GLANDSEALSYSTEM在汽輪機轉子穿過外缸的部位，必需采取措施用以防止外部空氣漏入汽缸，從而影響排汽缸的真空，同時也必需防止汽缸內蒸汽漏出汽缸，漏入前軸承箱容易呵斥油中帶水，漏至汽機房破壞汽機房環境。汽輪機的汽封系統就是為了完成這一功能而設置的。Measuresmustbetakenattheportionswheretheturbinerotorpassesthroughtheoutercasingtopreventtheairleakagefromoutsideintothecasingandaffectthevacuityoftheexhausthood.Inthemeantime,thesteaminsidethecasingmustalsobepreventedfromitsleakagetotheoutside,especially,tothefrontbearingboxtoleadtoamixingofthelubricationoilwithwaterandtotheturbinehousetodeteriorateitsenvironmentalconditions.Theglandsealsystemofasteamturbineisfurnishedjustforsuchapurpose.輔助蒸汽母管SteamsealcoolerSteamsealcoolerSteamsealcooler汽封系統圖本系統是高低壓分開供汽的汽封系統.ThepresentsystemisaglandsealsystemcapableofsupplyingsteamtoHPandLPcylinderseparatelydeveloped.系統中主要設備有：高壓軸封供汽調理站、低壓軸封供汽調理站、高壓噴水減溫調理站、低壓噴水減溫調理站、各種截止閥、疏水閥等，連同汽封冷卻器、疏水擴容器等設備，共同構成了該機組汽封系統。該系統可以維持汽封供汽母管的壓力在0.107～0.11MPa(A)之間，供汽溫度在121～150℃之間，控制部分可根據實踐情況接入控制室，經過DCS系統調理各執行機構動作。Thesystemmainlyincludesthefollowingmainequipmentitems:HPglandsealsteamsupplyregulatingstation,LPglandsealsteamsupplyregulatingstation,HPwaterspraydesuperheatingregulatingstation,LPwaterspraydesuperheatingregulatingstation,variouscut-offvalvesanddrainvalves,glandsealcoolersanddrainflasktanksetc.Itcanexerciseafunctionofmaintainingthesteampressureinsidetheglandsealsteamsupplymainlinebetween0.107Mpaand0.11Mpa,thesteamtemperaturebetween121℃and150℃.ThecontrolsignalscanbesenttothecontrolroomaccordingtothespecificcasesandthencontroltheactionofvariousactuatorsthroughtheDCSsystem.轉子汽封GlandSealofRotor在汽缸兩端裝有汽封體和汽封圈，汽封圈上汽封齒環繞轉子，外表僅留有為防止在運轉過程中發生接觸的間隙。Glandcasingsandsealingringsareequippedatbothendsofthecylinderandtheteethonthesealringssurroundtherotorwithaclearancebeingkepttopreventanycontactbetweenthesaidteethandtherotorsurfaceduringtheturbineinoperation.在汽輪機啟動時，凝汽器抽真空，汽缸內的壓力低于大氣壓力，供至“A〞腔室的汽封蒸汽在一側經過汽封漏入汽輪機汽缸內，在另一側漏入“B〞腔室，汽封抽汽器正常運轉，使“B〞腔室維持壓力稍低于大氣壓力，因此空氣經過端汽封漏入“B〞腔室，構成汽氣混合物，經過一個與汽封抽汽器相連的接口，從“B〞腔室被抽出。(見圖1)Duringstartupofthesteamturbine,thecondenserisevacuatedandthepressureinthecylindersislowerthantheatmosphericpressure.Thesteamsuppliedtothe“A〞chamberoftheglandsealisleakedtothecylinderoftheturbineatonesideandto“B〞chamberatanotherside.Iftheairejectorfortheglandsealsisinnormaloperationtomaintainthepressurein“B〞chamberslightlylowerthantheatmosphericpressure,theairisleakedintothe“B〞chamberthroughtheglandsealattheend,formingasteamandairmixture.Thenthemixtureisevacuatedfrom“B〞chamberviaaportconnectedwiththeairejectorfortheglandseals(seeFig.1).