Despite the emergence of alternative light sources, the DRL lamp is still one of the most demanded solutions used for lighting industrial premises and streets. This is not surprising when you consider the advantages of this lighting fixture:
It was believed that with the advent of sodium alternatives, it would lose its position, but this did not happen. If only because its white light spectrum is more natural to the human eye than an orange tint. luminous flux sodium solutions.
What is a DRL lamp?
The abbreviation "DRL" stands for a very simple mercury arc lamp. Sometimes the explanatory terms "luminescent" and "high pressure" are added. They all reflect one of the features this decision... In principle, when you say "DRL", you don't have to worry too much that a mistake may be made in the interpretation. This abbreviation has long become a household name, in fact, a second name. By the way, sometimes you can see the expression "DRL 250 lamp". Here the number 250 means the consumed electrical power. Quite convenient, since you can choose a model for
existing starting equipment.
Principle of operation and device
The DRL lamp is not something fundamentally new. The principle of generation of ultraviolet radiation invisible to the eye in a gaseous medium during electrical breakdown has been known for a long time and has been successfully used in luminescent tubular flasks (remember the "housekeepers" in our apartments). Inside the lamp, in an inert gas with added mercury, there is a quartz glass tube that can withstand high temperatures. When voltage is applied, an arc first occurs between two closely spaced electrodes (working and incendiary). In this case, the ionization process begins, the conductivity of the gap increases, and when a certain value is reached, the arc switches to the main electrode located on the opposite side of the quartz tube. In this case, the ignition contact leaves the process, since it is connected through a resistance, which means that the current on it is limited.
The main radiation of the arc is in the ultraviolet range, which is converted into visible light by a phosphor layer applied to the inner surface of the bulb.
Thus, the difference from the classical one is in a special way of striking the arc. The point is that an initial gas breakdown is required to start ionization. Formerly pulse electronic devices, capable of creating enough for a breakdown of the entire gap in a quartz tube, did not have sufficient reliability, so the developers in the 1970s made a compromise - they placed additional electrodes in the structure, ignition between which occurred at mains voltage. Anticipating a counter question about why the discharge in tube lamps is nevertheless created with the help of a choke coil, we will answer - it's all about power. Consumption of tubular solutions does not exceed 80 W, and DRL is not less than 125 W (reaching 400). The difference is palpable.
The DRL lamp connection diagram is very similar to the solution used to ignite tubular fluorescent lighting fixtures. It includes a series-connected choke (limitation electric current), a capacitor connected in parallel (elimination of disturbances in the network) and a fuse.
Mercury gas-discharge lamps of low and high pressure of various modifications are used everywhere today. They are installed on the streets and roads of settlements, perform the functions of architectural lighting, illuminate train stations, markets, automobile overpasses, bridges and many other objects.
Mercury lamps low pressure illuminate buildings of schools, hospitals, kindergartens, office buildings, sales areas. They are popular in the field of housing and communal services for lighting entrances, basements, wheelchairs and utility rooms. Powerful appliances are installed in courtyards and playgrounds. Narrow beam categories serve medical, forensic, livestock and poultry applications.
Despite the disadvantages, mercury devices also have a number of advantages. Until some time, they were the most economical and reliable for consumers of all levels. But scientific developments and their improvement are constantly moving forward. And now mercury devices are being replaced by slender rows of new generation sodium and LED lamps. In the meantime, 70% of the space around us is illuminated by gas-discharge lamps.
Types of mercury lamps and the specifics of their work
Lamps of this type are produced with a power of 8 to 1000 W and are conventionally divided into 2 groups:
- general purpose;
- highly specialized application.
By internal filling pressure:
- low pressure lamps (mercury vapor pressure\u003e 100 Pa)
- high pressure lamps (value of partial pressure \u003d 100 kPa);
- ultra-high pressure lamps (value \u003d 1 MPa and< 1 МПа).
High pressure mercury devices
A mercury gas discharge lamp (DRL) operates on the principle of optical radiation generated from mercury vapor by a gas discharge.
Until 1970, there were only 2 electrodes in the lamp design. This made lighting bulbs difficult, and the devices themselves unreliable. Then another pair of electrodes was added, located next to the main ones and connected to the opposite ones through resistors - current limiters.
When turned on, small discharges heat up the gas and pass to the main arc. Such a connection system also depends on the temperature of the surrounding space, so it is impossible to determine with accuracy how long the light passes from glowing to arc. Probably 1.5 to 8 minutes.
To ensure normal "entry" into the light mode, you need a regulating device - a choke. It partially extinguishes the voltage from the network and creates an even background necessary for the operation of the lamps. IN recent times lighting devices for DRL lamps have changed in their configuration the choke for ballasts - a new generation electronic ballast. The introduction of ballasts has helped to reduce lamp operating noise and improve light quality. The ignition time has been reduced to a minimum.
The lamp includes:
- glass flask;
- base;
- glass quartz tube containing argon gas and mercury vapor under pressure. The inner side of the bulb is coated with a phosphor in order to improve the quality of the luminous flux;
- limiting resistor;
- main electrode;
- additional electrode.
Arc metal halide (DRI) a lamp with emitting additives that increase the efficiency of light transmission. In DRI, not quartz, but ceramic burners are often installed, and a choke is included in the circuit. Power ranges from 125 to 1000 watts. Due to the added elements - metal halides, the lamp can emit different colors.
