New high power amalgam lamps are significantly more powerful than low pressure lamps. Other materials and gases are used to help start the lamp or control its color. They produce light when an electric current passes between two electrodes also called cathodes in a tube filled with low pressure mercury vapor and inert gases, such as argon and krypton. Job interview question, once a low pressure mercury vapour lamp has lit, the purpose of the chokeballast unit is to. Power factor correction of mercury vapour, sodium vapour and metal iodide lamps on these types of lamp the power factor generally 0. Within the tube are two electrode coils, one at either end.
Engineering high intensity discharge bulletin mercury lamps. Generally speaking, inorganic mercury compounds are not easily absorbed by the human body. Pdf measuring the pressure in ultrahighpressure mercury lamps. The mercury used in these lamps is an inorganic mercury compound. It includes information on the total amount of mercury in all lamp products that were sold in the u. Fluorescent lamp and working principle of fluorescent lamp. Helios quartz uv lamps are the result of a long and solid experience in the market. High pressure mercury lamp instruction sheet 45115 safety notes mercury content 1. Set up the highpressure mercury lamp roughly in the middle of the 1m optical bench. An electric current in the gas energizes mercury vapor which delivers ultraviolet radiation through discharge process and the ultraviolet radiation causes the phosphor coating of the lamp inner wall to radiate visible light. A low pressure mercury lamp is one of the most popular discharge lamps in labs, frequently used for wavelength calibration of optical measuring instruments and as a disinfection lamp to sterilize workspace and tools used in biology labs and medical facilities. The first practical mercury lamp was the cooperhewitt lamp developed by peter cooper hewitt in 1901.
In addition, rather than being made of ordinary borosilicate glass, the tube is made of fused quartz or sodalime glass which allow the 185nm andor 253. As ac voltage is applied, an arc is struck between the cathodes. 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. Air, water and surfaces disinfection and oxidation, ultraviolet curing, drying of uv glues, paints and varnishes. Us4199708a lowpressure mercury vapor discharge lamp. The limitation and disadvantage of lamps using ribbon seals is the low peak and rms currents that can be passed through the thin molybdenum ribbons used in the seals, effectively precluding them from being used. Table 2, 3, 4 and 5 show guideline values obtained from. In some versions, fluorescent powder is applied that converts the ultraviolet part, which is emitted together with visible light, into visible light to improve the color. Assessing the risk of mercury in drinking water after uv lamp breaks page 2 ionize the mercury, and as an effect, produce uv light.
Conventional low pressure and amalgam lamps are significantly more energy efficient than medium pressure lamps. In addition to the mercury, the tube is filled with argon gas at low pressure. The lamp works by creating an electric arc through vaporized sodium metal. Super high pressure mercury capillary flash lamps are used in a variety of applications due to the fact that they provide a high intensity source of both visible and ultraviolet radiation. All highintensitydischarge lamps produce light from an arc tube that is usually contained in an outer glass bulb. Mercury vapor lamps consist of an inner arc discharge tube constructed of quartz surrounded by an outer hard borosilicate glass envelope. The mercury in the tube is a liquid at normal temperatures. The luminous efficacy of any discharge lamp falls as wattage is reduced. Mercury vapor lamps are widely used to light both indoor and outdoor areas such as gymnasiums, factories, department stores, banks, highways, parks, and sports fields. In mediumpressure mercuryvapor lamps, the lines from 200600 nm are present. The clear mercury bulb has a bluish green appearance and the deluxe white has a higher color rendering. A fluorescent lamp tube is filled with a gas containing low pressure mercury vapor and argon, xenon, neon, or krypton. Place the adjustable slit another 10 cm or so beyond it, in such a way that the slit is well illuminated.
The first fluorescent lamp was patented over 100 years ago by american inventor, peter cooper hewitt. Now, our more efficient low pressure uv lamps although more efficient, run on around the same power as a regular light bulb around 20 100w making their useful uvc output for a 40w lamp around 24w, a difference of 976w between the w from the medium pressure lamp. Lowpressure amalgam lamps amalgam lamps use a mercury amalgam mix to control mercury vapor pressure. All philips uvc low pressure mercury lamps contain a unique coating on the inner glass wall that ensures the uvc output over the useful life of the lamp never drops below 85% of its initial output. Ultraviolet lamps ultraviolet heating helios quartz.
Rohs will ban high pressure mercury vapour lamp hpmv. Most modern mercury vapor lamps have this rectification done in them. Low pressure mercury lamp learn what goes into ours. Hg pressures are usually above 20 mpa and difficult to measure. At least one manufacturer uses them for a series of krypton arc lamps. These operated at pressures of less than 1 pa and produced a near monochromatic light spectrum around the sodium emission lines at 589.
