High Pressure Mercury Vapour Lamp

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.

High pressure mercury vapour lamp.

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. 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 arc then heats up the mercury and the mercury vapor then lights giving the lamp a bluish color. This phosphor technology offers better color rendition than the more efficient high or low pressure sodium vapor lamps but still falls short of metal halide and ceramic metal halide sources.

Later cooper hewitt mercury vapor tubes and historic fixture. Again transition of the electrons requires least amount of input energy from a colliding electron. The lamp is an improvement over the lps lamp in that it has more acceptable color with the great efficiency of the sodium lamp. Two varieties of such lamps exist.

The uv irradiation power can be as high as approximately 30 of the nominal power. While many applications are ideal for mercury vapor lamps they are being challenged by the higher efficiency and better color balance of metal halide. 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. High pressure sodium lamp hps lamp the hps lamp is the most ubiquitous lamp for street lighting on the planet.

Mercury vapor lamps feature low initial cost but have higher operating costs than hps or metal halide due to its lower efficiency. Mercury lamps get dimmer over time and rarely burn out so it is wise to replace them and restore light level. As pressure increases the chance of multiple collisions gets increased. 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.

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. 1906 higher pressure mercury vapor light in a fuzed quartz tube is developed kuch retschinsky siemens munich 1936 the modern high pressure mercury vapor lamp is developed type mb. 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.