FACTOID # 8: Bookworms: Vermont has the highest number of high school teachers per capita and third highest number of librarians per capita.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Sodium vapor lamp
A low pressure sodium/sodium oxide (LPS/SOX) streetlamp at full power
A low pressure sodium/sodium oxide (LPS/SOX) streetlamp at full power (detail)
A low pressure sodium/sodium oxide (LPS/SOX) streetlamp at full power (detail)

A sodium vapor lamp is a gas discharge lamp which uses sodium in an excited state to produce light. There are two varieties of such lamps: low pressure and high pressure. File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... A streetlight in front of a red sky at night A street light, also known as a light standard, is a raised light on the edge of a road, turned on or lit at a certain time every night. ... Low pressure Sodium vapor lamp at full power. ... Low pressure Sodium vapor lamp at full power. ... A streetlight in front of a red sky at night A street light, also known as a light standard, is a raised light on the edge of a road, turned on or lit at a certain time every night. ... It has been suggested that this article or section be merged with Fluorescent lamp. ... For sodium in the diet, see Salt. ... For other uses, see Light (disambiguation). ...

Contents

Low pressure LPS/SOX

Spectrum of low-pressure sodium lamp. The intense yellow band on the left is the atomic sodium D-line emission, comprising about 90% of the visible light emission for this lamp type.
Spectrum of low-pressure sodium lamp. The intense yellow band on the left is the atomic sodium D-line emission, comprising about 90% of the visible light emission for this lamp type.

Low pressure sodium (LPS) lamps, also known as sodium oxide (SOX) lamps, consist of an outer vacuum envelope of glass coated with an infrared reflecting layer of indium tin oxide, a semiconductor material that allows the visible light wavelengths out and keeps the infrared (heat) back. It has two inner borosilicate glass U-pipes that hold solid sodium and a small amount of neon and argon gas Penning mixture to start the gas discharge, so when the lamp is turned on it emits a dim red/pink light to warm the sodium metal and within a few minutes it turns into the common bright yellow color as the sodium metal vaporizes. These lamps produce a virtually monochromatic light averaging at a 589.3 nm wavelength (actually two dominant spectral lines very close together at 589.0 and 589.6 nm). As a result, the colors of objects cannot easily be distinguished since they are seen almost entirely by their reflection of this narrow bandwidth yellow light. Look up Vacuum in Wiktionary, the free dictionary. ... This article is about the material. ... For other uses, see Infrared (disambiguation). ... The reflection of a bridge in Indianapolis, Indianas Central Canal. ... Indium tin oxide (ITO) is a mixture of indium(III) oxide (In2O3) and tin(IV) oxide (SnO2), typically 90% In2O3, 10% SnO2 by weight. ... Semiconductor materials are insulators at absolute zero temperature that conduct electricity in a limited way at room temperature (see also Semiconductor). ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... For other uses, see Infrared (disambiguation). ... It has been suggested that Kimax be merged into this article or section. ... For sodium in the diet, see Salt. ... For other uses, see Neon (disambiguation). ... General Name, symbol, number argon, Ar, 18 Chemical series noble gases Group, period, block 18, 3, p Appearance colorless Standard atomic weight 39. ... A Penning mixture is a mixture of inert gas with another gas, with lower ionization voltage than either of them. ... This article is about the color. ... Evaporation is the process whereby atoms or molecules in a liquid state (or solid state if the substance sublimes) gain sufficient energy to enter the gaseous state. ... Something which is monochromatic has a single color. ... A nanometre (American spelling: nanometer, symbol nm) (Greek: νάνος, nanos, dwarf; μετρώ, metrÏŒ, count) is a unit of length in the metric system, equal to one billionth of a metre (or one millionth of a millimetre), which is the current SI base unit of length. ... For other uses, see Wavelength (disambiguation). ...


LPS lamps are the most efficient electrically powered light source when measured for photopic lighting conditions—up to 200 lm/W,[1] primarily because the output is dominated by light at a wavelength near the peak sensitivity of the eye. As a result they are widely used for outdoor lighting such as street lights and security lighting where color rendition is viewed by many to be less important. LPS lamps are available with power ratings from 10 W up to 180 W; however, length increases greatly with power creating problems for designers. The 1931 CIE photopic luminosity function. ... The lumen (symbol: lm) is the SI unit of luminous flux. ... For other uses, see Watt (disambiguation). ... A high pressure sodium vapor street lamp from Australia. ... In the field of physical security, security lighting is often used as a preventative and corrective measure against intrusions or other criminal activity on a physical piece of property. ... Transmission lines in Lund, Sweden Electric power, often known as power or electricity, involves the production and delivery of electrical energy in sufficient quantities to operate domestic appliances, office equipment, industrial machinery and provide sufficient energy for both domestic and commercial lighting, heating, cooking and industrial processes. ...


