[{"data":1,"prerenderedAt":841},["ShallowReactive",2],{"site-footer-common":3,"glossary:fluidisation-pad-aeration-pad":45,"glossary-related:fluidisation-pad-aeration-pad":197},{"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":53,"category":178,"description":179,"extension":180,"meta":181,"navigation":182,"path":183,"relatedTerms":184,"seo":187,"sources":190,"stem":194,"term":195,"__hash__":196},"glossary\u002Fglossary\u002Ffluidisation-pad-aeration-pad.md","Fluidisation pad \u002F aeration pad",[49,50,51,52],"fluidisation pad","aeration pad","air slide pad","aeration nozzle",{"type":54,"value":55,"toc":170},"minimark",[56,80,85,103,107,132,136,144,148],[57,58,59,63,64,68,69,74,75,79],"p",{},[60,61,62],"strong",{},"Fluidisation pads"," (also ",[65,66,67],"em",{},"aeration pads",") are porous ceramic, sintered-metal or fabric panels mounted in the lower wall of a ",[70,71,73],"a",{"href":72},"\u002Fglossary\u002Fhopper","hopper"," or ",[70,76,78],{"href":77},"\u002Fglossary\u002Fsilo","silo",". Low-pressure air admitted through the pad permeates upward through the material, partially fluidising the bed and restoring flow towards the outlet.",[81,82,84],"h2",{"id":83},"where-they-work","Where they work",[86,87,88,97,100],"ul",{},[89,90,91,92,96],"li",{},"Dry, fine Class-A powders (see ",[70,93,95],{"href":94},"\u002Fglossary\u002Fgeldart-classification","Geldart classification",") — cement, fly ash, alumina",[89,98,99],{},"Continuous-flow applications where some bed aeration is acceptable",[89,101,102],{},"Vessels where wall access for pad installation is straightforward",[81,104,106],{"id":105},"where-they-dont","Where they don't",[86,108,109,115,121,127],{},[89,110,111,114],{},[60,112,113],{},"Wet material"," — moisture blocks the pad pores or channels the air",[89,116,117,120],{},[60,118,119],{},"Hygroscopic material"," — added air picks up moisture and worsens cohesion",[89,122,123,126],{},[60,124,125],{},"Class C powders"," in some conditions — air channels through rather than fluidising",[89,128,129],{},[60,130,131],{},"Vessels where downstream equipment cannot tolerate aerated discharge",[81,133,135],{"id":134},"fluidisation-pads-vs-sonic-horns","Fluidisation pads vs sonic horns",[57,137,138,139,143],{},"Both are continuous-operation flow aids. Fluidisation pads add air to the material; ",[70,140,142],{"href":141},"\u002Fglossary\u002Fsonic-horn","sonic horns"," add vibration to the material. Pads suit a narrower range of materials (dry, fluidisable) but consume more compressed air over time. Horns suit a wider material range, are simpler to retrofit, and do not aerate the discharge.",[81,145,147],{"id":146},"related-terms","Related terms",[86,149,150,155,160,166],{},[89,151,152],{},[70,153,154],{"href":72},"Hopper",[89,156,157],{},[70,158,159],{"href":77},"Silo",[89,161,162],{},[70,163,165],{"href":164},"\u002Fglossary\u002Fanti-bridging-device","Anti-bridging device",[89,167,168],{},[70,169,95],{"href":94},{"title":171,"searchDepth":172,"depth":172,"links":173},"",2,[174,175,176,177],{"id":83,"depth":172,"text":84},{"id":105,"depth":172,"text":106},{"id":134,"depth":172,"text":135},{"id":146,"depth":172,"text":147},"hoppers-silos","Fluidisation pads (also aeration pads) are porous ceramic, sintered-metal or fabric panels mounted in the lower wall of a hopper or silo. Low-pressure air admitted through the pad permeates upward through the material, partially fluidising the bed and restoring flow towards the outlet.","md",{},true,"\u002Fglossary\u002Ffluidisation-pad-aeration-pad",[73,78,185,186],"anti-bridging-device","geldart-classification",{"title":188,"description":189},"Fluidisation