High Pressure Mercury Discharge Lamps Research Articles

A Method of Reducing Fluctuations of Lamp Power in a Continuous Dimmer Circuit for High-Pressure Mercury Discharge Lamps

In order to reduce fluctuations of lamp power and maintain constant power in a continuous dimmer circuit in high-pressure mercury discharge lamps, the authors propose to add a supplementary control circuit on the continuous dimmer circuit. This supplementary control circuit is equipped with a photosensor to control the levels of light. Moreover, we connect the by-pass circuit to the tap of ballast which is close to the power source side. The addition of a by-pass circuit, in which circuit constant is adjusted to reasonable value, make it possible to improve power factor and reduce harmonic current.

高圧水銀ランプバイパス回路共用複数灯点灯回路

Usillg both simulation and experiments, we investigated cause to ensure that the supply currellt in an electrical circuit with a common by-pass circuit can be kept approximately constant from start-up to reachillg steady state. In such circuit, the supply current can be distorted by about 2% when the power factor reaches 100%. We found that an approximately constant supply current can be achieved, thus making these circuits practical for usewith multiple high-pressure mercury discharge lamps, even when a larnp does not light.

Performance of a circuit configuration with a common bypass circuit for multiple high-pressure mercury discharge lamps

This paper deals with simulations and experiments carried out on a circuit suitable for use on a multiple number of lag-type high-pressure mercury lamps. One common bypass circuit is provided and a resistance is connected to the power source side of each ballast winding. The properties of the proposed circuit include a nearly sinusoidal input current at unity power factor when one or more lamps are in operation. The self-inductance of each ballast winding is made slightly larger than the rated inductance. The tap position of the bypass circuit is placed closer to the power source side of each ballast winding in order to reduce the input current distortion. The value of resistance in series with the power source side of each ballast winding is designed to provide simultaneous ignition of all lamps. The following findings are obtained with four-lamp circuits with a rated lamp power of 200 W: (1) under steady state, the input current distortion factor is as low as 2%, and the power factor is nearly 100%; and (2) the total loss contributed by the ballast windings, L/sub b/ of the bypass circuit and resistance connected to each ballast winding on the power source side, is as low as 11.4% of the total power.

Acceleration of re-ignition of high pressure mercury discharge lamps using photo-pre-ionization

High Intensity Discharge (HID) lamps are difficult to re-ignite rapidly because of the high pressure of metal vapor at high temperatures. We have succeeded in reducing the re-ignition time of high-pressure mercury lamps by using a pre-ionization step where an excess of electrons are generated by UV laser irradiation into the lamp. The effect of changing the laser focal point of the UV laser in the lamp and the position of an auxiliary electrode were also investigated. The time interval for re-ignition was reduced from 230s to 100s by laser irradiation near to the cathode. The results clearly showed that the effect of accelerating the re-ignition time by the pre-ionization step was determined by the behavior of excess electrons generated during the UV laser irradiation.

高圧水銀ランプバイパス回路共用複数灯点灯回路に関する考察

高圧水銀ランプバイパス回路共用複数灯点灯回路に関する考察

Modeling the warm-up phase of a high-pressure-lamps lighting network

This work presents a study of the dynamic regime of a lamp-network interaction corresponding to the warm-up phase of a high-pressure mercury discharge lamp. The lamp's behavior is described by a variable pressure model using the local thermodynamic equilibrium (LTE) concept. Indeed, this model covers the most interesting phase of the network dynamic regime, where discharge lamps appreciably impose their nonlinearity. We first analyze the electrical behavior of the discharge lamp in a single phase circuit, taking into account the ballast saturation. Then a micronetwork is studied and are show the influence of the discharge's evolution on currents in phases and neutral conductors. Finally, from the results of the physical model, we set up a simple parametric modeling which reproduces the electrical behavior of the lamp during its warm-up phase. Such an approach can be useful for electrical engineers working on the discharge supply circuits at industrial frequency (50-60 Hz).

高圧水銀ランプ同相形点灯回路の定電流特性に関する考察

高圧水銀ランプ同相形点灯回路の定電流特性に関する考察

An intensive hard UV-radiation source

A modified type of high pressure mercury discharge lamp has been developed in our laboratory as an intensive hard UV-radiation source by the optimizating the geometrical arrangement, form of electrodes, emission mix, amount of mercury, argon pressure, etc. Our business partners want to use the lamps in a single-purpose device for hardening their products. Their main requirements are an electric arc length of 360 mm and a power of 2000 W. This work also presents the emission spectra, a description of the construction, and the basic technical parameters.

