Document reprr1JRwr75L4Zwwan7Q4gb7

FILE NAME: Engineering (ENG) DATE: 1948 DOC#: ENG006 DOCUMENT DESCRIPTION: Book Excerpt - Design of Industrial Exhaust Systems DESIGN OF INDUSTRIAL EXHAUST SYSTEMS How to Design, Build or Buy an Exhaust System that Will Adequately and Economically Perform the Func tions Required by Law or Prescribed by Specialists in Industrial Hygiene. This Treatise Covers Exhaust Ventilation, Low-Pressure Pneumatic Conveying, the Design of Hoods, Piping and Structural Details, and the Selection of Dust Separators, Centrifugal and Axial-Flow Exhaust Fans. By JOHN L. ALDEN Member, American Society of Mechanical Engineers 194$ P R IN T IN G THE INDUSTRIAL PRESS 148 LAFAYETTE STREET, NEW YORK 13, N. Y. Publishers of HEATING AND VEN TILA TIN G Copyright, 1939, 1948 THE INDUSTRIAL PRESS N ew York 13, N . Y. PRINTED IN UNITED STATES OF AMERICA C A LIFO R N IA STA TE L IB R A R ? PREFACE HfieIlSds boofokhemaaltkheshanzoaradtst,eminpdtustotriaclovdeur stthse obrrotahde gpaatthoorslohgaicvael epxhtaesnedsedofthineduhsotrriizaolnhyogfitehnees.e Asubblejeicntvseismti imnfeonrsmeleyd ionf rtehceennteeydeafrosr. eIxnhdauussttrysa, ntihtaetrieofno.re,Itisiswneollt wpuerllpoinsfeoromf ethdisasbotookhoiswtobetsetlltothseateisnfgyinteheart hnoewedt.oTdhee swigilnl aadnedqubauteilldy oarndhoewcontoombiucyallaynpeerxfhoarumstthseysftuenmctitohnast preAslctrhiobuegdhbyexthhaeusitndvuesnttriilaaltiohnyghieansebeexepnerptraocrtibceydlafwor. mfoor remtohraenth7a0ny4ea0rsyeaanrds, htahse bleiteenrarteucroegnisizeadstobnyisshtaintugltye sincgantfya.ctoTrhs.ereFisreset,mthtoe hfaievled bheaesn btweeonmrealjaotrivceolyntrsimbuatll aonf dcoilnlecgoensspaicnudouosthaenrdinhdaespennodt eantttriancvteesdtigthaetoarst.tenTtiohne mseacnonyd,ofanthdopseerhwaipthsinprtehdeominindaunsttr,yfahcatovre htarseabteeednththeairt vacuclguemdulnaetietdhedrattoa caosmppreetcitiooruss ntorardteo sceucsrteotsmetors.beTdhie eaxuhthaourstawimosrktoanddisptoelemxporsetssofmthaenymoyfsttehreytrsaudrreousencdrientgs isnciosutrsaigohf t-thfoerwshaordrtceonmgiinnegesrinogf ttehrims sb.ooHke bisutfublleyliecvoens dtheasitgnsuoffficaiednetqudaattea ahnadvelobwe-ecnospt rseyssetnemteds otor tpoeramppitratihsee cIot mispheotiptievde tdheastigtnhse arenaddtehrewcillalibmeseonfcoriuvraalgecdonttoramcteoarss. euxreh,aursetcosyrdsteamnds toputbhleishendentghinaeteoriunrgcofallcetcstiocnonocferbnaisnigc daTtahewislul bbjeeccotmoef emxhoraeusctovmepnlteitleatiaonndemmobrreacreesliathbele.the otircyalodfesaiigrnf,lotwhe, tsheelecatpiopnlicoaftioconmomf ethrcisialthfeaonrsyatnodpdraucst tchoelletcetsotrins,g thofe thcoencsotrmucptlieotnedosfytshteemp.hyTshicearel pislannot laancdk of published material on the subject of fluid flow. Un- fmourtcuhnoatfeilty,istthoebeinffoourmndatiinonpaipserws indoetlyeasscilayttaecrecedssaibnlde ttoradthicetibounssyaerengeinneceoru. ntMeroerde,ovreeqr,uimrinangyinctoennfsuisviengstcuodny taoutrheocornhcialse csoenlefclitcetdingansdtataebmriedngtesdanthdecomnoclsutsiaountsh.eTnthiec