[{"data":1,"prerenderedAt":958},["ShallowReactive",2],{"site-footer-common":3,"glossary:back-corona":45,"glossary-related:back-corona":212},{"id":4,"extension":5,"footer":6,"meta":40,"navbar":41,"stem":43,"__hash__":44},"common\u002Fcommon.yml","yml",{"tagline":7,"links":8,"sections":9},"Acoustic cleaning intelligence for industrial fouling, soot, ash, dust and build-up.",[],[10,19,31],{"title":11,"links":12},"Product",[13,16],{"label":14,"to":15},"How it works","\u002F#product",{"label":17,"to":18},"Cost assessment","\u002F#hero",{"title":20,"links":21},"Company",[22,25,28],{"label":23,"to":24},"What we build","\u002F#about",{"label":26,"to":27},"Careers","\u002F#careers",{"label":29,"to":30},"Contact","\u002F#contact",{"title":32,"links":33},"Resources",[34,37],{"label":35,"to":36},"Blog","\u002Fresources\u002Fblog",{"label":38,"to":39},"Glossary","\u002Fglossary",{},{"links":42},[],"common","YocmZRy1AYfBbpgGVms-zhdiABlF8VTxHx6h4rDmZBA",{"id":46,"title":47,"aliases":48,"body":52,"category":189,"description":190,"extension":191,"meta":192,"navigation":193,"path":194,"relatedTerms":195,"seo":200,"sources":203,"stem":210,"term":47,"__hash__":211},"glossary\u002Fglossary\u002Fback-corona.md","Back-corona",[49,50,51],"reverse ionisation","back ionisation","back corona",{"type":53,"value":54,"toc":181},"minimark",[55,77,82,90,115,119,137,141,149,153],[56,57,58,61,62,65,66,71,72,76],"p",{},[59,60,47],"strong",{}," (also ",[63,64,49],"em",{},") is a destructive failure mode in an ",[67,68,70],"a",{"href":69},"\u002Fglossary\u002Felectrostatic-precipitator","electrostatic precipitator"," in which the dust layer on the ",[67,73,75],{"href":74},"\u002Fglossary\u002Fcollecting-electrode","collecting electrodes"," accumulates so much charge that the gas trapped within it breaks down and emits ions of the opposite polarity. These positive ions discharge incoming negatively-charged dust particles before they reach the plate, and collection efficiency collapses.",[78,79,81],"h2",{"id":80},"when-back-corona-occurs","When back-corona occurs",[56,83,84,85,89],{},"Back-corona is triggered by high-",[67,86,88],{"href":87},"\u002Fglossary\u002Fresistivity","resistivity"," ash — typically above ~10¹¹ Ω·cm — combined with a thick, undisturbed dust layer. The conditions are common on:",[91,92,93,97,109,112],"ul",{},[94,95,96],"li",{},"Low-sulphur Western US coals and sub-bituminous lignite",[94,98,99,100,104,105,108],{},"Some ",[67,101,103],{"href":102},"\u002Fglossary\u002Fwaste-to-energy","biomass"," and ",[67,106,107],{"href":102},"WtE"," ashes",[94,110,111],{},"ESPs that have slipped behind on rapper maintenance",[94,113,114],{},"Cement-kiln ESPs after fuel switches or raw-mill stoppages",[78,116,118],{"id":117},"symptoms","Symptoms",[91,120,121,128,131,134],{},[94,122,123,124],{},"Falling secondary voltage at the ",[67,125,127],{"href":126},"\u002Fglossary\u002Fdischarge-electrode","discharge electrode",[94,129,130],{},"Rising secondary current with falling efficiency (the classic back-corona signature)",[94,132,133],{},"Persistent stack opacity rise that does not respond to rapper intensification",[94,135,136],{},"Sparking and arcing in the ESP power supply",[78,138,140],{"id":139},"sonic-horns-and-back-corona","Sonic horns and back-corona",[56,142,143,144,148],{},"Because back-corona is fundamentally a dust-thickness problem, the strongest mitigation is to keep the plates thinner — continuously, not in periodic bursts. ",[67,145,147],{"href":146},"\u002Fglossary\u002Fsonic-horn","Sonic