A few decades ago, sodium lamps were the most in demand due to the lack of worthy analogues. They were almost universally used to illuminate streets and roads. They began to be used somewhat less often with the advent of LED bulbs, but at the same time they are not going to give up their positions completely.
What is a HPS lamp and its varieties
Lighting devices DNaT are one of the types of high pressure sodium lamps. The abbreviation DNaT stands for "Arc Sodium Tubular". Devices of this type are divided into several more varieties - DNaS, DNaZ and DNaMT. Each of them has its own individual characteristics, advantages and disadvantages.
- DNaS are light-scattering lighting devices. A special pigment is used as a light diffuser, with which the entire inner surface of the outer bulb is treated. The spectrum of this type of light bulb resembles a daylight.
- ДНаЗ - the burner glow has a certain direction. The device is characterized by a special sputtering of a mirror reflector on the outer flask of the device.
- ДНаМТ - equipped with a frosted bulb. This variety is an analogue of DNaS, which has already been discontinued today. They are used to replace DRL lighting devices without deteriorating the quality of lighting.
All sodium lighting devices are divided into two types depending on the principle of operation - low and high pressure lamps.
Low pressure sodium lamp
Low pressure luminaires have several specific features. For example, not an ordinary glass flask is used in the manufacture, but high-strength borosilicate glass. This is a necessary measure, since the effect of sodium vapor on glass surfaces is aggressive and destructive.
In abbreviated form, this type is called NLND, its efficiency depends primarily on the ambient temperature. To ensure optimal conditions for uninterrupted and long-term operation, the light bulb is additionally placed in a glass outer bulb, which not only protects the structure from aggressive environmental factors, but also serves as an unusual thermos.
High pressure sodium lamps for street lighting
In comparison with the previous version, high-pressure sodium lamps have several significant advantages - phenomenal efficiency and high-quality color reproduction. At a power of 30 to 1000 W, the luminous efficiency reaches 160 lm / W, the operating life is usually about 25000 hours.
Due to the high brightness and compact size, the field of application of the high pressure modules is wide.
Such types of sodium lamps are used necessarily with electronic or inductive ballast. Ignition takes place using a special electrical device - IZU, which guarantees uninterrupted supply of pulses up to 6 kW.
As a rule, it takes no more than 5 minutes from the moment the high-pressure sodium lamp starts up until full illumination appears.
Design features of the HPS lamp and the principle of operation
The principle of operation of a sodium gas-discharge lamp is based on the chemical properties of sodium vapor, which, under certain conditions, are capable of emitting bright monochromatic bright light. The gaseous medium is placed in a special tube called a burner. Heated sodium vapor has a destructive effect on glass surfaces, therefore, high-quality borosilicate glass or polycrystalline alumina is used in the production.
Each side of the burner is equipped with electrodes, the task of which is to create arcs that heat up the sodium vapor. This whole structure is placed in a sealed glass flask, which ends with a threaded base of various types.
The sodium lamp burner is ignited by an electric arc created by electrodes. As a result, a large number of charged particles are formed in the channel. For a better glow, the flask contains not only sodium vapors, but also mercury, xenon or argon. Today, mercury-free lighting devices have already been developed, but their design features are extremely complex.
Lighting of lighting devices occurs at the moment when a high impulse voltage is applied to the cathodes. The lamp can shine dimly for no more than 5 minutes, then it will reach its optimal operating temperature.
You can't just throw away sodium lamps. Failed devices must be handed over to special collection points. If the flask goes for processing with glass, the entire melt will be spoiled due to the content of aluminum oxide and quartz in the composition.
Diagrams for connecting the DNaT lamp
For the first start-up of a sodium lamp, it is not enough just to apply a supply voltage to it; for this, special pulsed ignition devices such as IZU are used once. This is due to the fact that a cold burner has a high resistance, as a result of which it simply does not start.
After the first start-up, the current flow through the lamp needs to be limited. For this, an electronic or electromagnetic ballast was created.
IZU is connected in parallel, the choke is connected in series with the light bulb. IZU are divided into two types: three-pin and two-pin. The cost of the latter is lower and it is easier to connect, while the former performs the tasks assigned to it more correctly.
It is important to install the HPS lamps using clean cloths or cotton gloves, as the bulb temperature of the instrument reaches 300 degrees Celsius. If you touch the bulb with greasy fingers, a layer of carbon will form, which does not conduct heat well.
Technical comparison with analogues
To understand why sodium lamps are still used, it is recommended to compare their technical characteristics with those of their counterparts.
| Lighting lamp type | Service life, h | Created luminous flux, lm | Nameplate power of the product, W |
| DNaT-100 | 6 000 | 9 400 | 100 |
| DNaT-150 | 10 000 | 14 000 | 150 |
| DNaT-250 | 15 000 | 24 000 | 250 |
| DNaT-400 | 15 000 | 47 500 | 400 |
| DRL-125 | 12 000 | 6 000 | 125 |
| DRL-250 | 12 000 | 13 000 | 250 |
| DRL-400 | 15 000 | 24 000 | 400 |
| LED analogue of DRL-125 | 10 000 | 2 500 | 40 |
| DRL-250 LED analog | 10 000 | 5 000 | 80 |
Scope of application
Due to their poor color accuracy, sodium vapor modules are not intended for use in everyday life; they are most often installed for lighting streets and backyards, as well as avenues and highways.
HPS lamps are installed in electrical equipment designed for backlighting and background lighting:
- In greenhouses, conservatories and greenhouses to ensure the base yield of cultivated plants, as well as to increase their growth rates.
- Container grounds, sports facilities and tunnels.
- Warehouse and industrial premises, workshops, where the quality of color rendering does not play a big role.
- Architectural structures and historical monuments.
- Airports, railway stations, etc.
In all of the above cases, sodium lamps provide adequate illumination with minimal power consumption.
Advantages and disadvantages
- Minimal power consumption, cost-effectiveness.
- Good light output.
- The operating temperature ranges from -60 to +40 degrees Celsius.
- Heat radiation.
- High efficiency.
- Long service life.
- The luminous flux does not change even after a while.
Among the disadvantages are:
- Ignition of the device and stabilization of the glow takes 5-7 minutes.
- The color range at the end of the useful life is subject to change.
- At abnormally low temperatures, the glow efficiency decreases.
- Lamps containing mercury cannot be considered safe.
It is recommended to purchase HPS lamps and its analogues in specialized stores, where they are accompanied by accompanying documentation and a warranty card.
