Nernst lamp
Encyclopedia
Nernst lamps were an early form of electrically powered
incandescent lamps. Nernst lamps did not use a glowing tungsten
filament. Instead, they used a ceramic
rod that was heated to incandescence
. Because the rod (unlike tungsten wire) would not further oxidize when exposed to air, there was no need to enclose it within a vacuum or noble gas
environment; the burners in Nernst lamps could operate exposed to the air and were only enclosed in glass to isolate the hot incandescent emitter from its environment. A ceramic of zirconium oxide - yttrium oxide was used as the glowing rod.
Developed by the German physicist and chemist Walther Nernst
in 1897 at Goettingen University, these lamps were about twice as efficient as carbon filament lamps and they emitted a more "natural" light (more similar in spectrum
to daylight
).
The lamps were quite successfully marketed for a time, although they eventually lost out to the more-efficient tungsten filament incandescent light bulb
.
One disadvantage of the Nernst design was that the ceramic rod was not electrically conductive at room temperature so the lamps needed a separate heater filament to heat the ceramic hot enough to begin conducting electricity on its own.
In the U.S., Nernst sold the patent to George Westinghouse
who founded the Nernst Lamp Company at Pittsburgh
in 1901.
Minerals for the production of the glowers were extracted from the company's own mines at the legendary Barringer Hill
, Texas (since 1937 buried beneath the waters of Lake Buchanan).
By 1904 a total of over 130,000 Nernst lamps had been placed in service throughout the country.
In Europe the lamps were produced by the German Allgemeine Elektrizitäts-Gesellschaft
(AEG
, General Electricity Company) at Berlin
.
At the World's Fair
1900
at Paris
the pavilion of the AEG was illuminated by 800 Nernst lamps which was quite spectacular at that time.
In addition to their usage for ordinary electric illumination, Nernst lamps were used in one of the first practical long-distance photoelectric facsimile (fax
) systems, designed by professor Arthur Korn in 1902, in Allvar Gullstrand
's slit lamp (1911) for ophthalmology
, for projection and in microscopy.
After Nernst lamps fell into obsolescence the term "Nernst glower
" went on to be used to describe the infrared-emitting source used in IR spectroscopy devices. (Recently, even this term has become obsolete as Nernst glowers have been largely replaced for this purpose by silicon carbide
glow bars or "globar
s" http://www.apptherm.com/ProductLines/Kanthal.htm which are conductive even at room temperature and therefore need no preheating.)
Electricity
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
incandescent lamps. Nernst lamps did not use a glowing tungsten
Tungsten
Tungsten , also known as wolfram , is a chemical element with the chemical symbol W and atomic number 74.A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as...
filament. Instead, they used a ceramic
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
rod that was heated to incandescence
Incandescence
Incandescence is the emission of light from a hot body as a result of its temperature. The term derives from the Latin verb incandescere, to glow white....
. Because the rod (unlike tungsten wire) would not further oxidize when exposed to air, there was no need to enclose it within a vacuum or noble gas
Noble gas
The noble gases are a group of chemical elements with very similar properties: under standard conditions, they are all odorless, colorless, monatomic gases, with very low chemical reactivity...
environment; the burners in Nernst lamps could operate exposed to the air and were only enclosed in glass to isolate the hot incandescent emitter from its environment. A ceramic of zirconium oxide - yttrium oxide was used as the glowing rod.
Developed by the German physicist and chemist Walther Nernst
Walther Nernst
Walther Hermann Nernst FRS was a German physical chemist and physicist who is known for his theories behind the calculation of chemical affinity as embodied in the third law of thermodynamics, for which he won the 1920 Nobel Prize in chemistry...
in 1897 at Goettingen University, these lamps were about twice as efficient as carbon filament lamps and they emitted a more "natural" light (more similar in spectrum
Spectrum
A spectrum is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. The word saw its first scientific use within the field of optics to describe the rainbow of colors in visible light when separated using a prism; it has since been applied by...
to daylight
Daylight
Daylight or the light of day is the combination of all direct and indirect sunlight outdoors during the daytime. This includes direct sunlight, diffuse sky radiation, and both of these reflected from the Earth and terrestrial objects. Sunlight scattered or reflected from objects in outer space is...
).
The lamps were quite successfully marketed for a time, although they eventually lost out to the more-efficient tungsten filament incandescent light bulb
Incandescent light bulb
The incandescent light bulb, incandescent lamp or incandescent light globe makes light by heating a metal filament wire to a high temperature until it glows. The hot filament is protected from air by a glass bulb that is filled with inert gas or evacuated. In a halogen lamp, a chemical process...
.