Metal halide lamp (DRIZ) with a mirror layer. In these mercury devices, a special base is installed, and one side is covered with a mirror layer, which makes it possible to obtain a directed light flux.
Mercury-tungsten arc lamp (DRV) does not require ballasts due to the presence of a tungsten coil. Such a high-pressure mercury lamp is also distinguished by the fact that, in addition to mercury vapor, its bulb is filled with a mixture of nitrogen and argon. Tungsten lamps provide the brightest, most pleasant light and are the most durable.
Mercury-quartz (straight) light bulb (PRK) or tubular high pressure mercury arc lamp (DRT)... They have cylindrical flasks with electrodes located at the ends.
Mercury-quartz ball lamp (DRSH).Distinctive features: a ball-shaped bulb and a high level of brightness of illumination together with ultraviolet radiation. The lamp operates under very high pressure with a cooling system.
High pressure mercury ultraviolet lamp (DRUF, DRUFZ) made from uviol black glass. Another option for such bulbs is to use europium-doped strontium borate to coat the inside of the bulb. They practically do not give visible light.
Low pressure mercury devices
The fluorescent mercury lamp is a gas-discharge lamp and is designed according to the same principle as high-pressure lamps.
Compact (CFL) fluorescent lamp appeared on the territory of our country in 1984. Such devices were originally equipped with standard types of plinths with electric ballasts mounted inside.
Therefore, in view of the energy-saving characteristic declared by the manufacturer, KKL models quickly appeared in many apartments. Unlike other types of mercury fluorescent lamps, compact devices ignite immediately and operate silently. The flickering frequency of such lamps is perceptible to the human eye, but not as clearly as in the case of other gas-discharge lamps.
Linear mercury lamp presented in the form of a long flask with two electrodes at the ends, filled with gas and mercury vapor. The flask itself is covered with a phosphor inside. When the lamp is turned on, an electric arc discharge occurs, the filling of the lamp heats up to the required level, and the device flares up in full force.
In this case, the phosphor absorbs the ultraviolet radiation emitted during operation. If the chemical composition of the phosphor is supplemented with various additives, then the color of the luminous flux can be changed in this way. Linear lamps differ in base types and fixture diameters.
Low Pressure Quartz Arc Mercury Fluorescent Lamp produces powerful ultraviolet radiation. It is used for disinfection of drinking water and air. Produces ozone in increased concentration. Requires subsequent ventilation of the room.
Germicidal lamp made of uviol glass. There is another technology, when the inner surface of the flask is treated with a special chemical composition (see DRUF). By generating powerful ultraviolet light, the lamp does not emit too much ozone. Therefore, there may be people in the room where the device is used.
Applications of lamps containing mercury
DRL - arc mercury fluorescent lamps - are used to illuminate roads, stations, bridges, crossings, squares, courtyards and other objects.
DRI lamps are used to organize outdoor lighting of streets, squares, parks, outdoor sports grounds, fairs, markets, etc. The ability to change the chemical composition to increase the spectrum of glow colors allows the use of metal halide lamps in architectural lighting.
Sailors on fishing boats use greenish lamps to attract plankton. Ultraviolet radiation, color temperature creation, brightness and bluish glow all contribute to the growth of plants or even corals.
DRIZ lamps are relevant in areas with poor visibility, and tungsten devices are installed on construction sites, parking lots, open storage rooms.
Mercury-quartz and DRT devices are used in the medical field. Ultraviolet germicidal irradiators are used to disinfect water, food or air. During the burning period of such lamps, a large concentration of ozone is formed in the air, therefore, the rooms in which processing or other work with the device takes place must be provided with good ventilation to ventilate the space. Lamps are also used for photochemical technologies and photopolymerization of dyes and varnishes.
High pressure mercury ultraviolet lamps are used for catching insects, taking into account the specifics of their visual apparatus. Lamps are used during performances, holidays, carnivals.
Devices with DRUF lamps help in the work of experts and forensic scientists, pointing out subtle traces of organic origin.
Linear fluorescent lamps have been widely used for many years to illuminate various public organizations and buildings. After the appearance of models with standard-sized socles, bulbs began to be used in the premises of houses and apartments.
Low pressure germicidal lamp is used for external and internal disinfection. Used for indoor and medical purposes.
Advantages of mercury discharge lamps
- compactness of lamps;
- sufficiently high luminous efficiency 50-60 lm / W;
- efficiency is 5-7 times higher than incandescent lamp;
- Durability - 10000-15000 thousand hours with proper operation;
- Body heating is much lower than incandescent lamps;
- Ability to reproduce different colors;
- Work at high and low temperatures from +50 to -40.
For DRV lamps:
- the possibility of replacing incandescent lamps for street lighting;
- the ability to work without special control equipment start-up.
Disadvantages of mercury-containing arc lamps
- work on alternating current (except RFE);
- inclusion through ballast (except for RFE);
- sensitivity to network fluctuations;
- unsatisfactory color rendering;
- flickering that tires the eyes;
- long period from switching on to the upper level of the lamp light (except CFL);
- after turning off until the next turn on, a long cooling period of the lamp (except CFL);
- from the 2nd half of the service life, a decrease in light output;
- hazard class 1 due to the content of mercury in the construction.
For DRV lamps:
- fragility of a tungsten filament.
Disposal of lamps containing mercury
All lamps containing mercury are hazard class 1. This means that after the end of its service life, such a device cannot simply be thrown into trash can... Moreover, it is unacceptable to get rid of a broken or cracked lamp in this way.