LPS lamps are more closely related to fluorescent than high intensity discharge lamps, since they have a low–pressure, low–intensity discharge source and a linear lamp shape. Also like fluorescents they do not exhibit a bright arc as do other HID lamps; rather they emit a softer luminous glow, resulting in less glare.


Another unique property of LPS lamps is that, unlike other lamp types, they do not decline in lumen output with age. As an example, mercury vapor HID lamps become very dull towards the end of their lives, to the point of being ineffective, whilst still drawing their full rated load of electricity. LPS lamps, however, do increase energy usage slightly (about 10%) towards their end of life, which is usually rated around 18,000 hours for modern lamps.


High pressure HPS/SON

Spectrum of high pressure sodium lamp. The yellow-red band on the left is the atomic sodium D-line emission; the turquoise line is a sodium line which is otherwise quite weak in a low pressure discharge, but become intense in a high pressure discharge. Most of the other green, blue and violet lines arise from mercury.
Spectrum of high pressure sodium lamp. The yellow-red band on the left is the atomic sodium D-line emission; the turquoise line is a sodium line which is otherwise quite weak in a low pressure discharge, but become intense in a high pressure discharge. Most of the other green, blue and violet lines arise from mercury.
Office building illuminated by high pressure sodium lamps. Location: Nijmegen, the Netherlands.
Office building illuminated by high pressure sodium lamps. Location: Nijmegen, the Netherlands.

High pressure sodium (HPS) lamps are smaller and contain additional elements such as mercury, and produce a dark pink glow when first struck, and a pinkish orange light when warmed. Some bulbs also briefly produce a pure to bluish white light in between. This is probably from the mercury glowing before the sodium is completely warmed. The sodium D-line is the main source of light from the HPS lamp, and it is extremely pressure broadened by the high sodium pressures in the lamp; due to this broadening and the emissions from mercury, colors of objects under these lamps can be distinguished. This leads them to be used in areas where good color rendering is important, or desired. Thus, its new model name SON is the variant for "Sun" (a name used primarily in Europe and the UK). Image File history File links Spectrum-hp-sodium. ... Image File history File links Spectrum-hp-sodium. ... This article is about the element. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ...


High pressure sodium lamps are quite efficient—about 100 lm/W—when measured for photopic lighting conditions. They have been widely used for outdoor lighting such as streetlights and security lighting. Understanding the change in human color vision sensitivity from photopic to mesopic and scotopic is essential for proper planning when designing lighting for roads. Photopic vision is the vision of the light-adapted eye; in many animals, color vision, mediated by cone cells. ... The 1931 CIE photopic luminosity function. ... Mesopic vision is a combination of photopic vision and scotopic vision in low but not quite dark lighting situations. ... The CIE 1951 scotopic luminosity function. ...


Because of the extremely high chemical activity of the high pressure sodium arc, the arc tube is typically made of translucent aluminum oxide (alumina). This construction led General Electric to use the tradename "Lucalox" for their line of high-pressure sodium lamps. In optics, transparency is the property of being transparent, or allowing light to pass. ... Aluminium oxide (or aluminum oxide) (Al2O3) is a chemical compound of aluminium and oxygen. ... GE redirects here. ...


Xenon at a low pressure is used as a "starter gas" in the HPS lamp. It has the lowest thermal conductivity and lowest ionization potential of all the non-radioactive noble gases. As a noble gas, it does not interfere with the chemical reactions occurring in the operating lamp. The low thermal conductivity minimizes thermal losses in the lamp while in the operating state, and the low ionization potential causes the breakdown voltage of the gas to be relatively low in the cold state, which allows the lamp to be easily started. General Name, Symbol, Number xenon, Xe, 54 Chemical series noble gases Group, Period, Block 18, 5, p Appearance colorless Standard atomic weight 131. ... K value redirects here. ... The ionization potential, ionization energy or EI of an atom or molecule is the energy required to remove one mole of electrons from one mole of isolated gaseous atoms or ions. ... Breakdown Voltage (Insulator) = The minimum voltage that makes an insulator react as a conductor. ...


