High Pressure Mercury Vapour Lamp

The lamp is an improvement over the lps lamp in that it has more acceptable color with the great efficiency of the sodium lamp.

High pressure mercury vapour lamp.

In such lamps there is also much stronger spectral broadening. The uv irradiation power can be as high as approximately 30 of the nominal power. The clear mercury bulb has a bluish green appearance and the deluxe white has a higher color rendering. High pressure mercury vapor arc lamps a type of high intensity discharge lamps are operated with a pressure of the order of one atmosphere and with much increased power densities so that more mercury is evaporated the high density of the vapor allows for light emission with a much higher radiance.

Two varieties of such lamps exist. 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. The mercury vapor fluorescent lamps can be either of low pressure lp or medium pressure mp i e gas pressure inside the lamp with nominal power that may vary in the ranges 4 115 w and 400 17 000 w philips 2017 respectively. 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.

As pressure increases the chance of multiple collisions gets increased. Later cooper hewitt mercury vapor tubes and historic fixture. High and low pressure uv mercury vapour lamps heraeus manufactures low and high pressure mercury vapour lamps used for applications such as photochemical processing fluorimetry mercury analysers medical and environmental equipment and fixed wavelength detectors. Mercury vapor lamps feature low initial cost but have higher operating costs than hps or metal halide due to its lower efficiency.

The arc then heats up the mercury and the mercury vapor then lights giving the lamp a bluish color. High pressure sodium lamp hps lamp the hps lamp is the most ubiquitous lamp for street lighting on the planet. While many applications are ideal for mercury vapor lamps they are being challenged by the higher efficiency and better color balance of metal halide. Mercury lamps get dimmer over time and rarely burn out so it is wise to replace them and restore light level.

When a mercury vapor lamp is first turned on it will produce a dark blue glow because only a small amount of the mercury is ionized and the gas pressure in the arc tube is very low so much of the light is produced in the ultraviolet mercury bands. As the main arc strikes and the gas heats up and increases in pressure the light shifts into the visible range and the high gas pressure causes. Again transition of the electrons requires least amount of input energy from a colliding electron.