Only organizations that have a license for this activity can store, transport and dispose of devices with hazard class 1. It is clear that everyone will not look for the coordinates of such a company. For this, in any locality there are places for temporary storage of such lamps.
The managing organization that serves your home is authorized to provide such reception facilities for citizens. After consulting the community's opening hours, you can simply take the faulty devices there. If the lamp is damaged, it must be put in a bag, sealed and handed over to a collection point.
The recycling process takes place in various, rather laborious ways: amalgamation, demercurization, high temperature firing or others.
The high pressure mercury lamp is gradually becoming a thing of the past. The fight to preserve the environment is gaining momentum. They were replaced by sodium gas-discharge devices. Homes and cities are increasingly finding safe, economical, durable and brilliant LED lighting fixtures. But nothing happens suddenly. And it depends on each person what "tomorrow" will replace "today". Take care of the land and appreciate what you have now.
Ultra-high pressure arc lamps (LSVD) include lamps operating at a pressure of 10 × 10 5 Pa and above. At high pressures of a gas or metal vapor, with a strong approach of the electrodes, the near-cathode and near-anode discharge regions contract. The discharge is concentrated in a narrow spindle-shaped region between the electrodes, and its brightness, especially near the cathode, reaches very high values.
This arc discharge is an indispensable light source for projector and projector types as well as a number of special applications.
The use of mercury vapor or inert gas in lamps gives them a number of features. Obtaining mercury vapor at an appropriate pressure, as can be seen from the examination of high pressure made in the article "", is achieved by dosing mercury in the lamp bulb. The discharge ignites as a low pressure mercury discharge at ambient temperature. Then, as the lamp burns up and heats up, the pressure increases. The working pressure is determined by the steady-state temperature of the bulb, at which the electric power supplied to the lamp becomes equal to the power dissipated in the surrounding space by radiation and heat transfer. Thus, the first feature of ultra-high pressure mercury lamps is that they are fairly easy to ignite but have a relatively long burn-up period. When they go out, re-ignition can be carried out, as a rule, only after complete cooling. When the lamps are filled with inert gases, the discharge after ignition almost instantly enters a steady state. Ignition of a discharge in a gas at high pressure presents certain difficulties and requires the use of special igniting devices. However, after extinguishing, the lamp can be re-lit almost instantly.
The second feature that distinguishes an ultra-high pressure mercury discharge with a short arc from the corresponding gas discharge is its electrical mode. Due to the large difference between the potential gradients in mercury and inert gases at the same pressure, the combustion voltage of such lamps is significantly higher than with gas filling, due to which, at equal powers, the current of the latter is much higher.
The third significant difference is the emission spectrum, which in gas-filled lamps corresponds in spectral composition to daylight.
These features have led to the fact that arc lamps are often used for filming and film projection, in simulators of solar radiation and other cases when correct color rendering is required.
Lamp device
The spherical shape of the lamp bulb is selected to ensure high mechanical strength at high pressures and small distances between the electrodes (Figure 1 and 2). The quartz glass spherical flask has two diametrically spaced long cylindrical legs, in which the inputs connected to the electrodes are sealed. A long leg is necessary to remove the lead from the hot bulb and prevent it from oxidizing. Some types of mercury lamps have an additional ignition electrode in the form of a tungsten wire soldered into the bulb.
Figure 1. General view of ultra-high pressure mercury-quartz lamps with a short arc of various power, W:
and - 50; b - 100; in - 250; r - 500; d - 1000
Figure 2. General view of xenon ball lamps:
and - constant current lamp with a power of 100 - 200 kW; b - 1 kW AC lamp; in - AC lamp with a power of 2 kW; r - constant current lamp with a power of 1 kW
Electrode designs differ depending on the type of current that powers the lamp. When operating on alternating current, for which mercury lamps are intended, both electrodes have the same design (Figure 3). They differ from the electrodes of tubular lamps of the same power in greater massiveness, due to the need to reduce their temperature.
Figure 3. Electrodes for short arc AC mercury lamps:
and - for lamps up to 1 kW; b - for lamps up to 10 kW; in - solid electrode for high-power lamps; 1
- core from tornated tungsten; 2
- tungsten wire sheathing coil; 3
- oxide paste; 4
- getter; 5
- base made of sintered tungsten powder with addition of thorium oxide; 6
- forged tungsten part
When the lamps are on direct current important is the position of the lamp burning, which should be only vertical - anode upward for gas lamps and preferably anode downward for mercury lamps. The location of the anode at the bottom reduces the stability of the arc, which is important due to the counterflow of electrons directed downwards and hot gases rising upward. The upper position of the anode forces to increase its dimensions, since in addition to heating it due to the higher power dissipated at the anode, it is additionally heated by a stream of hot gases. For mercury lamps, the anode is placed at the bottom in order to ensure more uniform heating and, accordingly, reduce the burn-up time.
Due to the small distance between the electrodes, mercury ball lamps can operate on alternating current from a mains voltage of 127 or 220 V. The working pressure of mercury vapor in lamps with a power of 50 - 500 W, respectively (80 - 30) × 10 5, and in lamps with a power of 1 - 3 kW - (20 - 10) × 10 5 Pa.
