High Pressure Sodium

Wednesday, February 10, 2010

Metal halide lamps are used both for general lighting purposes, and for very specific applications which require specific UV or blue-frequency Light. Due to their wide customable spectrum, they are used for indoor growing applications, in athletic facilities and are quite popular with reef aquarists, who a high intensity light need, source for their corals. Most types are fitted with an outer glass bulb to protect the inner components, support frame and arc tube from oxidation, heat loss and provide a shield to prevent the short wavelength UV light generated by the mercury vapor discharge, which is transmitted by the fused silica inner bulb or arc tube from escaping as it is blocked by the soda or borosilicate glass bulbs used on older single ended, (single base) models or by specially doped “U.V. stop” fused silica outer bulbs of more contemporary single ended and most double ended models. High pressure sodium grow lamps are made of a semi-transparent ceramic arc tube, filled with a mixture of sodium, mercury, and xenon. The arc tube is placed into the protective outer glass shield, similarly to metal halide bulbs. The power ranges of HPS bulbs vary from 35w to 1000w, while the most popular are 250w and 430w. The unique characteristics of Metal Halide ballast provide high performance such as: long life, better light quality, designable color, excellent color rendering, compact size, versatility and high efficiency. Since metal halide lamps deliver light more efficiently than incandescent, widespread acceptance of the technology has a positive effect on air quality and the environmental waste stream. Efficient long-life systems mean less landfill waste. Metal halide lamps generate 65-115 lumens per watt, more than incandescent, fluorescent or mercury vapor lamps.