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Topic: Corona discharge


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 Corona discharge - Wikipedia, the free encyclopedia
In electricity, a corona discharge is an electrical discharge brought on by the ionization of a fluid surrounding a conductor, which occurs when the potential gradient exceeds a certain value, in situations where sparking (also known as arcing) is not favoured.
A corona is a process by which a current, perhaps sustained, develops from an electrode with a high potential gradient in a neutral fluid, usually air, by ionising that fluid so as to create a plasma around the electrode.
This asymmetry is a result of the great difference in mass between electrons and positively charged ions, with only the electron having the ability to undergo a significant degree of ionising inelastic collision at common temperatures and pressures.
www.wikipedia.org /wiki/Corona_discharge   (733 words)

  
 Corona discharge air transporting arrangement - Patent 4812711
The construction of the corona electrode and the voltage of the voltage source are such that a corona discharge generating air ions occurs at the corona electrode.
An ion-wind is created when a corona electrode and a target electrode are arranged at a distance from one another and each connected to a respective terminal of a direct-current voltage source, the corona-electrode design and the voltage of the direct-current voltage source being such as to cause a corona discharge at the corona electrode.
The mutual distance between the wire-like electrode elements in the corona electrode K was 50 mm, and the electrode element of the excitation electrode E was arranged in the same plane as the electrode elements of the corona electrode K centrally therebetween.
www.freepatentsonline.com /4812711.html   (8591 words)

  
 Corona discharge   (Site not responding. Last check: 2007-08-11)
A corona is a process by which a current, perhaps sustained, develops between two high-potential electrodes in a neutralfluid, usually air, by ionising that fluid so as to create a plasma around one electrode, and by using the ions generated inplasma-processes as the charge carriers to the other electrode.
Corona discharge usually involves two asymmetric electrodes, one highly curved (such as the tip of a needle, or a narrow wire)and one of low curvature (such as a plate, or the ground).
However, the electrons in a positive corona are concentrated close to the surface of the curved conductor, in a region ofhigh-potential gradient (and therefore the electrons have a high energy), whereas in a negative corona many of the electrons arein the outer, lower-field areas.
www.therfcc.org /corona-discharge-92188.html   (1970 words)

  
 Corona discharge thermotherapy technique - Patent 4667677
A corona discharge beam is projected from the tip of the electrode and impinges on the skin to be absorbed by the underlying tissue of the patient and converted into therapeutic heat.
The corona discharge beam is derived from an energy generating unit in which a low radio-frequency carrier of relatively low power is overmodulated by a sonic frequency signal to create periodic bursts of radio-frequency energy whose repetition rate is at the sonic frequency and whose peak amplitude is such as to cause a corona discharge.
This energy is applied via a flexible wire 11 to a hand-held probe 12 having a pointed discharge electrode 12A from which is projected a corona discharge beam B. Beach B is directed toward and impinges on the skin surface 13 of a patient that overlies a problem region 14.
www.freepatentsonline.com /4667677.html   (2362 words)

  
 (Medical Plastics and Biomaterials) Corona Discharge Treatment for Medical Surface Preparation (MDDI archive, Feb 00)
In some cases, corona treating of an entire part can be done in a single split-second operation, with up to four discharge heads positioned to provide complete coverage of the surface of the part to prepare it for the application of labels, coatings, or direct printing of text or graphics.
Corona treating systems produce ozone as a byproduct, and various methods have been employed to trap or collect the ozone and treat or destroy it.
Corona discharge surface treatment is an effective and efficient process that is commonly used to increase the surface tension of a wide variety of materials, parts, and packaging in order to provide a surface that is more receptive to inks, coatings, or adhesives.
www.devicelink.com /mddi/archive/00/02/004.html   (2718 words)

  
 DayCor - A Dual-Spectrum Camera for Daytime Corona Detection   (Site not responding. Last check: 2007-08-11)
Corona and arcing activity, which may occur at numerous points on overhead transmission, substation, and distribution power systems, may result in audio noise (AN) or radio interference (RI) complaints or indicate a defective component that may be close to failure.
Corona discharges occur when surface electric field intensity surrounding an energized electrode exceeds a critical value resulting in a localized ionization of the surrounding gas, in most cases air.
However since daytime corona inspection is a new technology, a considerable amount of research is necessary to correlate observed activity with defective components or benign sources.
www.daycor.com /camera-arc.html   (3117 words)

  
 Corona Discharge
Corona Discharge treatment is the most common method of increasing the energy level of PP and PE materials (see below).
In the corona treatment system the voltage build-up ionises the air in the air gap creating a corona, which modifies the surface and increases the surface energy of the substrate passing over the electrically grounded roll.
The polar groups formed by the corona have an attraction for the molecular layer on the other side of the web, and when the two sides come into contact when they are on the roll, a self-adhering condition exists.
www.polytechconsultants.com /corona.htm   (885 words)