Ultra-high pressure lamps with a ball bulb are most often filled with xenon due to the convenience of its dosage. The distance between the electrodes is 3 - 6 mm for most lamps. Xenon pressure in a cold lamp (1 - 5) × 10 5 Pa for lamps with a power of 50 W to 10 kW. Such pressures make ultra-high pressure lamps explosive even when inoperative and require special enclosures to store them. Due to the strong convection, the lamps can only work in an upright position, regardless of the type of current.
Radiation lamps
High brightness of mercury ball lamps with a short arc is obtained due to an increase in the current and stabilization of the discharge at the electrodes, which prevent the expansion of the discharge channel. Depending on the temperature of the working part of the electrodes and their design, a different brightness distribution can be obtained. When the temperature of the electrodes is insufficient to provide the arc current due to thermionic emission, the arc contracts at the electrodes into bright luminous points of small sizes and takes on a spindle shape. The brightness near the electrodes reaches 1000 Mcd / m² and more. The small size of these areas leads to the fact that their role in the total radiation flux of lamps is insignificant.
When the discharge contracts at the electrodes, the brightness increases with increasing pressure and current (power) and with decreasing distance between the electrodes.
If the temperature of the working part of the electrodes ensures the receipt of the arc current due to thermionic emission, then the discharge, as it were, spreads over the surface of the electrodes. In this case, the brightness is more evenly distributed along the discharge and still increases with increasing current and pressure. The radius of the discharge channel depends on the shape and design of the working part of the electrodes and almost does not depend on the distance between them.
The light output of lamps increases with an increase in their power density. With a spindle-shaped discharge, the light output has a maximum at a certain distance between the electrodes.
Radiation of mercury ball lamps of the DRSh type has a line spectrum with a strongly pronounced continuous background. The lines are greatly expanded. Radiation with wavelengths shorter than 280 - 290 nm is absent at all, and due to the background, the proportion of red radiation is 4 - 7%.
 |
| Figure 4. Distribution of brightness along ( 1 ) and across ( 2 ) axis of discharge of xenon lamps |
The discharge cord of dc xenon ball lamps, when operating in a vertical position with the anode up, has the shape of a cone, resting with its tip on the tip of the cathode and expanding upward. A small cathode spot of very high brightness is formed near the cathode. The distribution of brightness in the discharge cord remains the same when changing the discharge current density in a very wide range, which makes it possible to construct uniform curves of the brightness distribution along and across the discharge (Figure 4). The brightness is directly proportional to the power per unit length of the arc discharge. The ratio of the luminous flux and luminous intensity in a given direction to the arc length is proportional to the ratio of the power to the same length.
The emission spectrum of ultrahigh pressure xenon ball lamps differs little from the emission spectrum.
Powerful xenon lamps have an increasing current-voltage characteristic... The slope increases with increasing electrode spacing and pressure. The anode-cathode potential drop for short-arc xenon lamps is 9-10 V, with the cathode being 7-8 V.
Modern ultra-high pressure ball lamps are produced in various designs, including those with collapsible electrodes and water cooling. The design of a special metal collapsible lamp-lamp of the DKsRM55000 type and a number of other sources used in special installations has been developed.
DRL type mercury lamps
The quartz burner considered in the article "DRL lamp operation" is strongly influenced by the external environment, on which the cooling conditions depend. The stability of the lamp with such a burner is ensured by placing it inside the outer bulb. The inner surface of the outer bulb is covered with a layer of phosphor, which, due to the absorption of the ultraviolet part of the radiation of the mercury discharge, adds to the visible radiation of this discharge the missing radiation in the red region of the spectrum. To ensure cooling of the quartz burner not only by radiation, but also by convection and heat transfer, the outer bulb is filled with gas, which must be inert with respect to the phosphor and lamp mounting parts. A mixture of argon and nitrogen is used as the filling gas.
The device of the DRL lamp is shown in Figure 1. The lamps are connected to the network using threaded socles similar to those used for incandescent lamps: E27 - for lamps with a power of up to 250 W and E40 - for lamps of higher power. To facilitate ignition, the lamp is made with a three- or four-electrode. In the latter, the main and auxiliary electrodes are connected through resistors.
The shape and size of the outer bulb and the position of the burner in it are chosen so that all the ultraviolet radiation of the burner falls on the phosphor layer and during and during the lamp operation the phosphor layer has the optimum temperature for its operation.
Heating of the outer flask occurs due to the absorption of a part of the discharge radiation by a layer of phosphor deposited on it and glass, as well as heat transfer through the inert gas filling the flask. Cooling is carried out by the radiation of the heated glass and heat transfer through the ambient air.
The uniformity of the temperature of the flask surface can be achieved if, neglecting in the first approximation the convection of the inert gas filling the flask, it is made in the form of a surface that provides uniform irradiation. Calculations show that the central part of the flask should have a surface close to an ellipsoid of revolution, with a major axis coinciding with the axis of the burner. Correction for convection forces to slightly increase the diameter of that part of the bulb, which is at the top during lamp operation. Since the lamps are practically operated in any position, no amendments are made to the shape of the bulb.
In a number of lamp designs, the bulb acts as an optical element that redistributes the luminous flux. In this case, the shape and size of the bulb must be calculated, as is done for luminaires, and its thermal regime must also be taken into account in the calculation.
Various types of phosphors are used to correct the chromaticity of DRL lamps. The use of phosphate-vanadate-yttrium phosphor instead of magnesium fluorogermanate made it possible to improve the parameters of DRL lamps.
