The inner surface of the lamp is coated with a fluorescent and often slightly phosphorescent coating made of varying blends of metallic and rareearth. Depending on the materials used, mercury low pressure uv lamps can be divided into two large families. An electric current in the gas excites mercury vapor, which produces shortwave ultraviolet light that then causes a phosphor coating on the inside of the lamp to glow. These lamps are usually lowpressure mercury vapor lamps.
Low pressure lamps operate with mercury vapor pressure ranging from about 100 to pa. In low pressure mercury vapor lamps only the lines at 184 nm and 254 nm are present. Rather inconveniently, the phosphors known at the time had the awkward habit of greatly losing their efficiency at such high operating temperatures. Related content glow discharges in mixtures of xenon s gortchakov and d uhrlandtac operation of lowpressure he xe lamp. Best applications for mercury vapor lamps eye lighting. 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. Engineering high intensity discharge bulletin mercury lamps. Mercury vapor standard hpl high pressure mercury philips.
Legally binding document step out from the old to the newjawaharlal nehru invent a new india using knowledge. But of more importance, high pressure mercury lamps run hotter than their low pressure counterparts the bulb wall temperature is typically of the order of 150 to 250c. High pressure sodium mercury vapor hid bulbs light. Product information high pressure and specification. The common fluorescent lamp is actually a low pressure mercury arc lamp. Mercury vapor lamps generally contain between 10 and 100 mg of mercury. A lowpressure mercury vapor lamp covered with commercial quartz uv lamp, emitting only at 254 nm 5. The lamps can be constructed to emit primarily in the uva around 400 nm or uvc around. One would tip the lamp, and electrical contacts on each side of the lamp would send electricity through a liquid mercury which started the lamp. Advances in lpuv technology have led to the development of low pressure high output lpho uv lamps, which contain additional elements bismuthindiumgallium rather than pure mercury. A low pressure mercury vapor discharge lamp, which emits light mainly in the three spectral ranges, and the color temperature of the light in the 2000 to 3000 degrees absolute temperature range, the lamp has a radiationpermeable gasimpermeable housing, mercury and inert gas with a pneumatic material, and a light emitting layer emitting.
This lamp has a highly stable output predominantly at the 253. As an example of application and efficiency of mercury lamps, the 61 samsung dlp rear projection tv hls6187w uses a 2 watt philips uhp lamp. Rather than a cold spot, the lamp s 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. Sox low pressure sodium lamps sox lamps are the most efficient hid light source. A strategy towards the next generation of low pressure. Once the lamp has warmed up and the mercury is fully vaporised, the discharge operates in unsaturated mercury vapour at a pressure varying from 18 bar for the smallest types, to 2 bar for the largest. 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. Figure 614 shows the basic configuration of a hid lamp. Again transition of the electrons requires least amount of input energy from a colliding electron. This is also standard practice in mercury lamps designed for use in colder atmospheres. This wavelength coincides well with one of the two peaks of the germicidal effectiveness curve i.
Mercury vapour lamp article about mercury vapour lamp by. Low pressure amalgam lamps amalgam lamps use a mercury amalgam mix to control mercury vapor pressure. Amalgam uv lamps contain solid spots which consist of an alloy of mercury and another element, such as indium or gallium. What are the advantages and disadvantages of the mercury. Mercury lamps get dimmer over time and rarely burn out, so it is wise to replace them and restore light level. In lowpressure mercuryvapor lamps only the lines at 184 nm and 254 nm are present. It is important to use a lamp that emits uvc, also termed far uv, deep uv, or vacuum ultraviolet, vuv. Both philips lamps, one brand new 50w and a very badly tortured 80w that still somehow runs. One of these peaks is at about 265 nm and the other at about 185 nm. What are the advantages and disadvantages of the mercury lamp, sodium vapour lamp and xenon lamp used in photocatalysis. A fluorescent lamp is a low weight mercury vapour lamp that uses fluorescence to deliver visible light. Amalgam lamps use a mercury amalgam mix to control mercury vapor pressure.
Investigating the spectrum of a high pressure mercury lamp. Turn off the highpressure mercury lamp and wait several minutes for it to cool down. A common discharge lighting luminary for use in an office environment would typically be a lowpressure mercuryvapour electronic discharge fluorescent lamp. The light sources were lowpressure mercury vapour lamps having identical geometry and electric parameters 15 w. Low pressure mercury lamp learn what goes into ours. Mercury vapor technology was developed throughout the 1800s in england and germany. All mercury vapor lamps contain some amount of mercury. Mercury vapor lamps and their relatives are often used because they are relatively efficient. Do not touch the body of the lamp after switching on. They have an efficiency of up to 190 lumens per watt compared to an incandescent street lamp which has between 15 and 19.
