Analysis of the cause of blackening incandescent lamp
One, An incandescent lamp will turn black after long use
Incandescent lamp for external use glass shell is made from heat resistant glass, built-in metal tungsten, pull air in the glass shell and injection of inert gas, avoid tungsten wire is heated evaporation, but long-term high temperature electric, internal tungsten wire is heated, part will evaporate into gas, the outward diffusion in the cold light bulbs, can from gas condenses into solid black, deposited on the light bulb layer, over time, The bulb gets darker and darker.
Two, Brief introduction of incandescent lamp
Incandescent lamp is a kind of heat radiation source, which is heated to incandescent state after electrification of the filament. It radiates at high temperature and emits brightness. Its color light is close to that of the sun. Incandescent lamps are easy to make, cheap and affordable, and are widely used in daily life.
Three, incandescent lamp used for a long time black reasons
1, modern incandescent lamp in the production of a lot of fine, in order to avoid the metal tungsten wire and air chemical reaction and be oxidized, generally will be the first air out of the glass shell, and then inject a certain inert gas, reduce the metal tungsten wire heating, avoid tungsten wire evaporation fracture, which can slow down the speed of the bulb dimming.
2, a bright lamp filament temperature is about 3000 degrees, because the effect of high temperature, incandescent filament will produce radiation, into the light for people, under the effect of high temperature, the part of the incandescent light bulb will be automatically converted into heat energy, the internal tungsten filament will encounter heat sublimation as gas, encountered in the process of to spread beyond cold light bulbs, on cooling China, incandescent lamp wall will become black.
3. Due to the physical reaction inside the bulb, the bulb becomes black and cannot be cleaned. The longer the time goes, the more and more black particles condense inside the bulb.
