner surface of the glass envelope, and allows it to be recycled back to the filament but, ofcourse, it is important that the process is even, otherwise some parts of the filament will receive more recycled tungsten at the expense of another part of the filament.
In order for this recycling to happen, the temperature must be kept high; but because of the recycling process, the temperature may be kept higher than would be normal for an ordinary tungsten bulb although the high temperature is also maintained not only by having a hotter filament, but because the envelope is smaller, so the glass is closer to the filament, and thus kept hotter.
Again, as I say, this is all from memory and it is too early in the morning for me to remember anything right now. Marked as best answer by on Today at Undo Best Answer.
I suppose you are right, that temperature differences due to spots on the glass are more likely than failure of the glass due to etching. But touching a new or cold bulb with your bare fingers is bad for the bulb. Occasionally I have to change bulbs in theatre projectors e. I use a new plastic bag I put over to bulb to retire it from the fitting and put it back in storage. Of course this can only be done on cold bulbs. Anyway, working on a projector with a hot bulb is a bad idea as hot filaments are more likely to break.
Maybe it can also depend on the fact that the organic film on the glass surface absorbs light more than glass, increasing the glass temperature and so reducing its life.
Another consequence should be the fact shorter wavelenghts are absorbed from the film, reducing the whiteness of the light emitted from the lamp.
0コメント