  
 Corona discharge ignition   (Site not responding. Last check: 2007-08-11)
Nevertheless, there are also numerous disadvantages of arc discharges, including the limited size of the discharge, the necessity for supporting electrodes that may interfere with the flow or combustion process, and the low "wall-plug" efficiency (i.e.
The subject of this investigation is the use of corona discharges (the portion of an electric discharge before the onset of the low-voltage, high current arc discharge) for the initiation of combustion in propulsion systems and internal combustion engines.
It can be see that the corona discharge ignites a cylindrical volume whose diameter is more than half of the combustion chamber diameter in a very short period of time.
carambola.usc.edu /research/coronaignition   (1276 words)

  
 Corona Modeling
Corona and glow discharges are somtimes confused, but they have one important distinction: Glow discharges are relatively "cold" breakdowns, whereas coronas are relatively hot breadowns.
Since the equations are approximations, the actual corona voltages should be higher in the case that the emitter doesn't accurately represent the model or is worn down by the corona, or that the atmospheric conditions cause e
Between 32.5 kv and 34 kv, the size of the corona is a non-linear function of the voltage.
www.ee.vill.edu /ion/p61.html   (1488 words)

  
 Project 2   (Site not responding. Last check: 2007-08-11)
Coronas are partial discharges that occur in regions of non-uniform electric fields adjacent to conductors stressed to high voltages.
Under the right conditions these coronas can be a precursor to complete electrical breakdown of the air gap due to a reduction in the density of neutral molecules resulting from a combination of localised heating and convective air flow generated by the movement of negative ions.
The scene arm of the fibre interferometer is subjected to controlled, repetitive bursts of infrared radiation from a CO2 laser and the combination of localised heating and convective cooling by the corona wind results in fringe shifts which are directly calibrated to the speed of the wind.
www.une.edu.au /Physics/Research/Photonics/PhotoRP2.htm   (261 words)

  
 L29. Destruction of Ethane in Corona Discharge: Experiment and Modeling   (Site not responding. Last check: 2007-08-11)
Destruction of ethane was studied using a flow corona discharge reactor coupled with on line GC/MS and quadrupole mass-spectrometry.
A tubular coaxial wire AC high-voltage dielectric barrier discharge flow reactor connected to a Hewlett-Packard 5973 GC/MS and a Finnigan 4021 quadrupole MS was used.
The active discharge power was varied in the range 0.01 – 4.0 W. The reactants (ethane) and the products of the destruction were monitored on line using the electron impact MS as well as the GC/MS.
www.cstl.nist.gov /div838/kinetics2001/agenda/l_session/l29/l29.htm   (899 words)

  
 Corona Discharge
High energy at the site of the corona discharge can cause serious damage to mechanical components and result in unexpected shutdowns and loss of service to virtually hundreds of thousands of customers.
Electrical phenomena such as corona discharge has a distinct popping and sizzling sound, not unlike the sound of frying bacon.
Corona discharge results when air molecules around conductors become electrically charged or "ionized." Loss of energy in alternating current high voltage transmission lines is one concern, and the deterioration and eventual failure of insulators is another.
www.sdt.be /03applications/acorona.html   (605 words)

  
 Corona discharge   (Site not responding. Last check: 2007-08-11)
A neutral atom in the medium, in a region of strong field (high potential gradient, near the curved electrode) is ionized by an exogenous environmental event (for example, as the reult of a photon interaction), to create a positive ion and an electron.
A corona begins with a rare natural 'background' ionisation event of a neutral air molecule, perhaps as the result of photo-excitation.
In a chain-reaction or 'electron avalanche' those additional electrons are also separated from their positive ions by the strong potential gradient, causing a large cloud of electrons and positive ions to be momentarily generated by just a single initial event.
www.portaljuice.com /corona_discharge.html   (2098 words)

  
 Electric power engineering - Is Corona Discharge a Problem?
I only recently became aware that corona is in fact a function of cable diameter due to the distribution of the voltage stresses around the perimeter.
One quick and effective way of pinpointing the corona (if you have it) is to mount a 35 mm SLR camera on a tripod, and take a 2-minute timed exposure photograph of the area of the substation where you think the corona may be coming from.
Corona noise has two components; one irregular noise caused by high frequency and hums caused by low frequency that is difficult to control.
www.eng-tips.com /gviewthread.cfm/lev2/11/lev3/47/pid/238/qid/30702   (1259 words)

  
 Corona Discharge vs. UV Ozone Generation - UV ozone generators and Corona Discharge ozone   (Site not responding. Last check: 2007-08-11)
The technologies involved in corona discharge ozone generation are varied, but all operate fundamentally by passing dried, oxygen-containing gas through an electrical field.
Since 85% to 95% of the electrical energy supplied to a corona discharge ozone generator produces heat, some method for heat removal is required.
At the heart of a corona discharge ozone system is the dielectric.
www.ozonemonitors.com /info/cd_vs_uv.htm   (589 words)