daAtackfonrowthleedgthmeeonretsticaarlepdourteiontos oCf. thHe. bBo.okH. otchkiss, Eofditthoer,mHaeteartiainlgth&rouVgehntsielraiatlinpgu,blwichaotiognu,idaendd ptoortEio. nJs. Ccrriatinceis,mWoefsttehren eEalrelcietrricchCaop.t,erIsn.c., for his advice and PREFACE TO SECOND EDITION puIbnlisthheed,inadtevravnecneisnganydearersfinseimnceenttshiisn ebxohoakuswt assysftiermst pdreavcetliocpesmehnatvs,e twtaokennewplacchea.pteIrns rheacvoegnbiteieonn porfepthareesde acshewmeilclaalspmroacneysselesssfoerr asdudrfiaticoensp.reTphareagtiroonwathndoffienlieschtirnog ocofnmtroelt.alsAxhiaasl fwloawrrafanntesd, ablsroo,adhearvetraecaqtmuierendt noefwfuimme poIrntan1c9e14intheexhaauutshtowr oirnks.talled a trial exhaust unit on uangitranwiates snuerfvaecrinfgulmlyacdheinveeloinpeBdarbreec,aVuseermoofntw. oTrkheisr osaptpisofsaictitoionn. Itht aist, htheerreefpoorert,swtihthe csouncsciedsesrfaublleefpfeorrstsonoalf oacthceerpstanwcheosoef pexerhsaisutsetncperotienctrieocnenint ytheearsstohnaes cguatitninedg indAupsptrrye.ciation is due to Miss Grace N. Donovan, LCoib.,raIrniac.n, ofofrthheeKr epaartnieyncWe oiinksreoafdtihnegWanedstearbnstErlaeccttirnigc tphreepsaervaetiroanl houf nthderesdectoencdhneicdaitlioanrtoicflethsisrebvoioekw.ed in the T he Author CHAPTER I. FLOW O F FLUIDS THtyEpesteorfmlo"we-xphraeusssutresyisntdemus"triaasl panpepulimedatitco scyesrtetamins cludiinsgnodtuasctccuorlaletecltyindge,ffiunmedebruetmuosvuaalllaynids ilnotwer-pprreestesudreas in dcoitniovneiynigngsysystsetemmss.areHedaetifningi,tevlyenetixlcaltuindgeda. ndAagirenceornal icnhgarathcrteoruigsthic tohfeepxihpaiunsgt sisysnteomt shoismtohgaetntehoeusf.luiIdt flioswa smoilxidtsurien, suussupaellnysioonf oarirvaapsorthoeuspoarregnatsefoluuisd,mcaatrerryiainlsg. Bsyrsotaedmlye,vaenn ethxohuaguhst istsyspterimmaisryappunrpeuomseatmicaycobneveqyuiintge difTfehreentchfraormacttehreistmicesreotfratnhseposrytasttieomn oafndmaittesriadless.ign opfrobthleemcsonavreeydinicgtaftleudidp. rinKcniopwallleydgbey othfethlaewses loafwfslowis efunngdinaemere.ntAaldmeqituteipdmlye, nstimfpolre tshyestecmosmopfettehnet tydpeseisgncionvg ecirfeicd rbefyersetnactee tcoodthees pmrianycipbleescoonfsftlruuicdtefldoww. itNhoeuvtersthpee leesssse,ntaiatlhotorouthgeh suuncdceerssstfaunldsinoglutoiofnthoef btahseicutnhceoonrvyenis tdiiosntianlgupirsohbelsemtheortrutoly tghoeodrejfoinbemfroenmt tohfedmeseirgenlywphaiscsh aisblde.esiArabslpeeaekvienng faocrquthaeintbaunyceerwoifthexthheaufsutnsdyasmteemntsalisf only to test the competence of the contractor-designer. Functions of the Conveying Fluid toTihtse cdoenstvienyaitniognflubiudt noaltsoonlisy tirnasntrsupmoretnstathle inmaitnetrrioal ducing the material into the system initially. Flying 1 22 HOOD FORMS itnh.anlotnogt.al Iwt eaigphpteaorfsduthsat tisnsuigmnbifeircsanotfinpathrteicelevsaluraatthioenr ofofuhnedarlythdhuasztsardinsv. esTtihguast,edi,t i9s9r%ep, obrtyednuthmabt eorf ocferptaairn wtichleesre, aswtehreeseofpadrtainclgeesrocuosmpsrizisee,d1b0utm2i7c%ronosf othre ftiontearl, weTighhet aoufththoer msaamkpelsesn.o