"White" SON

A variation of the high pressure sodium, the White SON, introduced in 1986, has a higher pressure than the typical HPS lamp, producing a color temperature of around 2700 K, with a CRI of 85; greatly resembling the color of incandescent light.[2] These are often indoors in cafes and restaurants to create a certain atmosphere. However, these lamps come at the cost of higher purchase cost, shorter life, and lower light efficiency. The CIE 1931 x,y chromaticity space, also showing the chromaticities of black-body light sources of various temperatures, and lines of constant correlated color temperature Color temperature is a characteristic of visible light that has important applications in photography, videography, publishing and other fields. ... For other uses, see Kelvin (disambiguation). ... CRI is a three letter abbreviation that may stand for: China Radio International Color rendering index Crown Research Institute (New Zealand) This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...


Theory of operation

Diagram of a high pressure sodium lamp.
Diagram of a high pressure sodium lamp.

The operation of a high-pressure sodium lamp is illustrated in the diagram on the right. Image File history File links This is a lossless scalable vector image. ... Image File history File links This is a lossless scalable vector image. ...


An amalgam of metallic sodium and mercury lies at the coolest part of the lamp and provides the sodium and mercury vapor in which the arc is drawn. The temperature of the amalgam is determined to a great extent by lamp power. The higher the lamp power, the higher will be the amalgam temperature. The higher the temperature of the amalgam, the higher will be the mercury and sodium vapor pressures in the lamp. An increase in these metal pressures will cause a decrease in the electrical resistance of the lamp. For a given voltage, there are generally three modes of operation: In chemistry, sodium amalgam is an amalgam, or alloy of mercury, with sodium metal. ...

  1. The lamp is extinguished and no current flows.
  2. The lamp is operating with liquid amalgam in the tube.
  3. The lamp is operating with all amalgam evaporated.

The first and last states are stable, because the lamp resistance is weakly related to the voltage, but the second state is unstable. Any anomalous increase in current will cause an increase in power, causing an increase in amalgam temperature, which will cause a decrease in resistance, which will cause a further increase in current. This will create a runaway effect, and the lamp will jump to the high-current state (#3). Since actual lamps are not designed to handle this much power, this would result in catastrophic failure. Similarly, an anomalous drop in current will drive the lamp to extinction. It is the second state which is the desired operating state of the lamp, because a slow loss of the amalgam over time from a reservoir will have less effect on the characteristics of the lamp than a fully evaporated amalgam. The result is an average lamp life in excess of 20,000 hours.


In practical use, the lamp is powered by an AC voltage source in series with an inductive "ballast" in order to supply a nearly constant current to the lamp, rather than a constant voltage, thus assuring stable operation. The ballast is usually inductive rather than simply being resistive which minimizes resistive losses. Also, since the lamp effectively extinguishes at each zero-current point in the AC cycle, the inductive ballast assists in the reignition by providing a voltage spike at the zero-current point. A ballast is a device used to start a gas discharge lamp, and, once the lamp is started, to limit the flow of electric current. ...


The light from the lamp consists of atomic emission lines of mercury and sodium, but is dominated by the sodium D-line emission. This line is extremely pressure (resonance) broadened and is also self-reversed due to absorption in the cooler outer layers of the arc, giving the lamp its improved color rendering characteristics. In addition, the red wing of the D-line emission is further pressure broadened by the Van der Waals forces from the mercury atoms in the arc. A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... Colour rendering index, or CRI, is a measure of the quality of colour light, devised by the International Commission on Illumination (CIE). ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ...


Light pollution considerations

For placements where light pollution is of prime importance (for example an observatory parking lot), low pressure sodium is preferred. Sodium emits light on only one wavelength, and therefore is the easiest to filter out. This time exposure photo of New York City shows sky glow, one form of light pollution. ... This article is about scientific observatories. ... This article does not cite any references or sources. ...


One consequence of widespread public lighting is that on cloudy nights, cities with enough public lighting are illuminated by light reflected off the clouds. As sodium vapor lights are often the source of urban illumination, this turns the sky a tinge of orange. If the sky is clear or hazy, the light will radiate over large distances, causing large enough cities to be recognizable by an orange glow when viewed from outside the city.


