[{"data":1,"prerenderedAt":1055},["ShallowReactive",2],{"site-footer-common":3,"glossary:bunker-coal-bunker":45,"glossary-related:bunker-coal-bunker":175},{"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":51,"category":153,"description":154,"extension":155,"meta":156,"navigation":157,"path":158,"relatedTerms":159,"seo":165,"sources":168,"stem":172,"term":173,"__hash__":174},"glossary\u002Fglossary\u002Fbunker-coal-bunker.md","Bunker \u002F coal bunker",[49,50],"coal bunker","bunkers",{"type":52,"value":53,"toc":146},"minimark",[54,77,82,98,101,105,117,121],[55,56,57,58,62,63,65,66,71,72,76],"p",{},"A ",[59,60,61],"strong",{},"bunker"," (in industrial usage almost always a ",[59,64,49],{},") is an intermediate coal-storage vessel located above each ",[67,68,70],"a",{"href":69},"\u002Fglossary\u002Fraw-mill-cement-mill-coal-mill","pulveriser mill"," on a ",[67,73,75],{"href":74},"\u002Fglossary\u002Fpc-boiler","PC boiler",". Coal arrives from the main coal-handling system, is held in the bunker for short-term buffering, and is metered by gravimetric feeders into the mill below. A typical utility unit has 4–8 bunkers, one per pulveriser.",[78,79,81],"h2",{"id":80},"why-coal-bunkers-bridge","Why coal bunkers bridge",[83,84,85,89,92,95],"ul",{},[86,87,88],"li",{},"Sub-bituminous and lignite coals are particularly prone to cohesion under self-weight",[86,90,91],{},"Wet coal from rain-exposed yards consolidates rapidly",[86,93,94],{},"Long residence times in lightly-loaded bunkers harden surface material",[86,96,97],{},"Vibration from operation gradually compacts the mass",[55,99,100],{},"A bridged bunker interrupts mill feed; the mill trips on low coal flow, the burner loses fuel, and the unit derates or trips. On a 600 MW utility unit, a single bunker pluggage can mean an hour or more of lost generation.",[78,102,104],{"id":103},"mitigation","Mitigation",[55,106,107,111,112,116],{},[67,108,110],{"href":109},"\u002Fglossary\u002Fsonic-horn","Sonic horns"," installed at the discharge cone keep the coal mobile. They are usually rated for ",[67,113,115],{"href":114},"\u002Fglossary\u002Fatex-directive","ATEX"," Zone 22 dust-area service and feature stainless-steel construction to handle the abrasive-and-corrosive environment of coal storage.",[78,118,120],{"id":119},"related-terms","Related terms",[83,122,123,129,135,141],{},[86,124,125],{},[67,126,128],{"href":127},"\u002Fglossary\u002Fsilo","Silo",[86,130,131],{},[67,132,134],{"href":133},"\u002Fglossary\u002Fhopper","Hopper",[86,136,137],{},[67,138,140],{"href":139},"\u002Fglossary\u002Fbridging","Bridging",[86,142,143],{},[67,144,145],{"href":109},"Sonic horn",{"title":147,"searchDepth":148,"depth":148,"links":149},"",2,[150,151,152],{"id":80,"depth":148,"text":81},{"id":103,"depth":148,"text":104},{"id":119,"depth":148,"text":120},"hoppers-silos","A bunker (in industrial usage almost always a coal bunker) is an intermediate coal-storage vessel located above each pulveriser mill on a PC boiler. Coal arrives from the main coal-handling system, is held in the bunker for short-term buffering, and is metered by gravimetric feeders into the mill below. A typical utility unit has 4–8 bunkers, one per pulveriser.","md",{},true,"\u002Fglossary\u002Fbunker-coal-bunker",[160,161,162,163,164],"silo","hopper","bridging","raw-mill-cement-mill-coal-mill","sonic-horn",{"title":166,"description":167},"Coal bunker — intermediate coal-storage vessel above the pulveriser","A coal bunker is an intermediate coal-storage vessel that feeds pulveriser mills. Bridging