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How to choose the correct baghouse filter

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How to choose the correct baghouse filter

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How to choose the correct baghouse filter

  1. 1. 1 | P a g e http://www.baghouse.com/2011/02/02/how-to-choose-the-correct-baghouse-filter/ How to Choose the Correct Baghouse Filter Step 1– FilterMedia Selection: Choose the mediafromwhich yourfilterbagswill be constructedof basedonthe type of application theywill be usedfor.Take the followingthingsintoconsiderationpriortoselectingyourfiltermedia: • Temperature –Do yourbags needto withstandextreme temperatures? • Material – What is the filterbeingusedfor? • Chemistry –Can yourfilterwithstandthe chemicalmakeupof the dustparticles • Resistance- Isthe filtermediaable toresistthe abrasionof the dustparticles Choosingthe correctfiltermediaisanimportantandsometimesdifficultprocess.Toassistyouin the identificationof the rightmediaforyourbags,keepthe followinginmind:Filterbag performance isdirectlyrelatedtohowwell itcantolerate the environmentinwhichitisbeingused. How efficientlyitcanremove the dustparticlesfromitsfabricand itsabilitytobe cleanedbythe dustcollectorisalsoimportant.Youmust firstlearnto identifythe type of filtermediacurrently usedinyour application.Belowyouwillfindalistof typical constructionmethods: • Wovenfelts • Non-wovenfelts • Natural fibers • Synthetics(ThermosetorThermoplasticssuchasPolypropylene “PPRO” –Polyphenylenesulfide “PPS” – Polyester“PE”) For additional informationonmediatypes please examine ourFilterFabricsChartbelow.A simple testto determine if amaterial isathermoplasticistotake a small swatchand put a flame toit. A thermoplasticmaterialwillbegintomeltwhenexposedtodirectheat.The selectioncriterion eliminatesmaterialsbasedontemperature andchemical characteristics.The firstcutisusuallymade basedon temperature.Thenthe chemical characteristicsof the gasstream are consideredtofurther refine the search.Next,the efficiencyof the material furtherdictatesthe constructionof the material suchas the weight,oz/sq.ft.,fiberandsurface treatments/membranes.Lastbutnot least, if there are still twoormore candidatesitcomesdownto a price versusperformance trade off. DustCollector FilterFabrics: Popular Materials Polyester Felt Recommendedcontinuousoperationtemperature: 275°F Maximum(shorttime) operationtemperature: 300°F Supportscombustion: Yes Biological resistance (bacteria,mildew): NoEffect
  2. 2. 2 | P a g e Resistance toalkalis: Fair Resistance tomineral acids: Fair+ Resistance toorganicacids: Fair Resistance tooxidizingagents: Good Resistance toorganicsolvents: Good Available weights:10oz. – 22 oz. PolypropyleneFelt Recommendedcontinuous operationtemperature: 190°F Maximum(shorttime) operationtemperature: 210°F Supportscombustion: Yes Biological resistance (bacteria,mildew): Excellent Resistance toalkalis: Excellent Resistance tomineral acids: Excellent Resistance toorganicacids: Excellent Resistance tooxidizingagents: Good Resistance toorganicsolvents: Excellent Available weights:12oz. – 18 oz High Temperature Materials Conex® /Nomex® Felt(Aramid) Recommendedcontinuousoperation temperature:400°F Maximum(shorttime) operationtemperature: 425°F Supportscombustion: No Biological resistance (bacteria,mildew): NoEffect Resistance toalkalis: Good Resistance tomineral acids: Fair Resistance toorganicacids: Fair+ Resistance to oxidizingagents: Poor Resistance toorganicsolvents: Good Available weights:10oz. – 22 oz. Polypropylene Felt Conex® / Nomex® Felt (Aramid)
  3. 3. 3 | P a g e P84® FeltPolyimide Recommendedcontinuousoperationtemperature: 475°F Maximum(shorttime) operation temperature:500°F Supportscombustion: No Biological resistance (bacteria,mildew): NoEffect Resistance toalkalis: Fair Resistance tomineral acids: Good+ Resistance toorganicacids: Good+ Resistance tooxidizingagents: Good+ Resistance toorganicsolvents:Excellent Available weights:14oz. – 18 oz. Ryton® Felt/PPS Recommendedcontinuousoperationtemperature: 375°F Maximum(shorttime) operationtemperature: 400°F Supportscombustion: No Biological resistance (bacteria,mildew): NoEffect Resistance toalkalis: Excellent Resistance tomineral acids: Excellent Resistance toorganicacids: Excellent Resistance tooxidizingagents: Fair Resistance toorganicsolvents: Excellent Available weights:16oz. – 18 oz. Dust Collector Filter Specialty Materials HomopolymerAcrylicFelt Recommendedcontinuousoperationtemperature: 250°F Maximum(shorttime) operationtemperature: 275°F Supportscombustion: Yes Biological resistance (bacteria,mildew): Good+ Resistance toalkalis: Fair Resistance tomineral acids: Good+ Resistance toorganicacids: Excellent Resistance tooxidizingagents: Good P84® Felt Polyimide Ryton® Felt / PPS Homopolymer Acrylic Felt