Low pressure mercury vapor discharge lamp having a closed elongated lamp envelope and comprising at least two electrodes disposed near a first end of the lamp envelope, at least one electrode is situated at the end of at least one inner tube situated within and sealed in a gastight manner to the lamp envelope, this inner tube having at least one opening to the inside of the lamp. As pressure increases the chance of multiple collisions gets increased. A fluorescent lamp is a low weight mercury vapour lamp that uses fluorescence to deliver visible light. The electric current excites the mercury vapor in the tube, generating radiant energy, primarily in the. Because mercury lamps are so prevalent in current outdoor lighting, and still safe when properly installed in a serviceable fixture, the need for these products will. The inner surface of the lamp is coated with a fluorescent and often slightly phosphorescent coating made of varying blends of metallic and rareearth. Lamps low pressure mercury discharge the most common form of germicidal lamp looks similar to an ordinary fluorescent lamp but the tube contains no fluorescent phosphor. A common discharge lighting luminary for use in an office environment would typically be a lowpressure mercury vapour electronic discharge fluorescent lamp.
Medium pressure lamps produce the greatest uv output per unit length of lamp of the 3 lamp types. Zhang et al studied the 254 nm radiant characteristics of t6 high output low pressure mercury lamp on radiant efficiency and the discharge parameters, obtained the optimum cold spot temperature at. As the main arc strikes mercury, the gas heats up and the pressure increases. A low pressure mercury lamp lp hg lamp is a highly efficient uv light source of short wavelength.
They are available in lengths from the very small of 150 mm to up to 2400mm. A lowpressure mercuryvapor lamp has a characteristic emission line at 253 nm. Germicidal uv lamps standard low pressure lamps from. The low pressure sodium arc discharge lamp was first made practical around 1920 owing to the development of a type of glass that could resist the corrosive effects of sodium vapor. China high pressure mercury lamp, high pressure mercury lamp. The extreme high color temperature of the snow white range creates very cool ambiances, making the lamp especially suitable in. No solvents or other volatiles are released during the curing process. Once a lowpressure mercury vapour lamp has lit, the.
Study of acoustic resonance phenomenon in high pressure discharge lamps type mercury vapour and sodium. Low pressure mercury vapor discharge lamp having a closed elongated lamp envelope and comprising at least two electrodes disposed near a first end of the lamp envelope, at least one electrode is situated at the end of at least one inner tube situated within and sealed in a gastight manner to the lamp envelope, this inner tube having at least one opening to the inside of the lamp envelope, the. Without some means of limiting the lamp current, the lamp would quickly be destroyed. Anderson was a professor at rensselaer polytechnic institute and employee of general electric with 27 patents 1970 1992 related to lamp technology. The phosphor coating on the inside of the glass tube absorbs uv photons and reradiates the energy as visible light. The tube contains a few milligrams of mercury and around 2550 torr of pure argon as a buffer gas to carry the discharge while the lamp warms up, producing. The heat generated by the arc then vaporizes the mercury and sodium. Description the high pressure mercury lamp supplies a light with high luminosity. They have a germicidal efficiency of 30% and can operate on lower current between 180 and 425ma. Figure 614 shows the basic configuration of a hid lamp. Standard high pressure mercury lamp product data general characteristics capbase e27 bulb bf70 bf 70mm bulb material soft glass bulb finish coated operating position any any or universal u life to 5% failures 6000 hr life to 20% failures 0 hr life to 50% failures 16000 hr lsf em 2000h rated, 12h cycle 99 % lsf em 4000h rated, 12h. Super high pressure mercury lamps jelight company, inc. It may be necessary to incline the tilting rider a little.
The snow white is a low pressure mercury discharge lamp with a tubular 26 mm envelope, available in 18 w, 36 w and 58 w. Rather than a cold spot, the lamps amalgam spot on pellet regulates mercury vapor pressure during operation and yields up to three times the uvc output of a standard low pressure mercury lamp of the same length. To facilitate starting of the lamp, a third electrode is mounted near one of the main electrodes and connected through a resistor to the other main electrode. See the photos lower on this page for more details. Standard high pressure mercury lamp product data general characteristics capbase e40 bulb ed120 ed 120mm bulb material hard glass bulb finish coated operating position any any or universal u life to 5% failures 6000 hr life to 20% failures 12000 hr life to 50% failures 16000 hr lsf em 2000h rated, 12h cycle 99 % lsf em 4000h rated.