in coal bunkers interrupts mill feed and forces unit derates; sonic horns are the standard flow aid.",[169],{"title":170,"url":171},"Power Engineering — Boiler Cleaning Methods & Techniques","https:\u002F\u002Fwww.power-eng.com\u002Foperations-maintenance\u002Fboiler-cleaning-methods-techniques\u002F","glossary\u002Fbunker-coal-bunker","Bunker (coal bunker)","zqZ8Fe_dyNGIpqil6irnNeB4Q6S3TJ4CqsyA7jVFY4g",[176,287,432,633,826],{"id":177,"title":128,"aliases":178,"body":181,"category":153,"description":274,"extension":155,"meta":275,"navigation":157,"path":127,"relatedTerms":276,"seo":278,"sources":281,"stem":285,"term":128,"__hash__":286},"glossary\u002Fglossary\u002Fsilo.md",[179,180],"silos","storage silo",{"type":52,"value":182,"toc":269},[183,193,197,208,212,217,230,244,246],[55,184,57,185,187,188,192],{},[59,186,160],{}," is a large vertical vessel for storing bulk solids — cement, fly ash, lime, ",[67,189,191],{"href":190},"\u002Fglossary\u002Fwaste-to-energy","biomass"," pellets, fertilizer granules, food powders, mining concentrate. Silos range from a few cubic metres to tens of thousands of cubic metres and are typically cylindrical with a conical discharge bottom feeding into a single outlet or a cluster of outlets.",[78,194,196],{"id":195},"why-silos-bridge","Why silos bridge",[55,198,199,200,202,203,207],{},"Most bulk solids show some degree of cohesion. Under the gravitational load of metres of stored material, the cohesive bond is enough to form a stable arch above the discharge outlet (",[67,201,162],{"href":139},") or a narrow flow channel surrounded by a hardened mass (",[67,204,206],{"href":205},"\u002Fglossary\u002Frat-holing","rat-holing","). The longer material sits in the silo, the more it consolidates and the harder it is to restart flow.",[78,209,211],{"id":210},"sonic-horns-as-flow-aids","Sonic horns as flow aids",[55,213,214,216],{},[67,215,110],{"href":109}," installed at the silo discharge cone provide continuous low-amplitude vibration that prevents cohesive structures from forming. A single horn typically covers the discharge cone and the lower 2–5 metres of the silo wall. Multiple horns address larger silos or persistent rat-holing zones.",[55,218,219,220,224,225,229],{},"Compared with ",[67,221,223],{"href":222},"\u002Fglossary\u002Fair-cannon-air-blaster","air cannons"," and ",[67,226,228],{"href":227},"\u002Fglossary\u002Fbin-vibrator","bin vibrators",":",[83,231,232,235,238,241],{},[86,233,234],{},"No structural impact on the silo",[86,236,237],{},"No discrete blast moments that introduce air pockets into the discharge",[86,239,240],{},"Lower total air consumption per unit cleaning effort",[86,242,243],{},"Single mounting versus arrays of cannons",[78,245,120],{"id":119},[83,247,248,252,256,260,265],{},[86,249,250],{},[67,251,134],{"href":133},[86,253,254],{},[67,255,47],{"href":158},[86,257,258],{},[67,259,140],{"href":139},[86,261,262],{},[67,263,264],{"href":205},"Rat-holing",[86,266,267],{},[67,268,145],{"href":109},{"title":147,"searchDepth":148,"depth":148,"links":270},[271,272,273],{"id":195,"depth":148,"text":196},{"id":210,"depth":148,"text":211},{"id":119,"depth":148,"text":120},"A silo is a large vertical vessel for storing bulk solids — cement, fly ash, lime, biomass pellets, fertilizer granules, food powders, mining concentrate. Silos range from a few cubic metres to tens of thousands of cubic metres and are typically cylindrical with a conical discharge bottom feeding into a single outlet or a cluster of outlets.",{},[161,277,162,206,164],"bunker-coal-bunker",{"title":279,"description":280},"Silo — large vertical storage vessel for bulk solids","A silo is a large vertical bulk-solids storage vessel. Cement, fly-ash, lime, biomass, fertilizer and food-powder silos all bridge and rat-hole; sonic horns are the leading flow aid.",[282],{"title":283,"url":284},"Wikipedia — Silo","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSilo","glossary\u002Fsilo","h1FnwqisFv53zNO36e7ZXskU_lfE0pCFuFSmOPzPKJ0",{"id":288,"title":134,"aliases":289,"body":293,"category":153,"description":418,"extension":155,"meta":419,"navigation":157,"path":133,"relatedTerms":420,"seo":423,"sources":426,"stem":430,"term":134,"__hash__":431},"glossary\u002Fglossary\u002Fhopper.md",[290,291,292],"hoppers","storage hopper","process hopper",{"type":52,"value":294,"toc":413},[295,324,328,360,364,378,380],[55,296,57,297,299,300,304,305,304,309,304,313,317,318,304,321,323],{},[59,298,161],{}," is an inverted-pyramid or conical vessel designed to store bulk solids and discharge them through a converging outlet. Hoppers appear under ",[67,301,303],{"href":302},"\u002Fglossary\u002Felectrostatic-precipitator","ESPs",", ",[67,306,308],{"href":307},"\u002Fglossary\u002Fbaghouse","baghouses",[67,310,312],{"href":311},"\u002Fglossary\u002Feconomiser","economisers",[67,314,316],{"href":315},"\u002Fglossary\u002Fair-heater","air heaters"," and process equipment of every kind across cement, power, ",[67,319,320],{"href":190},"WtE",[67,322,191],{"href":190},", refining, pharma, food and mining.",[78,325,327],{"id":326},"universal-failure-modes","Universal failure modes",[83,329,330,337,344,350],{},[86,331,332,336],{},[59,333,334],{},[67,335,140],{"href":139}," — stable arch forms above the outlet",[86,338,339,343],{},[59,340,341],{},[67,342,264],{"href":205}," — narrow channel above the outlet; surrounding material packs and hardens",[86,345,346,349],{},[59,347,348],{},"Pluggage"," — total blockage that stops discharge",[86,351,352,359],{},[59,353,354,355],{},"Funnel flow vs ",[67,356,358],{"href":357},"\u002Fglossary\u002Fmass-flow-vs-funnel-flow","mass flow"," — first-in, last-out behaviour leading to ageing material remaining indefinitely",[78,361,363],{"id":362},"why-acoustic-cleaning-works-on-hoppers","Why acoustic cleaning works on hoppers",[55,365,366,368,369,304,371,304,373,377],{},[67,367,110],{"href":109}," excel on hoppers because the geometry is small enough for the sound wave to fill the whole vessel and the dust is dry and friable. Compared with mechanical alternatives — ",[67,370,228],{"href":227},[67,372,223],{"href":222},[67,374,376],{"href":375},"\u002Fglossary\u002Fwhip-hammer","whip hammers"," — they cause no structural stress, no fatigue, and no impact damage to the hopper itself.",[78,379,120],{"id":119},[83,381,382,386,390,396,400,404,409],{},[86,383,384],{},[67,385,128],{"href":127},[86,387,388],{},[67,389,47],{"href":158},[86,391,392],{},[67,393,395],{"href":394},"\u002Fglossary\u002Fbin","Bin",[86,397,398],{},[67,399,140],{"href":139},[86,401,402],{},[67,403,264],{"href":205},[86,405,406],{},[67,407,408],{"href":357},"Mass flow vs funnel flow",[86,410,411],{},[67,412,145],{"href":109},{"title":147,"searchDepth":148,"depth":148,"links":414},[415,416,417],{"id":326,"depth":148,"text":327},{"id":362,"depth":148,"text":363},{"id":119,"depth":148,"text":120},"A hopper is an inverted-pyramid or conical vessel designed to store bulk solids and discharge them through a converging outlet. Hoppers appear under ESPs, baghouses, economisers, air heaters and process equipment of