The use of a phosphor deposited on the inner wall of the outer bulb, on the one hand, leads to the addition of missing red radiation in the spectrum, and, on the other hand, causes the absorption of part of the visible radiation in this layer. With increasing thickness of the phosphor layer, the radiation flux of the lamp has a maximum at a certain layer thickness, while the luminous flux of the discharge passing through the phosphor layer gradually decreases. To solve the problem of the optimal thickness of the phosphor layer and a general assessment of its effectiveness for the characteristics of DRL lamps, the concept of "red ratio" was introduced. The red ratio is the percentage ratio of the red luminous flux added by the phosphor to the total luminous flux of the lamps. Obviously, the best will be the phosphor and its layer, which, when creating a red ratio sufficient to ensure correct color rendering, provide the maximum luminous flux of the lamp as a whole, that is, the greatest luminous efficiency.
The red ratio is usually expressed as a percentage by dependence
where φ (λ) - spectral flux density of the lamp radiation; V (λ) is the relative sensitivity of the eye.
The red ratio for DRL lamps with an optimal phosphor thickness of fluorogermanate and magnesium arsenate reaches 8%, and the luminous flux is 87% of the luminous flux of the lamp without phosphor. The use of orthophosphate-zinc phosphors with the addition of strontium makes it possible to obtain a luminous flux 15% higher than the luminous flux of a lamp without a phosphor, and r cr \u003d 4 - 5%.
During the ignition of the lamps, cathode sputtering of the active substance of the cathode and the rod part of the electrode takes place. In the steady-state mode of combustion on an alternating current, due to re-ignition of the discharge in each half-period, the sputtering of the rod part of the electrode continues. This deteriorates over time the emission properties of both parts of the electrodes, respectively, the voltage required to ignite the lamps increases. The sputtering of the electrodes simultaneously leads to the absorption of molecules of the inert gas filling the lamp, the initial pressure of which was chosen from the conditions for the ignition of the discharge. These processes lead to the formation on the walls of the burner of a dark coating of particles of sputtered electrodes, which absorbs radiation, especially its ultraviolet component, and the red ratio decreases. Ignition interruption determines the full service life of DRL lamps, and the standardized decrease in luminous efficiency determines their useful service life.
 |
| Figure 2. Construction details of a high pressure mercury lamp burner: 1 - main electrode; 2 - molybdenum foil bushings of the main electrode and the ignition electrode; 3 - additional resistor in the ignition electrode circuit; 4 - ignition electrode circuit |
The conventional designation of DRL lamps is deciphered as follows: D - arc, R - mercury, L - luminescent. The numbers after the letters correspond to the power of the lamp in watts, then the red ratio in percentage is given in brackets and the development number, separated by a hyphen, is given. The overwhelming majority of DRL-type lamps are produced with four-electrode, that is, with additional electrodes to facilitate ignition (see Figure 2). Such lamps are lit directly from the mains voltage. A small part of DRL lamps are made of two-electrode type; special ignition devices are used to ignite them.
DRL lamps are used in outdoor lighting installations and for lighting high premises of industrial enterprises, where strict requirements are not imposed on the quality of color rendering.
The influence of the ambient temperature affects primarily the ignition voltage of the lamps. At negative temperatures, ignition of DRL-type lamps is difficult, which is associated with a significant decrease in the pressure of mercury, as a result of which ignition occurs in pure argon and requires higher voltages than in the presence of mercury vapor. According to GOST 16354-77, DRL lamps of all powers must ignite at a voltage of no more than 180 V at an ambient temperature of 20 - 40 ° C; at a temperature of -25 ° C, the ignition voltage of lamps increases to 205 V, at -40 ° C, the ignition voltage for lamps with a power of 80 - 400 W is not more than 250 V, with a power of 700 and 1000 W - 300 V. For the light and electrical parameters of lamps of the DRL type the change in external temperature has practically no effect. Table 1 shows the parameters of DRL lamps. The lamps are available in two versions with a red ratio of 6 and 10%.
Table 1
Basic parameters of DRL lamps in accordance with GOST 16357-79
| Lamp type | Power, W | Working voltage, V | Current, A | Luminous flux, lm | Dimensions, mm | Average service life | |
| outer bulb diameter | full length | ||||||
| DRL80 (6) -2 DRL125 (6) -2 DRL250 (6) DRL400 (6) -2 DRL700 (6) -2 DRL1000 (6) -2 DRL2000 (6) | 80 125 250 400 700 1000 2000 | 115 125 130 135 140 145 270 | 0,80 1,15 2,13 3,25 5,40 7,50 8,00 | 3400 6000 13000 23000 40000 57000 120000 | 81 91 91 122 152 181 187 | 165 184 227 292 368 410 445 | 10000 10000 12000 15000 15000 15000 6000 |
Mercury-tungsten lamps
Difficult ignition of DRL lamps at subzero temperatures, the use of inductive ballasts, and the need to correct the color of the radiation led to the creation of high-pressure lamps with ballast in the form of an incandescent lamp filament. Note that the large power losses in the active ballast, which is the filament, in comparison with the losses in the inductive ballast, are compensated by the simplicity of the active ballast with the possibility of simultaneously obtaining the missing red radiation with its help.
By placing a ballast filament in an external flask in which a quartz burner is placed to reduce the dependence of its parameters on the external temperature, it was possible to obtain a lamp suitable for direct connection to the network. The design of such a lamp is shown in Figure 3. Placing the filament inside the lamp bulb creates the additional advantage of shortening the burn-up period by heating the burner with the coil radiation.