One disadvantage of the Nernst design was that the ceramic rod was not electrically conductive at room temperature so the lamps needed a separate heater filament to heat the ceramic hot enough to begin conducting electricity on its own.
In the U.S., Nernst sold the patent to George Westinghouse
George Westinghouse
George Westinghouse, Jr was an American entrepreneur and engineer who invented the railway air brake and was a pioneer of the electrical industry. Westinghouse was one of Thomas Edison's main rivals in the early implementation of the American electricity system...
who founded the Nernst Lamp Company at Pittsburgh
Pittsburgh, Pennsylvania
Pittsburgh is the second-largest city in the US Commonwealth of Pennsylvania and the county seat of Allegheny County. Regionally, it anchors the largest urban area of Appalachia and the Ohio River Valley, and nationally, it is the 22nd-largest urban area in the United States...
in 1901.
Minerals for the production of the glowers were extracted from the company's own mines at the legendary Barringer Hill
Barringer Hill
Barringer Hill is a geological and mineralogical site in central Texas. It lies on the former west side of the Colorado river, beneath Lake Buchanan, about northeast of the town of Llano. The hill consists of a pegmatite and geologically, lies near the eastern edge of the Central Mineral Region...
, Texas (since 1937 buried beneath the waters of Lake Buchanan).
By 1904 a total of over 130,000 Nernst lamps had been placed in service throughout the country.
In Europe the lamps were produced by the German Allgemeine Elektrizitäts-Gesellschaft
AEG
Allgemeine Elektricitäts-Gesellschaft was a German producer of electrical equipment founded in 1883 by Emil Rathenau....
(AEG
AEG
Allgemeine Elektricitäts-Gesellschaft was a German producer of electrical equipment founded in 1883 by Emil Rathenau....
, General Electricity Company) at Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...
.
At the World's Fair
World's Fair
World's fair, World fair, Universal Exposition, and World Expo are various large public exhibitions held in different parts of the world. The first Expo was held in The Crystal Palace in Hyde Park, London, United Kingdom, in 1851, under the title "Great Exhibition of the Works of Industry of All...
1900
Exposition Universelle (1900)
The Exposition Universelle of 1900 was a world's fair held in Paris, France, from April 15 to November 12, 1900, to celebrate the achievements of the past century and to accelerate development into the next...
at Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
the pavilion of the AEG was illuminated by 800 Nernst lamps which was quite spectacular at that time.
In addition to their usage for ordinary electric illumination, Nernst lamps were used in one of the first practical long-distance photoelectric facsimile (fax
Fax
Fax , sometimes called telecopying, is the telephonic transmission of scanned printed material , normally to a telephone number connected to a printer or other output device...
) systems, designed by professor Arthur Korn in 1902, in Allvar Gullstrand
Allvar Gullstrand
Allvar Gullstrand was a Swedish ophthalmologist.Born at Landskrona, Sweden, Gullstrand was professor successively of eye therapy and of optics at the University of Uppsala. He applied the methods of physical mathematics to the study of optical images and of the refraction of light in the eye...
's slit lamp (1911) for ophthalmology
Ophthalmology
Ophthalmology is the branch of medicine that deals with the anatomy, physiology and diseases of the eye. An ophthalmologist is a specialist in medical and surgical eye problems...
, for projection and in microscopy.
After Nernst lamps fell into obsolescence the term "Nernst glower
Nernst glower
The Nernst glower is an obsolete device for providing a continuous source of infrared radiation for use in spectroscopy. Typically it was in the form of a cylindrical rod or tube composed of a mixture of certain oxides such as zirconium oxide , yttrium oxide and erbium oxide at a ratio of...
" went on to be used to describe the infrared-emitting source used in IR spectroscopy devices. (Recently, even this term has become obsolete as Nernst glowers have been largely replaced for this purpose by silicon carbide
Silicon carbide
Silicon carbide , also known as carborundum, is a compound of silicon and carbon with chemical formula SiC. It occurs in nature as the extremely rare mineral moissanite. Silicon carbide powder has been mass-produced since 1893 for use as an abrasive...
glow bars or "globar
Globar
A Globar is a silicon carbide rod of 5 to 10 mm width and 20 to 50 mm length which is electrically heated up to . When combined with a downstream variable interference filter, it emits radiation from 4 to 15 micrometres wavelength...
s" http://www.apptherm.com/ProductLines/Kanthal.htm which are conductive even at room temperature and therefore need no preheating.)
See also
- GlobarGlobarA Globar is a silicon carbide rod of 5 to 10 mm width and 20 to 50 mm length which is electrically heated up to . When combined with a downstream variable interference filter, it emits radiation from 4 to 15 micrometres wavelength...
, a silicon carbide rod used as thermal light source for infrared spectroscopy - List of light sources