[{"data":1,"prerenderedAt":835},["ShallowReactive",2],{"site-footer-common":3,"glossary:id-fan":45,"glossary-related:id-fan":234},{"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":55,"category":215,"description":61,"extension":216,"meta":217,"navigation":218,"path":219,"relatedTerms":220,"seo":224,"sources":227,"stem":231,"term":232,"__hash__":233},"glossary\u002Fglossary\u002Fid-fan.md","ID fan \u002F FD fan \u002F PA fan",[49,50,51,52,53,54],"induced draft fan","forced draft fan","primary air fan","ID fan","FD fan","PA fan",{"type":56,"value":57,"toc":208},"minimark",[58,62,140,145,167,175,179,186,190],[59,60,61],"p",{},"Industrial boilers use three principal fans to manage gas and air movement:",[63,64,65,81],"table",{},[66,67,68],"thead",{},[69,70,71,75,78],"tr",{},[72,73,74],"th",{},"Fan",[72,76,77],{},"Function",[72,79,80],{},"Location",[82,83,84,114,127],"tbody",{},[69,85,86,93,101],{},[87,88,89],"td",{},[90,91,92],"strong",{},"ID (Induced Draft)",[87,94,95,96],{},"Pulls flue gas through the ",[97,98,100],"a",{"href":99},"\u002Fglossary\u002Fconvective-pass-backpass","convective pass",[87,102,103,104,108,109,113],{},"Downstream of the ",[97,105,107],{"href":106},"\u002Fglossary\u002Felectrostatic-precipitator","ESP"," or ",[97,110,112],{"href":111},"\u002Fglossary\u002Fbaghouse","baghouse",", before the stack",[69,115,116,121,124],{},[87,117,118],{},[90,119,120],{},"FD (Forced Draft)",[87,122,123],{},"Pushes combustion air into the burners",[87,125,126],{},"Ahead of the air heater air-side inlet",[69,128,129,134,137],{},[87,130,131],{},[90,132,133],{},"PA (Primary Air)",[87,135,136],{},"Conveys pulverised coal from mills to burners",[87,138,139],{},"Between the coal mills and the burner deck",[141,142,144],"h2",{"id":143},"why-fans-foul","Why fans foul",[146,147,148,155,161],"ul",{},[149,150,151,154],"li",{},[90,152,153],{},"Fly-ash deposition on ID fan blades"," unbalances the impeller, causing vibration and bearing wear",[149,156,157,160],{},[90,158,159],{},"PA fan blade build-up"," from sticky coal fines",[149,162,163,166],{},[90,164,165],{},"FD fan inlet vane fouling"," from atmospheric dust accumulating on the air-intake filter or vane assembly",[59,168,169,170,174],{},"ID fans on coal-fired and ",[97,171,173],{"href":172},"\u002Fglossary\u002Fwaste-to-energy","biomass"," plants are particularly prone to blade fouling; a trip-causing imbalance is a regular outage risk.",[141,176,178],{"id":177},"sonic-horns-on-fan-housings","Sonic horns on fan housings",[59,180,181,185],{},[97,182,184],{"href":183},"\u002Fglossary\u002Fsonic-horn","Sonic horns"," installed on the upstream ducting and at the fan inlet keep the blades clean by preventing the dust from settling onto them in the first place. Cement preheater ID fans are a particularly common installation.",[141,187,189],{"id":188},"related-terms","Related terms",[146,191,192,198,203],{},[149,193,194],{},[97,195,197],{"href":196},"\u002Fglossary\u002Fboiler","Boiler",[149,199,200],{},[97,201,202],{"href":99},"Convective pass \u002F backpass",[149,204,205],{},[97,206,207],{"href":183},"Sonic horn",{"title":209,"searchDepth":210,"depth":210,"links":211},"",2,[212,213,214],{"id":143,"depth":210,"text":144},{"id":177,"depth":210,"text":178},{"id":188,"depth":210,"text":189},"hrsg-gas-path","md",{},true,"\u002Fglossary\u002Fid-fan",[221,222,223],"boiler","convective-pass-backpass","sonic-horn",{"title":225,"description":226},"ID, FD and PA fans — the three principal boiler fans explained","Boilers use three fans: ID (induced