every kind across cement, power, WtE, biomass, refining, pharma, food and mining.",{},[160,277,421,162,206,422,164],"bin","mass-flow-vs-funnel-flow",{"title":424,"description":425},"Hopper — converging vessel for storing and discharging bulk solids","A hopper is an inverted-pyramid or conical vessel for storing and discharging bulk solids. Bridging and rat-holing are the universal failure modes; sonic horns are a clean, low-maintenance remedy.",[427],{"title":428,"url":429},"Wikipedia — Hopper (particulate collection container)","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FHopper_(particulate_collection_container)","glossary\u002Fhopper","yaS0yQSinQlli40xEUR0l9zzxphPNmE4Pi2XHYeAc4k",{"id":433,"title":140,"aliases":434,"body":439,"category":153,"description":617,"extension":155,"meta":618,"navigation":157,"path":139,"relatedTerms":619,"seo":620,"sources":623,"stem":630,"term":631,"__hash__":632},"glossary\u002Fglossary\u002Fbridging.md",[435,436,437,438],"arching","arch formation","hopper bridging","silo bridging",{"type":52,"value":440,"toc":611},[441,458,462,465,487,491,505,509,587,589],[55,442,443,445,446,449,450,452,453,449,455,457],{},[59,444,140],{}," (also ",[447,448,435],"em",{}," or ",[447,451,436],{},") is the formation of a stable mechanical arch of bulk-solid material above the discharge outlet of a ",[67,454,161],{"href":133},[67,456,160],{"href":127},". Once a bridge forms, no material flows out of the outlet even though the vessel above is full. Bridging is the universal failure mode of bulk-solids storage.",[78,459,461],{"id":460},"how-a-bridge-forms","How a bridge forms",[55,463,464],{},"Cohesive forces between particles — moisture films, electrostatic charge, chemical bonding — combine with the converging-flow geometry to lock particles into an arch shape. The arch is self-supporting against the load above. Cohesion increases with:",[83,466,467,475,478,481,484],{},[86,468,469,470,474],{},"Fine particle size (especially Geldart-C powders — see ",[67,471,473],{"href":472},"\u002Fglossary\u002Fgeldart-classification","Geldart classification",")",[86,476,477],{},"Moisture",[86,479,480],{},"Hygroscopic chemistry (urea, ammonium nitrate, lime)",[86,482,483],{},"Long residence time (consolidation under sustained load)",[86,485,486],{},"Temperature cycling",[78,488,490],{"id":489},"diagnosing-a-bridge","Diagnosing a bridge",[83,492,493,496,499,502],{},[86,494,495],{},"Outlet flow stops while the level above remains high",[86,497,498],{},"Mass-flow indicators report no movement",[86,500,501],{},"A simple tap on the hopper outside the discharge cone produces a hollow sound",[86,503,504],{},"Borescope inspection from the inlet shows the arch directly",[78,506,508],{"id":507},"remedies","Remedies",[510,511,512,525],"table",{},[513,514,515],"thead",{},[516,517,518,522],"tr",{},[519,520,521],"th",{},"Technique",[519,523,524],{},"Notes",[526,527,528,538,548,558,568,579],"tbody",{},[516,529,530,535],{},[531,532,533],"td",{},[67,534,145],{"href":109},[531,536,537],{},"Continuous prevention; non-contact; minimal infrastructure",[516,539,540,545],{},[531,541,542],{},[67,543,544],{"href":222},"Air cannon",[531,546,547],{},"High-intensity periodic; effective on hard bridges; structural stress",[516,549,550,555],{},[531,551,552],{},[67,553,554],{"href":227},"Bin vibrator",[531,556,557],{},"Continuous vibration; can compact powder further if poorly sized",[516,559,560,565],{},[531,561,562],{},[67,563,564],{"href":375},"Whip hammer",[531,566,567],{},"Manual; legacy; HSE