End of life

At the end of life, high-pressure sodium lamps exhibit a phenomenon known as cycling, which is caused by a loss of sodium in the arc. Sodium is a highly reactive element, and is easily lost by combination with other elements, and migration through the arc tube walls. As a result, these lamps can be started at a relatively low voltage but as they heat up during operation, the internal gas pressure within the arc tube rises and more and more voltage is required to maintain the arc discharge. As a lamp gets older, the maintaining voltage for the arc eventually rises to exceed the voltage provided by the electrical ballast. As the lamp heats to this point, the arc fails and the lamp goes out. Eventually, with the arc extinguished, the lamp cools down again, the gas pressure in the arc tube is reduced, and the ballast can once again cause the arc to strike. The effect of this is that the lamp glows for a while and then goes out, repeatedly. International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ... A 3000 volt electricity arc between two nails Electricity arcs between the power rail and electrical pickup shoe on a London Underground train An electric arc can melt calcium oxide An electric arc is an electrical breakdown of a gas which produces an ongoing plasma discharge, resulting from a current... An automotive (ignition system) ballast resistor An electrical ballast (sometimes called control gear) is a device intended to limit the amount of current flowing in an electric circuit. ...


More sophisticated ballast designs detect cycling and give up attempting to start the lamp after a few cycles. If power is removed and reapplied, the ballast will make a new series of startup attempts.


LPS lamp failure does not result in cycling; rather, the lamp will simply not strike, and will maintain its dull red glow exhibited during the start up phase.


See also

A Common Household Light bulb This is a list of sources of light, including both natural and artificial sources, and both processes and devices. ... The use of street lighting was first recorded in London in 1417 when Sir Henry Barton, the mayor, ordered lanterns with lights to be hanged out on the winter evenings between Hallowtide and Candlemasse. ... A high pressure sodium vapor street lamp from Australia. ...

