High-pressure mercury lamps are still produced by the domestic industry due to their low cost, good color rendering and economy. For them, there are many different types of drill lamps. The abbreviation DRL stands for "arc mercury lamp of high pressure." This light source belongs to hazard class 1 equipment due to the content of mercury in its composition. Street lamps on poles in most cases are equipped with these lamps.
Main structural elements
The base is the part of the lamp through which the supply voltage is supplied to it. There are two leads from the electrodes on the base, 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. The base is the contact part. DRL 400 lamps with E40 sockets are installed without problems in any lamp equipped with the appropriate cartridges.
The burner is a sealed tube with 2 electrodes at opposite ends. Two of them -main, two - incendiary. An inert gas is pumped inside the burner and a drop of mercury is placed in a strictly metered amount. Burner material is chemical resistant and refractory.
The outer shell is made in the form of a glass flask with a burner fixed inside it. The volume is filled with nitrogen. To convert the radiation of a quartz burner, a phosphor coating is used on the inner surface of the bulb. In addition, two limiting resistors for ignition electrodes are installed inside this bulb.
The burners of the first DRLs were equipped with two electrodes. To light the lamp, it was necessary to have a high voltage pulse source in the switching circuit, which had a shorter service life than that of the lamp. Subsequently, the production of such lamps was discontinued and their production was started in a four-electrode version, which does not require third-party pulse devices.
The four-electrode DRL lamp consists of a bulb, a threaded base and a quartz burner mounted on the lamp leg, filled with argon with the addition of mercury. There are 2 electrodes on each side of the burner: the main one and the ignition electrode 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.
Working principle
After the lamp is connected to the power supply, conditions are created at both ends of the burner for a glow discharge to occur between the main and ignition electrodes. Running this processdue to the small distance between them. To break through this gap, a voltage of a lower magnitude is required than for the breakdown of the gap between the main electrodes. The current in this area 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, a glow discharge is ignited in the main gap, which then turns into an arc discharge.
In the off lamp, the mercury in the burner is presented in liquid or sprayed form. After ignition of the discharge 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 begins to operate in nominal mode with standard light output.
Fire up lasts about ten minutes. After turning off the DRL lamp, turning it on again is possible only after it has cooled down and the mercury has returned to its original form.
A power outage for any short period of time causes the discharge to fade. In order for the lamp to light up again, you need to wait for it to cool down.
Fluctuations in the supply voltage lead to a change in the light characteristics of the lamp. When the supply voltage drops to less than 80% of the nominal, the lamp does not light up, and the working one goes out.
Apparatus that regulates the operation of the lamp (PRA)
Connecting a four-electrode lamp to the mainscarried out through a choke, which must correspond to the power of the lamp. A choke is needed to limit the current on the lamp. This light source, connected to the network without control gear, immediately burns out as a result of the passage of too much current. To dampen reactive power, a capacitor can be included in the circuit.
PRAs are built into DRL fixtures.
There are also analogues that work without a throttle. These are DRV lamps.
As a built-in ballast, a tungsten filament 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.
Emission color
DRL lamps emit light through a phosphor that is as close to white as possible. It is formed by mixing the glow of the phosphor caused by ultraviolet radiation from the burner and the light from the discharge tube.
As a result of mixing the radiation of the burner and the phosphor, the final, close to white, light of the DRL lamp is obtained.
LED counterparts
As the best analogue of DRL, we can note an LED lamp with similar technical characteristics in terms of supply voltage and type of base.
Light output of LEDs: 100-120lm/W. For DRL lamps, this figure is 30-35 lm / W.
In terms of the duration of work, while maintaining all the lighting characteristics unchanged, LEDs are several times superior to DRL lamps. A complete phase-out of mercury-containing lamps is planned for 2020.
If you selectlighting with LED lamps, you can save on the wiring system, because in this case, smaller cables are needed.
DRL fixtures can be used as an installation light for these lamps.
The high efficiency of LEDs is ensured by the almost complete absence of heat loss.
They have increased mechanical strength and remain operational with significant fluctuations in the electrical parameters of the supply network and ambient temperature. The lamps do not flicker during operation. The lamps are environmentally friendly because they do not contain mercury.
Lamps
A luminaire is a device that redistributes the luminous flux in the right directions. Various devices and elements of the electrical circuit, as well as various switching connectors, are attached inside it. To redistribute the light flux from the lamp, it is equipped with a reflective system and diffuser.
Indoor luminaires are used to illuminate industrial, agricultural and warehouse premises.
DRL 250 luminaires are the most widely used, since lamps with such parameters are needed both for indoor and outdoor lighting.
The appearance of these devices is subject to increased requirements for the impact of climatic factors.
Street lamps on poles are outdoor lamps.
Lamps for DRL lamps have a wide enoughassortment.
Indoor models are resistant to high humidity and dust.
Due to the tightness of the case, street lamps DRL withstand the effects of rain, snow. They successfully resist strong gusts of wind.
DRL luminaires use heat-resistant wires and reliable quality connectors.
Where lamps are used
Designed for lighting industrial and agricultural enterprises; territories outside buildings; for all objects in which there is an urgent need for the use of economical lighting systems. Used for lighting streets, construction sites. In factories in workshops and warehouses, as well as in other facilities where good color reproduction is not needed.
Storage and disposal
Due to the fact that DRL lamps contain mercury, it is strictly forbidden to store these products with broken and cracked bulbs in rooms that have not been prepared for this. At enterprises, a separate isolated zone with hermetically sealed containers should be allocated for these purposes. The time of storage of such waste is allocated until the moment of removal from the zone for further destruction.