and aeration pads — aerate the lower bed to restore flow","Fluidisation pads are porous panels mounted on the lower hopper wall that admit low-pressure air to aerate the material above. Effective on dry Class-A powders; problematic on wet material.",[191],{"title":192,"url":193},"AIRMATIC — Pneumatic Flow Aids","https:\u002F\u002Fwww.airmatic.com\u002Fproducts\u002Fnon-vibrating-pneumatic-flow-aid-devices","glossary\u002Ffluidisation-pad-aeration-pad","Fluidisation and aeration pads","7JV93R3BfkUIMFrOUkMBlZgVDaAxJIR2-BPj6WKfEPQ",[198,362,463,651],{"id":199,"title":154,"aliases":200,"body":204,"category":178,"description":344,"extension":180,"meta":345,"navigation":182,"path":72,"relatedTerms":346,"seo":353,"sources":356,"stem":360,"term":154,"__hash__":361},"glossary\u002Fglossary\u002Fhopper.md",[201,202,203],"hoppers","storage hopper","process hopper",{"type":54,"value":205,"toc":339},[206,238,242,278,282,301,303],[57,207,208,209,211,212,216,217,216,221,216,225,229,230,216,234,237],{},"A ",[60,210,73],{}," is an inverted-pyramid or conical vessel designed to store bulk solids and discharge them through a converging outlet. Hoppers appear under ",[70,213,215],{"href":214},"\u002Fglossary\u002Felectrostatic-precipitator","ESPs",", ",[70,218,220],{"href":219},"\u002Fglossary\u002Fbaghouse","baghouses",[70,222,224],{"href":223},"\u002Fglossary\u002Feconomiser","economisers",[70,226,228],{"href":227},"\u002Fglossary\u002Fair-heater","air heaters"," and process equipment of every kind across cement, power, ",[70,231,233],{"href":232},"\u002Fglossary\u002Fwaste-to-energy","WtE",[70,235,236],{"href":232},"biomass",", refining, pharma, food and mining.",[81,239,241],{"id":240},"universal-failure-modes","Universal failure modes",[86,243,244,253,262,268],{},[89,245,246,252],{},[60,247,248],{},[70,249,251],{"href":250},"\u002Fglossary\u002Fbridging","Bridging"," — stable arch forms above the outlet",[89,254,255,261],{},[60,256,257],{},[70,258,260],{"href":259},"\u002Fglossary\u002Frat-holing","Rat-holing"," — narrow channel above the outlet; surrounding material packs and hardens",[89,263,264,267],{},[60,265,266],{},"Pluggage"," — total blockage that stops discharge",[89,269,270,277],{},[60,271,272,273],{},"Funnel flow vs ",[70,274,276],{"href":275},"\u002Fglossary\u002Fmass-flow-vs-funnel-flow","mass flow"," — first-in, last-out behaviour leading to ageing material remaining indefinitely",[81,279,281],{"id":280},"why-acoustic-cleaning-works-on-hoppers","Why acoustic cleaning works on hoppers",[57,283,284,287,288,216,292,216,296,300],{},[70,285,286],{"href":141},"Sonic horns"," 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 — ",[70,289,291],{"href":290},"\u002Fglossary\u002Fbin-vibrator","bin vibrators",[70,293,295],{"href":294},"\u002Fglossary\u002Fair-cannon-air-blaster","air cannons",[70,297,299],{"href":298},"\u002Fglossary\u002Fwhip-hammer","whip hammers"," — they cause no structural stress, no fatigue, and no impact damage to the hopper itself.",[81,302,147],{"id":146},[86,304,305,309,315,321,325,329,334],{},[89,306,307],{},[70,308,159],{"href":77},[89,310,311],{},[70,312,314],{"href":313},"\u002Fglossary\u002Fbunker-coal-bunker","Bunker \u002F coal bunker",[89,316,317],{},[70,318,320],{"href":319},"\u002Fglossary\u002Fbin","Bin",[89,322,323],{},[70,324,251],{"href":250},[89,326,327],{},[70,328,260],{"href":259},[89,330,331],{},[70,332,333],{"href":275},"Mass flow vs funnel flow",[89,335,336],{},[70,337,338],{"href":141},"Sonic