References

  1. ^ Why is lightning colored? (gas excitations). WebExhibits. Retrieved on 2007-09-24.
  2. ^ Philips SDW-T High Pressure Sodium White SON. WebExhibits. Retrieved on 2007-09-24.
  • de Groot, J.J.; J.A.J.M. van Vliet (1986). The High-Pressure Sodium Lamp. Antwerp: Kluwer Technische Bocken B.V.. ISBN 90-201-1902-8. 
  • Waymouth, John (1971). Electric Discharge Lamps. Cambridge, MA: The M.I.T. Press. ISBN 0-262-23048-8. 
Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 267th day of the year (268th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 267th day of the year (268th in leap years) in the Gregorian calendar. ... For devices such as table lamps and reading lamps, see Light fixture. ... Not to be confused with lightning. ... Molten glassy material glows orange with incandescence in a vitrification experiment. ... Light bulb redirects here. ... The incandescent light bulb uses a glowing wire filament heated to white-hot by electrical resistance, to generate light (a process known as thermal radiation). ... Nernst lamp, complete, model B with cloche, DC-lamp 0. ... A Parabolic Aluminized Reflector light, or PAR light, is a type of light commonly used in motion picture production when a substantial amount of light is required for a scene. ... The Centennial Light hanging in the Livermore, California Firehouse. ... Image File history File links Size of this preview: 361 × 600 pixelsFull resolution (768 × 1276 pixel, file size: 757 KB, MIME type: image/png) Other versions Original at Image:Gluehlampe 01 KMJ.jpg File historyClick on a date/time to view the file as it appeared at that time. ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized Cadmium selenide (CdSe) quantum dots. ... A spiral type compact fluorescent lamp. ... Fluorescent lamps Assorted types of fluorescent lamps. ... In contrast with all other electrical lamps that use electrical connections through the lamp envelope to transfer power to the lamp, in electrodeless lamps the power needed to generate light is transferred from the outside of the lamp envelope by means of (electro)magnetic fields. ... Germicidal lamps are simple low pressure mercury vapor discharges in a fused quartz envelope. ... 15 kW Xenon short-arc lamp used in IMAX projectors High-intensity discharge (HID) lamps include these types of electrical lamps: mercury vapor, metal halide (also HQI), high-pressure sodium (Son), low-pressure sodium (Sox) and less common, xenon short-arc lamps. ... A Mercury-vapor lamp is a gas discharge lamp which uses mercury in an excited state to produce light. ... Example of a light source using a broad spectrum metal halide lamp pointing upward towards the sky. ... Lighting neon lamp, two 220/230 volt and 110 V neon lamps and a screwdriver with neon lamp inside A neon lamp is a gas discharge lamp containing primarily neon gas at low pressure. ... This section may require cleanup to meet Wikipedias quality standards. ... Xenon flash lamp being fired. ... A 3000 volt electricity arc between two nails Electricity arcs between the power rail and electrical pickup shoe on a London Underground train An electric arc can melt calcium oxide An electric arc is an electrical breakdown of a gas which produces an ongoing plasma discharge, resulting from a current... The 300,000-watt Plasma Arc Lamp in the Infrared Processing Center (IPC) at Oak Ridge National Laboratory An arc lamp is a device that produces light by the sparking (or arcing, from voltaic arc) of a high current between two carbon rod electrodes. ... A Yablochkov candle (sometimes electric candle) is a type of electric carbon arc lamp, invented in 1876 by Pavel Yablochkov. ... This article is about the chemical reaction combustion. ... Lit carbide lamp A French manufactured Carbide of Calcium lamp on a bicycle Carbide of Calcium lamp in a coal mine Carbide lamps also known as Acetylene Gas lamps are simple lamps that produce and burn acetylene gas (C2H2) which is created by the reaction of calcium carbide (CaC2) with... The Argand lamp was invented and patented in 1780 by Aimé Argand . ... For other uses, see Candle (disambiguation). ... The Indian light festival Diwali is traditionally lit up by huge numbers of Diya (plural diyas). Diya is a contracted form of deep or light given by small earthen pots (also known as Pradeep), with wick made of cotton and dipped in ghee. ... Gas lighting is the process of burning piped natural gas or coal gas for illumination. ... Swiss kerosene lamp. ... For other uses, see Lantern (disambiguation). ... This article does not cite any references or sources. ... Antique bronze oil lamp with Christian symbol (replica) A terra-cotta oil lamp, Antique oil lamp (replica) An oil lamp is a simple vessel used to produce light continuously for a period of time from a fuel source. ... Safety lamp is the name of a variety of lamps for safety in coal-mines against coal dust, methane, or firedamp, a highly explosive mixture of natural gas apt to accumulate in them. ... It has been suggested that this article or section be merged into Kerosene lamp. ... A Rushlight is a type of candle formed using the dried pith of the rush plant as its wick. ... Tilley Lamp TL10 from 1922-1946 The Tilley Lamp derives from John Tilley’s invention of the hydro-pneumatic blowpipe in 1813. ... This article is about portable open fires. ... LBNL researcher examines prototype sulfur lamp. ... LED redirects here. ... LED Lamp with GU10 twist lock fitting, intended to replace halogen reflector lamps. ... Solid State Lighting (SSL) refers to a type of lighting that utilizes light-emitting diodes (LEDs), organic light-emitting diodes (OLED), or polymer light-emitting diodes as sources of illumination rather than electrical filaments or gas. ... This article or section does not cite its references or sources. ... Electroluminescent wire (often abbreviated to EL wire) is a thin copper wire coated in a phosphor which glows when an AC voltage is applied to it. ... A chemoluminescent reaction carried out in an erlenmeyer flask producing a large amount of light. ... Emission spectrum of an ultraviolet deuterium arc lamp clearly showing characteristic hydrogen emission lines (sharp peaks at 656 nm and 486 nm) and continuum emission in the ~160-400 nm region. ... Radioluminescence is the phenomenon by which luminescence is produced in a material by the bombardment of ionizing radiation such as beta particles. ...

  Results from FactBites:
 
Sodium vapor lamp - Wikipedia, the free encyclopedia (882 words)
A sodium vapor lamp is a gas discharge lamp which uses sodium in an excited state to produce light.
An amalgam of metallic sodium and mercury lies at the coolest part of the lamp and provides the sodium and mercury vapor in which the arc is drawn.
The lamp is powered by an AC voltage source in series with an inductive "ballast" in order to supply a nearly constant current to the lamp, rather than a constant voltage, thus assuring stable operation.
Encyclopedia: Sodium vapor lamp (443 words)
A lamp as in claim 1 wherein said inleads have an intermediate portion of tungsten embedded in the press of the stem and an outer portion of copper and an inner portion of titanium butt-welded to opposite ends of the intermediate portion.
A lamp as in claim 1 wherein the cathode electrode comprises a tungsten wire coil on a tungsten shank and an anti back-arcing shield mounted on the shank behind said coil, said shield being firmly attached in a manner precluding vibratory displacement on said shank.
I have determined that a major source of noise in sonic pulse operation of prior art lamps is the stem press or seal of the outer glass envelope or jacket wherein the welds of the inner and outer nickel portions to the intermediate portion of the inleads are embedded in glass.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m