Microfabricated high intensity discharge lamps

Miniaturization of high intensity discharge lamps can lead to cheaper, more efficient, and novel lighting systems for the lighting industry. We are applying micromachining and techniques used for manufacturing integrated circuits, to develop such miniature lamps. We have fabricated electrodeless and electroded high-pressure mercury discharge lamps in quartz substrates using integrated circuit and micromachining techniques, such as photolithography, etching, and wafer bonding. Patterned quartz wafers were bonded together using fusion wafer bonding. The resulting cavities are strong enough to withstand the high pressures (124 atm) and high temperatures (1000 °C) in these lamps. Lamps containing varying amounts of mercury were fabricated to obtain high-pressure discharges in the range of 10–175 atm. The electrodeless lamps were excited by a microwave source, operating at 2.45 GHz and the electroded lamps with a dc voltage. Lamp efficacies over 40 lumens (lm)/W were obtained for the electrodeless lamps and over 50 lm/W for the electroded lamps. These results demonstrate that high-pressure mercury discharges can be sustained in the lamp cavities formed by micromachining techniques. In addition, these cavities are not only hermetically sealed, but can also withstand the high-pressure and high-temperature environment of high-pressure mercury discharges.

高圧水銀ランプ連続調光式点灯回路の電流波形と力率の一改善法

高圧水銀ランプ連続調光式点灯回路の電流波形と力率の一改善法

ESR Spin Trapping Study of Sodium and Tetramethylammonium Mercaptoundecahydro-closo-dodecaborates(2-) and Sodium Tetraborate Aqueous Solutions Irradiated by UV Light at Room Temperature

The superoxide anion radicals O2-• were identified and determined in aqueous solutions of sodium and tetramethylammonium salts of mercaptoundecahydro-closo-dodecaborate(2-) (mercaptoborate), and sodium tetraborate, irradiated by high pressure mercury discharge lamp at room temperature by the of ESR spin trapping method. The quantity of the generated O2-. depends on the initial oxygen concentration in the irradiated solutions. The radical generation can play a crucial role in the application of mercaptoborate in boron neutron capture therapy (BNCT) of brain tumours.

Simulation of the high-pressure mercury discharge lamp during the middle phase of start-up (medium mercury pressure)

This paper deals with the modelling of the medium pressure Hg and Hg-Ar positive column (Hg pressure range 5-350 Torr). The aim of this work is to simulate, in a first approximation, the middle phase of the Hg high-pressure lamp warm-up. In this approach, the main assumption is that time evolution of the discharge can be divided into a succession of stationary sub-phases characterized by the Hg partial pressure. Thus, we present here a self-consistent steady-state collisional-radiative model describing the middle sub-phase. This model includes volume recombination of Hg atomic and molecular ions, as well as several atom-atom inelastic scattering mechanisms. Calculations are carried out for both pure Hg and Hg-Ar discharges. Our results, which are in good agreement with experimental data from the literature, confirm that plasma thermalization occurs in the middle start-up phase (electron and gas temperatures become equal during this phase). Furthermore, this simulation shows the importance of different elementary processes, like atom-atom inelastic scattering, for the medium pressure plasma description. In fact, these mechanisms cannot be neglected until LTE conditions are reached.

Three-dimensional natural convection in a high-pressure mercury discharge lamp

A three-dimensional computer model is used to calculate the convective flow in a 400 W high-pressure Hg discharge lamp. The model gives the expected axisymmetric flow when the arc tube axis is vertical, and more complex three-dimensional flows when it is not.

A search for an improved ultraviolet radiation source

This work examines the spectral modifications produced in high-pressure mercury discharge lamps by the iodides of iron, cobalt, manganese and antimony, both individually and in select combinations, at a lamp operating power of 1000 W. Individually, iron, cobalt and manganese iodide additives significantly improve the UVA spectral output at wavelengths beneficial to either the diazo photoprint or suntan application. Increasing the iodide quantity strongly depresses the radiation emitted in the UVB and UVC spectral regions. A select combination of iron and cobalt iodides, with mercury, enhances the UVA spectral response to a level beyond that achieved by the individual iodides alone. This combination has been used to develop a lamp with a spectrum covering adequately both the suntan and photoprint applications. None of the iodides in this trial improved on the performance of mercury in the UVC spectral region, supporting the view that water sterilisation may best be served by lamps dosed only with mercury.