High pressure sodium mercury vapor hid bulbs light bulbs the home depot. A common discharge lighting luminary for use in an office environment would typically be a low pressure mercury vapour electronic discharge fluorescent lamp. Ushio germicidal lamps are low pressure mercury arc lamps that emit radiation peaking at 253. When a mercury vapor lamp is to be disposed, it is subject to the current epa toxicity characteristic leaching procedure tclp disposal criteria. The term pressure is referred to the mercury pressure present in the lamps. But there are health hazards and environmental risks associated with the usage of such lamps. It is a gasdischarge lamp that uses sodium in an excited state to produce light. Mercury vapor lamps also offer a very long lifetime, as well as intense lighting for several applications. Get free 2day shipping on qualified mercury vapor, high pressure sodium, hid bulbs products or buy lighting department products today with buy online pick up in store.
Effects of ultraviolet led on bacteria springerlink. What is the working principle of mercury vapour lamp answers. Hps retrofits for mercury lamps, and will operate on all mercury reactor ballasts. Do not operate the high pressure mercury vapour lamp continuously for longer than 10 minutes. Hach replacement uv for toc analyzers, arc imaging, chromatography, photochemistry, calibration of uv detectors, calibrations of spectrophotometer, and more. Dec, 2015 low pressure sodium vapour lamp this lamp was invented first in 1920 by arthur h. Lp, amalgam lp and mp lamps are mercury based arc lamps, differing primarily by electrical excitation and ionization. Mercuryvapor lamps are subdivided into low pressure, high pressure, and superhigh pressure lamps according to the operating pressure. All highintensitydischarge lamps produce light from an arc tube that is usually contained in an outer glass bulb. A fluorescent lamp, or fluorescent tube, is a low pressure mercury vapor gasdischarge lamp that uses fluorescence to produce visible light.
Low pressure mercury vapour lamp hg2 lamp heraeus has developed a compact low pressure, low voltage mercury vapour lamp type hg2, principally for use in scientific instrumentation. However, the first low pressure lamps were sold commercially in the united states in 1901 after john cooper hewitt innovated the lamp s color. Uv lamps for sterilisation are low pressure mercury vapour lamps, which emit about 86% of their light at 254 nm. High pressure mercury light, halogen light, high pressure sodium lamp, street light. They have a germicidal efficiency of 30% and can operate on lower current between 180 and 425ma. Set up the high pressure mercury lamp roughly in the middle of the 1m optical bench. In these lamps, a material, such as sodium, mercury, or metal halide, is added to the arc tube. Mercury vapor lamps are subdivided into low pressure, high pressure, and superhigh pressure lamps according to the operating pressure. The light sources were low pressure mercury vapour lamps having identical geometry and electric parameters 15 w. A sodium vapor 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.
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. This gives a typical diffuse medium pressure uv spectrum see figure 3. The mercury vapor lamp was invented in the year 1901 by peter new york. Aug 20, 2016 a fluorescent lamp tube is filled with a gas containing low pressure mercury vapor and argon, xenon, neon, or krypton. In low pressure mercury vapor lamps, only the lines at 184 and 253 nanometers nm are. Among the light sources in use for general lighting, high pressure mercury vapour h. Softglass lamps are one of our quality low pressure mercury lamp products.
A mercury vapor lamp is a gasdischarge lamp that produces light via an electric arc through vaporized mercury. Pdf on mercury vapor lamps and their effect on the smart. Us6683406b2 low pressure mercury vapor fluorescent lamps. 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.
Low pressure lp, amalgam low pressure lp and medium pressure mp. Mercuryvapor lamp techsciencenews online reference. Sodium vapor lamps are some of the most efficient lamps in the world. Mercury lamps are used primarily for general street, parking and hibay industrial lighting applications where good efficiency and long life is desired and color rendering needs. A low pressure mercury vapor lamp covered with commercial quartz uv lamp, emitting only at 254 nm 5. Quartz low pressure standard 480 w 0,30,5 wcm low pressure mercury lamp lp hg lamp is a highly efficient uv light source of short wavelength. During operation the body of the lamp will get hot so that there is a risk of getting burned. A low mercury consumption electric lamp is provided having a layer of a luminescent material comprising a phosphor selected from the group consisting of. Low pressure mercury lamps have been manufactured in jelight company inc. Mercury vapor lamps are highintensity discharge lamps that predate modern high pressure sodium and metal halide lamps. Without a doubt mercury plays a central role in the market of light sources as an element to be found in the majority of discharge lamps from low pressure mercury.
A fluorescent lamp tube is filled with a gas containing low pressure mercury vapor and argon, xenon, neon, or krypton. Due to mercury being a liquid at room temperature, a low pressure is needed in order to make it a vapor which is what is more suitable for a discharge tube such as the fluorescent tube. Light sources incandescent lamp discharge lamp florescent lamp sodium lamp high pressure mercury vapour lamp 3. Highpressure mercury lamps installed at most fluorescence microscopes are not suitable because they do not emit the short wavelengths needed for this lithography. The mercury vapor now carries current within the arc. Per unit area, the effective germicidal output of a medium pressure lamp is much greater up to 30 times than a low pressure lamp, allowing high flow rates to be treated using fewer lamps. Ballast low pressure mercury vapor lamps cannot be directly operated on a 115 ac power line. Get in touch for more information on flow chemistry systems and services please use the contact methods below. Lamp output in the uv range depends on the amount of mercury and vapor pressure of mercury in the lamp. Due to the low heat load of the low pressure mercury lamps, lamps do not require filtering and allow a temperature range of 40c to 80c to be achieved.