I found that rohs restriction of hazardous substances directive of eu will prohibit use of high pressure mercury vapour lamp hpmv since 4. In low pressure mercury vapor lamps, only the lines at 184 and 253 nanometers nm are present. He would create an arc through a metal, then observe what colors it. Product information high pressure and specification. A mercury vapour lamp is a high pressure, electric arc discharge lamp that provides intense illumination over a selected range of wavelengths. Low pressure mercury lamps produce monochromatic radiation at 254 nm wavelength which makes them ideal for disinfection and sterilisation applications. Anderson developed many improvements in the fluorescent lamp. Ushios low pressure amalgam lamps are designed with a special coating for longer life. This rectification is done by applying phosphor on the inner surface of the bulb. Pdf 254 nm radiant efficiency and spectral lines of high. The lamps can be constructed to emit primarily in the uva around 400 nm or uvc around 250 nm.
The xenon gas which is easily ionized, facilitates striking the arc when voltage is applied across the electrodes. In these lamps, a material, such as sodium, mercury, or metal halide, is added to the arc tube. These lamps have an operating lifetime of up to 12,000 hours and convert up to 40% of the lamps electrical power into uvc, offering an efficient and costeffective alternative to medium. Mercury vapor pressure does the mercury vapor pressure affect uv output in amalgam lamps. Fit a lens f 50 mm in the tilting rider and set it up about 10 cm from the lamp. The mercury pellet is converted into a low pressure mercury vapor and when it mixes with the inert fill gasses, uv photons are produced. Amalgam lamps are able to achieve ten times the uv power density of standard low pressure lamps and five times more ozone production while operating at a higher temperature than conventional low pressure mercury lamps. 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. The average life of tube lights is about 5000 hours and also. High pressure mercury lamps 400w buy mercury vapour lamps. At the heart of the lamp is an arc tube which is fabricated from quartz, with a tungsten electrode disposed at either end.
Low pressure mercury lamps have been manufactured in jelight company inc. Assessing the risk of mercury in drinking water after uv lamp. A mercury vapor lamp is a gasdischarge lamp that produces light via an electric arc through vaporized mercury. 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. Best applications for mercury vapor lamps eye lighting.
High pressure mercury lamps are available in versions where the discharge takes place in vaporized mercury only and in versions in which metal halides are added so that the discharge takes place in mercury vapor and in vaporized metals from the metalhalide components 2, 3. This article discusses the construction and working principle of low pressure mercury fluorescent lamps also known as tube lights. Jelight company also produces super high pressure mercury lamps or short arc lamps. The lamp is constructed from a hollow glass tube with an aluminium cap at each end. Softglass lamps are one of our quality low pressure mercury lamp products. Study of acoustic resonance phenomenon in high pressure. Yes, it surely does the pressure determines the number of excited mercury atoms and thus determines uv output. Low pressure mercury lamp in addition to the medium pressure mercury and led light sources, vapourtec also offer three low pressure mercury lamps. Highpressure mercuryvapor lamps are those lamp commonly used for general lighting purposes. Medium pressure mercury arc ushio produces standard and custom uv emitters. The arc discharge is generally confined to a little fused quartz tube mounted within a larger borosilicate glass bulb. Ushio germicidal lamps are low pressure mercury arc lamps that emit radiation peaking at 253. Philips has always taken the lead in reducing the amount of mercury required to operate fluorescent. Cooper hewitts low pressure mercury arc lamp is the direct parent of todays modern fluorescent lights.
Germicidal uv lamps standard low pressure lamps from heraeus noblelight with highenergy uv light contaminated water, air and surfaces can be disinfected and cleaned safely. A common discharge lighting luminary for use in an office environment would typically be a low pressure mercury vapour electronic discharge fluorescent lamp. Dec 31, 2018 mercury vapour lamp december 31, 2018 february 24, 2012 by electrical4u 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. However, regardless of other factors it is safe to say that there is a certain optimal pressure for each lamp. He would create an arc through a metal, then observe what colors it produced when a prism. Depending on the materials used, mercury low pressure uv lamps can be divided into two large families. These lamps have an operating lifetime of up to 12,000 hours and convert up to 40% of the lamp s electrical power into uvc, offering an efficient and cost.
The low pressure mercury fluorescent lamps are commonly called as tube lights. Helios usually chooses quartz glass for the production of low pressure uv lamps because it ensures very high levels of uv transmission equal to or higher than 90%. A comparative study was performed to assess the efficacy of uvc light emitting diodes uvc leds at 277 nm and a low pressure mercury lpm lamp at. Oct 14, 2014 lamp that produces light as a result of an electrical discharge, generated between two electrodes, in a high pressure mercury vapor that is contained in a transparent bulb. Helios quartz uv lamps are suitable for many applications, even the most complex. Again transition of the electrons requires least amount of input energy from a colliding electron.
