Osram 'Vitalux' Ultraviolet Incandescent

Medical history has taught that many sicknesses can be cured by exposure to ultraviolet radiation, and from the early 1900s mercury-quartz lamps were made for this application. However, these also produced very short wavelengths which can be more harmful than beneficial. It was recognised from early trials with tungsten lamps having a UV-transmissive quartz window that these also produce ultraviolet radiation, which extends only into the reltively safe longer wavelengths. Quartz was too expensive for the large bulb of an incandescent lamp, and a 1916 German patent claimed a tungsten lamp having a UV-transmissive glass bulb. The commercialisation of such lamps had to wait until the development of a suitable glass in the 1920s, which resulted in the American CX-Ray lamps.

The Osram Vitalux lamp was a further development of Alfred Rüttenauer, introduced in 1929 following earlier medical trials at the Hamburg-Eppendorf hospital. It achieves a slight improvement in UV flux by using a bulb of Uviol V419 glass, following the surprising discovery that the blue-tinted cobalt glass of daylight incandescent lamps, normally intended to block certain wavelengths, in fact achieves greater ultraviolet transmission than the best clear glasses. The tinted glass also has the advantage of raising the colour temperature to create a visual impression closer to sunlight. This lamp was intended for use in a narrow-beam parabolic reflector to treat exposed parts of the human body with levels of ultraviolet radiation similar to that found in sunlight.

The Osram Vitalux was produced until 1937, when it was superseded by the Ultra-Vitalux. That combines the tungsten filament with a mercury arc tube to further increase UV flux.
Manufacturer: Osram Kommanditgesellschaft
Lamp Power: 540 Watts
Lamp Voltage: 220 Volts
Lamp Current: 2.45 Amperes
Cap Type: E27s/50x55 Ni plated brass
Bulb Type: A-120 A-38 (in eighths/inch)
Bulb Finish: Inside Frosted Uviol V419 blue glass
Filament Type: C-7A Single Coil Wreath-Vee
Atmosphere: Argon-Nitrogen Red P getter
Luminous Flux: 5500 lumens
Luminous Efficacy: 10.2 lm/W
UV Flux: UV-A 0.2 Watts UV-B
UV Irradiance: UV-A 73 mW/m2 @ 1m UV-B 3 mW/m2 @ 1m
Colour Temperature & CRI: CCT: 3500K CRI: Ra 98
Chromaticity Co-ordinates: CCx: 0.405 CCy: 0.390
Lifetime: 300 hours to L80F50
Burning Position: Universal
Overall Length: 210 mm 81/4 inches
Light Centre Length:
Factory: Berlin Rotherstraße Germany
Date of Manufacture: 1940 January Date Code: e10
Original Value: DM 24/- (1929)
References: 1) German Patent DE305798, Einrichtung zur Krankenbehandlung mittels Lichtstrahlen, Reiniger, Gebbert & Schall Akt.-Ges., 7-Jul-1916
2) Vitalux, die Lampe mit Sonnenähnliche Strahlung, Osram Brochure, Germany 1929
3) Die Osram Vitalux Lampe für Therapeutische Bestrahlungen, Siemens-Reiniger-Veifa Brochure, Germany c.1929
4) Gutachten über Osram Vitalux Lampen, Osram Brochure, Germany 1929
5) Die Osram Vitalux Lampe, ihre Eigneschaften und ihre Anwendung in der Praxis, Osram Brochure, Germany 1930
6) Die Ultraviolette Strahlung der Glühlampe, A.Ruttenauer, Technisch-wissenschaftliche Abhandlungen aus dem Osram-Konzern, Band 1 1930 pp.69-76
7) Die Entwicklung neuer künstliche Lichtquellen, A.Ruttenauer, Technisch-wissenschaftliche Abhandlungen aus dem Osram-Konzern, Band 2 1931 pp.77-82
8) Untersuchungen über die Ultraviolettstrahlung und Erythemwirkung der Osram-Vitaluxlampe in Abhängigkeit von der Brenndauer, A.Ruttenauer & E.Spiller, Technisch-wissenschaftliche Abhandlungen aus dem Osram-Konzern, Band 2 1931 pp.83-88
9) Der Osram Ultra-Vitalux Strahler, K.Larché, Technisch-wissenschaftliche Abhandlungen der Osram-Gesellschaft, Band 5 1953 pp.43-48
10) Ultraviolet Transmission of Clear and Cobalt-Blue Glasses, M.Luckiesh, Abstract-Bulletin of NELA Research Laboratory of National Lamp Works, v.1 no.3 1922, pp.490-491
11) Photmetric and Mean Horizontal Spectroradiometric measurements