The main thing when calculating lamps of mixed light, as mercury-tungsten lamps are sometimes called, is the choice of the parameters of the filament. The power of the filament is selected based on the condition for stabilizing the mercury discharge. the luminous efficacy of the filament has to be reduced in order to obtain a sufficiently red ratio, while at the same time the filament service life is commensurate with the service life of quartz burners. During the start-up period, the mains voltage falls entirely on the spiral, however, as the mercury lamp burns up, the voltage on it increases, and the voltage on the ballast spiral decreases to the operating value. The light output of mercury-tungsten lamps is 18 - 20 lm / W, since about 50% of the power is spent on heating the coil. Therefore, in terms of efficiency, these lamps cannot compete with DRL lamps and other high pressure lamps. Their use is limited to special fields, for example, irradiation technology.
Lamps of the DRVE type have an outer bulb made of special glass that transmits ultraviolet radiation. Such lamps are used for joint lighting and irradiation, for example, in greenhouses. The service life of such lamps is 3 - 5 thousand hours, it is determined by the service life of the tungsten filament.
Tubular mercury lamps
In addition to lamps operating on the basis of a high-pressure discharge in mercury vapor and intended for lighting purposes, several types of radiation sources are manufactured, the development of which is associated with the need to use not only visible, but also ultraviolet radiation. As you know, ultraviolet radiation has a chemical and biological effect. The actinicity of ultraviolet radiation is widely used, that is, the effect on light-sensitive materials used in the printing industry. Powerful streams of bactericidal radiation, greater than those of bactericidal, allow the use of high-pressure mercury lamps for the purpose of disinfecting water and other substances. The chemical activity of ultraviolet radiation and the ability to concentrate high radiation powers on small surfaces have led to the widespread use of high-pressure mercury lamps in the chemical, woodworking and other industries.
For lamps of this type, bulbs made of mechanically strong and refractory quartz glass are required. The applied quartz glass, which transmits ultraviolet radiation starting from a wavelength of 220 nm, that is, practically the entire spectrum of radiation of a mercury discharge, makes it possible to change the radiation parameters only by changing the working pressure. The opacity of silica glass for resonance radiation with a wavelength of 185 nm is of no practical importance, since ultraviolet radiation of this wavelength is almost completely absorbed by air.
This has led to the creation of high pressure mercury lamps, differing in design due to operating pressure and field of application. the main parameters of high pressure lamps are shown in table 2.
table 2
Basic parameters of high pressure mercury tubular lamps in accordance with GOST 20401-75
| Lamp type | Power, W | Voltage, V | Current, A | Arc length, mm | Overall length, mm | Burner diameter, mm | Average service life, h |
| DRT230 DRT400 DRT1000 DRT2500 DRT2800 DRT5000 DRT4000 | 230 400 1000 2500 2800 5000 4000 | 70 135 145 850 1150 1800 1900 | 3,8 3,25 7,5 3,4 2,4 3,1 2,4 | 60 120 175 1000 610 1100 1000 | 190 265 350 1200 700 1290 1118 | 20 22 32 21 15 20 14 | 1500 2700 1500 3500 1000 1500 13000 |
The industry produces mercury lamps of the DRT type (arc mercury tubular) with a pressure of up to 2 × 10 5 Pa in the form of straight tubes with a diameter of 14 - 32 mm. Figure 4 shows the general view and overall dimensions of DRT lamps of various powers. Both ends of the tubes have extensions of a smaller diameter, into which a molybdenum foil is soldered to serve as inlets. On the inner side of the lamps, tungsten activated self-heating electrodes are welded to the bushings, the design of which is shown in Figure 5. For fixing the lamps in the armature, the lamps are equipped with metal clamps with holders. The nose in the middle of the bulb is the remainder of the stem, sealed off after the vacuum treatment of the lamp. To facilitate ignition, the lamps have a special strip to which an ignition pulse is supplied.
Figure 4. General view of DRT lamps (mercury vapor pressure up to 0.2 MPa) with power, W:
and - 230; b - 400; in - 1000
Figure 5. Electrodes (cathodes) of high pressure mercury lamps:
1
- active substance (oxide); 2
- tungsten core; 3
- spiral
Tubular xenon lamps
High-pressure tubular lamps also include lamps that use xenon radiation at pressures from hundreds to millions of pascals. A characteristic feature of a discharge in inert gases at high pressures and high current densities is a continuous radiation spectrum, which provides good color rendering illuminated objects. In the visible region, the spectrum of a xenon discharge is close to that of the sun with a color temperature of 6100 - 6300 K. An important feature of such a discharge is its increasing volt-ampere characteristic at high current densities, which makes it possible to stabilize the discharge using small ballast resistances. Xenon tube lamps of considerable length can be connected to the network without any additional ballast at all. The advantage of xenon lamps is that there is no burn-in period. The parameters of xenon lamps practically do not depend on the ambient temperature down to temperatures of -50 ° C, which makes it possible to use them in outdoor lighting installations in any climatic zone. At the same time, xenon lamps have a high ignition voltage and require the use of special ignition devices. The low potential gradient led to the use of more massive bushings in lamps.
