Halogen lamp (halogen lamp), referred to as halogen bubble or halogen lamp, also called tungsten halogen lamp and quartz bulb, is a variant of incandescent lamp.
The principle is to inject iodide or bromine halogen gas into the bulb. At high temperature, the sublimated tungsten wire is chemically acted with halogen. The tungsten after cooling will be re solidified on the tungsten wire, forming a balanced cycle to avoid premature rupture of tungsten wire. So halogen bulbs live longer than incandescent lamps.
The power supply voltage of halogen lamp is usually divided into two types: AC 220V and DC 12V and 24V.
Halogen lamps are made of tungsten wire but are wrapped in a smaller quartz glass shell. Because the glass shell is very close to the filament. If it is made of glass, it will melt easily. The gas in the glass shell is composed of halogen lamps by different gases. These gases have a very interesting characteristic: they combine with tungsten vapor. If the temperature is not high enough, the tungsten atoms combined with halogen gas will evaporate and redeposit on the filament. This cycle makes the filament last many times. In addition, it can run hot filament, which means you get more light energy. You still get a lot of heat, but because the glass shell of quartz is so close to filament, it is hotter than a normal bulb.
Halogen bulbs can also operate at higher temperatures than ordinary incandescent lamps, and their brightness and efficiency are higher. But at this temperature, ordinary glass may soften, so halogen bulbs need to use higher melting point quartz glass. Because quartz glass can not block ultraviolet rays, halogen bulbs usually require ultraviolet filters.
If there is oil on the halogen bulb, if there is oil, it will cause different temperatures on the glass and reduce the life of the bulb. Therefore, we should avoid touching the glass of the bulb when changing the halogen bulb. If the finger is touched, it should be cleaned with alcohol.
Advantages and disadvantages
The halogen lamp is an improvement in the incandescent lamp, which maintains the advantages of the incandescent lamp: simple, low cost, easy to adjust and control brightness, and good color display (Ra=100). At the same time, the halogen lamp overcomes many shortcomings of the incandescent lamp, such as short service life and low luminous efficiency (usually only 6% to 10% can be converted to light energy, and the rest are lost in the form of heat energy).
Halogen lamp: the rain and snow weather is strong and the light is uniform. In the low visibility weather, such as rain, snow and haze, the penetration of halogen light source is much better than the xenon light source with high color temperature.
Halogen lamps are usually used for concentrated irradiation, used in CNC machine tools, rolling mills, lathes, turning centers and metal processing machines, rear lights for automobile headlights, and public places such as families, offices, office buildings and so on.
(1). When installing halogen bulbs, please turn off the power supply and use plastic cover to protect the glass shell of the bulb. Do not touch it with hand, if you touch it carelessly, wipe clean with alcohol.
(2). The halogen bulbs are made of high temperature resistant quartz glass, such as hand or oil, which will lose the gloss of the quartz glass, reduce the brightness, shorten the life and even rupture of the glass shell.
(3) when the halogen bulb is lit, the temperature at the seal should not exceed 350 degrees, otherwise the life of the halogen bulb will be shortened. Therefore, the ventilation and heat dissipation of the halogen lamp must be good.
(4) when halogen bulbs are lighted, avoid direct cooling of the air-conditioner to the bulb.
(5) avoid halting or shock when lighting halogen bulbs.
(6) when the halogen bulb is switched on or after the lamp is turned off, it is absolutely impossible to touch the bulb because the bulb temperature is still high.
(7) halogen lamps should not be frequently switched on or off, otherwise they will obviously shorten their life. The reason is that: compared with normal working time, the temperature of tungsten wire in the lamp is very low at the moment of light opening, so the resistance is very small, and at the same voltage, the current is much larger than the normal working current, so the tungsten atom evaporates fast; at the same time, the temperature of the gas in the light bulb is relatively low, so the decomposition rate of tungsten halide is so low. It is slower, so tungsten atoms returning to tungsten wire are much less than normal. As a result, the consumption of tungsten filament is the biggest in the moment of turning on the lights, so frequent opening / closing will obviously shorten the filament life.