horn",{"title":171,"searchDepth":172,"depth":172,"links":340},[341,342,343],{"id":240,"depth":172,"text":241},{"id":280,"depth":172,"text":281},{"id":146,"depth":172,"text":147},"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.",{},[78,347,348,349,350,351,352],"bunker-coal-bunker","bin","bridging","rat-holing","mass-flow-vs-funnel-flow","sonic-horn",{"title":354,"description":355},"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.",[357],{"title":358,"url":359},"Wikipedia — Hopper (particulate collection container)","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FHopper_(particulate_collection_container)","glossary\u002Fhopper","yaS0yQSinQlli40xEUR0l9zzxphPNmE4Pi2XHYeAc4k",{"id":363,"title":159,"aliases":364,"body":367,"category":178,"description":451,"extension":180,"meta":452,"navigation":182,"path":77,"relatedTerms":453,"seo":454,"sources":457,"stem":461,"term":159,"__hash__":462},"glossary\u002Fglossary\u002Fsilo.md",[365,366],"silos","storage silo",{"type":54,"value":368,"toc":446},[369,377,381,390,394,399,408,422,424],[57,370,208,371,373,374,376],{},[60,372,78],{}," is a large vertical vessel for storing bulk solids — cement, fly ash, lime, ",[70,375,236],{"href":232}," 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.",[81,378,380],{"id":379},"why-silos-bridge","Why silos bridge",[57,382,383,384,386,387,389],{},"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 (",[70,385,349],{"href":250},") or a narrow flow channel surrounded by a hardened mass (",[70,388,350],{"href":259},"). The longer material sits in the silo, the more it consolidates and the harder it is to restart flow.",[81,391,393],{"id":392},"sonic-horns-as-flow-aids","Sonic horns as flow aids",[57,395,396,398],{},[70,397,286],{"href":141}," 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.",[57,400,401,402,404,405,407],{},"Compared with ",[70,403,295],{"href":294}," and ",[70,406,291],{"href":290},":",[86,409,410,413,416,419],{},[89,411,412],{},"No structural impact on the silo",[89,414,415],{},"No discrete blast moments that introduce air pockets into the discharge",[89,417,418],{},"Lower total air consumption per unit cleaning effort",[89,420,421],{},"Single mounting versus arrays of cannons",[81,423,147],{"id":146},[86,425,426,430,434,438,442],{},[89,427,428],{},[70,429,154],{"href":72},[89,431,432],{},[70,433,314],{"href":313},[89,435,436],{},[70,437,251],{"href":250},[89,439,440],{},[70,441,260],{"href":259},[89,443,444],{},[70,445,338],{"href":141},{"title":171,"searchDepth":172,"depth":172,"links":447},[448,449,450],{"id":379,"depth":172,"text":380},{"id":392,"depth":172,"text":393},{"id":146,"depth":172,"text":147},"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.",{},[73,347,349,350,352],{"title":455,"description":456},"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.",[458],{"title":459,"url":460},"Wikipedia — Silo","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FSilo","glossary\u002Fsilo","h1FnwqisFv53zNO36e7ZXskU_lfE0pCFuFSmOPzPKJ0",{"id":464,"title":165,"aliases":465,"body":469,"category":178,"description":638,"extension":180,"meta":639,"navigation":182,"path":164,"relatedTerms":640,"seo":644,"sources":647,"stem":649,"term":165,"__hash__":650},"glossary\u002Fglossary\u002Fanti-bridging-device.md",[466,467,468],"anti-arching device","flow promoter","flow aid",{"type":54,"value":470,"toc":633},[471,486,490,588,592,599,601],[57,472,473,475,476,216,478,480,481,74,483,485],{},[60,474,165],{}," is the generic procurement term for any flow-aid hardware installed to prevent or break ",[70,477,349],{"href":250},[70,479,350],{"href":259}," and other discharge stoppages in a ",[70,482,73],{"href":72},[70,484,78],{"href":77},". The category covers a range of technologies with overlapping use cases.",[81,487,489],{"id":488},"anti-bridging-device-families","Anti-bridging