The luminous efficiency of lamps increases with an increase in the specific power and diameter of the discharge tube. At high current densities, the discharge in inert gases has a very high brightness. According to theoretical estimates, the limiting brightness of a discharge in xenon can reach 2 × 10³ Mcd / m². The main parameters of high-pressure xenon lamps are shown in Table 3. Tubular xenon lamps work with both natural and water cooling. The use of water cooling made it possible to raise the luminous efficiency of lamps from 20 - 29 to 35 - 45 lm / W, but somewhat complicated the design. The water-cooled lamp burner is enclosed in a glass vessel, and distilled water circulates in the space between the burner and the outer cylinder vessel.
Table 3
Main Parameters of High Pressure Xenon Lamps
| Lamp type | Power, W | Voltage, V | Current, A | Luminous flux, 10³, lm | Tube inner diameter, mm | Full length, mm | Average service life, h | Connection diagram |
| DKsT2000 DKsT5000 DKsT10000 DKsT20000 DKsT50000 DKsTV3000 DKsTV5000 | 2000 5000 10000 20000 50000 3000 5000 | 40 110 220 380 380 90 150 | 49 44 46 56 132 30 30 | 35,7 97,6 250 694 2230 81,2 139 | 24 22 21 21 38 4 4 | 356 646 1260 1990 2700 285 315 | 300 300 800 800 500 100 100 | with ballast with ballast without ballast without ballast without ballast with ballast, DC also without ballast with rectifier without ballast without ballast |
High tube temperatures (about 1000 K) require the use of quartz glass and appropriate designs of molybdenum bushings, designed for high currents. The lamp electrodes are made of activated tungsten. One of the designs of a water-cooled xenon lamp is shown in Figure 6.
Figure 6. General view of a tubular xenon lamp with a power of 6 kW with water cooling
The parameters of ballastless xenon lamps are strongly influenced by the mains voltage. If the mains voltage deviates by ± 5% of the nominal, the lamp power changes by about 20%.
The designation of the lamps consists of the letters D - arc, Xenon X, T - tubular, B - water-cooled and numbers indicating the lamp power in watts and, through a hyphen, the development number.
To name all types of such light sources in domestic lighting technology, the term "discharge lamp" (RL) is used, which is included in the International Lighting Dictionary, approved by the International Commission on Lighting. This term should be used in technical literature and documentation.
Depending on the filling pressure, a distinction is made between low pressure RL (RLND), high pressure (RLVD) and ultra-high pressure (RLSVD).
The RLND includes mercury lamps with a partial pressure of mercury vapor in a steady state of less than 100 Pa. For RLVD, this value is about 100 kPa, and for RLVD - 1 MPa or more.
Low pressure mercury lamps (RLND) High pressure mercury lamps (RLVD)
RLVD are divided into lamps of general and special purpose... The first of them, which include, first of all, the widespread DRL lamps, are actively used for outdoor lighting, but they are gradually being replaced by more efficient sodium and metal halide lamps. Special-purpose lamps have a narrower range of applications, they are used in industry, agriculture, medicine.
Emission spectrum
Mercury vapors emit the following spectral lines used in gas discharge lamps:
The most intense lines are 184.9499, 253.6517, 435.8328 nm. The intensity of the remaining lines depends on the mode (parameters) of the discharge.
Kinds
DRL type high pressure mercury lamps
DRL (Dugovaya Rmulberry Lluminescent) - the designation of RLVD, adopted in domestic lighting engineering, in which to correct the color of the luminous flux aimed at improving color rendering, the radiation of a phosphor applied to the inner surface of the bulb is used. To obtain light in DRL, the principle of constant burning of a discharge in an atmosphere saturated with mercury vapor is used.
It is used for general lighting of workshops, streets, industrial enterprises and other facilities that do not impose high requirements on the quality of color rendering and premises without a constant stay of people.
Device
The first DRL lamps were manufactured with two-electrode technology. To ignite such lamps, a source of high-voltage pulses was required. As it was used the device PURL-220 (Launcher of Mercury Lamps for voltage 220 V). The electronics of those times did not allow the creation of sufficiently reliable igniting devices, and the PURL included a gas spark gap that had a shorter service life than the lamp itself. Therefore, in the 1970s. the industry gradually discontinued the production of two-electrode lamps. They were replaced by four-electrode ones, which do not require external ignition devices.
To match the electrical parameters of the lamp and the power supply, almost all types of radars that have a falling external current-voltage characteristic need to use a ballast, which in most cases is a choke connected in series with the lamp.
The four-electrode DRL lamp (see the figure on the right) consists of an external glass bulb 1, equipped with a threaded base 2. A quartz burner (discharge tube, RT) 3, filled with argon with the addition of mercury, is mounted on the lamp leg, mounted on the geometric axis of the external bulb. Four-electrode lamps have main electrodes 4 and auxiliary (ignition) electrodes 5 located next to them. Each ignition electrode is connected to the main electrode located at the opposite end of the RT through a current-limiting resistance 6. Auxiliary electrodes facilitate lamp ignition and make its operation more stable during the start-up period. The conductors in the lamp are made of thick nickel wire.
Recently, a number of foreign firms have been manufacturing three-electrode DRL lamps equipped with only one ignition electrode. This design differs only in greater manufacturability in production, having no other advantages over the four-electrode design.
Operating principle
The lamp burner (RT) is made of a refractory and chemically resistant transparent material (quartz glass or special ceramics), and is filled with strictly dosed portions of inert gases. In addition, a metal is introduced into the burner, which in a cold lamp looks like a compact ball, or settles in the form of a deposit on the walls of the flask and (or) electrodes. The luminous body of the RLVD is a column of an electric arc discharge.