  
 The Removal of NOx Using a Pulsed Streamer Corona Discharge in the Presence of Ethylene - Storming Media
Abstract: Corona technology is based upon the application of an electric discharge to produce highly reactive free radicals in a gaseous medium.
In this study, a pulsed streamer corona discharge reactor was designed, constructed, and operated to study the removal of NO containing gases.
Different physical characteristics of the discharge such as the rise time, peak voltage, and pulse width of the voltage pulse were measured.
www.stormingmedia.us /93/9343/A934373.html   (158 words)

  
 Corona, Arcing, Partial Discharge & Predictive Maintenance UV Inspection Magazine
The last annual UV Inspection Users Group Meeting (UGM), an EPRI / OFIL coproduction, was a unique opportunity for corona camera users to present and exchange experience and know-how on corona and arcing inspection in HV transmission lines, distribution and substation maintenance as well as various high voltage testing applications.
Potential users were supplied with useful material for evaluation of the cost-effectiveness of corona inspection, and acquisition justification of a corona camera for the maintenance tasks in their electric utilities/ service companies.
Among the issues presented are: return of investment (ROI) cases, applications related to radio interference (RI) prevention; maintenance consideration to preventing flashovers that lead to outages; railway line inspection for corona; mechanism of polymer insulator failure, (causing flashovers).
www.seeing-corona.com   (381 words)

  
 Talk:Corona discharge - Wikipedia, the free encyclopedia
Yes, Omegatron, the purplish fuzzy discharge is a corona or brush discharge, and the white or yellow momentary discharge is a spark.
If that electric field is strong enough, the air will breakdown and a corona will form around the sphere, regardless of the presence or lack of another electrode.
I think the important point here is that corona is dependent on electric field strength (~=potential gradient), anyway, not potential.
www.wikipedia.org /wiki/Talk:Corona_discharge   (1103 words)

  
 DayCor®: corona discharge detection camera for high voltage predictive maintenance   (Site not responding. Last check: 2007-08-11)
Corona discharge inspection increases power distribution reliability and enables successful commissioning of substations as well.
Corona causes damage to TandD HV power lines due to generation of corrosive materials that shorten the life span of high voltage lines, substation components and insulators.
Corona can also be an indicator of faults due to severe maintenance and safety problems.
www.daycor.com   (384 words)

  
 L18. Destruction of Isotopically Enriched Nitric Oxide, 15N18O, in Corona Discharge   (Site not responding. Last check: 2007-08-11)
During the last decade corona discharge was extensively studied as one of the prospective technologies of treatment of gas flows contaminated with nitrogen oxides.
O) in air in corona discharge was studied using a tubular flow coaxial wire AC dielectric barrier discharge reactor coupled to a quadrupole mass-spectrometer.
Formation of oxygen atoms (responsible for the ozone formation) occurs with high efficiency in corona discharge, which explains the high efficiency of oxygen isotopes scrambling and the conversion of nitric oxide to nitrogen dioxide.
www.cstl.nist.gov /div838/kinetics2001/agenda/l_session/l18/l18.htm   (710 words)

  
 Ozone Generators, Hankin Atlas Ozone What is Ozone Page   (Site not responding. Last check: 2007-08-11)
In the same way that ozone is formed naturally by the discharge of electricity during a thunderstorm, large quantities of ozone are produced commercially in the modern electrical ozone generator.
The passage of a high voltage, alternating electric discharge through a gas stream containing oxygen will result in the breakdown of the molecular oxygen, to atomic oxygen.
In order to control the electrical discharge, and maintain a "corona" or silent discharge in the gas space and avoiding as much as possible, arcing, a dielectric space or discharge gap is formed, using a dielectric material such as glass or ceramic.
www.hankinozone.com /ozone.html   (1157 words)

  
 INCN-37 - Development of Low Energy Corona Discharge Technology for VOCs, NOx and SOx Destruction   (Site not responding. Last check: 2007-08-11)
The objectives are the development and characterization of the corona discharge technology for control of VOCs, NOx and SOx in air streams such as in stock emission and flue gases.
The treatment of air streams is performed by a dielectric barrier corona discharge.
A patent application on the corona discharge reactor is planned in Fall, 96.
www.njit.edu /HSMRC/RESEARCH/incn-37.htm   (357 words)

  
 Articles - Corona discharge   (Site not responding. Last check: 2007-08-11)
The current carried by the corona is determined by integrating the current density over the surface of the conductor.
The power loss is determined by multiplying the current and the voltage.
In a positive corona, secondary electrons, for further avalanches, are generated predominantly in the fluid itself, in the region outside the plasma or avalanche region.
www.centralairconditioners.net /articles/Corona_discharge   (2101 words)

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