horns"," installed across the field deliver gentle, frequent dislodging that holds the plate dust layer below the critical thickness for back-corona, while reducing the re-entrainment penalty of aggressive rapping. Acoustic cleaning is therefore one of the most cost-effective retrofits on a back-corona-limited ESP.",[78,150,152],{"id":151},"related-terms","Related terms",[91,154,155,160,165,171,176],{},[94,156,157],{},[67,158,159],{"href":69},"Electrostatic precipitator",[94,161,162],{},[67,163,164],{"href":87},"Resistivity (fly-ash)",[94,166,167],{},[67,168,170],{"href":169},"\u002Fglossary\u002Fcorona-discharge","Corona discharge",[94,172,173],{},[67,174,175],{"href":74},"Collecting electrode",[94,177,178],{},[67,179,180],{"href":146},"Sonic horn",{"title":182,"searchDepth":183,"depth":183,"links":184},"",2,[185,186,187,188],{"id":80,"depth":183,"text":81},{"id":117,"depth":183,"text":118},{"id":139,"depth":183,"text":140},{"id":151,"depth":183,"text":152},"esp","Back-corona (also reverse ionisation) is a destructive failure mode in an electrostatic precipitator in which the dust layer on the collecting electrodes accumulates so much charge that the gas trapped within it breaks down and emits ions of the opposite polarity. These positive ions discharge incoming negatively-charged dust particles before they reach the plate, and collection efficiency collapses.","md",{},true,"\u002Fglossary\u002Fback-corona",[196,88,197,198,199],"electrostatic-precipitator","corona-discharge","collecting-electrode","sonic-horn",{"title":201,"description":202},"Back-corona — what it is, why it kills ESP performance, and how sonic horns help","Back-corona is reverse ionisation through a high-resistivity dust layer on ESP collecting plates. It collapses collection efficiency and is mitigated by keeping plates clean.",[204,207],{"title":205,"url":206},"Power Engineering — Tuning in to Acoustic Cleaning","https:\u002F\u002Fwww.power-eng.com\u002Fcoal\u002Ftuning-in-to-acoustic-cleaning\u002F",{"title":208,"url":209},"EPA — Monitoring Knowledge Base: Electrostatic Precipitators","https:\u002F\u002Fwww.epa.gov\u002Fair-emissions-monitoring-knowledge-base\u002Fmonitoring-control-technique-electrostatic-precipitators","glossary\u002Fback-corona","G6FyEgaY8SP8-TTBfd1_Oq0GIZQSeNR8jVcFF2LPxto",[213,381,524,627,727],{"id":214,"title":215,"aliases":216,"body":220,"category":189,"description":361,"extension":191,"meta":362,"navigation":193,"path":69,"relatedTerms":363,"seo":368,"sources":371,"stem":379,"term":159,"__hash__":380},"glossary\u002Fglossary\u002Felectrostatic-precipitator.md","Electrostatic precipitator (ESP)",[217,218,219],"ESP","electrostatic precipitators","dry ESP",{"type":53,"value":221,"toc":355},[222,236,240,254,258,293,297,328,330],[56,223,224,225,228,229,232,233,235],{},"An ",[59,226,227],{},"electrostatic precipitator (ESP)"," is an air-pollution-control device that removes particulate matter from a flue-gas stream by electrostatically charging dust particles and collecting them on grounded plate electrodes. ESPs are the dominant particulate-control technology on coal-fired boilers, cement kilns, ",[67,230,231],{"href":102},"waste-to-energy"," plants, ",[67,234,103],{"href":102}," plants, sinter strands and many other heavy-industry off-gas streams.",[78,237,239],{"id":238},"how-an-esp-works","How an ESP works",[56,241,242,243,245,246,249,250,253],{},"Flue gas flows horizontally between a parallel array of vertical ",[67,244,75],{"href":74}," (plates) and ",[67,247,248],{"href":126},"discharge electrodes"," (high-voltage wires or rigid spikes). A negative DC potential of 40–80 kV applied to the discharge electrodes generates a ",[67,251,252],{"href":169},"corona discharge"," that ionises the gas. Charged dust particles drift to the collecting plates, accumulate as a dust layer, are rapped down into hoppers below and removed by ash-handling equipment.",[78,255,257],{"id":256},"where-sonic-horns-fit","Where sonic horns fit",[56,259,260,261,265,266,268,269,273,274,278,279,282,283,287,288,292],{},"ESPs accumulate dust faster than mechanical rapping can release it, and hoppers below ESP fields routinely ",[67,262,264],{"href":263},"\u002Fglossary\u002Fbridging","bridge"," and choke. ",[67,267,147],{"href":146}," installed on the ESP ",[67,270,272],{"href":271},"\u002Fglossary\u002Fesp-penthouse","penthouse"," and on hopper walls keep dust dislodged, supplement ",[67,275,277],{"href":276},"\u002Fglossary\u002Fesp-rapper","rappers",", prevent ",[67,280,281],{"href":194},"back-corona"," by limiting plate dust thickness, and eliminate hopper ",[67,284,286],{"href":285},"\u002Fglossary\u002Frat-holing","rat-holing"," without the structural fatigue of ",[67,289,291],{"href":290},"\u002Fglossary\u002Ftumbling-hammer-rapper","tumbling-hammer rappers",".",[78,294,296],{"id":295},"common-failure-modes","Common failure modes",[91,298,299,305,310,316,322],{},[94,300,301,304],{},[59,302,303],{},"High opacity \u002F particulate emissions"," from thick dust layers reducing collection efficiency",[94,306,307,309],{},[59,308,47],{}," in high-resistivity ash that reverses ionisation and collapses collection",[94,311,312,315],{},[59,313,314],{},"Re-entrainment"," as rapper puffs return dust to the gas stream",[94,317,318,321],{},[59,319,320],{},"Hopper bridging"," that stops ash extraction and triggers field shutdowns",[94,323,324,327],{},[59,325,326],{},"Discharge-electrode breakage"," from rapper fatigue or sparking",[78,329,152],{"id":151},[91,331,332,336,341,345,351],{},[94,333,334],{},[67,335,175],{"href":74},[94,337,338],{},[67,339,340],{"href":126},"Discharge electrode",[94,342,343],{},[67,344,47],{"href":194},[94,346,347],{},[67,348,350],{"href":349},"\u002Fglossary\u002Fesp-hopper","ESP hopper",[94,352,353],{},[67,354,180],{"href":146},{"title":182,"searchDepth":183,"depth":183,"links":356},[357,358,359,360],{"id":238,"depth":183,"text":239},{"id":256,"depth":183,"text":257},{"id":295,"depth":183,"text":296},{"id":151,"depth":183,"text":152},"An electrostatic precipitator (ESP) is an air-pollution-control device that removes particulate matter from a flue-gas stream by electrostatically charging dust particles and collecting them on grounded plate electrodes. ESPs are the dominant particulate-control technology on coal-fired boilers, cement kilns, waste-to-energy plants, biomass plants, sinter strands and many other heavy-industry off-gas streams.",{},[364,198,365,197,366,367,281,199],"wet-esp","discharge-electrode","esp-hopper","esp-rapper",{"title":369,"description":370},"Electrostatic precipitator (ESP) — how it works and how it fouls","An ESP removes particulate from flue gas by charging dust and collecting it on plate electrodes. Sonic horns are widely used to dislodge ash from plates and to keep hoppers from bridging.",[372,375,376],{"title":373,"url":374},"Wikipedia — Electrostatic precipitator","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FElectrostatic_precipitator",{"title":208,"url":209},{"title":377,"url":378},"Babcock & Wilcox — Basics of ESP Operation","https:\u002F\u002Fwww.babcock.com\u002Fhome\u002Fabout\u002Fresources\u002Flearning-center\u002Fbasic-esp-operation","glossary\u002Felectrostatic-precipitator","hT_C4hmid3iZaYWhLpiSJ2tBfL0bSJ-uhzn7TY4Vtj4",{"id":382,"title":164,"aliases":383,"body":387,"category":189,"description":514,"extension":191,"meta":515,"navigation":193,"path":87,"relatedTerms":516,"seo":517,"sources":520,"stem":522,"term":393,"__hash__":523},"glossary\u002Fglossary\u002Fresistivity.md",[384,385,386],"ash resistivity","fly ash resistivity","dust resistivity",{"type":53,"value":388,"toc":508},[389,403,407,459,463,477,481,488,490],[56,390,391,394,395,397,398,400,401,292],{},[59,392,393],{},"Fly-ash resistivity"," is the electrical resistance of the dust layer deposited on the ",[67,396,75],{"href":74}," of an ",[67,399,217],{"href":69},". It is the single most important fuel-dependent variable in ESP performance, because it controls whether the collected dust can discharge its acquired charge to ground or instead accumulates trapped charge that triggers ",[67,402,281],{"href":194},[78,404,406],{"id":405},"the-resistivity-window","The resistivity window",[408,409,410,423],"table",{},[411,412,413],"thead",{},[414,415,416,420],"tr",{},[417,418,419],"th",{},"Resistivity (Ω·cm)",[417,421,422],{},"ESP behaviour",[424,425,426,440,448],"tbody",{},[414,427,428,432],{},[429,430,431],"td",{},"Below 10⁸",[429,433,434,435,439],{},"Dust discharges too quickly; ",[67,436,438],{"href":437},"\u002Fglossary\u002Fre-entrainment","re-entrainment"," dominates",[414,441,442,445],{},[429,443,444],{},"10⁸–10¹¹",[429,446,447],{},"Ideal range; standard ESP operation",[414,449,450,453],{},[429,451,452],{},"Above 10¹¹",[429,454,455,456,458],{},"High risk of ",[67,457,281],{"href":194},"; collection efficiency collapses",[78,460,462],{"id":461},"what-raises-resistivity","What raises resistivity",[91,464,465,468,471,474],{},[94,466,467],{},"Low sulphur content in coal (less SO₃ to condition the ash)",[94,469,470],{},"Low gas temperature near the acid dew point",[94,472,473],{},"High-alkali biomass ash",[94,475,476],{},"Certain cement-kiln dust compositions",[78,478,480],{"id":479},"mitigation","Mitigation",[56,482,483,484,487],{},"The classic remedy is flue-gas conditioning — injecting SO₃ or ammonia ahead of the ESP to lower ash resistivity. A complementary remedy is to keep the plate dust layer thin enough that back-corona cannot establish, which is where ",[67,485,486],{"href":146},"sonic horns"," earn their keep on high-resistivity ESPs: continuous gentle dislodging prevents the critical thickness from developing.",[78,489,152],{"id":151},[91,491,492,496,500,504],{},[94,493,494],{},[67,495,159],{"href":69},[94,497,498],{},[67,499,47],{"href":194},[94,501,502],{},[67,503,170],{"href":169},[94,505,506],{},[67,507,180],{"href":146},{"title":182,"searchDepth":183,"depth":183,"links":509},[510,511,512,513],{"id":405,"depth":183,"text":406},{"id":461,"depth":183,"text":462},{"id":479,"depth":183,"text":480},{"id":151,"depth":183,"text":152},"Fly-ash resistivity is the electrical resistance of the dust layer deposited on the collecting electrodes of an ESP. It is the single most important fuel-dependent variable in ESP performance, because it controls whether the collected dust can discharge its acquired charge to ground or instead accumulates trapped charge that triggers