[{"data":1,"prerenderedAt":1074},["ShallowReactive",2],{"site-footer-common":3,"glossary:esp-rapper":45,"glossary-related:esp-rapper":287},{"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":263,"description":264,"extension":265,"meta":266,"navigation":267,"path":268,"relatedTerms":269,"seo":275,"sources":278,"stem":285,"term":47,"__hash__":286},"glossary\u002Fglossary\u002Fesp-rapper.md","ESP rapper",[49,50,51],"rapper","collecting plate rapper","discharge electrode rapper",{"type":53,"value":54,"toc":256},"minimark",[55,89,94,112,116,212,219,223],[56,57,58,59,62,63,68,69,73,74,78,79,83,84,88],"p",{},"An ",[60,61,47],"strong",{}," is a mechanical device used to dislodge accumulated dust from the ",[64,65,67],"a",{"href":66},"\u002Fglossary\u002Fcollecting-electrode","collecting"," and ",[64,70,72],{"href":71},"\u002Fglossary\u002Fdischarge-electrode","discharge electrodes"," of an ",[64,75,77],{"href":76},"\u002Fglossary\u002Felectrostatic-precipitator","electrostatic precipitator",". Two principal designs dominate: ",[64,80,82],{"href":81},"\u002Fglossary\u002Ftumbling-hammer-rapper","tumbling-hammer rappers",", favoured in European-style ESPs, and ",[64,85,87],{"href":86},"\u002Fglossary\u002Fmagnetic-impulse-gravity-rapper","magnetic-impulse-gravity (MIGI) rappers",", favoured in American-style ESPs.",[90,91,93],"h2",{"id":92},"how-rapping-is-sequenced","How rapping is sequenced",[56,95,96,97,101,102,106,107,111],{},"Rappers are fired in a programmed sequence — usually one rapper at a time per field — to avoid simultaneous releases that would overwhelm the ",[64,98,100],{"href":99},"\u002Fglossary\u002Fesp-hopper","hopper",". The interval depends on dust load: every few minutes on heavily-loaded inlet fields, every 20–60 minutes on lightly-loaded outlet fields. Tuning the rap interval is a perennial trade-off between low ",[64,103,105],{"href":104},"\u002Fglossary\u002Fopacity","opacity"," (frequent rapping) and high ",[64,108,110],{"href":109},"\u002Fglossary\u002Fre-entrainment","re-entrainment"," (also frequent rapping).",[90,113,115],{"id":114},"sonic-horns-vs-rappers","Sonic horns vs rappers",[117,118,119,137],"table",{},[120,121,122],"thead",{},[123,124,125,129,131],"tr",{},[126,127,128],"th",{},"Attribute",[126,130,47],{},[126,132,133],{},[64,134,136],{"href":135},"\u002Fglossary\u002Fsonic-horn","Sonic horn",[138,139,140,152,163,174,190,201],"tbody",{},[123,141,142,146,149],{},[143,144,145],"td",{},"Mechanism",[143,147,148],{},"Mechanical impact",[143,150,151],{},"Acoustic vibration",[123,153,154,157,160],{},[143,155,156],{},"Release pattern",[143,158,159],{},"Large, periodic",[143,161,162],{},"Small, frequent",[123,164,165,168,171],{},[143,166,167],{},"Re-entrainment risk",[143,169,170],{},"High",[143,172,173],{},"Low",[123,175,176,179,182],{},[143,177,178],{},"Hopper coverage",[143,180,181],{},"Plates only",[143,183,184,185,189],{},"Plates ",[186,187,188],"em",{},"and"," hoppers",[123,191,192,195,198],{},[143,193,194],{},"Wear \u002F fatigue",[143,196,197],{},"Discharge-electrode breakage, hammer-shaft failure",[143,199,200],{},"Diaphragm replacement every 3–5 years",[123,202,203,206,209],{},[143,204,205],{},"Cost",[143,207,208],{},"Hardware + ongoing maintenance",[143,210,211],{},"Lower lifecycle cost in retrofit",[56,213,214,215,218],{},"In practice, modern ESPs increasingly use ",[60,216,217],{},"both",": rappers handle the heavy bottom of the plate, sonic horns handle the upper plate area, the discharge electrodes and the hopper. The combination outperforms either alone.",[90,220,222],{"id":221},"related-terms","Related terms",[224,225,226,232,237,242,247,252],"ul",{},[227,228,229],"li",{},[64,230,231],{"href":76},"Electrostatic precipitator",[227,233,234],{},[64,235,236],{"href":81},"Tumbling-hammer rapper",[227,238,239],{},[64,240,241],{"href":86},"Magnetic-impulse-gravity