Mercury use in lighting this fact sheet summarizes the use of mercury in lighting devices, such as fluorescent lamps, high intensity discharge hid lamps e. Mercury vapor standard hpl high pressure mercury philips. Ultrahigh pressure uhp mercury lamps are important as highbrightness light sources for digital projection. Uv lamps from senlights crystec technology trading gmbh. The mercury vapor raises the gas pressure and operating. Quartz glass softglass lamps are one of our quality low pressure mercury lamp products. The line spectrum of the radiation, which has a high uv component, is in the wavelength range from about 579 nm to 248 nm. Since the light emitted by a mercury vapor light has a blue tone, this needs to be accounted for, or color corrected as it is called. These high intensity uv line sources are specifically designed for pcb. Even with low intensity uv sources, cures can be obtained quickly. The arc discharge is generally confined to a small fused quartz arc tube mounted within a larger borosilicate glass bulb.
These offer specific wavelength emission and provide wavelengths not available with the medium pressure mercury or led light sources. Low pressure mercury lamp learn what goes into ours soft glass vs. Low pressure mercury vapor lamps cannot be directly operated on a 115 ac power line. Investigating the spectrum of a high pressure mercury lamp. However, mercury vapor is harmful in any form, so if the lamp is broken or ruptures during use and any mercury vapor is inhaled, consult a physician immediately. Hach replacement uv for toc analyzers, arc imaging, chromatography, photochemistry, calibration of uv detectors, calibrations of spectrophotometer, and more. Low pressure mercury fluorescent lamps or tube lights. Advanced technology, careful selection of materials and maximum reliability. It needs to be vaporized and ionized before the lamp can produce its full light output. 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 uv lamps alphacure uv lamp manufacturer. Classified as in the same group as fluorescent lamps or germicidal lamps, the main light emission is a 254nm line comprising an 185nm line of far shorter wavelength. A sodiumvapor lamp is a gasdischarge lamp that uses sodium in an excited state to produce light at a characteristic wavelength near 589 nm two varieties of such lamps exist. Lamp that produces light as a result of an electrical discharge, generated between two electrodes, in a high pressure mercury vapor that is contained in a transparent bulb. This was a tubular source about 4 feet long which produced light that was distinctly bluishgreen in color at a high efficacy compared with the incandescent lamps of those days.
Mercury vapor lamps feature low initial cost, but have higher operating costs than hps or metal halide due to its lower efficiency. Heraeus noblelight offers a broad range of germicidal uv lamps that are manufactured from high quality quartz glass. Low pressure mercury lamps use mercury in an excited state to produce light. High pressure sodium lamps may be used in open luminaires except for item 67527 lu400t7 rsc and sox low pressure. Fluorescent lamps3 operate at a very low gas pressure. Mercury vapour pressure is typically around ten atmospheres. Since the lamp s arc size is nearly that of a point light source, the light can be readily converged and diffused by the optical system, and uniform illuminance distribution is easily obtained. Ushios super high pressure uv lamps have been developed to effectively utilize three ultraviolet wavelengths 436, 405 and 365 nm as highintensity light sources with stable irradiance and long life. China high pressure mercury lamp manufacturers select 2020 high quality high pressure mercury lamp products in best price from certified chinese lamp manufacturers, pressure control switch suppliers, wholesalers and factory on. In this process, there is a potential for lamp breaks to occur, in which case mercury can be released and enter the distribution system. The lamps come in both standard and high output selections and are ozone free. The reason for the creation of this second category of mercury lamp was to allow the efficacy to be maintained as high as possible for low wattage sources.
Mercury lamps get dimmer over time and rarely burn out, so it is wise to replace them and restore light level. The analysis of modern low pressure amalgam characteristics. Our production facility is designed to meet specific customer requirements to produce customized oneoff lamps, as well as achieve consistent quality in mass production. Download electrical engineering interview questions and answers pdf. Space constraints, highflow requirements low pressure medium pressure kw per lamp. Get in touch for more information on flow chemistry systems and services please use the contact methods below. In a high pressure sodium lamp, a compact arc tube contains a mixture of xenon, sodium and mercury. Typical applications include street lighting, parking lot lighting, building floodlighting and general area lighting. All credits and sources are located at the bottom of each lighting page. The lamps have a socalled negative resistance, meaning that the lamp s electrical resistance falls with rising lamp current.
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