draft) pulls flue gas through the convective pass, FD (forced draft) pushes combustion air, PA (primary air) conveys pulverised coal to the burners.",[228],{"title":229,"url":230},"Wikipedia — Boiler","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FBoiler","glossary\u002Fid-fan","ID, FD and PA fans","YjfqFgTbzrQzwlPIf72ZoVKgmffznjVyqIloOT6aaMo",[235,477,606],{"id":236,"title":197,"aliases":237,"body":241,"category":221,"description":457,"extension":216,"meta":458,"navigation":218,"path":196,"relatedTerms":459,"seo":467,"sources":470,"stem":475,"term":197,"__hash__":476},"glossary\u002Fglossary\u002Fboiler.md",[238,239,240],"industrial boiler","utility boiler","steam generator",{"type":56,"value":242,"toc":452},[243,269,273,385,389,421,423],[59,244,245,246,248,249,252,253,255,256,260,261,255,265,268],{},"A ",[90,247,221],{}," is a closed vessel in which fuel chemical energy is converted to steam by transferring heat into water flowing through tube banks. Industrial and utility boilers serve electricity generation, district heating, process steam, ",[97,250,251],{"href":172},"WtE",", ",[97,254,173],{"href":172}," and ",[97,257,259],{"href":258},"\u002Fglossary\u002Frecovery-boiler","pulp-and-paper"," operations. All of them foul; the only variables are ",[262,263,264],"em",{},"how much",[262,266,267],{},"with what",".",[141,270,272],{"id":271},"boiler-families","Boiler families",[63,274,275,288],{},[66,276,277],{},[69,278,279,282,285],{},[72,280,281],{},"Type",[72,283,284],{},"Fuel",[72,286,287],{},"Notes",[82,289,290,304,318,332,345,359,370],{},[69,291,292,298,301],{},[87,293,294],{},[97,295,297],{"href":296},"\u002Fglossary\u002Fpc-boiler","PC boiler",[87,299,300],{},"Pulverised coal",[87,302,303],{},"Dominant utility design",[69,305,306,312,315],{},[87,307,308],{},[97,309,311],{"href":310},"\u002Fglossary\u002Fcfb-boiler","CFB boiler",[87,313,314],{},"Coal, biomass, RDF, lignite",[87,316,317],{},"Tolerates wider fuel range; lower NOx",[69,319,320,326,329],{},[87,321,322],{},[97,323,325],{"href":324},"\u002Fglossary\u002Fbfb-boiler","BFB boiler",[87,327,328],{},"Biomass, sludge, low-grade fuels",[87,330,331],{},"Bubbling fluidised bed",[69,333,334,339,342],{},[87,335,336],{},[97,337,338],{"href":258},"Recovery boiler",[87,340,341],{},"Black liquor (kraft pulp mills)",[87,343,344],{},"Combines chemicals recovery with steam",[69,346,347,353,356],{},[87,348,349],{},[97,350,352],{"href":351},"\u002Fglossary\u002Fhog-fuel-boiler-bark-boiler","Hog-fuel boiler",[87,354,355],{},"Wood waste, bark",[87,357,358],{},"Common at pulp mills as side boilers",[69,360,361,364,367],{},[87,362,363],{},"Gas \u002F oil boiler",[87,365,366],{},"Natural gas, fuel oil",[87,368,369],{},"Lower particulate, less fouling",[69,371,372,375,378],{},[87,373,374],{},"HRSG",[87,376,377],{},"Gas-turbine exhaust",[87,379,380,381],{},"See ",[97,382,384],{"href":383},"\u002Fglossary\u002Fheat-recovery-steam-generator","heat-recovery steam generator",[141,386,388],{"id":387},"where-sonic-horns-sit","Where sonic horns sit",[59,390,391,393,394,252,398,252,402,255,406,410,411,415,416,420],{},[97,392,184],{"href":183}," installed across the convective pass — between ",[97,395,397],{"href":396},"\u002Fglossary\u002Feconomiser","economiser",[97,399,401],{"href":400},"\u002Fglossary\u002Fsuperheater","superheaters",[97,403,405],{"href":404},"\u002Fglossary\u002Freheater","reheater",[97,407,409],{"href":408},"\u002Fglossary\u002Fair-heater","air heater"," — dislodge ash and soot continuously, supplementing or partially replacing steam ",[97,412,414],{"href":413},"\u002Fglossary\u002Fsteam-sootblower","sootblowers",". The benefit shows up as ",[97,417,419],{"href":418},"\u002Fglossary\u002Fheat-rate","heat rate"," recovery, deferred outages and longer intervals between water washes.",[141,422,189],{"id":188},[146,424,425,429,433,437,443,448],{},[149,426,427],{},[97,428,297],{"href":296},[149,430,431],{},[97,432,311],{"href":310},[149,434,435],{},[97,436,338],{"href":258},[149,438,439],{},[97,440,442],{"href":441},"\u002Fglossary\u002Fwaterwall","Waterwall",[149,444,445],{},[97,446,447],{"href":396},"Economiser",[149,449,450],{},[97,451,207],{"href":183},{"title":209,"searchDepth":210,"depth":210,"links":453},[454,455,456],{"id":271,"depth":210,"text":272},{"id":387,"depth":210,"text":388},{"id":188,"depth":210,"text":189},"A boiler is a closed vessel in which fuel chemical energy is converted to steam by transferring heat into water flowing through tube banks. Industrial and utility boilers serve electricity generation, district heating, process steam, WtE, biomass and pulp-and-paper operations. All of them foul; the only variables are how much and with what.",{},[460,461,462,463,464,397,465,466,223],"pc-boiler","cfb-boiler","bfb-boiler","recovery-boiler","waterwall","superheater","air-heater",{"title":468,"description":469},"Boiler — industrial steam generator types and acoustic-cleaning needs","A boiler is a vessel that converts fuel chemical energy into steam by heating water. Coal-fired, biomass, oil, gas and recovery boilers all foul; sonic horns clean heat-transfer surfaces.",[471,472],{"title":229,"url":230},{"title":473,"url":474},"Babcock & Wilcox — Sootblower and Boiler Cleaning Terminology","https:\u002F\u002Fwww.babcock.com\u002Fhome\u002Fabout\u002Fresources\u002Flearning-center\u002Fsootblower-and-boiler-cleaning-terminology-principles-and-applications","glossary\u002Fboiler","pamAnZGo_UeIedDHhYrfv0nP3GCXkNTGi0a197n4b5Q",{"id":478,"title":202,"aliases":479,"body":483,"category":221,"description":593,"extension":216,"meta":594,"navigation":218,"path":99,"relatedTerms":595,"seo":596,"sources":599,"stem":603,"term":604,"__hash__":605},"glossary\u002Fglossary\u002Fconvective-pass-backpass.md",[100,480,481,482],"backpass","boiler backpass","back pass",{"type":56,"value":484,"toc":588},[485,505,509,512,533,545,549,557,559],[59,486,487,488,490,491,493,494,496,497,499,500,502,503,268],{},"The ",[90,489,100],{}," (also ",[90,492,480],{},") is the downstream section of a boiler where heat transfer is by conduction across tube banks rather than radiation from a flame. The convective pass contains, in order of decreasing gas temperature: the finishing ",[97,495,465],{"href":400},", the ",[97,498,405],{"href":404},", the primary superheater, the ",[97,501,397],{"href":396},", and finally the ",[97,504,409],{"href":408},[141,506,508],{"id":507},"why-the-convective-pass-is-the-prime-sonic-horn-zone","Why the convective pass is the prime sonic-horn zone",[59,510,511],{},"Three reasons:",[513,514,515,521,527],"ol",{},[149,516,517,520],{},[90,518,519],{},"Deposits are dry",", not molten. Ash arriving at convective surfaces has cooled below its sticking temperature; it deposits as a friable layer that acoustic energy can lift.",[149,522,523,526],{},[90,524,525],{},"Surfaces are extensive"," and partly inaccessible to retract sootblowers — perfect for non-contact cleaning.",[149,528,529,532],{},[90,530,531],{},"Heat-rate sensitivity"," is high. Every degree of approach temperature loss in the economiser or air heater translates