Lamp metal halogen: features
The metal halide lamp belongs to the classdischarge lamps. In their work, such devices use a gas discharge, rather than a thermal glow of the filament. Such lamps can be called relatively young sources of light, the history of which is not more than fifty years. Their birth is connected with a number of experiments of scientists on the improvement of gas-discharge mercury lamps. From the point of view of the filling, their distinctive feature is the use as a working mixture of mercury vapors, salt compositions and gases. The composition of the salt mixture influences the shade of the emitted light. A metal halide lamp can emit light of a bluish or reddish hue. Inside the bulb, the gas is at very high pressure.
Lamps metal halide are included in the same way,as luminescent, as well as other gas-discharge ones. For ignition, they require connection to the network by means of special starting-regulating equipment. When it is switched on in the fixture, the discharge in argon first starts, triggering an electric arc between the electrodes of the bulb of the lamp. In the switched off lamp, mercury and salts settle on the walls of the bulb in the form of particles. After starting, the electric arc immediately heats the flask, evaporating solid particles, after which the discharge continues in pairs of salts and mercury. The first minute the temperature increases very much, as does the brightness of the radiation. The metal halide lamp at work is heated to a temperature that exceeds a thousand degrees, which is why floodlights, in which such devices are used, are so large. To cool them, you need a large metal surface of the searchlight.
A metal halide lamp of low power canUsed in the same place, where traditional halogen - in devices for office, home, advertising, inside museum expositions and shops. It is much more economical and efficient than halogen, but it needs additional ballasts.
Metal halide lamp 150w is useful forlighting a large room or for a lamp in the courtyard of a private home. High power devices are suitable for professional lighting equipment - powerful searchlights, theater spotlights, photo and movie lighting equipment, as well as for some types of projectors.
An interesting field of use of metal halide lamps can be the illumination of greenhouses and aquariums. They possess a spectrum of radiation favorable for the growth of plants and corals.
Such devices can be produced with two bulbs - external and internal. It is believed that this option has improved color characteristics.