concerns",[516,569,570,576],{},[531,571,572],{},[67,573,575],{"href":574},"\u002Fglossary\u002Ffluidisation-pad-aeration-pad","Fluidisation pad",[531,577,578],{},"Aerates the lower vessel; not suitable for wet material",[516,580,581,584],{},[531,582,583],{},"Mechanical screw extractor",[531,585,586],{},"Bypasses the bridge entirely; high capex",[78,588,120],{"id":119},[83,590,591,595,599,603,607],{},[86,592,593],{},[67,594,134],{"href":133},[86,596,597],{},[67,598,128],{"href":127},[86,600,601],{},[67,602,264],{"href":205},[86,604,605],{},[67,606,408],{"href":357},[86,608,609],{},[67,610,145],{"href":109},{"title":147,"searchDepth":148,"depth":148,"links":612},[613,614,615,616],{"id":460,"depth":148,"text":461},{"id":489,"depth":148,"text":490},{"id":507,"depth":148,"text":508},{"id":119,"depth":148,"text":120},"Bridging (also arching or arch formation) is the formation of a stable mechanical arch of bulk-solid material above the discharge outlet of a hopper or silo. Once a bridge forms, no material flows out of the outlet even though the vessel above is full. Bridging is the universal failure mode of bulk-solids storage.",{},[161,160,206,422,164],{"title":621,"description":622},"Bridging — stable arch above the discharge of a hopper or silo","Bridging (also arching) is the formation of a stable arch of bulk solids above the discharge outlet of a hopper or silo, stopping material flow. The universal failure mode of bulk-solids storage.",[624,627],{"title":625,"url":626},"Powder & Bulk Solids — Preventing Rat-Holing and Bridging in Powder Silos","https:\u002F\u002Fsgsystemsglobal.com\u002Fglossary\u002Fsilo-rat-holing-and-bridging\u002F",{"title":628,"url":629},"Accendo Reliability — Bridging in Silos and Hoppers","https:\u002F\u002Faccendoreliability.com\u002Fbridging-silos-hoppers\u002F","glossary\u002Fbridging","Bridging (bulk-solids)","qG-iJwvR3z5_NliCxfeui3lEL9wxjVY3kU3rO9JWn8g",{"id":634,"title":635,"aliases":636,"body":641,"category":810,"description":645,"extension":155,"meta":811,"navigation":157,"path":69,"relatedTerms":812,"seo":816,"sources":819,"stem":823,"term":824,"__hash__":825},"glossary\u002Fglossary\u002Fraw-mill-cement-mill-coal-mill.md","Raw mill \u002F cement mill \u002F coal mill",[637,638,639,640],"raw mill","cement mill","coal mill","ball mill (cement)",{"type":52,"value":642,"toc":805},[643,646,726,730,733,750,754,780,785,787],[55,644,645],{},"Cement plants run three principal mills, each grinding a different material:",[510,647,648,664],{},[513,649,650],{},[516,651,652,655,658,661],{},[519,653,654],{},"Mill",[519,656,657],{},"Input",[519,659,660],{},"Output",[519,662,663],{},"Destination",[526,665,666,686,706],{},[516,667,668,673,676,679],{},[531,669,670],{},[59,671,672],{},"Raw mill",[531,674,675],{},"Limestone + clay + sand + iron",[531,677,678],{},"Raw meal (cement-fineness powder)",[531,680,681,685],{},[67,682,684],{"href":683},"\u002Fglossary\u002Fpreheater-tower","Preheater tower"," feed",[516,687,688,693,700,703],{},[531,689,690],{},[59,691,692],{},"Cement mill",[531,694,695,699],{},[67,696,698],{"href":697},"\u002Fglossary\u002Fclinker","Clinker"," + gypsum + additives",[531,701,702],{},"Finished cement powder",[531,704,705],{},"Bagging \u002F despatch",[516,707,708,713,716,719],{},[531,709,710],{},[59,711,712],{},"Coal mill",[531,714,715],{},"Raw coal or petcoke",[531,717,718],{},"Pulverised fuel",[531,720,721,725],{},[67,722,724],{"href":723},"\u002Fglossary\u002Frotary-kiln","Rotary kiln"," main burner",[78,727,729],{"id":728},"mill-technology","Mill technology",[55,731,732],{},"Two