back-corona.",{},[196,281,197,199],{"title":518,"description":519},"Fly-ash resistivity — why high-resistivity ash triggers ESP back-corona","Fly-ash resistivity is the electrical resistance of a deposited dust layer. Resistivity above ~10¹¹ Ω·cm triggers back-corona and degrades ESP performance.",[521],{"title":208,"url":209},"glossary\u002Fresistivity","J1-xKuznLqtCFjFw4yljyJW2c3Rl6O26UKlXuDzmDdo",{"id":525,"title":170,"aliases":526,"body":529,"category":189,"description":615,"extension":191,"meta":616,"navigation":193,"path":169,"relatedTerms":617,"seo":618,"sources":621,"stem":625,"term":170,"__hash__":626},"glossary\u002Fglossary\u002Fcorona-discharge.md",[527,528],"corona (electrical)","negative corona",{"type":53,"value":530,"toc":610},[531,546,550,553,557,587,590,592],[56,532,533,534,536,537,539,540,542,543,545],{},"A ",[59,535,252],{}," is a self-sustaining electrical discharge that occurs when the field gradient around a sharp electrode exceeds the breakdown threshold of the surrounding gas. In an ",[67,538,217],{"href":69}," the corona forms around the ",[67,541,127],{"href":126},", ionises flue-gas molecules, and the resulting ions attach to dust particles. The charged particles then drift to the ",[67,544,75],{"href":74}," under the electric field.",[78,547,549],{"id":548},"negative-corona-dominates","Negative corona dominates",[56,551,552],{},"Industrial ESPs almost always run on negative corona because it sustains a higher voltage before sparking — but it also produces some ozone, which is one of the reasons WESPs in confined ventilation paths sometimes use positive corona instead.",[78,554,556],{"id":555},"what-disrupts-the-corona","What disrupts the corona",[91,558,559,565,575,581],{},[94,560,561,564],{},[59,562,563],{},"Excessive dust on the collecting plate"," — raises plate-face voltage, narrows the working gap",[94,566,567,572,573],{},[59,568,569,570],{},"High ash ",[67,571,88],{"href":87}," — traps charge in the dust layer, leading to ",[67,574,281],{"href":194},[94,576,577,580],{},[59,578,579],{},"Bent or broken discharge electrodes"," — local field collapse, sparking, eventual short",[94,582,583,586],{},[59,584,585],{},"Fouled discharge electrode tips"," — suppressed corona, reduced ion current",[56,588,589],{},"Acoustic cleaning addresses two of these (plate dust thickness and discharge-electrode fouling) without the broken-electrode risk of aggressive mechanical rapping.",[78,591,152],{"id":151},[91,593,594,598,602,606],{},[94,595,596],{},[67,597,159],{"href":69},[94,599,600],{},[67,601,340],{"href":126},[94,603,604],{},[67,605,47],{"href":194},[94,607,608],{},[67,609,164],{"href":87},{"title":182,"searchDepth":183,"depth":183,"links":611},[612,613,614],{"id":548,"depth":183,"text":549},{"id":555,"depth":183,"text":556},{"id":151,"depth":183,"text":152},"A corona discharge is a self-sustaining electrical discharge that occurs when the field gradient around a sharp electrode exceeds the breakdown threshold of the surrounding gas. In an ESP the corona forms around the discharge electrode, ionises flue-gas molecules, and the resulting ions attach to dust particles. The charged particles then drift to the collecting electrodes under the electric field.",{},[196,365,281,88],{"title":619,"description":620},"Corona discharge — the ionisation mechanism that powers an ESP","Corona discharge is the electrical breakdown around an ESP's discharge electrode that ionises gas molecules and charges dust particles for collection.",[622],{"title":623,"url":624},"Wikipedia — Corona discharge","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FCorona_discharge","glossary\u002Fcorona-discharge","dShpP0lym_kkFMbohrkUgv75_uA0O8qlKu9VJ1eimyA",{"id":628,"title":175,"aliases":629,"body":633,"category":189,"description":717,"extension":191,"meta":718,"navigation":193,"path":74,"relatedTerms":719,"seo":720,"sources":723,"stem":725,"term":175,"__hash__":726},"glossary\u002Fglossary\u002Fcollecting-electrode.md",[630,631,632],"collecting plate","collection plate","ESP plate",{"type":53,"value":634,"toc":711},[635,645,649,669,673,679,683,686,688],[56,636,637,638,641,642,644],{},"The ",[59,639,640],{},"collecting electrode"," — usually called the \"collecting plate\" in plate-type ESPs — is the grounded surface on which charged particulate accumulates inside an ",[67,643,70],{"href":69},". Collecting plates are typically 9–15 m tall, rolled or profiled steel sections with stiffening pockets, hung in parallel rows 250–400 mm apart.",[78,646,648],{"id":647},"how-dust-accumulates-and-releases","How dust accumulates and releases",[56,650,651,652,654,655,657,658,661,662,664,665,668],{},"Charged particles migrate from the ",[67,653,127],{"href":126}," towards the grounded plate, transfer their charge and adhere as a dust layer. The layer must be released regularly: too thick and it raises plate-face voltage, reducing the field, eventually triggering ",[67,656,281],{"href":194},". Release is achieved by ",[67,659,660],{"href":276},"rapping"," (mechanical impact) or ",[67,663,486],{"href":146}," (acoustic vibration), with the released dust sheet falling into the ",[67,666,667],{"href":349},"hopper"," below.",[78,670,672],{"id":671},"the-re-entrainment-problem","The re-entrainment problem",[56,674,675,676,678],{},"Aggressive rapping releases dust faster than the hopper can swallow it, and some of the falling sheet is caught back up by the gas stream — this is ",[67,677,438],{"href":437},", and it shows up as periodic opacity spikes on stack CEMS traces. Sonic horns produce gentler, more continuous release that reduces re-entrainment compared to mechanical rapping alone.",[78,680,682],{"id":681},"profile-types","Profile types",[56,684,685],{},"Collecting plates come in many profiled forms (CW, ZT, ECO, Opzel, baffle, etc.), each chosen to balance electrical performance against dust-release behaviour. Specialist ESP vendors (B&W, FLSmidth, Hamon, Mitsubishi) supply matched plate-and-rapping packages.",[78,687,152],{"id":151},[91,689,690,694,698,703,707],{},[94,691,692],{},[67,693,159],{"href":69},[94,695,696],{},[67,697,340],{"href":126},[94,699,700],{},[67,701,702],{"href":276},"ESP rapper",[94,704,705],{},[67,706,180],{"href":146},[94,708,709],{},[67,710,314],{"href":437},{"title":182,"searchDepth":183,"depth":183,"links":712},[713,714,715,716],{"id":647,"depth":183,"text":648},{"id":671,"depth":183,"text":672},{"id":681,"depth":183,"text":682},{"id":151,"depth":183,"text":152},"The collecting electrode — usually called the \"collecting plate\" in plate-type ESPs — is the grounded surface on which charged particulate accumulates inside an electrostatic precipitator. Collecting plates are typically 9–15 m tall, rolled or profiled steel sections with stiffening pockets, hung in parallel rows 250–400 mm apart.",{},[196,365,367,199,438],{"title":721,"description":722},"Collecting electrode (ESP plate) — function, fouling and cleaning","The collecting electrode is the grounded plate or tube on which charged particulate accumulates