rapper",[227,243,244],{},[64,245,246],{"href":66},"Collecting electrode",[227,248,249],{},[64,250,251],{"href":109},"Re-entrainment",[227,253,254],{},[64,255,136],{"href":135},{"title":257,"searchDepth":258,"depth":258,"links":259},"",2,[260,261,262],{"id":92,"depth":258,"text":93},{"id":114,"depth":258,"text":115},{"id":221,"depth":258,"text":222},"esp","An ESP rapper is a mechanical device used to dislodge accumulated dust from the collecting and discharge electrodes of an electrostatic precipitator. Two principal designs dominate: tumbling-hammer rappers, favoured in European-style ESPs, and magnetic-impulse-gravity (MIGI) rappers, favoured in American-style ESPs.","md",{},true,"\u002Fglossary\u002Fesp-rapper",[270,271,272,273,110,274],"electrostatic-precipitator","tumbling-hammer-rapper","magnetic-impulse-gravity-rapper","collecting-electrode","sonic-horn",{"title":276,"description":277},"ESP rapper — mechanical cleaning of collecting plates and discharge electrodes","An ESP rapper is the mechanical hammer or magnetic impulse device used to dislodge accumulated dust from ESP plates and discharge electrodes. Sonic horns complement and partly replace this duty.",[279,282],{"title":280,"url":281},"EPA — Monitoring Knowledge Base: Electrostatic Precipitators","https:\u002F\u002Fwww.epa.gov\u002Fair-emissions-monitoring-knowledge-base\u002Fmonitoring-control-technique-electrostatic-precipitators",{"title":283,"url":284},"Neundorfer — Sonic Horns to Enhance RA & Shaker Cleaning","https:\u002F\u002Fwww.neundorfer.com\u002Fknowledge-base\u002Fsonic-horns-to-enhance-ra-shaker-cleaning\u002F","glossary\u002Fesp-rapper","QhQ46PxPUjS4GrAWsOxuHzUNaT9DIyjEK5DT4bGc6os",[288,457,573,658,758,841],{"id":289,"title":290,"aliases":291,"body":295,"category":263,"description":436,"extension":265,"meta":437,"navigation":267,"path":76,"relatedTerms":438,"seo":444,"sources":447,"stem":455,"term":231,"__hash__":456},"glossary\u002Fglossary\u002Felectrostatic-precipitator.md","Electrostatic precipitator (ESP)",[292,293,294],"ESP","electrostatic precipitators","dry ESP",{"type":53,"value":296,"toc":430},[297,312,316,331,335,369,373,404,406],[56,298,58,299,302,303,307,308,311],{},[60,300,301],{},"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, ",[64,304,306],{"href":305},"\u002Fglossary\u002Fwaste-to-energy","waste-to-energy"," plants, ",[64,309,310],{"href":305},"biomass"," plants, sinter strands and many other heavy-industry off-gas streams.",[90,313,315],{"id":314},"how-an-esp-works","How an ESP works",[56,317,318,319,322,323,325,326,330],{},"Flue gas flows horizontally between a parallel array of vertical ",[64,320,321],{"href":66},"collecting electrodes"," (plates) and ",[64,324,72],{"href":71}," (high-voltage wires or rigid spikes). A negative DC potential of 40–80 kV applied to the discharge electrodes generates a ",[64,327,329],{"href":328},"\u002Fglossary\u002Fcorona-discharge","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.",[90,332,334],{"id":333},"where-sonic-horns-fit","Where sonic horns fit",[56,336,337,338,342,343,346,347,351,352,355,356,360,361,365,366,368],{},"ESPs accumulate dust faster than mechanical rapping can release it, and hoppers below ESP fields routinely ",[64,339,341],{"href":340},"\u002Fglossary\u002Fbridging","bridge"," and choke. ",[64,344,345],{"href":135},"Sonic horns"," installed on the ESP ",[64,348,350],{"href":349},"\u002Fglossary\u002Fesp-penthouse","penthouse"," and on hopper walls keep dust dislodged, supplement ",[64,353,354],{"href":268},"rappers",", prevent ",[64,357,359],{"href":358},"\u002Fglossary\u002Fback-corona","back-corona"," by limiting plate dust thickness, and eliminate hopper ",[64,362,364],{"href":363},"\u002Fglossary\u002Frat-holing","rat-holing"," without the structural fatigue