INVENTORS OF HIGH PRESSURE SODIUM VAPOUR LAMP
A
researcher named Robert L. Coble working at the General Electric Research Lab
developed a material called Lucalox.
Lucalox was a commercial term for aluminum
oxide ceramic.
His
work helped pave the way for William Louden, Kurt Schmidt, and Elmer Homonnay
to invent the HPS lamp.
General
Electric first developed this lamp and it came on the market in 1964.
The
lamp is an improvement over the LPSV lamp in that it has more acceptable colour
with the great efficiency of the sodium lamp.
The
better color rendering comes with a bit of sacrifice, it has less efficiency
than the LPSV lamp.
1.
High pressure sodium (HPS) vapour lamps are smaller than
LPS lamps.
2.
High Pressure Sodium Vapour lamps with a polycrystalline
translucent aluminum oxide discharge tube
enclosed in a
tubular outer glass envelope.
3.
The discharge tube is internally coated with aluminum oxide
powder.
4.
The discharge tube contains an amalgam of mercury and
sodium along with xenon gas.
5.
Xenon is a colorless, dense, odorless and noble gas that
occurs in the Earth's atmosphere in trace
amounts.
6.
The outer shell is evacuated and a better maintains this high
degree of vacuum throughout the lamp life.
7.
These lamps need a control gear comprising of ballast, ignitor
and capacitor for optimum
performance.
8.
They produce a dark pink glow when first struck, and a
pinkish orange light when warmed.
9.
Some lamps also briefly produce a pure to bluish white light
in between.
10.
This is formed by the mercury glowing before the sodium is
completely warmed.
ADVANTAGES
1.
Very high lamp efficacy hence highly energy efficient.
2.
Long life and low light depreciation.
3.
Very high lumen output.
4.
Golden white light admitted by lamps gives a warm
appearance and better visual acuity.
5.
Ideally suited for fog, dust rainfall conditions.
DISADVANTAGES
1.
The light produced is a golden white color, which may not
be appropriate for certain applications.
2.
Requires a ballast.
3.
Once started can take from five to ten minutes to reach full
light output
4.
They also require at least a one minute cool-down to re-
strike.
5.
End of life is characterized by on-off-on cycling, and
continued operation can damage the lamp
ballast if not
replaced quickly.
APPLICATIONS
1.
It is 7 times as efficient as incandescent lamp.
2.
Ideally suitable for reducing energy consumption in both
indoor/outdoor applications.
3.
Suitable for Highway streets, flyovers, junctions etc.
4.
Airport apron's parking areas, storage yards, docks etc.
5.
Industries warehouses, goodness etc.
6.
Floodlighting of monuments, exhibition sites etc.
7.
Long lamp life - 24,000 hours.
8.
Excellent lumen maintenance.
9.
Wide range of lamp types with wattages ranging from 35 to
1000 watts.
10.
Most HPS lamps can operate in any position.
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