High pressure sodium lamps lighting associates, inc. In a low pressure sodium vapour lamp, argon or neon gas is first heated up to emit a slight red or purple glow. The basic principle behind the working of sodium vapor lamp is passing electric current through sodium gas to make the gas emit light. For an easy start up, small amounts of neon and argon gases are also present along with sodium gas inside the glass. Better efficiency, life and size are few of the advantages of hps lamp over lps lamp. Two centuries of electric light source innovations pdf. Principle of working of a sodium vapour lamp answers. High pressure sodium lamp hps lamp the hps lamp is the most ubiquitous lamp for street lighting on the planet. What are the advantages and disadvantages of the mercury lamp, sodium vapour lamp and xenon lamp used in photocatalysis. In normal operation, standby lamps alternate operation between the arc tubes.
In 1959, the development of polycrystalline alumina pca opened a new path to introduce the highpressure sodium vapor lamp, as this material is very rarely affected by high pressure and temperature sodium vapor. There are several versions of the lamp but the basic principle is the same. Sodium vapor lamps are some of the most efficient lamps in the world. The heat from this warms sodium metal in the light to the point of vaporizing, which. The end caps of the arc tube would get as hot as 800 degrees c in operation, then cool to room temperature when the lamp was turned. Basic operation in a high pressure sodium lamp, a compact arc tube contains a mixture of xenon, sodium and mercury. Learn about this popular light invented in 1901 by peter cooper hewitt. They have an efficiency of up to 190 lumens per watt compared to an incandescent street lamp which has between 15 and 19 lumens per watt.
The yellow light given off by a sodium vapor lamp used for public lighting has a wavelength of 589 nm. Hps lamp is the better version of its counterpart lps lamp. Mesoptic street lighting demonstration and evaluation final report pdf. The construction and applications of sodium vapour lamps. The first lamp with 400 w, 42000 initial lumens and 6000hour life first came in the market in 1965. The presence of neon gas serves to start the discharge envelope is usually bent into u shape. A lowpressure sodiumvapour lps lamp contains an inner discharge tube made of borosilicate glass that is fitted with metal electrodes and filled with neon and argon gas and a little metallic sodium. A lowpressure sodium vapor lamp or lpsv lamp is termed as a miscellaneous discharge lamp as it possesses some characteristics of. Principally the sodium vapour lamp consists of the bulb containing a small amount of metallic sodium, neon gas, and two sets of electrodes connected in a pin type base. This blog showcases in detail the working of highpressure sodium vapour lamp. What are the advantages and disadvantages of the mercury.
Working principle it works by electric discharge passage of electricity through sodium vapours at low and high pressure filaments of the. A sodiumvapor lamp is a gasdischarge lamp that uses sodium in an excited state to produce. The better color rendering comes with a bit of sacrifice. A mercuryvapor lamp is a gas discharge lamp that uses an electric arc through vaporized. Working principle of sodium vapour lamp polytechnic hub. High pressure sodium lamps or hps lamps electrical4u.
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