of ",[64,367,82],{"href":81},".",[90,370,372],{"id":371},"common-failure-modes","Common failure modes",[224,374,375,381,387,392,398],{},[227,376,377,380],{},[60,378,379],{},"High opacity \u002F particulate emissions"," from thick dust layers reducing collection efficiency",[227,382,383,386],{},[60,384,385],{},"Back-corona"," in high-resistivity ash that reverses ionisation and collapses collection",[227,388,389,391],{},[60,390,251],{}," as rapper puffs return dust to the gas stream",[227,393,394,397],{},[60,395,396],{},"Hopper bridging"," that stops ash extraction and triggers field shutdowns",[227,399,400,403],{},[60,401,402],{},"Discharge-electrode breakage"," from rapper fatigue or sparking",[90,405,222],{"id":221},[224,407,408,412,417,421,426],{},[227,409,410],{},[64,411,246],{"href":66},[227,413,414],{},[64,415,416],{"href":71},"Discharge electrode",[227,418,419],{},[64,420,385],{"href":358},[227,422,423],{},[64,424,425],{"href":99},"ESP hopper",[227,427,428],{},[64,429,136],{"href":135},{"title":257,"searchDepth":258,"depth":258,"links":431},[432,433,434,435],{"id":314,"depth":258,"text":315},{"id":333,"depth":258,"text":334},{"id":371,"depth":258,"text":372},{"id":221,"depth":258,"text":222},"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.",{},[439,273,440,441,442,443,359,274],"wet-esp","discharge-electrode","corona-discharge","esp-hopper","esp-rapper",{"title":445,"description":446},"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.",[448,451,452],{"title":449,"url":450},"Wikipedia — Electrostatic precipitator","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FElectrostatic_precipitator",{"title":280,"url":281},{"title":453,"url":454},"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":458,"title":236,"aliases":459,"body":462,"category":263,"description":561,"extension":265,"meta":562,"navigation":267,"path":81,"relatedTerms":563,"seo":564,"sources":567,"stem":571,"term":236,"__hash__":572},"glossary\u002Fglossary\u002Ftumbling-hammer-rapper.md",[460,461],"tumbling hammer","European-style rapper",{"type":53,"value":463,"toc":556},[464,474,478,524,528,536,538],[56,465,466,467,470,471,473],{},"A ",[60,468,469],{},"tumbling-hammer rapper"," uses a horizontal shaft fitted with weighted hammers that strike anvils attached to the ",[64,472,273],{"href":66}," frame. As the shaft slowly rotates, each hammer falls under gravity onto its anvil, transferring an impact pulse along the plate row. It is the dominant rapper design in European-style ESPs from suppliers such as ALSTOM, FLSmidth, Hamon and SHU Power.",[90,475,477],{"id":476},"strengths-and-weaknesses","Strengths and weaknesses",[117,479,480,490],{},[120,481,482],{},[123,483,484,487],{},[126,485,486],{},"Strength",[126,488,489],{},"Weakness",[138,491,492,500,508,516],{},[123,493,494,497],{},[143,495,496],{},"Robust mechanical design",[143,498,499],{},"Shaft and hammer fatigue under continuous service",[123,501,502,505],{},[143,503,504],{},"Even distribution along long plate rows",[143,506,507],{},"Risk of hammer-shaft breakage during outages",[123,509,510,513],{},[143,511,512],{},"Tunable by hammer mass and shaft speed",[143,514,515],{},"Difficult to retrofit additional intensity",[123,517,518,521],{},[143,519,520],{},"Low electrical infrastructure",[143,522,523],{},"Cannot easily target individual plates",[90,525,527],{"id":526},"why-sonic-horns-are-common-on-european-style-esps","Why sonic horns are common on European-style ESPs",[56,529,530,532,533,535],{},[64,531,345],{"href":135}," installed on the ESP penthouse complement tumbling-hammer rappers by reaching the upper plate area and the ",[64,534,72],{"href":71},", neither of which the hammer can clean effectively. They also reduce the duty cycle on the hammers themselves, extending shaft and hammer