directly into fuel cost.",[59,534,535,536,542,543,268],{},"A typical large utility boiler benefits from ",[90,537,538,539],{},"8–20 ",[97,540,541],{"href":183},"sonic horns"," distributed across the convective pass, complementing existing steam ",[97,544,414],{"href":413},[141,546,548],{"id":547},"sequencing","Sequencing",[59,550,551,552,556],{},"Horns are fired in a programmed sequence that respects ",[97,553,555],{"href":554},"\u002Fglossary\u002Fcompressed-air","compressed-air"," supply, avoids overlapping firing on adjacent fields, and times their action between sootblower cycles to maintain continuous low-level dust release.",[141,558,189],{"id":188},[146,560,561,565,569,574,579,584],{},[149,562,563],{},[97,564,197],{"href":196},[149,566,567],{},[97,568,447],{"href":396},[149,570,571],{},[97,572,573],{"href":400},"Superheater",[149,575,576],{},[97,577,578],{"href":404},"Reheater",[149,580,581],{},[97,582,583],{"href":408},"Air heater",[149,585,586],{},[97,587,207],{"href":183},{"title":209,"searchDepth":210,"depth":210,"links":589},[590,591,592],{"id":507,"depth":210,"text":508},{"id":547,"depth":210,"text":548},{"id":188,"depth":210,"text":189},"The convective pass (also backpass) is the downstream section of a boiler where heat transfer is by conduction across tube banks rather than radiation from a flame. The convective pass contains, in order of decreasing gas temperature: the finishing superheater, the reheater, the primary superheater, the economiser, and finally the air heater.",{},[221,397,465,405,466,223],{"title":597,"description":598},"Convective pass (backpass) — where sonic horns earn most of their cleaning work","The convective pass is the downstream section of a boiler where heat transfer is by conduction across tube banks: superheater, reheater, economiser. The primary zone for sonic-horn cleaning.",[600],{"title":601,"url":602},"Wikipedia — Water-tube boiler","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FWater-tube_boiler","glossary\u002Fconvective-pass-backpass","Convective pass and backpass","RDd0-n-v3frmmPFQ6GEIJ8gl1FK8dl11Q9pHezUj0Tk",{"id":607,"title":207,"aliases":608,"body":611,"category":810,"description":811,"extension":216,"meta":812,"navigation":218,"path":183,"relatedTerms":813,"seo":820,"sources":823,"stem":833,"term":207,"__hash__":834},"glossary\u002Fglossary\u002Fsonic-horn.md",[541,609,610],"sonic cleaning horn","industrial sonic horn",{"type":56,"value":612,"toc":803},[613,642,646,654,658,720,724,760,764,771,773],[59,614,245,615,618,619,623,624,252,627,252,631,252,635,255,638,268],{},[90,616,617],{},"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 ",[97,620,622],{"href":621},"\u002Fglossary\u002Facoustic-cleaner","acoustic cleaner"," and the default specification for cleaning ",[97,625,626],{"href":106},"ESPs",[97,628,630],{"href":629},"\u002Fglossary\u002Ffabric-filter","baghouses",[97,632,634],{"href":633},"\u002Fglossary\u002Fselective-catalytic-reduction","SCR catalysts",[97,636,637],{"href":400},"boiler heat-transfer surfaces",[97,639,641],{"href":640},"\u002Fglossary\u002Fhopper","hoppers and silos",[141,643,645],{"id":644},"how-a-sonic-horn-works","How a sonic horn works",[59,647,648,649,653],{},"Compressed plant air admitted through a ",[97,650,652],{"href":651},"\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.",[141,655,657],{"id":656},"key-parameters","Key parameters",[63,659,660,670],{},[66,661,662],{},[69,663,664,667],{},[72,665,666],{},"Parameter",[72,668,669],{},"Typical