technologies dominate:",[83,734,735,741],{},[86,736,737,740],{},[59,738,739],{},"Ball mill"," — rotating cylinder containing steel balls; mature, robust, energy-intensive",[86,742,743,749],{},[59,744,745],{},[67,746,748],{"href":747},"\u002Fglossary\u002Fvertical-roller-mill","Vertical roller mill (VRM)"," — modern preferred design; 30–40% lower energy use; dominant for raw and coal mills",[78,751,753],{"id":752},"mill-related-fouling","Mill-related fouling",[83,755,756,762,768,774],{},[86,757,758,761],{},[59,759,760],{},"Mill duct fouling"," — fine powder coats hot-gas ducts, reducing flow",[86,763,764,767],{},[59,765,766],{},"Coarse-fines bridging"," in mill discharge silos",[86,769,770,773],{},[59,771,772],{},"Sticky cement coating"," in cement-mill ducting during high-humidity periods",[86,775,776,779],{},[59,777,778],{},"Coal-mill blade and classifier fouling"," — fire hazard",[55,781,782,784],{},[67,783,110],{"href":109}," on mill exhaust ducting and discharge silos prevent the build-up that disrupts mill throughput.",[78,786,120],{"id":119},[83,788,789,793,797,801],{},[86,790,791],{},[67,792,748],{"href":747},[86,794,795],{},[67,796,698],{"href":697},[86,798,799],{},[67,800,684],{"href":683},[86,802,803],{},[67,804,145],{"href":109},{"title":147,"searchDepth":148,"depth":148,"links":806},[807,808,809],{"id":728,"depth":148,"text":729},{"id":752,"depth":148,"text":753},{"id":119,"depth":148,"text":120},"cement",{},[813,814,815,164],"vertical-roller-mill","clinker","preheater-tower",{"title":817,"description":818},"Raw mill, cement mill and coal mill — the three principal mills in a cement plant","Cement plants run three principal mills: raw mill (limestone+clay→raw meal), cement mill (clinker→cement), coal mill (raw coal→pulverised fuel for the kiln burner).",[820],{"title":821,"url":822},"Wikipedia — Cement mill","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FCement_mill","glossary\u002Fraw-mill-cement-mill-coal-mill","Raw mill, cement mill and coal mill","iJ4kLnTA_LvBQqMbpIg6l2W4nYjA-XKyyHSgPxOI7Ww",{"id":827,"title":145,"aliases":828,"body":832,"category":1030,"description":1031,"extension":155,"meta":1032,"navigation":157,"path":109,"relatedTerms":1033,"seo":1040,"sources":1043,"stem":1053,"term":145,"__hash__":1054},"glossary\u002Fglossary\u002Fsonic-horn.md",[829,830,831],"sonic horns","sonic cleaning horn","industrial sonic horn",{"type":52,"value":833,"toc":1023},[834,862,866,874,878,940,944,979,983,991,993],[55,835,57,836,839,840,844,845,304,847,304,850,304,854,224,858,861],{},[59,837,838],{},"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 ",[67,841,843],{"href":842},"\u002Fglossary\u002Facoustic-cleaner","acoustic cleaner"," and the default specification for cleaning ",[67,846,303],{"href":302},[67,848,308],{"href":849},"\u002Fglossary\u002Ffabric-filter",[67,851,853],{"href":852},"\u002Fglossary\u002Fselective-catalytic-reduction","SCR catalysts",[67,855,857],{"href":856},"\u002Fglossary\u002Fsuperheater","boiler heat-transfer surfaces",[67,859,860],{"href":133},"hoppers and silos",".",[78,863,865],{"id":864},"how-a-sonic-horn-works","How a sonic horn works",[55,867,868,869,873],{},"Compressed plant air admitted through a ",[67,870,872],{"href":871},"\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.",[78,875,877],{"id":876},"key-parameters","Key parameters",[510,879,880,890],{},[513,881,882],{},[516,883,884,887],{},[519,885,886],{},"Parameter",[519,888,889],{},"Typical range",[526,891,892,900,908,916,924,932],{},[516,893,894,897],{},[531,895,896],{},"Fundamental