UnitThreeDataCommunicationsPassageADataCommunications

PassageBCharacteristicsofCommunicationChannels

PassageCCommunicationEquipmentandSoftware

PassageADataCommunicationsTherapidgrowthofdatacommunicationshasbeeninfluencedprimarilybytheincreasingneedtomoveinformationtoandfromcomputers.Moderntime-sharedcomputerscancommunicatewithmanydatastationssimultaneously.Otherformsofdatatransmissionwhichthetelephoneandtelegraphlinesarecalledupontohandlearebatchdatatransmission,real-timetransmission(asinthecaseofairlinereservationsystems),bankingandcreditdata,man-computerconversationwiththeaidofgraphics,datacollectionsystemsandautomaticmeterreading.Thecombinationofcomputersanddatacommunicationplacessuchnewrequirementsonthesystems,whichmusthandlethem,thatonecanrefertothembetterasteleprocessingratherthantelecommunications.[1]

Teleprocessingstartedwiththeairlinereservationsystems,wherethedistributionofcomputerdataisnotasimportantasthemaintenanceofaninventoryofseatsforthewholesystemandtheabilitytoaccesssuchaninventoryrapidlyatanumberofdistantpoints.Anotherexampleisthatofthebanks,whodesiredtocentralizetheiraccountingandprovideaccesstoacentralfileforalltheirbranches.Basically,therearethreereasonsforthedevelopmentofteleprocessingsystems:therequirementforcentralizedfiles,theneedtodistributecomputerservicesandtheadvantagegainedbyhavingflexibilityinlocationoftheoperatingstaffwhichutilizesthesystem.Initially,boththeairlineandbankingoperationscanbeestablishedonaprivatebasis,whichwouldminimizetheneedforswitchingoperations.Butinbothcases,theneedtoexpandbeyondprivateoperationssoonarises.Inthecaseoftheairlines,theneedarisestoaccessthefacilitiesofotherairlines;andinthecaseofthebanks,certaincommondatafacilitiesmaybesharedwithotherbanks.Eventhoughprivatenetworksmaysufficeformanyservices,theneedtoprovidedatacommunicationsbetweenurbancentersleadstoregionalandnationalnetworks.IntheU.S.,theBellSystem,theindependenttelephonecompaniesandspecializeddatacommunicationnetworksareinvolvedascarriersofsuchdata.Themostapplicablemodelfordatacommunicationsrequirementsisthecentralcomputerconversingwithmanysimpleterminalssimultaneously.Differingfromtelephonecommunications,adatacommunicationsnetworkmustbeabletointerconnectawidevarietyofsubscriber’sequipment.Severaldifferenttypesofcomputerperipheralsmayappearasnetworkterminals,andsoalsocancomputersfunctioninginseveraldifferentways.[2]Terminalspeedsrangingfrom100bitspersecto10,000bitspersecarelikelytobeimportant.Manyterminalsincurrentuseareconstrainedbytheavailablecommunicationsservices,butmanyofthemhavevariablespeeds.Oneapproachtothissituationistoprovideabufferstoreattheterminal,butthisapproachisexpensive.Atpresent,multi-accesscomputersusuallyhandleterminalsofonlyonespeedorwithasmallnumberoffixedspeeds.Ithasbeenproposedthatfeedbackfromtheoutputdevicebeusedtopermitonesimpleoutputprogramtodriveterminalswithdifferentcharacteristics.Ofcourse,suchfeedbacksignalswouldhavetobehandledbythecommunicationsnetwork.Atdatatechnologydevelops,eachmulti-accesscomputerisconnectedtoanincreasingnumberofterminals,makingitexpensiveanddifficulttoprovideseparatelinesfromthecomputertothenetworkforeachoftheterminals.Thus,aneedformultiplexedconnectionsbetweenthecomputerandtheterminalsarises.Butthisneedcannotnecessarilybemetinastraightforwardmanner.Onecharacteristicofadatacommunicationsnetworkdifferingfromconventionaltelephonenetworksisthatthetwoendsofthecommunicationlinkareverydifferent.Oneendisacomputercapableofflexiblebehavior,andtheotherendisarelativelyslowterminalwithnointelligence.Sincethetwoendsaresodifferent,itwouldappearthatthenetworkwouldcommunicatedifferentlywiththem.Theflowofinformationinadatacommunicationsystemisintermittentjustasitisinthecaseoftelephoneconversations.However,insteadofminutesofconversation,onlyafewsecondswillelapsefortheinformationflowinonedirection,followedbyapauseandsomeflowofinformationintheoppositedirection.Theaccesstimesfortypicalcomputersinuseatthistimeareabout100ms,butthiswillbecomefasterasbettermemoriesareutilized.[3]Thetimescalefortheinterchangeofdatamessagesneedstobeofthisorder.KEYWORDS

reservation保留，預(yù)定graphics圖示，圖解inventory清單，報表teleprocessing遠程(信息)處理，遙控處理constrain約束，強迫multi-access多路存取，多路進入feedback反饋，回授intelligence智能，智力，信息intermediate中間的elapse(時間)經(jīng)過，消失※※※becalleduponto用來…，(被)要求…withtheaidof借助于，用，通過appearas作為…出現(xiàn)belikelyto可能，大約，像要NOTES[1]?Thecombinationofcomputersanddatacommunicationplacessuchnewrequirementsonthesystems,whichmusthandlethem,thatonecanrefertothembetterasteleprocessingratherthantelecommunications.