inside an ESP. Dust must be released to hoppers without re-entraining into the gas stream.",[724],{"title":377,"url":378},"glossary\u002Fcollecting-electrode","9E4jLiOYVWf0Kj-hlJN58FMZ0Nz2mF0Iv1OuBtFwtqM",{"id":728,"title":180,"aliases":729,"body":732,"category":935,"description":936,"extension":191,"meta":937,"navigation":193,"path":146,"relatedTerms":938,"seo":945,"sources":948,"stem":956,"term":180,"__hash__":957},"glossary\u002Fglossary\u002Fsonic-horn.md",[486,730,731],"sonic cleaning horn","industrial sonic horn",{"type":53,"value":733,"toc":928},[734,765,769,777,781,843,847,884,888,896,898],[56,735,533,736,739,740,744,745,748,749,748,753,748,757,104,761,292],{},[59,737,738],{},"sonic horn"," is a pneumatically-driven sound emitter that produces high-intensity, low-frequency sound waves — typically between 60 and 400 Hz at sound pressure levels of 140 to 180 dB — used to dislodge particulate fouling from inside industrial process equipment. Sonic horns are the most common form of ",[67,741,743],{"href":742},"\u002Fglossary\u002Facoustic-cleaner","acoustic cleaner"," and the default specification for cleaning ",[67,746,747],{"href":69},"ESPs",", ",[67,750,752],{"href":751},"\u002Fglossary\u002Ffabric-filter","baghouses",[67,754,756],{"href":755},"\u002Fglossary\u002Fselective-catalytic-reduction","SCR catalysts",[67,758,760],{"href":759},"\u002Fglossary\u002Fsuperheater","boiler heat-transfer surfaces",[67,762,764],{"href":763},"\u002Fglossary\u002Fhopper","hoppers and silos",[78,766,768],{"id":767},"how-a-sonic-horn-works","How a sonic horn works",[56,770,771,772,776],{},"Compressed plant air admitted through a ",[67,773,775],{"href":774},"\u002Fglossary\u002Fsolenoid-valve","solenoid valve"," drives a metal diaphragm — typically titanium or 316 stainless — into resonant oscillation at the horn's fundamental frequency. The oscillating pressure field is amplified by an exponential bell horn and projected into the vessel as a near-spherical sound wave. Particulate already deposited on internal surfaces receives an oscillating acceleration that overcomes adhesion; loosened material is then carried out with the gas flow before it can sinter, bridge or bond. Because the cleaning is acoustic and non-contact, the horn can fire while the plant is online without tube erosion, refractory damage or thermal shock.",[78,778,780],{"id":779},"key-parameters","Key parameters",[408,782,783,793],{},[411,784,785],{},[414,786,787,790],{},[417,788,789],{},"Parameter",[417,791,792],{},"Typical range",[424,794,795,803,811,819,827,835],{},[414,796,797,800],{},[429,798,799],{},"Fundamental frequency",[429,801,802],{},"60–400 Hz",[414,804,805,808],{},[429,806,807],{},"Sound pressure level",[429,809,810],{},"140–180 dB",[414,812,813,816],{},[429,814,815],{},"Compressed-air consumption",[429,817,818],{},"8–14 Nm³\u002Fmin at 4–7 bar",[414,820,821,824],{},[429,822,823],{},"Operating temperature (with appropriate materials)",[429,825,826],{},"−40 °C to +500 °C",[414,828,829,832],{},[429,830,831],{},"Firing cycle",[429,833,834],{},"5–15 s burst, repeated every 3–15 minutes",[414,836,837,840],{},[429,838,839],{},"Mass",[429,841,842],{},"15–60 kg depending on horn size",[78,844,846],{"id":845},"frequency-selection","Frequency selection",[56,848,849,850,748,854,858,859,748,863,867,868,748,871,875,876,104,880,292],{},"Lower frequencies (60–125 Hz) project longer wavelengths and penetrate further into large open vessels — ",[67,851,853],{"href":852},"\u002Fglossary\u002Fpreheater-cyclone","preheater