玻璃厂毕业设计外文翻译玻璃熔窑的最优设计Word文档格式.docx

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WHATISTHEBESTDESIGNFORAGLASSFURNACE

N.Ya.Suvorov

（KurlovGlassworks）

During195354therewasadiscussioninGlassandCeramicsonthedesignoftankfurnace.Thediscussionwasveryinformativeforworkersintheglassindustry,foritacquaintedthemwiththeexistingviewsonthismatter,althoughitwasnotcompletedbythepresentationofconclusionsrelatingtothecoursestobefollowedinthedesignofglassfurnaces.

Itmustbeacknowledgedthatsciencehasnotyetsucceededinmakingacompletestudyandsystematizationofexperiencegainedintheoperationofglassfurnaceandhasnotyetbeenabletotellushowtodesignfurnacesthatwillcorrespondtothepresentlevelofknowledgeandtechnology.

Whatisthefundamentalprinciplewhich,inouropinion,mustformthebasisofthedesignofperfecttankfurnaces,Itwillbeobviousthatbya＂perfecttankfurnace＂wemeanonethatisasefficientaspossibleintechnicalandeconomicrespects.

Thedesignofatankfurnacemustbesuchthatthemeltedglasspassedtothemachinesinstrictsequence.Forexample,ifthecapacityofthefurnacesis1000tonsofglassandthemachinesonlyaftertendays.

Weconsiderthatthetimehascomewhenitshouldbepossibletoarriveatawellgroundedconclusionconcerningthedistributionofcurrentsofglassintankfurnacesandtodesignafurnaceaccordingly,sothatourbasicprincipleofthestrictsequenceofthemeltedglasstothemachinescanberealized.

Itisessentialtoeliminateundesirablecurrentsofglassandtheformationoflayersdifferingincomposition,i.e.tokeepthekineticsofglasswithinlimitssetbythespecialdesignofthetankfurnace,bytheheatingscheduleadopted,andpossiblybythemechanicalactionexertedionthemeltedglass.Ourproposeddesignforsuchafurnaceisrepresentedinfigures1-6.

Wedonotconsiderthattheproblemofconstructingaglasstankfurnaceofourdesignismoredifficultthanmanyothersproblemsalreadysolvedbyscienceandtechnology.Thesolutionofthisproblemiswithinthepowerofourplanninganderectionorganizations.

Inthelightoftherequirementsthatwehavemadewithrespecttothedesignofglassfurnaces,thetanksoftheverylargetankfurnacenowinuseintheglassindustrygivetheimpressionoflarge＂fryingpans＂inwhich,attheglasssurface,theglassisnotmeltedbut＂roasted＂,andintheroastedcondition,afterbeingcooledfor10-12hours,ispassedtothemachines.

Whensuchapparentlywell-meltedglassisexaminedoptically,itisfoundthatthereareinnumerabledefects:

streaks,whirls,stripes,threads,etc.,whichdifferfromthesurroundingmass.Suchaglassisnon-uniforminmechanicalandtechnicalproperties;

theproductivityofthemachinesisnotashighasitmightbeandtheglassisoflowerutility.

Inthemanufactureofopticalglassthesedefectsareeliminatedbyprolongedstirringoftheglasswithspecialstirrers.Inthemanufactureofsheetglass,pressedware,etc.,noeffortismadetoovercomethesedefects,andallisleftinthecareofthe＂lawsofthermalmovementintheglassmass＂.Rapidcoolingofglass,particularlywhenthereinanegativepressureovertheglasssurfaceinthecoolingzone–nottospeakoftheuseofcoolersandblowers–resultsintheformationoflayersdifferinginviscosityandthereforeintheproductionofglassfullofwhirlsandwaves,varyinginthickness,badlyannealed,notthermallydurable,givingmuchbreakageduringprocessing,andnotdurableinuse.

Slowcoolinggivesglassthatismorestableagainstleaching.Rapidlycooledglasshasdifferentphysicochemicalpropertiesthanthesameglasscooledslowly,Wecannotagreewiththeassertionthatglass,havingattainedtoadefinitedegreeofclarityduringmelting,cannotbesubmittedtoatemperaturehigherthanthatpreviouslyattained,norwiththerecommendationthatcoolingshouldberapidandsofixthestateoftheglasswithallitsestablishedandnon-establishedequilibria.Also,wecannotaccepttheadvicethatweshouldalwaysadjusttheatmosphericregimeofthefurnacetothecourseofthemeltingprocess.Suchadviceistheoreticalandcannotserveasaguidingprincipleforproductionpersonal.

Preventionoftheoverheatingoftheglassbyincreaseinthedimensionsofthefurnaceorwiththeaidofcoolersandventilatorsmustberegardedashighlyerroneous.

Themainandgreatestdefectoflargetankfurnaceandofallfurnacesingeneral,particularlythosewithoutbarriers（floatingbridges,bridgewallsetc.）isthattheupperlayerofglassmovesveryrapidlytotheworkingend.Thishasmanyundesirableconsequence,particularlyinthenon-barriermethodofformingsheetglassbyverticaldrawingmachines.

