Heinrich Daniel Ruhmkorff
| Heinrich Daniel Ruhmkorff | |
|---|---|
 | |
| Nascimento | 15 de janeiro de 1803 Hannover |
| Morte | 20 de dezembro de 1877 (74 anos) Paris |
| Nacionalidade |  Alemão
|
| Campo(s) | Mecânica |
Heinrich Daniel Ruhmkorff (Hannover, 15 de janeiro de 1803 — Paris, 20 de dezembro de 1877) foi um mecânico alemão que comercializou a bobina de indução (muitas vezes referida como a bobina de Ruhmkorff.)
Ruhmkorff nasceu em 'Hanover'. Ele mudou o "ü" para "u" no seu nome quando foi viver para o estrangeiro. Após um período de aprendizagem com um mecânico alemão, mudou-se para a Inglaterra. Biografias dizem que ele trabalhou com o inventor Joseph Bramah, mas isso é improvável, já que Bramah morreu em 1814. Ele pode, porém, ter trabalhado para the empresa. Em 1855, montou uma loja em Paris, onde ele ganhou uma reputação para a alta qualidade dos seus aparelhos elétricos. Apesar de Ruhmkorff ser muitas vezes creditado com a invenção da bobina de indução, na verdade essa foi inventada por Nicholas Callan em 1836. A primeira bobina de Ruhmkorff, que ele patenteou em 1851, utilizava longos enrolamentos de fio de cobre para alcançar uma centelha de aproximadamente 2 polegadas (50 mm) de comprimento. Em 1857, depois de examinar uma versão aprimorada, feita por um inventor americano, Edward Samuel Ritchie,[1][2] Ruhmkorff melhorou o seu design (como fizeram outros engenheiros), usando o vidro como isolamento e outras inovações para permitir a produção de faíscas de mais de 30 centímetros de comprimento.[3] Ruhmkorff patenteou a primeira versão de sua bobina de indução, em 1851, e seu sucesso foi tal que em 1858 foi agraciado com um Prêmio de 50,000-franc por Napoleon III pela descoberta mais importante na aplicação da electricidade. Ele morreu em Paris em 1877.
A lâmpada de "Ruhmkorff"
In several of Jules Verne's science-fiction novels,[4] so-called "Ruhmkorff lamps" are mentioned. These were an early form of portable electric lamp. The lamp consisted of a Geissler tube that was excited by a battery-powered Ruhmkorff induction coil. Initially the lamp generated white light by using a Geissler tube filled with carbon dioxide. However, the carbon dioxide tended to break down. Hence in later lamps, the Geissler tube was filled with nitrogen (which generated red light), and the glass was replaced with glass containing uranium salts (which fluoresced with a green light).[5]
Intended for use by miners, the lamp was actually developed both by Alphonse Dumas, an engineer at the iron mines of Saint-Priest and of Lac, near Privas, in the départment of Ardèche, France, and by Dr. Camille Benoît, a medical doctor in Privas.[6] In 1864, the French Academy of Sciences awarded Dumas and Benoît a prize of 1,000 francs for their invention.[7]
This lamp could be considered as a predecessor of modern fluorescent lanterns, because as in the "Ruhmkorff lamp," portable actual ones use an inverter (oscillator + step-up transformer) to convert low voltage DC current from dry cells or storage batteries to AC or even pulsating current at a voltage high enough as to ionize the fluorescent tube and power it at the required nominal power. This one has no nitrogen nor C02, neither uranium glass; instead a modern fluorescent tube is filled with argon at a very low pressure, along with a few milligrams of mercury. Their electrodes are usually constituted by a triple wounded tungsten wire covered with electron emitting substances, as alkaline metal oxides, that easily give free electrons to aid to ionizing, striking and sustaining the electric arc. The inner walls of the tube are coated with a thin layer of fluorescent substances that when excited by the 253,7 nM line of UV radiation from mercury arc, emit visible light, usually in the range of 6500ºK (daylight). The spectral characteristics (coloration) of such a light depends entirely on the chemical nature of those "phosphors."
Modern inverters for portable fluorescent lanterns don't rely on electromechanical and electromagnetic vibrating switching contacts to produce the required current interruptions on primary circuit to provide induced voltages through the secondary winding as occur in Ruhmkorff coils; instead, the primary of the transformer is switched by means of one or two transistors oscillating at frequencies of tens or even hundreds of thousand cycles per second which results in smaller and lighter devices having also a very good efficiency in lumens/watt for a given battery consumption or a longer battery charge life for a given light flux when compared with incandescent lamps, but the principle remains the same as in the Dumas & Benoit original mining electric lamp.
Asteróide
O asteróide 15273 Ruhmkorff, descoberto em 1991 por E. W. Elst, foi assim nomeado em homenagem a Heinrich Daniel Ruhmkorff.
Referências
- ↑ American Academy of Arts and Sciences, Proceedings of the American Academy of Arts and Sciences, Vol. XXIII, May 1895 - May 1896, Boston: University Press, John Wilson and Son (1896), pp. 359-360: Ritchie's most powerful version of his induction coil, using staged windings, achieved electrical bolts two feet (61 cm) or longer in length
- ↑ Page, Charles G., History of Induction: The American Claim to the Induction Coil and Its Electrostatic Developments, Washington, D.C.: Intelligencer Printing House (1867), pp. 104-106
- ↑ American Academy, pp. 359-360
- ↑ Journey to the Center of the Earth (1864), From the Earth to the Moon (1865), and 20,000 Leagues Under the Sea (1869).
- ↑ Paolo Brenni (2007) "Uranium glass and its scientific uses," Bulletin of the Scientific Instrument Society, no. 92, pages 34-39; see page 37.
- ↑ See:
- A. Dumas and Benoit (1862) "Physique Appliquée — Note sur un appareil propre à éclairer les ouvriers mineurs dans leurs travaux souterrains au moyen de la lumière d'induction" (Applied physics — Note on an apparatus suitable for providing light for miners in their underground work by means of the induction lamp), Comptes Rendus, vol. 55, pages 439-440.
- Dumas, "Note descriptive de la lampe photo-électrique," Bulletin de la Société de l'Industrie Minérale, vol. 9, pages 5-14 (1863-1864).
- "Lampe Dumas," Bulletin de la Société de l'Industrie Minérale, vol. 9, pages 113-117 (1863-1864).
- "Note sur la lampe électrique de Dumas et Benoît," Bulletin de la Société de l'Industrie Minérale, vol. 9, pages 118-120 (1863-1864).
- Bulletin des Lois de l'Empire Francais, series 9, vol. 23, page 639 (1864); see patent application no. 1160°.
- "New safety light for coal mines," Journal of the Franklin Institute, 3rd series, vol. 49, pages 262-263 (1865). Reprinted from the Athenæum (literary magazine of London, England), February 25, 1865.
- comte Théodose Du Moncel, "Application à l'éclairage des galeries de mines," Notice sur l'appareil d'induction électrique de Ruhmkorff (Paris, France: Gauthier-Villars, 1867), pages 394-398.
- See also: "Jules Verne und die Elektrizität: Kapitel 2: Die Ruhmkorfflampe" [in German]. Available on-line at: Jules Verne.
- ↑ "Prix dit des arts insalubres," Comptes rendus, 60 : 273 (1865).
Further reading
- H.S. Norrie, Ruhmkorff Induction-Coils, Their Construction, 0peration and Application. (New York, New York: Spon & Chamberlain, 1896).
Ligações externas
- Biography with photographs accessed April 12, 2006
"Ruhmkorff, Heinrich Daniel". Encyclopedia Americana. (1920). - Spark Museum—Induction coils