range",[82,671,672,680,688,696,704,712],{},[69,673,674,677],{},[87,675,676],{},"Fundamental frequency",[87,678,679],{},"60–400 Hz",[69,681,682,685],{},[87,683,684],{},"Sound pressure level",[87,686,687],{},"140–180 dB",[69,689,690,693],{},[87,691,692],{},"Compressed-air consumption",[87,694,695],{},"8–14 Nm³\u002Fmin at 4–7 bar",[69,697,698,701],{},[87,699,700],{},"Operating temperature (with appropriate materials)",[87,702,703],{},"−40 °C to +500 °C",[69,705,706,709],{},[87,707,708],{},"Firing cycle",[87,710,711],{},"5–15 s burst, repeated every 3–15 minutes",[69,713,714,717],{},[87,715,716],{},"Mass",[87,718,719],{},"15–60 kg depending on horn size",[141,721,723],{"id":722},"frequency-selection","Frequency selection",[59,725,726,727,252,731,734,735,252,739,743,744,252,747,751,752,255,756,268],{},"Lower frequencies (60–125 Hz) project longer wavelengths and penetrate further into large open vessels — ",[97,728,730],{"href":729},"\u002Fglossary\u002Fpreheater-cyclone","preheater cyclones",[97,732,733],{"href":258},"recovery-boiler superheaters",", large ",[97,736,738],{"href":737},"\u002Fglossary\u002Fesp-field-bus-section","ESP fields",[97,740,742],{"href":741},"\u002Fglossary\u002Fsilo","silos",". Higher frequencies (230–400 Hz) carry more energy per unit volume and suit finer dust loads in ",[97,745,746],{"href":629},"fabric-filter compartments",[97,748,750],{"href":749},"\u002Fglossary\u002Fhoneycomb-catalyst","catalyst layers"," and smaller hopper geometries. See ",[97,753,755],{"href":754},"\u002Fglossary\u002Flow-frequency-acoustic-cleaner","low-frequency acoustic cleaner",[97,757,759],{"href":758},"\u002Fglossary\u002Fhigh-frequency-acoustic-cleaner","high-frequency acoustic cleaner",[141,761,763],{"id":762},"sonic-horn-vs-steam-sootblower","Sonic horn vs steam sootblower",[59,765,766,767,770],{},"Sonic horns are increasingly specified alongside or in place of ",[97,768,769],{"href":413},"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.",[141,772,189],{"id":188},[146,774,775,780,786,792,798],{},[149,776,777],{},[97,778,779],{"href":621},"Acoustic cleaner",[149,781,782],{},[97,783,785],{"href":784},"\u002Fglossary\u002Fsonic-sootblower","Sonic sootblower",[149,787,788],{},[97,789,791],{"href":790},"\u002Fglossary\u002Fbell-horn","Bell horn",[149,793,794],{},[97,795,797],{"href":796},"\u002Fglossary\u002Fdiaphragm-horn","Diaphragm horn",[149,799,800],{},[97,801,802],{"href":754},"Low-frequency acoustic cleaner",{"title":209,"searchDepth":210,"depth":210,"links":804},[805,806,807,808,809],{"id":644,"depth":210,"text":645},{"id":656,"depth":210,"text":657},{"id":722,"depth":210,"text":723},{"id":762,"depth":210,"text":763},{"id":188,"depth":210,"text":189},"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.",{},[814,815,816,817,818,819],"acoustic-cleaner","acoustic-cleaning-system","sonic-sootblower","bell-horn","diaphragm-horn","low-frequency-acoustic-cleaner",{"title":821,"description":822},"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.",[824,827,830],{"title":825,"url":826},"Power Engineering — Sonic Horns: A User's Introduction","https:\u002F\u002Fwww.power-eng.com\u002Fcoal\u002Fsonic-horns-a-userrsquos-introduction\u002F",{"title":828,"url":829},"Power Engineering — Tuning in to Acoustic Cleaning","https:\u002F\u002Fwww.power-eng.com\u002Fcoal\u002Ftuning-in-to-acoustic-cleaning\u002F",{"title":831,"url":832},"Wikipedia — Sonic soot blowers","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSonic_soot_blowers","glossary\u002Fsonic-horn","YzrhN0kKzqSaQo0wfn0rueNZ-V43mcg5zahqeWi3lnU",1782613743286]