Wemaintainthatglassoftheupper,workinglayer,movingovertheintermediatelayerdisposedbetweenitandtheoppositelymovinglowerlayer,particularlyentrainesglassformtheintermediatelayer.Initsturn,glassoftheupperlayerpartiallyfallsintotheintermediatelayer.Theseprocessesbringaboutthephysicochemicalandthermalnon-uniformityoftheglass–thecauseofallofthedefectsindicatedabove.

Weconsiderthatinexistingtankfurnaces-particularlyinverylargefurnace-atleast90%oftheglassenteringhemachineshasbeencarriedtherewithin12-16hoursaftermeltingbythemainworkingupperlayeroftheglassmass,whichisformedatthehottestmasspointofthisviewcanbereadilyconfirmedbycoloringtheglassmass.

Fromourknowledgeoftheformationofcurrentsinmeltedglassintankfurnacesweconcludedthatitisnecessarytolearnhowtocontrolthesecurrents,toeliminatetheirharmfuleffect,andtocausethemtoassisttheprocessbymixingthelayersofglasstogetherandbringingabouttheirhomogenization.

Thereisnoneedtosayverymuchabouttheharmfuleffectsofthelayersofglassdisposedbelowtheupperworkingcurrentinexistingglasstankfurnaces,particularlythoseoflargedimensions.Iftheuseoffurnacesoflargedimensionshaseffectedsomeimprovementintheunfavorableeffectofthedirectfeedingofthemachineswithglassfromthetankfurnace.

Ourlargefurnacesdonothavehighspecificoutputs,whereasweknowfromthetechnicalliteraturethatfurnaceof1500㎏

outputandhigherareinexistence.

Inouropiniontankfurnacesprovidedwiththroatsdeserveattention.Atthetechnicalliteraturethatfurnacesforthemanufactureofglassofallkinds,apartfromspecialglasses.

Theresultsoftheexperimentsthathavebeencarriedoutonthemanufactureofsheetglassinfurnacesprovidedwiththroatsarenotconclusive,anditisveryunfortunatethat,owingtoaninsufficiencyoffuelandbatch,suchexcellentfurnaceshavebeentestedundersuchunfavorablecondition.

Wewishtodesignaglasstankfurnaceinsuchawaythattheworkingstreampassingtothemachinesshallnotbeintheupperlayeroftheglass,butinthelowerlayer.Onlyundertheseconditionswillthephysicochemicalandthermalhomogeneitybeattainedwhichwillconfergoodworkingpropertiesofwell-annealedsheetglasswithoutthicknessvariationswithaminimumofbreakage.

Whentheworkingcurrentinaglasstankfurnacebecomesthelowerlayer,theimperfectionintheglasswhichoccurintankfurnaceshavinganupperworkingcurrentareeliminated.Theglasswillberenewedthroughoutthewholetankwithinastrictlydefiniteperiodofstagnation-inthetankandinthechannelattheworkingend-whichwemaintainarethemainsourcedofstripiness,thicknessvariation,friableplaces,andthreadlikewhirls.Thisviewisconfirmedbyresultsoftheproductionofsheetglassfrombridgelesstankswithdirectfeedingofmachinesfromthetankfurnace.

Ascanbeseenfromthediagramsshowingtheprincipleofthedesignofourproposedglasstankfurnace,thebottomofthetankisnothorizontalthroughoutitslengthandbreadth,sothatthedepthofthetankvariescorrespondingly.Thebottomslopestowardsthethroat,thefallinlevelbeing400-800mm.Thefallfromthesidetothecenterofthebottomis200-500mm.Thebottomofthefurnaceisthereforeintheformofagutter.

Thebottombeingofthisform,theglassisboundtomoveoveritsslopingsurfaceinthedirectionofthethroat.Theglasswillmovealsofromthesidesofthetankbottomtothecenterofthetankand,mixingwiththecentralstreamandbecominghomogeneous,passintothethroat（fig.3）.

Itwillbeseenfromthetemperaturecurvethatthemaximumtemperatureoccursattheendofthefurnaceneartothethroat.Sincetheglassmovesalongthebottominthedirectionofthethroatandthemaximumtemperatureisatthethroat,theupperlayerofglasswillmovefromthethroattowardthedoghouseand,acquiringincreaseddensityandhomogeneity,fallintothebottomlayerandmoveintothethroatasalowerworkinglayer.Weareconvincedthatinatankofthisdesignoperatingunderthegiventemperatureconditionstherewillbenoreturncurrentofglassmovingalongthebottominthedirectionofthedoghouse1.

ItwillbeseenfromFig.4thatthecrownofthetankfurnacerisesfromthethroatinthedirectionofthedoghouse.Acrownofthissortisessentialinordertoestablishthenecessarytemperaturedistributioninthefurnace（Fig.2）andalsosothatanyair-carriedswirlsofbatchwillbecarriedawaytothedoghousebytheuppercurrentsofhotgases.Theportsandcrownmustbeaslowaspossibleoverthetankfurnace.

Theportsintheupperpartmustbeunifiedwiththecrownofthefurnace（Fig.5）.Theburnersmustdifferincrosssectionandinthedirectionsoftheirflames.Thearrangemento