device families",[491,492,493,509],"table",{},[494,495,496],"thead",{},[497,498,499,503,506],"tr",{},[500,501,502],"th",{},"Family",[500,504,505],{},"Mechanism",[500,507,508],{},"Best suited to",[510,511,512,525,538,551,564,577],"tbody",{},[497,513,514,519,522],{},[515,516,517],"td",{},[70,518,338],{"href":141},[515,520,521],{},"Continuous acoustic vibration",[515,523,524],{},"Most powders, especially cohesive Class-C; non-contact",[497,526,527,532,535],{},[515,528,529],{},[70,530,531],{"href":294},"Air cannon \u002F air blaster",[515,533,534],{},"Periodic high-pressure pneumatic blast",[515,536,537],{},"Hard bridges, large silos, established practice",[497,539,540,545,548],{},[515,541,542],{},[70,543,544],{"href":290},"Bin vibrator",[515,546,547],{},"Continuous mechanical or pneumatic vibration",[515,549,550],{},"Small bins; can compact wet material",[497,552,553,558,561],{},[515,554,555],{},[70,556,557],{"href":183},"Fluidisation pad",[515,559,560],{},"Aerates the lower bed",[515,562,563],{},"Dry, fluidisable powders",[497,565,566,571,574],{},[515,567,568],{},[70,569,570],{"href":298},"Whip hammer",[515,572,573],{},"Manual impact",[515,575,576],{},"Legacy practice; HSE concerns",[497,578,579,582,585],{},[515,580,581],{},"Mechanical extractor",[515,583,584],{},"Bypasses the discharge",[515,586,587],{},"Continuous-flow processes",[81,589,591],{"id":590},"selecting-a-device","Selecting a device",[57,593,594,595,598],{},"Selection depends on material properties (",[70,596,597],{"href":94},"Geldart class",", moisture, temperature), vessel geometry and operating mode. Sonic horns are increasingly the default specification because they cause no structural stress, work continuously, and integrate cleanly into existing control systems.",[81,600,147],{"id":146},[86,602,603,607,611,615,619,623,627],{},[89,604,605],{},[70,606,251],{"href":250},[89,608,609],{},[70,610,154],{"href":72},[89,612,613],{},[70,614,159],{"href":77},[89,616,617],{},[70,618,338],{"href":141},[89,620,621],{},[70,622,531],{"href":294},[89,624,625],{},[70,626,544],{"href":290},[89,628,629],{},[70,630,632],{"href":631},"\u002Fglossary\u002Fmaterial-flow-promotion","Material flow promotion",{"title":171,"searchDepth":172,"depth":172,"links":634},[635,636,637],{"id":488,"depth":172,"text":489},{"id":590,"depth":172,"text":591},{"id":146,"depth":172,"text":147},"Anti-bridging device is the generic procurement term for any flow-aid hardware installed to prevent or break bridging, rat-holing and other discharge stoppages in a hopper or silo. The category covers a range of technologies with overlapping use cases.",{},[349,73,78,352,641,642,643],"air-cannon-air-blaster","bin-vibrator","material-flow-promotion",{"title":645,"description":646},"Anti-bridging device — flow-aid hardware for hoppers and silos","An anti-bridging device is any flow-aid hardware installed to prevent or break material bridging in a hopper or silo: sonic horns, air cannons, vibrators, fluidisation pads.",[648],{"title":358,"url":359},"glossary\u002Fanti-bridging-device","F84_oGC7LK5MbkcV3H8w2y2q4Rlq57hK9oqpx-7MSRs",{"id":652,"title":95,"aliases":653,"body":656,"category":178,"description":828,"extension":180,"meta":829,"navigation":182,"path":94,"relatedTerms":830,"seo":832,"sources":835,"stem":839,"term":95,"__hash__":840},"glossary\u002Fglossary\u002Fgeldart-classification.md",[654,655],"Geldart A B C D","Geldart powder classification",{"type":54,"value":657,"toc":822},[658,664,668,752,756,791,795,800,802],[57,659,660,661,663],{},"The ",[60,662,95],{}," (Derek Geldart, 1973) groups powders by particle size and density into four classes