life.",[90,537,222],{"id":221},[224,539,540,544,548,552],{},[227,541,542],{},[64,543,47],{"href":268},[227,545,546],{},[64,547,241],{"href":86},[227,549,550],{},[64,551,231],{"href":76},[227,553,554],{},[64,555,136],{"href":135},{"title":257,"searchDepth":258,"depth":258,"links":557},[558,559,560],{"id":476,"depth":258,"text":477},{"id":526,"depth":258,"text":527},{"id":221,"depth":258,"text":222},"A tumbling-hammer rapper uses a horizontal shaft fitted with weighted hammers that strike anvils attached to the collecting-electrode frame. As the shaft slowly rotates, each hammer falls under gravity onto its anvil, transferring an impact pulse along the plate row. It is the dominant rapper design in European-style ESPs from suppliers such as ALSTOM, FLSmidth, Hamon and SHU Power.",{},[443,272,270,274],{"title":565,"description":566},"Tumbling-hammer rapper — European-style ESP plate cleaning","A tumbling-hammer rapper uses a rotating shaft and weighted hammers that strike anvils on the ESP plate frame. It is the dominant rapper design in European-style ESPs.",[568],{"title":569,"url":570},"Neundorfer — Sonic Horn Application on European-Style ESPs","https:\u002F\u002Fwww.neundorfer.com\u002Fknowledge-base\u002Fsonic-horn-application-on-european-style-esps\u002F","glossary\u002Ftumbling-hammer-rapper","j6zS8tEtz6XPr4FyXpOlEd7lpz5GO7yVOdji9IJQIL4",{"id":574,"title":575,"aliases":576,"body":581,"category":263,"description":648,"extension":265,"meta":649,"navigation":267,"path":86,"relatedTerms":650,"seo":651,"sources":654,"stem":656,"term":241,"__hash__":657},"glossary\u002Fglossary\u002Fmagnetic-impulse-gravity-rapper.md","Magnetic-impulse-gravity rapper (MIGI)",[577,578,579,580],"MIGI rapper","MIGI","American-style rapper","top rapper",{"type":53,"value":582,"toc":643},[583,592,596,607,611,623,625],[56,584,466,585,588,589,591],{},[60,586,587],{},"magnetic-impulse-gravity (MIGI) rapper"," uses an electromagnet to lift a steel plunger and then release it, letting the plunger fall under gravity onto an anvil rod that conducts the impact down into the ",[64,590,273],{"href":66}," frame. It is the dominant rapper design in American-style ESPs from suppliers including B&W, Mitsubishi Heavy Industries, Hamon Research-Cottrell, and Siemens \u002F KC Cottrell legacy designs.",[90,593,595],{"id":594},"operation","Operation",[56,597,598,599,602,603,606],{},"A MIGI rapper is normally mounted on the ",[64,600,601],{"href":349},"ESP penthouse"," above the plate stack. Plunger lift, drop height and firing frequency are programmed in the rapper-controller PLC, with each rapper firing in sequence across the field. Compared with ",[64,604,605],{"href":81},"tumbling-hammer designs",", the MIGI rapper offers individual plate targeting and easy tuning of impact intensity, but at the cost of greater electrical infrastructure and a more complex top-of-ESP layout.",[90,608,610],{"id":609},"where-sonic-horns-complement-migi-rappers","Where sonic horns complement MIGI rappers",[56,612,613,614,616,617,619,620,622],{},"MIGI rappers excel at the top of the plate but lose impact transmission towards the bottom. ",[64,615,345],{"href":135}," installed on the penthouse cover the upper plate volume and discharge electrodes; horns mounted at the ",[64,618,100],{"href":99}," wall cover the bottom region. The combination defends against both ",[64,621,359],{"href":358}," and hopper bridging that MIGI rapping alone leaves vulnerable.",[90,624,222],{"id":221},[224,626,627,631,635,639],{},[227,628,629],{},[64,630,47],{"href":268},[227,632,633],{},[64,634,236],{"href":81},[227,636,637],{},[64,638,231],{"href":76},[227,640,641],{},[64,642,136],{"href":135},{"title":257,"searchDepth":258,"depth":258,"links":644},[645,646,647],{"id":594,"depth":258,"text":595},{"id":609,"depth":258,"text":610},{"id":221,"depth":258,"text":222},"A