frequency",[531,898,899],{},"60–400 Hz",[516,901,902,905],{},[531,903,904],{},"Sound pressure level",[531,906,907],{},"140–180 dB",[516,909,910,913],{},[531,911,912],{},"Compressed-air consumption",[531,914,915],{},"8–14 Nm³\u002Fmin at 4–7 bar",[516,917,918,921],{},[531,919,920],{},"Operating temperature (with appropriate materials)",[531,922,923],{},"−40 °C to +500 °C",[516,925,926,929],{},[531,927,928],{},"Firing cycle",[531,930,931],{},"5–15 s burst, repeated every 3–15 minutes",[516,933,934,937],{},[531,935,936],{},"Mass",[531,938,939],{},"15–60 kg depending on horn size",[78,941,943],{"id":942},"frequency-selection","Frequency selection",[55,945,946,947,304,951,955,956,304,960,962,963,304,966,970,971,224,975,861],{},"Lower frequencies (60–125 Hz) project longer wavelengths and penetrate further into large open vessels — ",[67,948,950],{"href":949},"\u002Fglossary\u002Fpreheater-cyclone","preheater cyclones",[67,952,954],{"href":953},"\u002Fglossary\u002Frecovery-boiler","recovery-boiler superheaters",", large ",[67,957,959],{"href":958},"\u002Fglossary\u002Fesp-field-bus-section","ESP fields",[67,961,179],{"href":127},". Higher frequencies (230–400 Hz) carry more energy per unit volume and suit finer dust loads in ",[67,964,965],{"href":849},"fabric-filter compartments",[67,967,969],{"href":968},"\u002Fglossary\u002Fhoneycomb-catalyst","catalyst layers"," and smaller hopper geometries. See ",[67,972,974],{"href":973},"\u002Fglossary\u002Flow-frequency-acoustic-cleaner","low-frequency acoustic cleaner",[67,976,978],{"href":977},"\u002Fglossary\u002Fhigh-frequency-acoustic-cleaner","high-frequency acoustic cleaner",[78,980,982],{"id":981},"sonic-horn-vs-steam-sootblower","Sonic horn vs steam sootblower",[55,984,985,986,990],{},"Sonic horns are increasingly specified alongside or in place of ",[67,987,989],{"href":988},"\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.",[78,992,120],{"id":119},[83,994,995,1000,1006,1012,1018],{},[86,996,997],{},[67,998,999],{"href":842},"Acoustic cleaner",[86,1001,1002],{},[67,1003,1005],{"href":1004},"\u002Fglossary\u002Fsonic-sootblower","Sonic sootblower",[86,1007,1008],{},[67,1009,1011],{"href":1010},"\u002Fglossary\u002Fbell-horn","Bell horn",[86,1013,1014],{},[67,1015,1017],{"href":1016},"\u002Fglossary\u002Fdiaphragm-horn","Diaphragm horn",[86,1019,1020],{},[67,1021,1022],{"href":973},"Low-frequency acoustic cleaner",{"title":147,"searchDepth":148,"depth":148,"links":1024},[1025,1026,1027,1028,1029],{"id":864,"depth":148,"text":865},{"id":876,"depth":148,"text":877},{"id":942,"depth":148,"text":943},{"id":981,"depth":148,"text":982},{"id":119,"depth":148,"text":120},"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.",{},[1034,1035,1036,1037,1038,1039],"acoustic-cleaner","acoustic-cleaning-system","sonic-sootblower","bell-horn","diaphragm-horn","low-frequency-acoustic-cleaner",{"title":1041,"description":1042},"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.",[1044,1047,1050],{"title":1045,"url":1046},"Power Engineering — Sonic Horns: A User's Introduction","https:\u002F\u002Fwww.power-eng.com\u002Fcoal\u002Fsonic-horns-a-userrsquos-introduction\u002F",{"title":1048,"url":1049},"Power Engineering — Tuning in to Acoustic Cleaning","https:\u002F\u002Fwww.power-eng.com\u002Fcoal\u002Ftuning-in-to-acoustic-cleaning\u002F",{"title":1051,"url":1052},"Wikipedia — Sonic soot blowers","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSonic_soot_blowers","glossary\u002Fsonic-horn","YzrhN0kKzqSaQo0wfn0rueNZ-V43mcg5zahqeWi3lnU",1782613740936]