Halogen Infrared Ruby Slim HH574

Aside from their primary application in industrial heating and drying, the original infrared quartz lamps were also trialled for spaceheating. Although small radiant heaters had been employed in domestic situations, most rooms were heated by convective methods to first heat the air, then indirectly warm the occupants. In spaces with high ceilings this is inefficient since the hot air rises above the occupants. Infrared lamps then become more efficient since their radiation passes through the air without absorption, and is absorbed directly by people and objects in the light path.

High power IR lamps also produce a great deal of light, and the high levels of glare limited this application. Traditional red glass filters and coatings could not be applied as with lower power lamps, as the quartz surface temperatures were far too high. Westinghouse was the first to attack this by flamespraying its quartz lamps with orange iron (III) oxide pigment, but this still transmitted a lot of light and absorbed too much infrared. In 1963 Corning developed Ruby Vycor 96%-silica tubing for use as a halogen lamp envelope, but this was prohibitively expensive as both the ends and the inner surface had to be kept free of the red colour dopants.

The design on this page was conceived by Alex Halberstadt of Thorn Enfield, in which short lengths of clear quartz are fused to the ends of the ruby tube. They were only made on a limited scale because the process was very difficult, and the white light escape from the ends and exhaust tip was troublesome. The ruby quartz also degraded too fast during life, becoming opaque and reducing transmission as can be seen here. It was not until the mid-1980s that the Ruby Jacket lamp was introduced, which solved these problems but was still a rather expensive construction.
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:
Luminous Efficacy:
Luminous Intensity: N/A
Beam Distribution: N/A
Colour Temperature & CRI: CCT: Ra
Chromaticity Co-ordinates: CCx: CCy:
Lifetime: 7500 hours
Burning Position: Horizontal ± 5°
Overall Length: 346mm 135/8 Inches
Factory: Leicester England
Date of Manufacture: 1992 April Date Code: G28
Original Value:
References: 1) Photoelectric measurement.