magnetic-impulse-gravity (MIGI) rapper uses an electromagnet to lift a steel plunger and then release it, letting the plunger fall under gravity onto an anvil rod that conducts the impact down into the collecting-electrode frame. It is the dominant rapper design in American-style ESPs from suppliers including B&W, Mitsubishi Heavy Industries, Hamon Research-Cottrell, and Siemens \u002F KC Cottrell legacy designs.",{},[443,271,270,274],{"title":652,"description":653},"Magnetic-impulse-gravity (MIGI) rapper — American-style ESP cleaning","A MIGI rapper lifts and drops a steel plunger by electromagnet onto an anvil rod connected to the ESP collecting plate. Standard design in American-style ESPs from B&W, Mitsubishi and Hamon.",[655],{"title":280,"url":281},"glossary\u002Fmagnetic-impulse-gravity-rapper","pu5D4_JxDRN1Vyq-rUU_UcetjEHIjGgO15BD8rOdCbk",{"id":659,"title":246,"aliases":660,"body":664,"category":263,"description":748,"extension":265,"meta":749,"navigation":267,"path":66,"relatedTerms":750,"seo":751,"sources":754,"stem":756,"term":246,"__hash__":757},"glossary\u002Fglossary\u002Fcollecting-electrode.md",[661,662,663],"collecting plate","collection plate","ESP plate",{"type":53,"value":665,"toc":742},[666,676,680,701,705,711,715,718,720],[56,667,668,669,672,673,675],{},"The ",[60,670,671],{},"collecting electrode"," — usually called the \"collecting plate\" in plate-type ESPs — is the grounded surface on which charged particulate accumulates inside an ",[64,674,77],{"href":76},". Collecting plates are typically 9–15 m tall, rolled or profiled steel sections with stiffening pockets, hung in parallel rows 250–400 mm apart.",[90,677,679],{"id":678},"how-dust-accumulates-and-releases","How dust accumulates and releases",[56,681,682,683,686,687,689,690,693,694,697,698,700],{},"Charged particles migrate from the ",[64,684,685],{"href":71},"discharge electrode"," 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 ",[64,688,359],{"href":358},". Release is achieved by ",[64,691,692],{"href":268},"rapping"," (mechanical impact) or ",[64,695,696],{"href":135},"sonic horns"," (acoustic vibration), with the released dust sheet falling into the ",[64,699,100],{"href":99}," below.",[90,702,704],{"id":703},"the-re-entrainment-problem","The re-entrainment problem",[56,706,707,708,710],{},"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 ",[64,709,110],{"href":109},", 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.",[90,712,714],{"id":713},"profile-types","Profile types",[56,716,717],{},"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.",[90,719,222],{"id":221},[224,721,722,726,730,734,738],{},[227,723,724],{},[64,725,231],{"href":76},[227,727,728],{},[64,729,416],{"href":71},[227,731,732],{},[64,733,47],{"href":268},[227,735,736],{},[64,737,136],{"href":135},[227,739,740],{},[64,741,251],{"href":109},{"title":257,"searchDepth":258,"depth":258,"links":743},[744,745,746,747],{"id":678,"depth":258,"text":679},{"id":703,"depth":258,"text":704},{"id":713,"depth":258,"text":714},{"id":221,"depth":258,"text":222},"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.",{},[270,440,443,274,110],{"title":752,"description":753},"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.",[755],{"title":453,"url":454},"glossary\u002Fcollecting-electrode","9E4jLiOYVWf0Kj-hlJN58FMZ0Nz2mF0Iv1OuBtFwtqM",{"id":759,"title":251,"aliases":760,"body":763,"category":263,"description":830,"extension":265,"meta":831,"navigation":267,"path":109,"relatedTerms":832,"seo":833,"sources":836,"stem":839,"term":251,"__hash__":840},"glossary\u002Fglossary\u002Fre-entrainment.md",[761,762],"rapping re-entrainment","dust re-entrainment",{"type":53,"value":764,"toc":825},[765,778,782,791,795,800,802],[56,766,767,769,770,772,773,775,776,368],{},[60,768,251],{}," is the recapture of just-released dust