計算機和數(shù)據(jù)通信的結(jié)合向系統(tǒng)提出必須對這些信息進行處理的新要求，以至人們最好稱它們?yōu)檫h程信息處理，而不是遠程通信。

·?“thatone…telecommunications”為結(jié)果狀態(tài)從句。

·?“whichmusthandlethem”定語從句修飾“system”。

·句中“place”有“放置”的含義，這里引申為“提出”。

·在科技英語中，有時用“one”泛指“人們”。[2]?Severaldifferenttypesofcomputerperipheralsmayappearasnetworkterminals,andsoalsocancomputersfunctioninginseveraldifferentways.

幾種不同的計算機外圍設(shè)備可能作為網(wǎng)絡(luò)終端出現(xiàn)，幾種不同方式運行的計算機也可能作為網(wǎng)絡(luò)終端出現(xiàn)。

·?“soalso…differentways”為并列句，該并列句主謂倒裝，用于強調(diào)。

·句中“so”表示“appearasnetworkterminals”，翻譯時應(yīng)重復(fù)敘述，使譯文表達更明確。[3]?Theaccesstimesfortypicalcomputersinuseatthistimeareabout100ms,butthiswillbecomefasterasbettermemoriesareutilized.

目前所用的典型計算機存取時間大約為100毫秒，但當(dāng)采用較好的存儲器時，存取時間將會縮短。

·?“butthiswill…areutilized”為并列句。其中“asbettermemoriesareutilized”為時間狀語從句。

·在科技英語中“as”運用很靈活，此句“as”作連詞。EXERCISES1.?Fillintheblankswiththebestchoice.(1)?Thetypesofdatapacketare

modedatafromdigitalterminalsand______modedatafromothersources.a.digital,nondigital b.store-and-forward,nonstore-and-forwardc.packet,nonpacket d.computer,noncomputer(2)?Ascomparedwithcircuitswitching,thepacketswitchinghastheadvantagewhen

ischeap.a.transmissionmedium b.computingpowerc.bufferstorage d.processingpower(3)?ThemainelementsinARPAnetworkare

and

.a.interfacemessageprocessors,hostsb.localterminals,IMPsc.multi-accesscomputers,peripheralequipmentd.hosts,sharingcomputers2.?True/False.(1)TheARPAnetworkisalong-distanceprivatedatanetwork,whichcanincludeseveralmulti-access,time-sharingcomputersystemforswitchingpackets.()(2)Thehostcandumpacompletemessageintotheinterfacemessageprocessors,whichcanbeconnectedby50,000bitspersecondcircuits.()(3)Thelargestpublicpacket-switchingnetwork,throughwhich200databasesareaccessible,intheU.S.serves250computers,andlinkstogethercomputersinothercountries.()(4)Thepublicpacket-switchednetworkwillbeenhancedbyprovidingforconnectionbetweenthepublictelephonenetworkandthepacketnetwork.()3.?Answerthequestions.(1)Whatarethedifferencesbetweenpacket-switchingnetworkandconventionalstore-and-forwardnetwork?(2)?WhatisthefunctionoftheARPAnetwork?PassageBCharacteristicsofCommunicationChannelsDatacommunicationsistheelectronictransmissionofinformationincludingdata,televisionpictures,soundandfacsimiles.Itusuallyinvolvesacomputer,amodem,software,andaprinter.Withthisequipment,youcancommunicatewithafriendinSt.Louis,Missouri,orParis,France,sendingandreceivinganythingfromamanuscripttoasimplemessageoverthetelephonelines.Usingthesamemethod,ahome-boundchildcaninteractwithateacherintheclassroom,anofficeworkercanworkathome,andadoctorcanaccessaremotecomputerforresearchdata.Thereasonsforusingcommunicationssystemareconvincing.It·isexpedientandefficient,·lessensjobstress,·decreasescarpollution,·savestimeandmoney,·allowsthehometoserveasanoffice,and·promotesdistantlearninginwhichstudentscanshareinformationandcomputerresearch?findings.Whenyouconnectonecomputertoanother,youusehardwareandsoftware.Inthemajorityofcases,thehardwareconsistsofequipmentthatsendsthedataoversometypeofcommunicationsline,suchasatelephoneline.Thesoftwarecontrolstheflowofthisdata.Thenecessaryhardwareconsistofamodemandtelephonelines.Themodemmodulatesthecomputeroutputtoanacceptablesignalfortransmissionandthendemodulatesthesignalbackforcomputerinput.Themodemonthetransmittingcomputerconvertsthedigitalsignalstomodulatedanalogsignaltonesandtransmitsthemoverthetelephonelines.[1]Thereceivingcomputer’smodemtransformstheincominganalogsignalsbacktotheirdigitalequivalentsinordertounderstandthem.TransmissionRateThetransmissionrateofacommunicationschannelisdeterminedbyitsbandwidthanditsspeed.Thebandwidthistherangeoffrequenciesthatachannelcancarry.Sincetransmitteddatacanbeassignedtodifferentfrequencies,thewiderthebandwidth,themorefrequencies,andthemoredatacanbetransmittedatthesametime.Thespeedatwhichdataistransmittedisusuallyexpressedasbitspersecondorasabaudrate.Bitspersecond(bps)isthenumberofbitsthatcanbetransmittedinonesecond.Usinga10-bitbytetorepresentacharacter(7databits,1start,1stop,and1paritybit),a2,400bpstransmissionwouldtransmit240characterspersecond.Atthisrate,a20,single-spacedreportwouldbetransmittedinapproximatelyfiveminutes.Thebaudrateisthenumberoftimespersecondthatsignalbeingtransmittedchanges.Witheachchange,oneormorebitscanbetransmitted.Atspeedsupto2,400bps,usuallyonlyonebitistransmittedpersignalchangeand,thus,thebitspersecondandthebaudratearethesame.Toachievespeedsinexcessof2,400bps,morethanonebitistransmittedwitheachsignalchangeand,thus,thebpswillexceedthebaudrate.DirectionofTransmissionThedirectionofdatatransmissionisclassifiedaseithersimplex,half-duplex,orfull-duplex.Insimplextransmission,dataflowsinonedirectiononly.Simplexisusedonlywhenthesendingdevice,suchasatemperaturesensor,neverrequiresaresponsefromthecomputer.Forexample,ifacomputerisusedtocontrolthetemperatureofabuilding,numeroussensorsareplacedthroughoutit.Eachsensorisconnectedtothecomputerwithasimplextransmissionlinebecausethecomputeronlyneedstoreceivedatafromthetemperaturesensorsanddoesnotneedtosenddatabacktothesensors.[2]