As the current continues to increase to its full potential, a ballast, which can be found in a mercury vapor lamp, serves as a resistor. Low pressure uv lamps alphacure uv lamp manufacturer. In medium pressure mercury vapor lamps, the lines from 200600 nm are present. This pressure in turn depends on the temperature of the coldest section of the arc tube and the quantity of mercury introduced into the tube. Mar 23, 2015 just a bit of a ramble about two mercury vapour lamps with some illumination of said lamps. The aperture phosphorcoated lamps that jelight company produces employ the same basic design as the doublebore, low pressure mercury vapor lamps with the exception of a special phosphor coating. Mercury vapor lamps are primarily used in industrial applications and outdoor lighting e. A fluorescent lamp refers to a low pressure mercury vapor gasdischarge lamp that uses fluorescence in order to produce visible light. They emit a characteristic monochromatic yellow light that is ideal for certain exterior street and area lighting applications. As pressure increases the chance of multiple collisions gets increased. Cambridge x33n deliver engaging instruction and brilliant projected imageswithout. Phosphor coated bulbs offer better color rendition than either high or low pressure sodium vapor lamps. The coating on the inside of the tube is because the uv light that is emitted when electrons pass through the mercury vapor needs to be converted to visible. Capacitors for use in tubular fluorescent high pressure mercury and low pressure sodium vapour discharge lamp circuit number of amendments.
Aside from mercury free, uv led is low consumption. What are the advantages and disadvantages of the mercury lamp. Lowpressure amalgam lamps amalgam lamps use a mercury amalgam mix to control mercury vapor pressure. 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%. Standard mercury vapor lamps have found greatest use in industrial applications and outdoor lighting, because of their low cost and long life 16,000 to 24,000 hours, with lamp sizes ranging from 40 to 1,000 watts. A lamp is a device that illuminates a light on supplying electric current. 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 cost. A high pressure sodiumvapor lamp a sodiumvapor lamp is a gasdischarge lamp that uses sodium in an excited state to produce light at a characteristic wavelength near 589 nm. Mar 15, 2020 a fluorescent lamp is a low weight mercury vapour lamp that uses fluorescence to deliver visible light. After the experiment, leave the high pressure mercury vapour lamp to cool. The first mercury vapor lamps were in a lower pressure tube. Conventional uv lamps hold their mercury either in a liquid form more common in medium pressure lamps or an amalgam more common in low pressure, high output lamps. We are quite fond of using mercury vapor lamps in our homes and offices as they are cost effective and energy efficient as well. Low pressure mercury vapor lamps contains mercury and it has harmful effects to an environment and human body.
The lamps come in both standard and high output selections and are ozone free. The first practical mercury lamp was the cooperhewitt lamp developed by peter cooper hewitt in 1901. Dec 31, 2018 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. Medium pressure lamps draw a much greater current than low pressure lamps, leading to a rapid rise in the mercury vapor pressure. The construction and applications of sodium vapour lamps. Whats the difference between low pressure lp, amalgam low pressure lp, and medium pressure mp uv lamps. This coating covers more than 70% of the diameter of the lighted length of the lamp.
The mercury vapour lamp in construction is similar to sodium vapour lamp. The lamp is constructed from a hollow glass tube with an aluminium cap at each end. Set up the ocular such that the yellow lines are well in focus. There are different types of electrical lamps they are, incandescent, mercury, sodium, clf, led lamps. 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. Applications of lowpressure mercury vapor lamps for. 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. Selfballasted mercury lamp applications the most common applications for selfballasted style mercury vapor lamps are. Light source 218w phillips, low pressure mercury vapor lamp life typical 5,000 hrs. Within the tube are two electrode coils, one at either end. So as the current is increasing, the ballast reduces the supply voltage simultaneously to keep the mercury vapor lamp running under stable operation. 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. The clear mercury bulb has a bluish green appearance and the deluxe white has a higher color rendering. Mercury vapor lamps feature low initial cost, but have higher operating costs than hps or metal halide due to its lower efficiency.
In this study, we investigate effects of highintensity ultraviolet light emitting diode uv led on e. The low pressure refers to the pressure of the mercury vapour inside the lamp, which is approximately 0. In mediumpressure mercuryvapor lamps, the lines from 200600 nm are present. 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.
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. Fluorescent lamp and working principle of fluorescent lamp. The arc discharge is generally confined to a small fused quartz arc tube mounted within a larger borosilicate glass bulb. Turn on the mercury lamp and observe the double yellow line as the lamp heats up. Mercury vapor conducts electricity, completing the circuit. Which material for substrate to make a free standing metal thin film. In the mercury lamp, light is produced by the passage of an electric current through a gas or vapor under pressure instead of through a tungsten wire as in the incandescent lamp. Fused silica is used in the manufacturing to keep the 184 nm light from being absorbed. What is the working principle of mercury vapour lamp.
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