Mercury vapor lamps were the first high intensity discharge lamps to be commercially available for a wide variety of lighting applications.
High pressure mercury lamp construction.
Ushio germicidal lamps are low pressure mercury arc lamps that emit radiation peaking at 253 7nm uv c.
High pressure mercury vapor lamps are commonly used for general lighting purposes.
In case of fluorescent lamp the mercury vapour pressure is maintained at lower level such that 60 of the total input energy gets converted into 253 7 nm single line.
1901 the first commercial mercury vapor lamp peter cooper hewitt new york city had a history of innovations in other fields and when he set about on the project of the mercury vapor lamp in 1898 it only took 3 years to develop the first reliable lamp with a acceptable color of light.
The tube contains a few milligrams of mercury and around 25 50 torr of pure argon as a buffer gas to carry the discharge while the lamp warms up producing.
Most models produce a bluish white light.
The newer lps lamps contain less mercury than before but this has effected performance negatively.
In medium pressure mercury vapor lamps the lines from 200 600 nm are present.
Designed by experienced engineers and by using quality material in combination with a tightly controlled manufacturing process we provide high quality lamps free of impurities to maintain strong and stable output throughout life of the lamp.
They emit primarily in the blue and green.
Figure 1 a typical high pressure mercury lamp.
Again transition of the electrons requires least amount of input energy from a colliding electron.
The lamps can be constructed to emit primarily in the uv a around 400 nm or uv c around 250 nm.
Mercury vapor lamps are gas discharge lamps that uses an electric arc through vaporized mercury to produce light.
High pressure sodium lamp hps lamp the hps lamp is the most ubiquitous lamp for street lighting on the planet.
A sodium vapor lamp is a gas discharge lamp that uses sodium in an excited state to produce light at a characteristic wavelength near 589 nm.
As pressure increases the chance of multiple collisions gets increased.
Mercury vapor lamps have found the greatest use in industrial applications and outdoor lighting because of their low cost and long life and lamp sizes of up to 1 000 watts.
Low pressure and high pressure low pressure sodium lamps are highly efficient electrical light sources but their yellow light restricts applications to outdoor lighting such as street lamps where they are widely used.
Two varieties of such lamps exist.