by the flue-gas stream before it can fall into the ",[64,771,425],{"href":99},". It is the dominant cause of ",[64,774,105],{"href":104}," spikes on rapped ESPs and a major reason continuous acoustic cleaning is increasingly preferred over (or alongside) mechanical ",[64,777,692],{"href":268},[90,779,781],{"id":780},"how-re-entrainment-happens","How re-entrainment happens",[56,783,784,785,787,788,790],{},"When a ",[64,786,49],{"href":268}," impacts a ",[64,789,661],{"href":66},", a sheet of dust detaches and slides down the plate. Some of this falling dust is caught by the horizontal gas flow and carried out of the field instead of reaching the hopper. The faster and harder the rap, the larger the released sheet and the worse the re-entrainment.",[90,792,794],{"id":793},"why-sonic-horns-reduce-re-entrainment","Why sonic horns reduce re-entrainment",[56,796,797,799],{},[64,798,345],{"href":135}," firing every few minutes deliver small, frequent dust releases instead of large, occasional ones. The released particles are smaller in aggregate per event, fall more gently and have time to settle into the hopper before being picked up. Plants that retrofit horns to back-corona- or re-entrainment-limited ESPs commonly see opacity reductions of 20–40% with no other process change.",[90,801,222],{"id":221},[224,803,804,808,812,816,821],{},[227,805,806],{},[64,807,231],{"href":76},[227,809,810],{},[64,811,47],{"href":268},[227,813,814],{},[64,815,246],{"href":66},[227,817,818],{},[64,819,820],{"href":104},"Opacity",[227,822,823],{},[64,824,136],{"href":135},{"title":257,"searchDepth":258,"depth":258,"links":826},[827,828,829],{"id":780,"depth":258,"text":781},{"id":793,"depth":258,"text":794},{"id":221,"depth":258,"text":222},"Re-entrainment is the recapture of just-released dust by the flue-gas stream before it can fall into the ESP hopper. It is the dominant cause of opacity spikes on rapped ESPs and a major reason continuous acoustic cleaning is increasingly preferred over (or alongside) mechanical rapping.",{},[270,443,273,105,274],{"title":834,"description":835},"Re-entrainment — why rapping spikes ESP opacity and how to reduce it","Re-entrainment is the recapture of just-rapped dust by the flue-gas stream before it falls into the hopper. It causes opacity spikes and is the main reason continuous sonic cleaning is preferred.",[837,838],{"title":280,"url":281},{"title":453,"url":454},"glossary\u002Fre-entrainment","WGUvUI6GbyUbof8DdYEOwylwqKzZZprnpNkuX3GAMzo",{"id":842,"title":136,"aliases":843,"body":846,"category":1049,"description":1050,"extension":265,"meta":1051,"navigation":267,"path":135,"relatedTerms":1052,"seo":1059,"sources":1062,"stem":1072,"term":136,"__hash__":1073},"glossary\u002Fglossary\u002Fsonic-horn.md",[696,844,845],"sonic cleaning horn","industrial sonic horn",{"type":53,"value":847,"toc":1042},[848,879,883,891,895,957,961,998,1002,1010,1012],[56,849,466,850,853,854,858,859,862,863,862,867,862,871,68,875,368],{},[60,851,852],{},"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 ",[64,855,857],{"href":856},"\u002Fglossary\u002Facoustic-cleaner","acoustic cleaner"," and the default specification for cleaning ",[64,860,861],{"href":76},"ESPs",", ",[64,864,866],{"href":865},"\u002Fglossary\u002Ffabric-filter","baghouses",[64,868,870],{"href":869},"\u002Fglossary\u002Fselective-catalytic-reduction","SCR catalysts",[64,872,874],{"href":873},"\u002Fglossary\u002Fsuperheater","boiler heat-transfer surfaces",[64,876,878],{"href":877},"\u002Fglossary\u002Fhopper","hoppers and silos",[90,880,882],{"id":881},"how-a-sonic-horn-works","How a sonic horn works",[56,884,885,886,890],{},"Compressed plant air admitted through a ",[64,887,889],{"href":888},"\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.",[90,892,894],{"id":893},"key-parameters","Key