GE Hardglass Infrared Reflector with Ruby Filter

Following GE's invention of the blown reflector incandescent lamp, a natural progression was to adopt similar designs for infrared heating applications. GE's first industrial infrared lamps were made in G-30 spherical bulbs for use with an external reflector, and the integrated reflector versions in R-40 bulbs made a dramatic step forward both in terms of initial performance, and also because a new, clean reflector was provided with each lamp replacement.

Initially the R-40 infrared reflectors were made in soft glass bulbs, even up to the most powerful 375W rating. Their high operating temperature rendered them liable to shatter with some violence if splashed with liquids or touched against cold objects whilst in operation, due to the low thermal shock resistance of soda-lime type glasses. Additionally, the highly focussed infrared beam resulted in uncomfortable levels of glare arising from the concentration of visible light into the same area. Both problems were elegantly solved with the 1946 launch of the lamp featured on this page, which set new standards in the infrared lamps business.

The bulb is blown in borosilicate hard glass which exhibits excellent thermal shock resistance. The front area of the bulb crown is externally stained by penetration of cadmium ions to produce a deep ruby colour, and its transmission is controlled so as to allow unhindered passage of the infrared wavelengths while blocking the majority of the visible light emission. The lamp cap was also changed at this time from an expensive mechanically-locked skirted screw base to a simple standard screw cap affixed with high temperature cement. A ceramic baffle plate in the lamp neck serves to keep the cap temperature low enough to permit this change.
Manufacturer: General Electric Co. U.S.A. Type: 250R40/10
Lamp Power: 250 Watts
Lamp Voltage: 115-125 Volts
Lamp Current: 2.08 Amperes
Cap Type: E26s/25 Aluminium + vitrite
Bulb Type: R-125 R-40 in eighths/inch
Bulb Finish: Ruby stained front Borosilicate glass
Filament Type: C-9 Wreath
Atmosphere: Gas Filled 90:10 Ar:N2
Luminous Flux: N/A
Luminous Efficacy: N/A
Beam Intensity: N/A
Beam Distribution: N/A
Colour Temperature & CRI: CCT: N/A CRI: N/A
Chromaticity Co-ordinates: CCx: 0.700 CCy: 0.300
Rated Lifetime: 5000h
Burning Position: Universal
Overall Length: 174.6 mm 67/8 inches
Light Centre Length: N/A N/A
Factory: Ohio Lamp Plant, Warren U.S.A.
Date of Manufacture: March 1949 Date Code: 15 ._
Original / Present Value: US $2.95 (1946) US $32.40 (2009)
References: 1) GE Lamp Catalogue, USA, 1948, p.28
2) GE Large Lamp Letter No. 46-34 : A New Reflector Infrared Heat Lamp, August 2 1946