高圧水銀ランプの特性方程式

高圧水銀ランプの特性方程式

Photocyclization of N-(3-chloro-2-benzo[b]thienocarbonyl)-N'-monosubstituted thioureas

N-(3-Chloro-2-benzo[b]thienocarbonyl)-N'-monosubstituted thioureas, when irradiated with a high-pressure mercury discharge lamp through a pyrex or quartz filter, give the corresponding benzothienothiazine derivatives in lower yields than the analogous N',N'-disubstituted thioureas. The reactivity lowering of the N'-monosubstituted thioureas is ascribed to the intramolecular hydrogen bond C=O...H-N due to which these compounds in their ground states exist in the six-membered cyclic conformation unfavourable for the cyclization. The photolysis of N'-phenylthiourea results - due to a stronger hydrogen bond - in splitting of the molecule to give 3-chlorobenzo[b]thiophene-2-carboxamide and phenyl isothiocyanate.

A source of highly spin-polarised slow electrons based on the 'Fano effect' on caesium atoms

The source of spin-polarised electrons recently used in a 'triple-scattering experiment' in Munster is described in detail. The polarised electrons are generated by the photoionisation of caesium atoms with circularly polarised UV radiation from a high-pressure mercury discharge lamp (Fano effect). Electron intensities of 5 nA with polarisation of 84% have been routinely obtained during continuous runs of up to 200 hours in the kinetic energy range between 17 and 500 eV with an energy spread of <or=1.5 eV. The polarisation and intensity fluctuation was +or-1% and +or-10% in 10 hours, respectively.

Investigations on the fundamental longitudinal acoustic resonance of high pressure discharge lamps

Cylindrical high pressure mercury discharge lamps were operated on a sinusoidal supply voltage at frequencies in the vicinity of their fundamental longitudinal acoustic resonance band. The sound spectrum emitted from the lamp allows the detection of pressure waves in the lamp gas volume. With this method it is shown that there are acoustic resonances which are not combined with visual arc instabilities. In this case the influence of the acoustic resonance on arc and wall temperature profiles was measured. The experimental results can be explained by an additional axial heat flow caused by the acoustic pressure waves.

A study on harmonic power of lead type operating circuit for high pressure mercury discharge lamp.

This research relates to energy saving method in a system that includes non-liner load. The research has been conducted in the following sequence. Firstly, voltage and current waveforms at each element of lead type operating circuit for high pressure mercury discharge lamp are developed in Fourier series, then using the Fourier expansion, the electric power of each harmonic at each element of the operating circuit is obtained theoretically, and at the same time experiment is performed. The following are the results of the research.(1) From the voltage and current of distorted wave of mercury lamp, the impedance (and its resistance and reactance components) is obtained for each harmonic, and their characteristics are clarified.(2) Based on the voltage-current characteristics of choke coil, method of capacitance (μF) determination is clarified for lead type operating circuit.(3) When a mercury lamp (H100) is operated by lead type operating circuit, load distribution (VA) among choke coil and capacitor is obtained theoretically and the limit of the distribution for the value α=xL/xC is clarified, where xL and xC are reactances of choke coil and capacitor respectively for the fundamental wave.

Dual lamp operating circuit for high pressure mercury discharge lamps

The present research has been conducted with a view to energy saving and contemplates to use a single three-leg iron-core reactor in place of two core type iron core reactors used respectively in the capacitive and inductive ciruits of the conventional flickerless lighting device of the two-lamp or dual high pressure mercury lamp. It has become apparent from this research that, with the length la of the two air gaps between the central leg and the respective outer legs selected to be equal to 2mm, the capacitive and inductive circuit can be made substantially independent from each other and that, for the same voltages and currents in the various operating portions and the same mercury lamp power rating, the volume of the silicon steel plate and the iron loss can be reduced about 18% with the novel lighting device as compared to the conventional device.