parameters",[117,896,897,907],{},[120,898,899],{},[123,900,901,904],{},[126,902,903],{},"Parameter",[126,905,906],{},"Typical range",[138,908,909,917,925,933,941,949],{},[123,910,911,914],{},[143,912,913],{},"Fundamental frequency",[143,915,916],{},"60–400 Hz",[123,918,919,922],{},[143,920,921],{},"Sound pressure level",[143,923,924],{},"140–180 dB",[123,926,927,930],{},[143,928,929],{},"Compressed-air consumption",[143,931,932],{},"8–14 Nm³\u002Fmin at 4–7 bar",[123,934,935,938],{},[143,936,937],{},"Operating temperature (with appropriate materials)",[143,939,940],{},"−40 °C to +500 °C",[123,942,943,946],{},[143,944,945],{},"Firing cycle",[143,947,948],{},"5–15 s burst, repeated every 3–15 minutes",[123,950,951,954],{},[143,952,953],{},"Mass",[143,955,956],{},"15–60 kg depending on horn size",[90,958,960],{"id":959},"frequency-selection","Frequency selection",[56,962,963,964,862,968,972,973,862,977,981,982,862,985,989,990,68,994,368],{},"Lower frequencies (60–125 Hz) project longer wavelengths and penetrate further into large open vessels — ",[64,965,967],{"href":966},"\u002Fglossary\u002Fpreheater-cyclone","preheater cyclones",[64,969,971],{"href":970},"\u002Fglossary\u002Frecovery-boiler","recovery-boiler superheaters",", large ",[64,974,976],{"href":975},"\u002Fglossary\u002Fesp-field-bus-section","ESP fields",[64,978,980],{"href":979},"\u002Fglossary\u002Fsilo","silos",". Higher frequencies (230–400 Hz) carry more energy per unit volume and suit finer dust loads in ",[64,983,984],{"href":865},"fabric-filter compartments",[64,986,988],{"href":987},"\u002Fglossary\u002Fhoneycomb-catalyst","catalyst layers"," and smaller hopper geometries. See ",[64,991,993],{"href":992},"\u002Fglossary\u002Flow-frequency-acoustic-cleaner","low-frequency acoustic cleaner",[64,995,997],{"href":996},"\u002Fglossary\u002Fhigh-frequency-acoustic-cleaner","high-frequency acoustic cleaner",[90,999,1001],{"id":1000},"sonic-horn-vs-steam-sootblower","Sonic horn vs steam sootblower",[56,1003,1004,1005,1009],{},"Sonic horns are increasingly specified alongside or in place of ",[64,1006,1008],{"href":1007},"\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.",[90,1011,222],{"id":221},[224,1013,1014,1019,1025,1031,1037],{},[227,1015,1016],{},[64,1017,1018],{"href":856},"Acoustic cleaner",[227,1020,1021],{},[64,1022,1024],{"href":1023},"\u002Fglossary\u002Fsonic-sootblower","Sonic sootblower",[227,1026,1027],{},[64,1028,1030],{"href":1029},"\u002Fglossary\u002Fbell-horn","Bell horn",[227,1032,1033],{},[64,1034,1036],{"href":1035},"\u002Fglossary\u002Fdiaphragm-horn","Diaphragm horn",[227,1038,1039],{},[64,1040,1041],{"href":992},"Low-frequency acoustic cleaner",{"title":257,"searchDepth":258,"depth":258,"links":1043},[1044,1045,1046,1047,1048],{"id":881,"depth":258,"text":882},{"id":893,"depth":258,"text":894},{"id":959,"depth":258,"text":960},{"id":1000,"depth":258,"text":1001},{"id":221,"depth":258,"text":222},"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.",{},[1053,1054,1055,1056,1057,1058],"acoustic-cleaner","acoustic-cleaning-system","sonic-sootblower","bell-horn","diaphragm-horn","low-frequency-acoustic-cleaner",{"title":1060,"description":1061},"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.",[1063,1066,1069],{"title":1064,"url":1065},"Power Engineering — Sonic Horns: A User's Introduction","https:\u002F\u002Fwww.power-eng.com\u002Fcoal\u002Fsonic-horns-a-userrsquos-introduction\u002F",{"title":1067,"url":1068},"Power Engineering — Tuning in to Acoustic Cleaning","https:\u002F\u002Fwww.power-eng.com\u002Fcoal\u002Ftuning-in-to-acoustic-cleaning\u002F",{"title":1070,"url":1071},"Wikipedia — Sonic soot blowers","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSonic_soot_blowers","glossary\u002Fsonic-horn","YzrhN0kKzqSaQo0wfn0rueNZ-V43mcg5zahqeWi3lnU",1782613735394]