When there was the first glow lamp?
In 1809 the Englishman to Delar builds the first glow lamp (with the platinum spiral). In 1838 Belgian Zhobar invents the coal glow lamp. In 1854 German Heinrich Gyobel developed the first "modern" lamp - the charred bamboo thread in the vacuumized vessel. In the next 5 years he developed what many call the first practical lamp. In 1860 the English chemist and the physicist Joseph Wilson Swan showed the first results and took out the patent, however difficulties in receiving the vacuum led to the fact that Swan's lamp worked not for long and inefficiently.
On July 11, 1874 the USAn engineer Alexander Nikolaevich Lodygin took out the patent behind number 1619 for the nitevy lamp. As filament he used the coal rod placed in the vacuumized vessel.
In 1875 V.F. Didrikhson improved Lodygin's lamp, having carried out pumping of air from it and having applied several hairs (in case of burn-out of one of them following joined automatically) in the lamp.
The English inventor Joseph Wilson Swan took out in 1878 the British patent for the lamp with coal fiber. In its lamps fiber was in the rarefied oxygen atmosphere that allowed to receive very bright light.
In the second half of the 1870th years the American inventor Thomas Edison carries out research in which he tries different metals as thread. In 1879 it patents the lamp with platinum thread. In 1880 it returns to coal fiber and creates the lamp with the lifetime of 40 hours. At the same time Edison invented the household rotary switch. Despite so short lifetime, its lamps force out the gas lighting used until then.
In the 1890th years A.N. Lodygin invents several types of lamps with filaments from high-melting metals. Lodygin suggested to apply in thread lamps from tungsten (such are applied in all modern lamps) and molybdenum and to twist incandescence thread in the form of the spiral. He made the first attempts to pump out air from lamps that kept thread from oxidation and increased their service life many times over. The first American commercial lamp with the tungsten spiral was made afterwards according to Lodygin's patent. It made also gas-filled lamps (with coal thread and filling with nitrogen).
Since the end of the 1890th years there were lamps with incandescence thread from oxide of magnesium, thorium, zirconium and yttrium (Nernst's lamp) or thread from metal osmium (Auer's lamp) and tantalum (Bolton and Feyerleyn's lamp). In 1904 Hungarians Dr. Shandor Yust and Franjo Hanaman took out the patent for No. 34541 for use in lamps of tungsten thread. The first such lamps which entered the market through the Hungarian firm Tungsram in 1905 were manufactured in Hungary. In 1906 Lodygin sells the patent for tungsten thread of the General Electric company.
In the same 1906 in the USA he constructed and used the plant on electrochemical receiving tungsten, chrome, titanium. Because of the high cost of tungsten the patent finds only limited application. In 1910 William David Coolidge invents the improved method of production of tungsten thread. Afterwards tungsten thread forces out all other types of threads.
The remaining problem with fast evaporation of thread in the vacuum was solved by the American scientist, the famous specialist in the field of the vacuum equipment Irving Lengmyur who, working since 1909 in General Electric, entered into production filling of the flask of lamps inert, more precisely heavy noble, gases (in particular, argon) that significantly increased time of their work and increased luminous efficiency.
Efficiency and durability
All energy which is almost given to the lamp turns into radiation. Losses due to heat conductivity and convection are small. Only small range of lengths of waves of this radiation, however, is available to the human eye. The main part of radiation lies with the invisible infrared range and is perceived in the form of heat.
Efficiency of glow lamps reaches at the temperature about 3400 K of maximum value of 15%. At almost achievable temperatures in 2700 K (the normal lamp on 60 W) efficiency is 5 %.
With increase of temperature of efficiency of the glow lamp increases, but at the same time its durability significantly decreases. At the temperature of thread of 2700 K the lifetime of the lamp makes about 1000 hours, at 3400 K only several hours, at increase in tension by 20 % brightness increases twice. Along with it the lifetime decreases by 95 %.
Reduction of supply voltage though lowers efficiency, but increases durability. So, undervoltage twice (at consecutive inclusion) reduces the efficiency about 4-5 times, but increases the lifetime almost in one thousand times. Often use this effect when it is necessary to provide reliable emergency lighting without special requirements to brightness, for example on landings. Often for this purpose at alternating current feed the lamp is connected consistently with the diode thanks to what current goes to the lamp only during the half of the period.
As cost the consumed glow lamp during service of the electric power in tens of times exceeds the cost of the lamp, there is optimum tension at which the cost of the luminous flux is minimum. Optimum tension is slightly higher rated therefore ways of increase in durability by undervoltage of the power supply from the economic point of view are absolutely unprofitable.
The limitation of the lifetime of the glow lamp is caused to a lesser extent by thread material evaporation during the operating time and more not uniformity arising in thread. Uneven evaporation of material of thread leads to emergence of the thinned sites with the increased electrical resistance that leads to the bigger heating and evaporation of material in such places. When one of these narrowings becomes thinner so that thread material in this place melts or completely evaporates, current is interrupted and the lamp fails.
The greatest wear of filament occurs at sharp giving of tension on the lamp therefore considerably it is possible to increase the term of its service, using any devices of smooth start.
Tungsten thread of incandescence has the unit resistance which is twice higher than everything, than aluminum resistance in the cold state. At burn-out of the lamp often happens that the copper conductings connecting contacts of the socle with holders of the spiral burn down. So, the normal lamp on 60 W at the time of inclusion consumes over 700 W, and 100-watt — more than a kilowatt. In process of warming up of the spiral its resistance increases, and power falls to rated.
For smoothing of peak power thermoresistors with strongly falling resistance in process of warming up, reactive ballast in the form of the capacity or inductance, dimmer can be used (automatic or manual). Tension on the lamp grows in process of warming up of the spiral and can be used for shunting of ballast by automatic equipment. Without shutdown of ballast the lamp can lose from 5 to 20 % of power that too can be favorable to increase in the resource.
Low-voltage glow lamps at the same power have the bigger resource and luminous efficiency thanks to the bigger section of the body of incandescence. Therefore in multilamp lamps (chandeliers) application of consecutive inclusion of lamps on smaller tension instead of parallel inclusion of lamps on mains voltage is reasonable. For example, instead of six lamps of 220B 60 W connected in parallel to apply six consistently included lamps of 36 V 60 W, that is to replace six thin spirals of one thick.
Kinds of lamps
Glow lamps share on (are located in the order of increase of efficiency):
- the vacuum (simplest);
- argon (nitrogen - argon);
- krypton (about +10% of brightness of argon);
- xenon (is twice brighter than argon);
- halogen (filler I or Br, is 2,5 times brighter argon, big service life, do not love the nedokal as the halogen cycle does not work);
- halogen with two flasks (more effective halogen cycle due to the best heating of the internal flask);
- xenon - halogen (Xe + I or Br filler, the most effective filler, are up to 3 times brighter than argon);
- xenon - radiations, halogen with the IK reflector (as the most part of radiation of the lamp is the share of the Infrared range, reflection of IK of radiation in the lamp considerably increases efficiency, are made for hunting lamps);
- incandescence with the covering transforming IK radiation to visible range. Developments of lamps with the high-temperature phosphor which when heating radiates the visible range are conducted.