隨著機組負荷的不斷提高，高中壓缸兩端的壓力逐漸添加，但因“C〞腔室與2號低壓加熱器(JD2)相連，所以高中壓汽封的“A〞腔室一直堅持送汽形狀；由于低壓缸壓力仍堅持一定的真空形狀，所以低壓汽封的“A〞腔室一直堅持送汽形狀。當除氧器能供汽時，那么切到正常運轉系統，即由除氧器來供汽(見圖2)。Withacontinuousincreaseoftheloadofthesteamturbine,thepressuresatbothendsofHPandIPcylinderwillgraduallyincrease.Asthe“C〞chamberisconnectedtothe2#LPheater(JD2),sothe“A〞chambersinHPandIPcylinderisalwayskeptinasteam-supplyingstate.DuetotheLPcylinderbeingmaintainedatavacuumstate,the“A〞chamberofLPglandsealsisalwayskeptinasteam-supplyingstate.Whenthedeaeratorhasanabilitytosupplysteam,thenormaloperationsystemshallbeputintoservice,i.e.supplyingsteambythedeaerator(seeFig.2).蒸汽壓力溫度控制安裝SteamPressureandTempController在汽輪機啟動和低負荷運轉形狀下〔普通低于40%負荷〕，輔助汽源經過軸封壓力調理閥減壓及噴水減溫調理閥控制的減溫器減溫后，向汽封母管供蒸汽。隨著負荷不斷提高(約40%負荷左右)，當除氧器的汽平衡室壓力建立起來時，那么切換到正常運轉系統，即由除氧器來供汽。供汽母管配有熱電偶及壓力變送器(設計院選配)，母管的溫度和壓力變化是經過與其相連的熱電偶和壓力變送器傳送的，信號傳到主控制室，由主控制室DCS系統完成對調理閥的溫度和壓力控制。Undertheconditionofthesteamturbineoperatinginthestartupstateandatalowload(generallylowerthan40%oftheratedload),theauxiliarysteamsourceshallsupplysteamtotheglandsealsteammainlineafterthesteampressurehasbeenreducedbytheglandsealsteampressureregulatingvalveandthesteamtemperaturehasbeendesuperheatedbyanattemperatorcontrolledbythewaterspraydesuperheatingregulatingvalve.Withacontinuousincreaseoftheload(toabout40%oftheratedload),whenasteampressureisestablishedinthesteamequilibriumchamberofthedeaerator,thenormaloperationsystemshallbeputintooperation,i.e.thesteamtotheglandsealsshallbesuppliedbythedeaerator.Thesteamsupplymainlineshallbeequippedwiththermocouplesandpressuretransmitters(selectedbyanelectric-powerdesigninginstitute).ThesignalsshowingthechangeofsteamtemperatureandpressureinthemainlinearetransmittedbythethermocouplesandpressuretransmitterstothemaincontrolroomandthentheDCScontrolsystemshallexerciseacontroloverthesteamtemperatureandpressurebyuseoftheregulatingvalvebasedonthesignals.汽封壓力調理閥能在一切運轉條件下以其DCS系統的給定壓力向各汽封供汽。軸封送汽調理閥壓力給定值為0.107～0.11MPa〔A〕。〔因母管壓損未知可按實踐情況調整〕TheglandsealsteampressureregulatingvalveshallsupplysteamtovariousglandsealsatapressuresetbytheDCScontrolsystematalltheoperatingconditions.Theglandsealsteampressuresetpointbytheregulatingvalverangesfrom0.107～0.11MPa〔A〕(duetothepressurelossinthemainlinebeingunknown,onecanmakeanadjustmentaccordingtothespecificcase).