Halogen Infrared Ruby Slim HH574
When the original infrared quartz lamps were first trialled in spaceheating applications, one of their principal drawbacks was the unacceptable level of visual glare that accompanied these high power sources. This surprisingly simple situation took several decades to solve, because the lamps ran far too hot to be able to use the traditional lamp filter coatings.

Westinghouse was first to attack this by flamespraying its lamps with orange iron (III) oxide pigment, but this still transmitted a lot of light and absorbed too much infrared. In 1963 Corning developed a ruby-coloured Vycor 96%-silica tubing for use as a halogen lamp envelope, but this was prohibitively expensive as both the ends of the tube as well as the inner surface had to be kept free of the red colour dopants, which interfered with the halogen cycle as well the pinch-sealing process. It was not until the mid-1980s that the Ruby Jacket lamp was invented by Thorn, which solved these problems but was still a rather expensive construction.

The design on this page was conceived by Alex Halberstadt of Thorn Enfield in the early 1980s, in which short lengths of clear quartz are butt-sealed to the ends of a ruby quartz tube. The quartz was drawn with a dopant of copper oxide, which was then reduced to metallic copper nanoparticles in a hydrogen furnace to achieve the ruby colour. The original design did not work because the seals would fracture during use, but it was discovered in 1989 that if the internal gas pressure was reduced from the usual 1500mmHg to around 250-750mmHg, the lamps were successful. However they were only made on a limited scale because the joining process was difficult, and as seen in the photos the original ruby materials tended to develop opaque patches during life.
Manufacturer: GE-Thorn
Lamp Power: 1500 Watts
Lamp Voltage: 225 Volts
Lamp Current: 6.67 Amperes
Cap Type: SK15 + U-Terminals Teflon Cables 230mm
Bulb Type: T-10.5 T-3 in eighths/inch
Bulb Finish: Ruby Quartz Clear Ends
Filament Type: C-8 Single Coil Axial
Lighted Length: 260mm 101/4 Inches
Atmosphere: Argon 0.1% Hydrogen Bromide
Luminous Flux: 250 lumens
Luminous Efficacy: 0.17 lm/W
Luminous Intensity: N/A
Beam Distribution: N/A
Colour Temperature & CRI: CCT: 2500K (Filament) Ra: 40
Chromaticity Co-ordinates: CCx: 0.645 CCy: 0.280
Lifetime: 7500 hours
Burning Position: Horizontal ± 5°
Overall Length: 346mm 135/8 Inches
Factory: Enfield, London United Kingdom
Date of Manufacture: 1992 April Date Code: G28
Original Value:
References: 1) Photoelectric measurement.
2) GE-Thorn Halcion Infrared Technical Manual, 1991 UK.
3) GE-Thorn Lighting Product Data Sheet 93:11:05, 1991 UK.
4) EU Patent 0,429,230 - Infrared Halogen Lamp with Ruby Quartz Bulb - Filed 1989.
5) US Patent 3,258,631 - Lamp Having a Colored Bulb - Elmer & Nordberg, Corning Glass Inc - Filed 1963.
6) Revolution in Lamps, R.Kane & H.Sell, publ. The Fairmont Press, 2001, pp. 65-74.