The process of ignition of a lamp equipped with ignition electrodes is as follows. When a supply voltage is applied to the lamp, a glow discharge arises between the closely spaced main and ignition electrodes, which is facilitated by a small distance between them, which is significantly less than the distance between the main electrodes, therefore, the breakdown voltage of this gap is also lower. The appearance in the RT cavity of a sufficiently large number of charge carriers (free electrons and positive ions) promotes the breakdown of the gap between the main electrodes and the ignition of a glow discharge between them, which almost instantly turns into an arc discharge.
The stabilization of the electrical and light parameters of the lamp occurs 10-15 minutes after switching on. During this time, the lamp current significantly exceeds the nominal and is limited only by the resistance of the ballast. The duration of the starting mode strongly depends on the ambient temperature - the colder, the longer the lamp will light up.
Electric discharge in a mercury burner arc lamp creates visible blue or violet radiation as well as powerful ultraviolet radiation. The latter excites the glow of a phosphor deposited on the inner wall of the outer bulb of the lamp. The reddish glow of the phosphor, mixing with the white-greenish radiation of the burner, gives a bright light close to white.
A change in the supply voltage up or down causes a change in the luminous flux: a deviation of the supply voltage by 10-15% is permissible and is accompanied by a corresponding change in the luminous flux of the lamp by 25-30%. When the supply voltage decreases less than 80% of the nominal, the lamp may not light up, and when lit, it may go out.
The lamp becomes very hot when it burns. This requires the use of heat-resistant wires in lighting devices with mercury arc lamps, and makes serious demands on the quality of the cartridge contacts. Since the pressure in the burner of a hot lamp increases significantly, its breakdown voltage also increases. The supply voltage is insufficient to ignite a hot lamp, so the lamp must cool down before re-ignition. This effect is a significant disadvantage of high-pressure mercury arc lamps: even a very short interruption in the power supply extinguishes them, and re-ignition requires a long cooling pause.
Traditional scopes of DRL lamps
Lighting of open areas, industrial, agricultural and warehouse premises. Wherever this is due to the need for large energy savings, these lamps are gradually being replaced by NLVD (lighting of cities, large construction sites, high production workshops, etc.).
The RLVD Osram of the HWL series (analogue of the DRV) is distinguished by a rather original design, which has a conventional filament as a built-in ballast, placed in an evacuated cylinder, next to which a separately sealed burner is placed in the same cylinder. The filament stabilizes the supply voltage due to the bartering effect, improves color characteristics, but, obviously, very noticeably decreases both the overall efficiency and the resource due to wear of this filament. Such RLVDs are also used as household ones, as they have improved spectral characteristics and are included in a conventional lamp, especially in large rooms (the lowest-power representative of this class creates a luminous flux of 3100 lm).
Arc mercury metal halide lamps (DRI)
Lamps DRI (Dugovaya Rmulberry with ANDradiant additives) is structurally similar to DRL, however, strictly metered portions of special additives - halides of some metals (sodium, thallium, indium, etc.) are additionally introduced into its burner, due to which the light output significantly increases (about 70 - 95 lm / W and above) with a sufficiently good chromaticity of the radiation. Lamps have ellipsoidal and cylindrical bulbs, inside which a quartz or ceramic burner is located. Service life - up to 8 - 10 thousand hours.
In modern DRI lamps, mainly ceramic burners are used, which are more resistant to reactions with their functional substance, due to which, over time, burners darken much less than quartz ones. However, the latter are also not removed from production because of their relative cheapness.
Another difference between modern DRI is the spherical shape of the burner, which allows to reduce the decline in light output, stabilize a number of parameters and increase the brightness of the "point" source. There are two main versions of these lamps: with E27, E40 sockets and soffit - with Rx7S sockets and the like.
To ignite DRI lamps, a breakdown of the interelectrode space with a high voltage pulse is required. In the "traditional" circuits for switching on these steam lamps, in addition to the inductive ballast choke, a pulsed ignitor is used - IZU.
By changing the composition of impurities in DRI lamps, it is possible to achieve "monochromatic" glow of various colors (purple, green, etc.). Due to this, DRI is widely used for architectural illumination. DRI lamps with an index "12" (with a greenish tint) are used on fishing vessels to attract plankton.
Arc mercury metal halide lamps with a mirror layer (DRIZ)
Lamps DRIZ (Dugovaya Rmulberry with ANDradiant additives and Zmirror layer) is an ordinary DRI lamp, part of the bulb of which is partially covered from the inside with a specular reflective layer, due to which such a lamp creates a directed stream of light. Compared to the use of a conventional DRI lamp and a mirror spotlight, losses are reduced by reducing re-reflections and light transmission through the lamp bulb. High focusing accuracy of the torch is also obtained. In order to change the direction of radiation after screwing the lamp into the cartridge, DRIZ lamps are equipped with a special base.
Mercury-quartz ball lamps (DRSH)
Lamps DRSH (Dcoal Rmulberry Shary) are ultra-high pressure mercury arc lamps with natural cooling. They are spherical and emit strong ultraviolet radiation.
High pressure mercury-quartz lamps (PRK, DRT)
High pressure mercury arc lamp type DRT (Dcoal Rmulberry Tcorrugated) represent a cylindrical quartz flask with electrodes soldered at the ends. The flask is filled with a metered amount of argon, in addition, a metal
