What is the metallic vapor lamp and its applications!
The metallic vapor lamps appeared about 40 years ago, these metallic multi vapor lamps have been perfected becoming one of the main solutions presenting a complete set of advantages. A metallic vapor lamp is not a mercury vapor lamp, a common question among electricians. Metallic vapor lamps offer much greater color reproduction than sodium and mercury vapor lamps, as well as better efficiency. Come with us to learn a little more about metallic vapor lamps, in this article, we will discuss what it is like and its applications without mysteries.
What is a metallic vapor lamp
Metallic vapor lamps arose from an evolution of mercury lamps, becoming a particular type of mercury vapor lamp. The difference between the two lamps is to add a mixture of metals in the discharge tube of the lamp, these added metals are indium, thallium, and sodium, together they provided a significant improvement in the emission of colors through the luminous flux of the lamp.
Metallic vapor lamps provide a luminous flux of excellent color reproduction, thus being able to illuminate the environment with great quality, far superior to mercury lamps. Metallic vapor lamps generally have a color temperature of 4000K and have high luminous efficiency, long life and low depreciation. These advantages far outweighed mercury vapor lamps.
Metallic vapor lamps are manufactured in ovoid and tubular forms, and ovoid lamps are covered with a layer to increase the light emission, but reduce the luminance of the lamp. Today on the market we can find metal vapor lamps with varying powers from 400 W to 2,000 W.
Metal vapor lamp applications
Metal vapor lamps, because they have an excellent luminous flux, are indicated for applications in areas of patios and parking lots, they are also used for public lighting and open areas, in addition to sports courts, soccer fields and warehouses intended for exhibition or in areas where excellent image resolution is required.
Their application is also widely used in industrial areas, where visual control of production is necessary to guarantee the quality, these metallic vapor lamps provide a more detailed view of objects through the luminous flux of excellent color reproduction.
For the application of these bulbs is required NBR / ISO 8995 that the metal vapor lamps are used in closed luminaires, due to high-pressure lamp and very high internal working temperatures, another point for this requirement is that some types of metal halide lamps emit harmful ultraviolet radiation to people, remembering that this radiation is only present in some models.
The metallic vapor lamp, generally has an average life span of 24,000h and an average lighting efficiency of 98 lumens/watts, the color rendering index of these lamps can vary from 80 to 90 (IRC), whereas the vapor lamps of mercury, which generally have an average life span of 18,000h and an average lighting efficiency of 55 lumens/watts the color rendering index of these lamps is 40 (IRC), observe the technical data for the superiority of metallic vapor lamps.
Operation of metal vapor lamps
Metal vapor lamps consist of a small quartz tube where two main electrodes and an auxiliary electrode are usually installed at the ends, they are connected in series at a high value resistance.
The metal mixture is placed inside the tube, together with a few drops of mercury, some inert gas, usually argon, is also inserted to facilitate the formation of the initial discharge.
When a voltage is applied to the terminals of the metallic steam lamp, an electric field is created between the auxiliary and the main electrodes, which causes the formation of an electric arc between them, in turn the heat emitted from the electric arc heats the light-emitting substances, resulting in the ionization of the gas and consequently the formation of metallic vapor in the lamp.
At this moment the electrons collide with the atoms of the metallic vapor inside the tube, transforming the atomic structure of the substance, the light is finally produced by the release of energy from the atoms reached when they return to their normal structure.
Metallic vapor lamps generally require a reactor to stabilize the current at the lamp design level, electrically the reactors are presented as a series reactance of the lamp circuit, being an essential component for the correct functioning of the metallic steam lamp. Observe the correct way to start a reactor.
A point that must be taken into account when installing this type of lighting is the variation of the electrical voltage in the supply circuit of these lamps, the variations in voltage, however small, may impair the functioning and efficiency of the lamps, which may even cause burning. premature loss of the lamp or damage to the reactor, according to João Mamede, the voltage drops of 1% in the supply generate losses of 3% in the luminous flux, starting from 5% compromises the ignition of the lamp.
We have made available a video where Henrique Mattede makes some clarifications on lighting, especially metallic vapor lamps, it is worth taking a look and solving that doubt that still persists.