供汽母管蒸汽溫度主要是由減溫器來控制的，減溫水來自于凝結水泵，減溫水量是由減溫水調理閥來控制的，溫度信號取自供汽母管的溫度，將溫度信號轉換為4～20mA電信號送到主控制室，由DCS系統來控制減溫水調理閥的執行機構，使供汽母管蒸汽溫度控制在121～150℃之間。Thesteamtemperatureinthesteamsupplymainlineismainlycontrolledbythedesuperheaterwiththedesuperheatingwatercomingfromthecondenstatewaterpumpandthedesuperheatingwaterquantitybeingcontrolledbythedesuperheatingwaterregulatingvalve.Thetemperaturesignalisobtainedfromthesteamsupplymainlineandthenconvertedintoa4～20mAelectronicsignalwhichissenttothemaincontrolroom.Basedontheelectronicsignal,theDCScontrolsystemtakescontrolovertheactuatorofthedesuperheatingwaterregulatingvalve,maintainingthesteamtemperatureinthesteamsupplymainlinebetween121℃and150℃.汽封冷卻器GlandCooler汽封冷卻器以稍低于大氣壓力即0.095MPa〔A〕的壓力接納閥桿及汽封“B〞腔室的漏汽，因此保證“B〞腔室不斷堅持負壓。Theglandsealcoolerreceivesthesteamleakagefromthestemsandtheglandseal“B〞chamberbyoperatingatapressureof0.095MPa〔A〕slightlylowerthantheatmosphericpressure,thuskeepingthe“B〞chamberbeingalwaysatanegativepressure.蒸汽過濾器SteamFilter為了防止外部物質進入汽封和引起轉子的損壞，在每個汽封的供汽管道中運用了蒸汽過濾器，過濾器“Y〞形支管是程度安裝或置于管道的頂部，所以可以自行排空。Topreventforeignmattersfromenteringintotheglandsealsandcausingadamagetotherotor,thesteamfiltersareusedineverysteamsupplypipelinesoftheglandsealsandthe“Y〞-shapedbranchpipesshallbeinstalledhorizontallyorplacedonthetopofthepipes,thusensuringanairventbythefiltersthemselves.汽封系統的運轉OperationofGlandSystem冷態啟動Cold-stateStartup1.在汽輪機和進汽管道一切疏水閥翻開的情況下，投入盤車。Undertheconditionthatallthedrainwatervalvesonthesteamturbineandsteamintakingpipelinesareopened,theturninggearshallbeputintoservice.2.建立經過凝汽器的水循環。Establishawatercirculationthroughthecondenser.3.啟動凝結水泵并建立經過汽封抽汽器的冷卻水流。Startupthecondensatewaterpumpandestablishacoolingwaterflowratethroughtheairejectoroftheglandseals.4.開啟汽封抽汽器水室上的放氣口，直至全部殘留氣體排入大氣。Opentheairventonthewaterboxoftheairejectoroftheglandsealsuntilalltheresidualgasisdischargedtotheatmosphere.5.確認疏水擴容器殼體的疏水系統對凝汽器是翻開的。Makesurethatthedrainsysteminsidetheenclosureofthedrainwaterflashtankisopenedtothecondenser.6.確認汽封抽汽器水位報警器在運轉中，且儀表截止閥是翻開的。Makesurethatthewaterlevelalarmoftheairejectorfortheglandsealsisinoperationandthecut-offvalvesoftheinstrumentsareopened.7.確認每個汽封壓力、溫度調理站及旁路閥處于封鎖形狀。Makesurethateveryglandsealsteampressureandtemperatureregulatorstationsandbypassvalvesareintheclosingstate.8.確認啟動汽源溫度必需具有不小于14℃的過熱度。Makesurethatthetemperatureofthestartupsteamsourcecompulsorilyhasadegreeofsuperheatofnotlessthan14℃.9.確認調理閥入口的供汽管道中無水。