XingJi HMB Mercury Blended with Halogen Ballast

Self-ballasted mercury lamps have been on the market since their invention in 1935 by Siemens Bros in England, and traditionally they have always consisted of a bare tungsten filament inside the outer jacket of the mercury lamp.

This results in a compromise since the filament and the arc tube both have different requirements for the gas filling in the outer jacket. The arc tube functions most efficiently if the gas filling pressure is low, to provide good thermal insulation, and additionally nitrogen has to be used since it will not break down in the regions where a high electric field strength may be present.

The filament however requires a high gas filling pressure to extend its life by reducing the rate of tungsten evaporation. A high molecular weight gas such as argon is also beneficial, but is not compatible with the mercury arc tube. So a compromise has to be made and self-ballasted mercury lamps usually contain nitrogen at a pressure in excess of 500 torr for the outer jacket.

In 1962 Osram-GEC showed a prototype lamp in which these problems were overcome by employing one of the newly developed linear halogen lamps as the ballast. The halogen ballast also boosted the total luminous flux of the lamp and improved the red colour rendering ratio, but in those early halogen days it was deemed too expensive to commercialise the idea. It was not until 2002 that a number of Chinese companies again picked up the idea, and now the halogen ballast is used almost universally among smaller companies. The halogen technology allows the customer to choose either increased luminous flux or a long-life mercury blended lamp.
Manufacturer: XingJi Special Lamp Factory
Lamp Power: 500 Watts
Lamp Current: 2.15 Amps
Lamp Voltage: 220-240 Volts
Cap: E40s/40x45 nickel plated
Bulb Finish: Clear borosilicate
Bulb Type: BT-116
Overall Length: 295 mm
Light Centre Length: 185 mm
Electrodes: Backwound thoriated Double Carbonate emitter
Inner / Outer Atmosphere: Inner : Ar | Hg Outer: Nitrogen
Luminous Flux: 14,500 lm at 100 hours
Luminous Efficacy: 29 lm/W at 100 hours
Colour Temperature & CRI: CCT: 4500K CRI: Ra 50
Chromaticity Co-ordinates:
Burning Position: Universal
Rated Life: 12,000 hours (to 50% survival)
Warm Up / Re-strike Time: 4 minutes 10 minutes max.
Factory: Jiangsu, China
Date of Manufacture: October 2003
Original / Present Value: £3.00 (2003) - sale price in China
References: 1) XingJi Special Lamp Factory Catalogue, 2003.