that predict fluidisation, bridging and discharge behaviour. It is the most widely used powder-behaviour map in industrial bulk-solids handling.",[81,665,667],{"id":666},"the-four-classes","The four classes",[491,669,670,686],{},[494,671,672],{},[497,673,674,677,680,683],{},[500,675,676],{},"Class",[500,678,679],{},"Particle size \u002F density",[500,681,682],{},"Behaviour",[500,684,685],{},"Example materials",[510,687,688,704,720,736],{},[497,689,690,695,698,701],{},[515,691,692],{},[60,693,694],{},"A",[515,696,697],{},"Small (30–100 µm), low density",[515,699,700],{},"Fluidises well; expands before bubbling",[515,702,703],{},"Cracking catalyst, alumina fines",[497,705,706,711,714,717],{},[515,707,708],{},[60,709,710],{},"B",[515,712,713],{},"Medium (100–500 µm), medium density",[515,715,716],{},"Bubbles immediately on fluidisation",[515,718,719],{},"Sand, salt, larger cement particles",[497,721,722,727,730,733],{},[515,723,724],{},[60,725,726],{},"C",[515,728,729],{},"Very fine (\u003C 30 µm), cohesive",[515,731,732],{},"Hard to fluidise; channels; cohesive arching",[515,734,735],{},"Cement, fly ash, flour, talc",[497,737,738,743,746,749],{},[515,739,740],{},[60,741,742],{},"D",[515,744,745],{},"Large (> 500 µm), dense",[515,747,748],{},"Spouts rather than fluidises",[515,750,751],{},"Coal, gravel, grain",[81,753,755],{"id":754},"why-it-matters-for-hopper-design","Why it matters for hopper design",[86,757,758,773,779,785],{},[89,759,760,762,763,404,765,767,768,216,770,772],{},[60,761,125],{}," are the most prone to ",[70,764,349],{"href":250},[70,766,350],{"href":259},". ",[70,769,286],{"href":141},[70,771,295],{"href":294}," and aeration are routinely needed",[89,774,775,778],{},[60,776,777],{},"Class A powders"," flow well from properly-designed hoppers; problems usually trace to wet incoming material",[89,780,781,784],{},[60,782,783],{},"Class B powders"," are predictable and well-suited to standard hopper geometry",[89,786,787,790],{},[60,788,789],{},"Class D powders"," rarely bridge but are abrasive and shock-loading the hopper",[81,792,794],{"id":793},"acoustic-cleaning-fit","Acoustic-cleaning fit",[57,796,797,799],{},[70,798,286],{"href":141}," are most often deployed on Class C powders — fly ash, cement, lime, fine carbon black, food powders — because that is where cohesive flow problems concentrate.",[81,801,147],{"id":146},[86,803,804,808,812,816],{},[89,805,806],{},[70,807,154],{"href":72},[89,809,810],{},[70,811,251],{"href":250},[89,813,814],{},[70,815,260],{"href":259},[89,817,818],{},[70,819,821],{"href":820},"\u002Fglossary\u002Ffly-ash-hopper","Fly-ash hopper",{"title":171,"searchDepth":172,"depth":172,"links":823},[824,825,826,827],{"id":666,"depth":172,"text":667},{"id":754,"depth":172,"text":755},{"id":793,"depth":172,"text":794},{"id":146,"depth":172,"text":147},"The Geldart classification (Derek Geldart, 1973) groups powders by particle size and density into four classes that predict fluidisation, bridging and discharge behaviour. It is the most widely used powder-behaviour map in industrial bulk-solids handling.",{},[73,349,350,831],"fly-ash-hopper",{"title":833,"description":834},"Geldart classification (A\u002FB\u002FC\u002FD) — powder behaviour map for bulk-solids handling","The Geldart classification groups powders by particle size and density into A, B, C and D classes. Predicts fluidisation, bridging and discharge behaviour.",[836],{"title":837,"url":838},"Wikipedia — Geldart classification","https:\u002F\u002Fen.wikipedia.org\u002Fwiki\u002FGeldart_classification","glossary\u002Fgeldart-classification","ZNR1dvtOZBK6Zw0u8RvjOYajHOiEu_9J39jSWHljRes",1782613740968]