High-pressure mercury lamps are still produced by the domestic industry because of their low cost, good color rendering and cost-effectiveness. For them, there are many different types of drill lights. The acronym DRL stands for "high-pressure arc mercury lamp." This light source belongs to equipment of hazard class 1 due to the content of mercury in its composition. Street lamps on poles in most cases are equipped with these lamps.
Basic structural elements
The base is the part of the lamp through which power is supplied to it. On the base there are two leads from the electrodes, one of which is soldered to the threaded part, and the second to the lower end point. Through the contacts of the cartridge, electricity from the network is transmitted to the lamp. Base - contacting part. DRL 400 lamps with E40 sockets can be easily installed in any lamp equipped with the appropriate lampholders.
The burner is a sealed tube, inside of which at the opposite ends there are 2 electrodes. Two of them are the main ones, two are arsonists. An inert gas is pumped into the burner and a drop of mercury is placed in a strictly metered amount. The material of the burner is chemically resistant and refractory.
The outer shell is made in the form of a bulb made of glass with a burner fixed inside it. The volume is filled with nitrogen. To convert the radiation of a quartz burner, a phosphor coating of the inner surface of the bulb is used. In addition, two limit resistors for the ignition electrodes are installed inside this bulb.
The burners of the first DRL were equipped with two electrodes. To light the lamp, it was necessary to have a source of high voltage pulses in the switching circuit, which had a service life less than that of the lamp. In the future, the production of such lamps was discontinued and their production began in a four-electrode design, which does not require the presence of third-party pulse devices.
The four-electrode DRL lamp consists of a bulb, a threaded base and a quartz burner mounted on the lamp foot, filled with argon with the addition of mercury. There are 2 electrodes on each side of the burner: the main one and the igniter located next to it. To limit the current on the electrodes in the lamp, current-limiting resistances are provided, which are located in the outer bulb.
DRL 400 is widely used in lighting networks.
Principle of operation
After connecting the lamp to the mains at both ends of the burner, conditions are created for a glow discharge between the main and ignition electrodes. The start of this process is due to the small distance between them. To break through this gap, a voltage of a lower magnitude is required than to break through the gap between the main electrodes. The current in this section is limited by the resistances installed in the circuit of additional electrodes in front of the discharge tube.
After reaching a sufficient degree of ionization in the burner in the main gap, a glow discharge is ignited, which then passes into the arc.
When the lamp is off, the mercury in the burner is in liquid or atomized form. After the discharge is ignited between the main and ignition electrodes, the temperature in the burner rises and the mercury gradually evaporates, thereby improving the quality of the discharge in the main discharge gap. After the transition of all mercury to the vapor state, the lamp starts to work in the nominal mode with standard light output.
The flare-up lasts about ten minutes. After turning off the DRL lamp, it is only possible to restart it after it has cooled and the mercury has returned to its original form.
A power outage for any short period of time leads to the extinction of the discharge. For the lamp to light up again, you need to wait for it to cool.
Fluctuations in the supply voltage lead to a change in the light characteristics of the lamp. When the supply voltage is reduced to less than 80% of the nominal, the lamp does not light up, and the working lamp goes out.
Lamp Regulators
The four-electrode lamp is connected to the mains through a choke, which must correspond to the lamp power. A choke is needed to limit the current on the lamp. This light source connected to the network without a ballast immediately burns out as a result of the passage of a current of too large a value. To quench reactive power, a capacitor can be included in the circuit.
Ballasts are integrated in DRL-luminaires.
There are analogues that work without a throttle. These are DRV lamps.
As an integrated ballast, a tungsten spiral is placed in the outer bulb of this lamp in addition to the discharge tube. Such a lamp is installed in a conventional DRL lamp.
Radiation color
DRL lamps emit light as close to white as possible through the phosphor. It is formed as a result of mixing the phosphor glow caused by ultraviolet radiation from the burner and light from the discharge tube.
As a result of mixing the radiation of the burner and the phosphor, the result is a total, close to white, light of the DRL lamp.
LED analogues
As the best analogue of the DRL, we can mention an LED lamp with similar technical characteristics in terms of supply voltage and type of base.
LED light output: 100-120 lm / W. For DRL lamps, this indicator is 30-35 lm / W.
According to the duration of work, while maintaining all the light characteristics without change, the LEDs are many times superior to DRL lamps. A complete cessation of the production of lamps containing mercury is planned by 2020.
If you choose lighting with LED lamps for an object, you can save on the wiring system, since in this case, smaller cables are needed.
As an installation light device for these lamps, DRL lamps can be used.
High efficiency of LEDs is provided due to the almost complete absence of heat loss.
They have increased mechanical strength and maintain working capacity with significant fluctuations in the electrical parameters of the supply network and the ambient temperature. When the lamps work, there is no flicker. Lamps are environmentally friendly because they do not contain mercury.
Fixtures
A lamp is a device that redistributes the light flux in the desired directions. Inside it are attached various devices and elements of the electrical circuit, as well as various switching connectors. To redistribute the light flux from the lamp, it is equipped with a reflective system and a diffuser.
Indoor luminaires are used for lighting industrial, agricultural and storage facilities.
The most widely used luminaires are with DRL 250, because lamps with such parameters are necessary both for lighting inside buildings and for outside.
The external types of these devices are subject to increased requirements for the impact of climatic factors.
Street lamps on poles belong to outdoor luminaires.
Fixtures for DRL lamps have a fairly wide range.
Models designed for indoor use are resistant to high humidity and dust.
Due to the tightness of the housing, DRL streetlights withstand the effects of rain and snow. They successfully resist strong gusts of wind.
Fixtures with DRL lamps use heat-resistant wires and reliable connectors.
Where are the lights used?
Designed for lighting industrial and agricultural enterprises; territories outside buildings; for all objects in which there is an urgent need to use economical lighting systems. Used to illuminate streets, construction sites. In factories in workshops and warehouses, as well as in other facilities where good color rendering is not needed.
Storage and disposal
Due to the fact that the composition of the DRL lamps includes mercury, it is strictly forbidden to store these products with broken and cracked flasks in rooms that were not prepared for this. At enterprises, a separate isolated zone with hermetically sealed containers must be allocated for these purposes. The storage time of such waste is allocated until the moment of removal from the zone for further destruction.