09.09.2015
High pressure mercury vapor arc-discharge lamps range between 10 and 100 times brighter than incandescent lamps (such as the tungsten-halogen) and can provide intense illumination over selected wavelength bands throughout the visible spectral region when combined with the appropriate filters.
The most popular mercury lamp for optical microscopy is the HBO 100 (a 100-watt high-pressure mercury plasma arc-discharge lamp), which has the highest radiance and mean luminance, due to its very small source size, of the commonly used lamps of any wattage. Mercury arc discharge lamps produce among the highest luminance and radiance output levels of any continuously operating light source for optical microscopy and very closely approach the ideal model for a point source of light. Aside from the numerous artifacts associated with mercury arc lamps, they also suffer from limited life spans of approximately 200 hours and significant variations in spatial and temporal stability. Presented in Table 1 are the optical output power values of a typical 100-watt HBO light source after passing through the microscope optical train and selected fluorescence filter sets. The rated lifetime of mercury arc lamps depends upon how they are used, and the usual 200-hour limit can be compromised by an excessive number of starts (ignitions) or by repeated ignition of warm or hot lamps.
The emission profile of mercury arc lamps is distinct from incandescent lamps in that several prominent emission lines are present in the ultraviolet, blue, green, and yellow spectral regions, which are significantly brighter (up to 100 times) than the continuous background (see Figure 1). A considerable effort has been expended on developing specialized fluorophores that have absorption maxima located near the prominent mercury spectral lines (see Table 2). The extremely high flux density (brightness) generated by mercury arc lamps is achieved by producing the arc in a limited region between two closely spaced electrodes in a high-pressure gas medium. Arc lamp electrode manufacturing variables are critical in determining the starting characteristics, lifetime, and performance variables of mercury lamps. The mercury arc lamp envelope is produced with pure fused silica or quartz glasses, which are impermeable to most gasses at high temperature and pressure, and are thus ideal for containing the hot plasma. One of the most critical features of arc lamp construction is the hermetic metal-to-quartz seal that is necessary to isolate the electrodes from the surrounding atmosphere and for mechanical support of the lamp. In a typical optical microscope configuration, the mercury lamp is positioned inside a specialized illuminator consisting of a lamp housing containing the lamp, a concave reflector mirror, an adjustable collector lens system to focus the lamp output, an electrical socket for securing and alignment of the bulb, and the external power supply (Figure 3).


As discussed above, mercury arc lamps contain a precisely measured amount of metallic mercury within the envelope, and they are filled with argon or xenon, which acts as a starter gas as the mercury vaporizes. Mercury arc lamps require a direct current (DC) power supply that is specifically designed to meet the ignition and operational requirements for each lamp design. Power supplies for the HBO 100 mercury arc lamps used in optical microscopy are usually equipped with several features that enable the operator to monitor the operating conditions and lifetime. The specific wavelengths responsible for this reaction are situated between 240 - 280 nanometers (referred to as nm) with a peak wavelength at 265 nm. Davidson - National High Magnetic Field Laboratory, 1800 East Paul Dirac Dr., The Florida State University, Tallahassee, Florida, 32310. UV-C PRODUCTION The Ultra Violet source is basically a fused silica quartz tube, typically l5mm to 25mm diameter ranging from 100mm-1200mm long.
The inert gas with which the tube is filled, provides the primary discharge and the necessary action to excite and vaporize the miniscule deposits of mercury within. An increase in the current supplied would cause the UV lamp to rapidly heat up thus increasing the mercury pressure to produce the typical medium pressure spectral output shown in Diagram 2. Back to Top ULTRAVIOLET DOSE The UV dose is the product of UV intensity (expressed as energy per unit surface area) and residence time. Average and cumulative doses offered by others depend on turbulent flow characteristics which can disappear when flow is variable.
Willand recommend the appropriate UV dose for each application taking into account water quality, arc tube ageing, industry specifications, as well as microbiological standards. Therefore doubling the dose required for 90% destruction will produce 99% destruction of the target organism. Back to Top LOW PRESSURE LAMPS Ideal for low flow situations with power ratings from 15w to 200w.


Back to Top IRRADIATION CHAMBERS The disinfection process involves the exposure of fluids with microbiological contamination to a UV energy source which is mounted centrally in an irradiation chamber. Lenntech have always believed that correct chamber design is a significant part of effective disinfection and to this end computer modeling is used to establish turbulent flow, which ensures good mixing and balanced exposure at high and low flows and residence time characteristics. Lenntech UV Systems design equipments so that the dose is AT THE WALL, AT THE END OF LAMP LIFE. This protects the process from possible inadequate treatment which may occur through short circuiting when average and cumulative doses are is used.
The inlet and outlet orientation, size and end termination are to customers specification to aid installation.
Back to Top SINGLE ARC TUBE CONFIGURATION Single arc tube configuration greatly enhances performance. Multi-tube designs utilizing quantities of low pressure lamps housed in one chamber present both hydraulic and mechanical problems. Baffles are required to introduce turbulence and through the shadowing effect of these it is possible for untreated water to pass through the chamber shielded from the monitor. Back to Top SYSTEM SIZING To ensure customers are supplied with the correct unit for the intended application we recommend they contact Lenntech UV to arrange an appointment with a trained Lenntech consultant. Information necessary to correctly size a Lenntech unit includes, but is not limited to: 1.




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Comments Ultraviolet arc lamp gas

  1. EzoP
    With weld compound and a few light sources can also.
  2. lowyer_girl
    Method is good for welding though, glasses (particularly cheaper and adjust the amount of urea.
  3. Lapula
    With applicator, one LED UV light, and lab setting, but the product is being developed.
  4. Elnur_Nakam
    Adhesives cure in seconds upon exposure to ultraviolet light and/or visible mobile phone housings, bumper reinforcements easy.