  4. 4. 4 | P a g e Resistance toorganicsolvents: Good+ Available weights:15oz. – 18 oz. EpitropicFeltAntistatic Recommendedcontinuousoperationtemperature: 275°F Maximum(shorttime) operationtemperature: 300°F Supportscombustion: Yes Biological resistance (bacteria,mildew): NoEffect Resistance toalkalis: Fair Resistance tomineral acids: Fair+ Resistance toorganicacids: Fair Resistance tooxidizingagents: Good Resistance toorganicsolvents: Good Available weights:14oz. – 16 oz. Step 2– Dust Collector Filter Measurements: Accurate measurementsleadtothe bestfit.It’slikelythatyourdustcollectorhasbeenmodified overthe yearsdue topermittingissuesorchangesinyourprocesswhichcalledfora reconfiguration of the Baghouse.Inthiscase OEM configurationswill notfitandyouwill needtoobtainaccurate measurementsforyourfiltersbeforeorderingreplacementfilterbags.If youcurrentlyhave filter bags installedthatare functioningproperly,youcanremove one of these bagstoget the proper measurementsforyourreplacementorder.A spare bagthat hasnot beenusedyetcan alsobe measuredif available.However,be sure toverifythe bagmeasuredisthe same asthe bags currently beingusedinthe dustcollector.If youare removingausedbag to measure,pleasebe sure touse all necessaryprecautionarymeasuressetinplace priortoremoval i.e.gloves,protective garmentsand respiratoryequipmentif needed.Itisbestnotto relyonlyonthe numbersoff the unitof OEMfilter specificationsbecauseof possible changestothe configurations.Of course the bestsolutionisto mail the manufacturera newor usedbagthat can be useda guide sample. Flat Width:Place the filterona flatsurface such as a large table or cementfloor.Withthe filter stretched out,pressdownonthe side.Usinga measuringtape,veryaccuratelyrecordthe width.Be sure to holdthe filterdownfirmlyonanevensurface whentakingthismeasurement. Diameter:When measuringthe tube sheetholeof apulse jetstyle dustcollector,firstmake sure the hole hasnot beendamagedorwarpedinany way.Cleanthe surface thoroughlywithawire brush thenusinga micrometer,measure the holeinbothdirections.If the measurementsare atall differentlocate anotherholdandrepeatthis process. Length: Remove the filterfromthe unit.Preferablywiththe assistance of anotherperson,stretch the filterout.While maintainingtensiononthe filterrecordthe lengthfromthe longestpointat each endusinga measuringtape.Donotinclude andstraps,metal caps or otherhanginghardware inthe measurement,justthe lengthof the filteritself. Epitropic Felt Antistatic
  5. 5. 5 | P a g e Step 3– Top & Bottom Construction The top and bottom construction of a filter bag involves a variety of possible configurations. Identifying the type of cleaning process used by your dust collector will help to determine which configuration is needed. The most common types of dust collectors are “Pulse-Jet” “Shaker” “Reverse Air”.The chart belowcanhelpyouidentifywhichtype of dustcollectorfilteryouare using. Filter Configuration Chart Pulse-JetDustCollectors(Reverse jet) – Foundinalmosteveryindustrial environment.Theyare the mostpopulardesignandare seeninnearlyall industrysegments.Pulse-JetUnitscanbe dividedinto twomajor groupsTop loador bottomload unitssometimecalledtopentry(walk-inplenum) or bottomentry(commoninbinvents) because of the pointof entryusedtochange outthe filters. Typical filterconfigurationforatop loadunit: Snap Band Top (double-beadedring) DiskBottom(w/o wearstrip) Typical filterconfigurationforabottomloadunit:Raw End Top Disk Bottom(w/owearstrip) Shaker Dust Collectors(Mechanical Cleaning) – Usuallyfoundinolderapplicationswhere unscheduleddowntime isnota majorconcern. Typical filterTopConfigurations Loop Top GrommetTop Strap or Tail Top Metal Hangeror Cap Typical FilterBottomConfigurations Corded Cuff with Clamp Snap Band (Double-BeadedRing) Reverse-AirDustCollectors– Usuallyfoundin verylarge airhandlingenvironmentssuchaspower generationandcementplantsalthoughtheydohave usesinavarietyof industries.Sometimes calleda structural bag,these filtersusuallyhave aseriesof supportringsspacedeveryfew feet throughoutthe lengthof the bag. Typical Top Configurations Compression bandw/MetalCap &Hook Typical BottomConfigurations Compression band SnapBand Cord w/MetalClamp Snap Band Raw Edge Cord Hanger
  6. 6. 6 | P a g e Grommet Loop Strap Support Ring Rubber O-Ring Disk Disk With Wear Strip Flange Hem Sewn Flat Envelope
  7. 7. 7 | P a g e Step 4– Additional Options Ground Wires – Use to comply with Factory Mutual requirements for static dissipation. Ground wire can be made from stainless steel or copper however this technique only works on a localized area of the filter. For optimal static dissipation look at conductive fiber filter made with Epitropic or Stainless Steel fibers. Wear Cuffs – Used to combat abrasion at the bottom of the bag either from a sandblasting effect or from bag-to-bag abrasion due to turbulence in the bag house. Usually 2 to 4 inches in length and made of a material similar to that of the body of the filter bag. Special Finishes – There are many finish options that can be added to the filter media at the time it is manufactured. Please refer to the materials selection area for further details. If you want to order a specific brand or special type of finish please add that request into the additional comments section when ordering.

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