Makesurethatthereisnowaterinthesteamsupplypipelinetotheinletoftheregulatingvalve.10.啟每個調理閥兩側的手動截止閥。Openthemanually-operatedvalvesatbothsidesofeachregulatingvalves.11.汽封系統在冷態啟動形狀時，輔助汽源向各個汽缸前后汽封供汽，蒸汽經過軸封壓力調理閥減壓，再經過減溫器減溫到121～150℃向高低壓前后軸封供汽。假設除氧器能供汽，那么切到正常運轉系統。Duringacold-statestartupoftheglandsealsystem,theauxiliarysteamsourceshallprovidesteamtotheglandsealsinthefrontandattherearofvariouscylinders.Thesteampressureisreducedbytheglandsealsteampressureregulatingvalveandthesteamtemperatureisdesuperheatedto121℃and150℃byanattemperator.Then,thesteamissuppliedtotheHPandLPfrontandrearglandseals.Ifthedeaeratorhasanabilitytosupplythesteam,thenthenormaloperationsystemshallbeputintoservice.12.當汽封供汽母管壓力建立并暖管后，立刻啟動汽封抽汽器。Whenthesteampressureinthesteamsupplymainlineoftheglandsealsisestablishedandthesaidmainlineiswarmedup,oneshallimmediatelystartuptheairejectorfortheglandseals.13.確認汽缸的每個汽封腔室均有低度真空。Makesurethateachchamberoftheglandsealsforthecylindershasavacuityatalowdegree.14.確認各汽封腔室內蒸汽沒有漏入大氣，假設發現漏汽，那么提高汽封抽汽器真空，或調整壓力調理閥或各送汽支路上的送汽截止閥，調理各截止閥開度，以降低汽封母管的蒸汽壓力，直至停頓向外部漏汽。Makesurethatthesteaminvariousglandsealchambersdoesnotleaktotheatmosphere.Ifanyleakageofsteamisfound,thevacuitymaintainedbyuseoftheairejectorshallbeenhancedorthepressureregulatingvalveorthecut-offvalvesonvariousbranchlinesforsteamsupplyshallbeadjustedortheopeningdegreesofvariouscut-offvalvesshallberegulatedtoreducethesteampressureintheglandsealsteammainlineuntilthesaidleakageofsteamtotheoutsideisstopped.15.檢查汽封供汽母管的溫度，檢查高壓缸內壁溫度與汽封腔室內蒸汽溫度之差值，確保差值小于110℃，確保后汽封送汽腔室內蒸汽溫度在121～150℃之間，檢查汽封蒸汽管路疏水能否通暢。Inspectthetemperatureintheglandsealsteamsupplymainline,inspectthetemperaturedifferencebetweentheinnerwalltemperatureoftheHPcylinderandsteamintheglandsealchambers,ensurethesaiddifferencetobelessthan110℃andthesteamtemperatureintherearglandsealsteamsupplychambertobebetween121℃to150℃.Inspecttheglandsealsteampipelinestoseewhetherthedraininsideflowsfreely.16.封鎖凝汽器的真空破壞門，啟動抽氣設備，并在凝汽器內建立盡能夠高的真空，在每個汽封建立起最大流量之前，所需的汽封蒸汽量隨凝汽器真空的改善而添加。Closethevacuumbreakingvalve,startuptheairejectorequipmentandestablishavacuityashighaspossibleinthecondenser.Priortoanestablishmentofamaximumflowrateineachglandseals,thesteamamountnecessaryfortheglandsealswillincreasewithanincreaseofthevacuityinthecondenser.17.當負荷逐漸添加時，來自除氧器的蒸汽可以滿足高、低汽封供汽時，那么輔助汽源供汽切換到除氧器供汽。這樣高中壓汽封系統與低壓汽封系統相互獨立，整個系統相對穩定。