pretense of treating the patho lsotgroicnagllyasptheacttstohfe dmusotrse arnedcefnutmleitse.raItturies rbeecocmomnseunltdeedd. Ietffmecutsstisbefarercforgonmizecdomthpaltetken.owTlehdegefieolfddhuassts baenednthceuilr triivalatheadsinbteeennsipvuelbyl,ishhoewd.evTerh,eanendgminuecehr cvoanlucearbnleedmwaitteh dinufsotrmcohnitmroslelifnofhathzaerdlaotuesst irnedsuuslttsrieasvawilailblled.o well to Relative Dust Hazard taiWn hinildeuasutrtihaolrdituiessts,diaffefrewasatroe tkhneohwanrmdfeuflinneitseslyoftocebre hmaoznalrydoauss. qCuahritezf. amItonisg tehnecsoeunistesrielidca,inocicnudrurisntrgiecsomas tdhiessiomnielahr aansdgaranndittehocsuettienmgpalonydinhgaradb-rraoscikvempirnoicnegssoens tsousc,haalssos,ainsdknbolawstnintgo apnrdodgurcinedpinuglmoonntahreyodthisearb.ilAitysb. es othTehres, toaxreichdauzsatrsd,oiunscluwdhinegn lienahda,lemde.rcIunryf,aacrt,setnhiecreanids cthornosuidgehraibnlhealeavtiidoenncmeatyhabtethgerealitkeerlithhoaond tohfatpothisroonuignhg fooCdoaclondtuasmt ianlaotnioeni.s believed not to produce disabling fsiebnrtoesdis.byCallicmiuesmtonane,d mmaargbnlee,siudmolocmairtbeonaantdesmaasgrneepsriete hvaevgeetabbeleendsuhsotswnsutcoh baes ccoomttopna,rajtuivtee,lyhehmarpmlaenssd. wToohde eavlsiodenarcee tihnatthaisgicvaetengdoruys.t isHnoowtehvaerrm, fluacl,kiintgispboessittivtoe HOOD FORMS 23 pasrosutemcteiotnh.at it is dangerous and to provide adequate Dispersion of Dusts funTchtieonmoafnnpearrtiacnled sdizeeg.reeLaorgfedipsapretricsiloesn tohfrodwunst firsoma abywvhieretlueorocfutthteerirmkainyetbice denisetrrgibieusteadndovweritahowuitdeasasirseta ahnacned,faroremdeapirencduernretnetns.tireSlmy aulpl opnaratiirclceus,rreonntsthfeoroththeeirr dthisepekrisnieotnic. eTnheergmyassos loifttlae ttihnyatpiatrtiiscliencisapsaoblsemaolfl saunsd tparionjeedctefdligfhatr. fIrot mlostehse vpeolionctitoyf rgaepniderlaytioannd.2 cannot be cuFrriennets.dusTtsheinir sduissppeenrssiioonn ddreifptenwdisth atlhmeogsteneernatlirealiyr ubpyoncondtrrioftl.linFginthee dfuloswts, otfhetrheefoerne,traminuisntgbaeir.conCtrooallresde ploacratilclceus,rreonntsthoef mcoinldtrainryte,nsairtey.buTtheliitrtledisapfeferscitoedn bbyy dtayrngaemt-liickep,rosjoecttihoant rtehqeuipreasrticthleast tahree hthoroodwbne dpilraeccetldy, into the pipe mouth. Local Air Movements and Counteracting Velocities befSoorme eefefvecatliuvaetiocnounotfersatcratiyngaivrelcoucritrieenstscains nbeecedsestaerry mfuirnneadc.esCsoenldvoemctioenxceceudrre2n5tstofr7o5mf.pra.mdi.atoDrisr,ecotvewnisndaonwd dbryafctlsosminagywbiendmowucshomr obrye ibnrsitsakllibnugt sccarneebnes, cboanfftlreoslleodr dwehfeleeclstorfsr.eqFuleynwdhyeeclasu,sleardgiestuprubllaenycse aonvderevceonnsaibdrearasibvlee falraetap. aEnexlcessusrifvaecems,aocfhtiennekveiebprastiionns,upspaertnisciuolnardlyusotfwlahrigche would settle otherwise. The first puff of dust-bearing *A io micron abrasive particle thrown from a wheel at 10,000 f.p.m, can fly about 1 in. in still air. At the same speed a particle r / 1 6 In. diameter may be thrown 100 ft.