cyclones",[67,855,857],{"href":856},"\u002Fglossary\u002Frecovery-boiler","recovery-boiler superheaters",", large ",[67,860,862],{"href":861},"\u002Fglossary\u002Fesp-field-bus-section","ESP fields",[67,864,866],{"href":865},"\u002Fglossary\u002Fsilo","silos",". Higher frequencies (230–400 Hz) carry more energy per unit volume and suit finer dust loads in ",[67,869,870],{"href":751},"fabric-filter compartments",[67,872,874],{"href":873},"\u002Fglossary\u002Fhoneycomb-catalyst","catalyst layers"," and smaller hopper geometries. See ",[67,877,879],{"href":878},"\u002Fglossary\u002Flow-frequency-acoustic-cleaner","low-frequency acoustic cleaner",[67,881,883],{"href":882},"\u002Fglossary\u002Fhigh-frequency-acoustic-cleaner","high-frequency acoustic cleaner",[78,885,887],{"id":886},"sonic-horn-vs-steam-sootblower","Sonic horn vs steam sootblower",[56,889,890,891,895],{},"Sonic horns are increasingly specified alongside or in place of ",[67,892,894],{"href":893},"\u002Fglossary\u002Fsteam-sootblower","steam sootblowers"," because they consume no boiler-grade steam, cause no tube erosion, require almost no moving parts and can fire every few minutes without operator intervention. They are less effective on hard, fused slag than retractable steam lances, so on furnace waterwalls and high-temperature superheaters they typically complement rather than replace mechanical cleaning.",[78,897,152],{"id":151},[91,899,900,905,911,917,923],{},[94,901,902],{},[67,903,904],{"href":742},"Acoustic cleaner",[94,906,907],{},[67,908,910],{"href":909},"\u002Fglossary\u002Fsonic-sootblower","Sonic sootblower",[94,912,913],{},[67,914,916],{"href":915},"\u002Fglossary\u002Fbell-horn","Bell horn",[94,918,919],{},[67,920,922],{"href":921},"\u002Fglossary\u002Fdiaphragm-horn","Diaphragm horn",[94,924,925],{},[67,926,927],{"href":878},"Low-frequency acoustic cleaner",{"title":182,"searchDepth":183,"depth":183,"links":929},[930,931,932,933,934],{"id":767,"depth":183,"text":768},{"id":779,"depth":183,"text":780},{"id":845,"depth":183,"text":846},{"id":886,"depth":183,"text":887},{"id":151,"depth":183,"text":152},"core-technology","A sonic horn is a pneumatically-driven sound emitter that produces high-intensity, low-frequency sound waves — typically between 60 and 400 Hz at sound pressure levels of 140 to 180 dB — used to dislodge particulate fouling from inside industrial process equipment. Sonic horns are the most common form of acoustic cleaner and the default specification for cleaning ESPs, baghouses, SCR catalysts, boiler heat-transfer surfaces and hoppers and silos.",{},[939,940,941,942,943,944],"acoustic-cleaner","acoustic-cleaning-system","sonic-sootblower","bell-horn","diaphragm-horn","low-frequency-acoustic-cleaner",{"title":946,"description":947},"Sonic horn — definition, frequency, SPL and industrial applications","A sonic horn is a pneumatically-driven low-frequency sound emitter (typically 60–400 Hz at 140–180 dB SPL) used to dislodge particulate fouling from boilers, ESPs, baghouses and process vessels.",[949,952,953],{"title":950,"url":951},"Power Engineering — Sonic Horns: A User's Introduction","https:\u002F\u002Fwww.power-eng.com\u002Fcoal\u002Fsonic-horns-a-userrsquos-introduction\u002F",{"title":205,"url":206},{"title":954,"url":955},"Wikipedia — Sonic soot blowers","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSonic_soot_blowers","glossary\u002Fsonic-horn","YzrhN0kKzqSaQo0wfn0rueNZ-V43mcg5zahqeWi3lnU",1782613734844]