WhentheloadgraduallyincreasesandthesteamflowratefromthedeaeratorcanmeetthesteamamountrequiredbytheHPandIPglandsealsystem,thesteamcanbeswitchedoverfromsuppliedbytheauxiliarysteamsourcetosuppliedbythedeaerator.Insuchacase,theHPandIPglandsealsystemareindependentfromtheLPglandsealsystemandthewholesystemisrelativelystable.控制降負荷ControlLoadReduction在控制降負荷時，汽封母管的蒸汽壓力高于0.107MPa(A)，那么汽封系統維持正常形狀，高、低壓汽封供汽由除氧器供應；當汽封母管壓力低于0.107MPa(A)時，即除氧器的汽源不能保證母管壓力時，改由輔助汽源供汽。Whentheloadreductioniscontrolledandthesteampressureintheglandsealsteammainlineishigherthan0.107Mpa(A),theglandsealsystemiskeptinanormaloperationstateandHPandLPglandsealsteamissuppliedbythedeaerator.Whenthesteampressureintheglandsealsteammainlineislowerthan0.107Mpa(A),i.e.thesteamfromthedeaeratorcannotmaintainthepressureinthemainline,thenthesteamshallbesuppliedbyanauxiliarysteamsource.汽輪機停機TurbineShutdown只需存在著堅持汽缸內真空的必要，就必需向汽輪機各汽封提供密封蒸汽，在凝汽器的抽氣設備停頓運轉和凝汽器的真空完全消逝以前，不得切斷汽封供汽，否那么冷空氣流入會使轉子外表金屬急劇冷卻，而且還會導致熱的靜止的汽封體變形。Aslongasaneedforkeepingavacuityinthecylindersexists,oneshallsupplysteamtovariousglandsealsoftheturbine.Priortothestoppageoftheairextractionequipmentofthecondenserandafulllossofvacuityinthecondenser,thesteamsuppliedtotheglandsealsshallnotbecutoff,otherwise,coldairenteringintothesteamturbinewouldcauseanabruptcoolingoftherotorsurfacemetalandalsoresultinadeformationofthehotandstillglandcasings.汽輪機停機順序ShutdownSequence1.在機組盤車和汽封供汽來自外部汽源的情況下，確認凝汽器真空已完全消逝。Undertheconditionthatthesteamformaintainingtheturbineturningandtheglandsealsisfromthesteamsourceattheoutside,oneshallmakesurethatthevacuityinthecondenserhasbeenfullylost.2.封鎖汽封冷卻器風機。Closethefanoftheglandsealcooler.3.封鎖各汽封壓力調理閥兩側的手動截止閥。Closevariousmanually-operatedcut-offvalvesatbothsidesoftheglandsealsteampressureregulatingvalve.在切斷汽封冷卻器的風機后，應立刻封鎖上述閥門，在汽封體內無真空的情況下，汽封供汽的投入導致蒸汽漏入大氣，這些蒸汽會進入光滑油中，并凝結成為污染雜質，積存在油箱中。Afterthefanoftheglandsealcoolerhasbeenstopped,oneshallimmediatelyclosealltheabove-mentionedvalves.Undertheconditionthatthesealcasingisatzerovacuity,iftheglandsealsaresuppliedwithsteam,thelatterwillbeescapedtotheatmosphereandalsotothebearingbox,mixedwiththelubricationoilandcoagulatedtopollutantsanddepositedintheoiltank.熱態啟動Hot-stateStartup熱態啟動形狀，機組轉子溫度接近滿負荷運轉工況下的轉子溫度，此時一切閥門形狀同冷態啟動，只是添加一股熱態啟動汽源(P=1.0MPa，T=450℃)，經過高溫電動、手動截止閥后，向圖2中的高壓前汽封的“D〞腔室送汽。其它同冷態啟動送汽，假設除氧器能供汽，那么切到正常運轉系統。Hot-statestartupstatus:therotortemperatureofthesteamturbineshallapproximatetothatatthefull-loadoperationcondition.Insuchacase,thestatesofallthevalvesaresameasthe