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High Pressure Mercury Vapour
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Updated
30-VII-2024 |
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High pressure mercury lamps are classified as the MB type. They operate at a vapour pressure of about ten atmospheres, the discharge dissipates between 10 and 100 watts per centimetre of arc length, and their arc tubes are made of extremely refactory fused silica (quartz), which can withstand higher temperatures and pressures.
The high pressure MB lamps solved a problem with the earlier medium pressure MA lamps in that the efficacy of mercury lamps always decreases at lower powers, which prevented the successful development of low wattage MA lamps. However, the higher pressures that can be achieved with quartz arc tubes causes an increase in efficacy which is most pronounced in the smaller lamps.
The technology was introduced in 1936 by Philips of the Netherlands, by combining its deep understanding of discharge physics with a new kind of tungsten-to-quartz graded seal that facilitated the use of the new arc tube material. The following year high pressure lamps were adopted by most manufacturers around the world, but some chose an alternative molybdenum foil seal developed in Britain.
The first lamps were in the low power range from 80-125W, and although MB lamps are more efficient than MA types in the higher wattages, the efficacy benefit is somewhat reduced. The quartz material for the arc tubes as well as the labour-intensive seals made these lamps extremely expensive, and it took a further three decades of cost reduction before the higher power MA types were finally displaced. Improved variants of the high pressure lamps were made in the form of the MBF Fluorescent and MBT self-ballasted designs, as well as a wide variety of projection and ultraviolet variants. Detailed information on the development and fundamentals of high pressure mercury lamps can be found at the MB Technical Section. |
| | Graded-Seal Lamps |
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GE |
85W |
| H-3 early model with graded seals to tungsten |
| 1937 |
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GE-Mazda |
100W |
| H-4 early model with graded seals to tungsten |
| 1938 |
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GE-Mazda |
250W |
| H-5 early model with graded seals to tungsten |
| 1943 |
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| | Shrink-Seal Lamps |
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GEC |
125W |
| Osira MB/V first model with moly shrink-seals |
| 1944 |
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Siemens |
125W |
| Sieray Type QH with Siemens Foil Seals |
| 1944 |
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Mazda |
80W |
| MB/V with earliest mechanised seal design |
| 1947 |
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Mazda |
80W |
| MB/V first model with moly shrink-seals |
| 1947 |
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| | Pinch-Seal Lamps |
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Crompton |
80W |
| MB/U in pear shaped pearl bulb |
| ~1955 |
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GEC |
125W |
| MB/U in pear shaped pearl bulb |
| 1978 |
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Mazda |
125W |
| MB/U in ellipsoidal shaped pearl bulb |
| 1969 |
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Sylvania |
40W |
| H45-AZ Low Wattage Mercury Discharge |
| ~1965 |
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Osram |
125W |
| HQA with new emitter to reduced blackening |
| 1965 |
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Narva |
125W |
| NF125-00 with sintered emitter pellet electrodes |
| 1972 |
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GE |
100W |
| H100/A23 for retrofit into GLS luminaires |
| 1979 |
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Philips |
400W |
| MB/V Long tubular style to replace MA size lamp |
| 1964 |
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Atlas |
400W |
| MB/V Long tubular style to replace MA size lamp |
| 1970 |
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GEC |
250W |
| MB/U short tubular style for new applications |
| 1974 |
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Sylvania |
400W |
| H33-1CD Rough Service lamp with girder frame |
| 1968 |
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Iwasaki |
2000W |
| H2000B High Wattage |
| 1997 |
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| | Reflector Lamps |
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Sylvania |
100W |
| H44GS-100 Mercury Sealed Beam Reflector |
| 2003 |
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Iwasaki |
50W |
| HR50W/S Mercury Spot Reflector Lamp |
| 2001 |
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| | Special Lamps |
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BTH Mazda |
40W |
| MBM Coal Mine lamp for compressed air system |
| 1947 |
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Thorn EMI |
40W |
| MBM Coal Mine lamp for compressed air system |
| 1988 |
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