Inhalf-duplextransmission,datacanflowinbothdirectionsbutinonlyonedirectionatatime.Anexampleisacitizensbandradio.Theusercantalkorlistenbutnotdobothatthesametime.Half-duplexisoftenusedbetweenterminalsandacentralcomputer.Infull-duplextransmission,datacanbesentinbothdirectionsatthesametime.Anormaltelephonelineisanexampleoffull-duplextransmission.[3]Bothpartiescantalkatthesametime.Full-duplextransmissionisusedformostinteractivecomputerapplicationsandforcomputer-to-computerdatatransmission.TransmissionModes:AsynchronousandSynchronousInasynchronoustransmissionmode(Figure3.1),individualcharacters(madeupofbits)aretransmittedatirregularintervals,forexample,whenauserentersdata.Todistinguishwhereonecharacterstopsandanotherstarts,theasynchronouscommunicationmodeusesastartandastopbit.Anadditionalbitcalledaparitybitissometimesincludedattheendofeachcharacter,andtheydetectifoneofthedatabitshasbeenchangedduringtransmission.Theasynchronoustransmissionmodeisusedforlowerspeeddatatransmissionandisusedwithmostcommunicationsequipmentdesignedforpersonalcomputers.Figure3.1Inthesynchronoustransmissionmode(Figure3.1),largeblocksofdataaretransmittedatregularintervals.Timingsignalssynchronizethecommunicationsequipmentatboththesendingandreceivingendsandeliminatetheneedforstartandstopbitsforeachcharacter.Error-checkingbitsandstartandendindicatorcalledsyncbytesarealsotransmitted.Synchronoustransmissionrequiresmoresophisticatedandexpensiveequipment,butitdoesgivemuchhigherspeedsandaccuracythanasynchronoustransmission.KEYWORDS

bps(bitspersecond)每秒鐘傳輸?shù)谋忍豣audrate波特率simplextransmission單工傳輸half-duplextransmission半雙工傳輸full-duplextransmission全雙工傳輸asynchronoustransmission異步傳輸?synchronoustransmission同步傳輸NOTES[1]?Themodemonthetransmittingcomputerconvertsthedigitalsignalstomodulatedanalogsignaltonesandtransmitsthemoverthetelephonelines.

發(fā)送端計算機的調(diào)制解調(diào)器把數(shù)字信號調(diào)制為模擬信號，并通過電話線發(fā)送出去。

·主句結(jié)構(gòu)為“Themodem…converts…andtransmits…”。[2]?Eachsensorisconnectedtothecomputerwithasimplextransissionlinebecausethecomputeronlyneedstoreceivedatafromthetemperaturesensorsanddoesnotneedtosenddatabacktothesensors.

每一個傳感器都通過一根單工傳輸線連接到計算機上，這是因為計算機只需要接收來自溫度傳感器的數(shù)據(jù)，而不需要向傳感器發(fā)送數(shù)據(jù)。[3]?Anadditionalbitcalledaparitybitissometimesincludedattheendofeachcharcter,andtheydetectifoneofthedatabitshasbeenchangedduringtransmissiom.

在每個字符的后面有時還包括一個稱為奇偶校驗位的附加位，它們測試數(shù)據(jù)位在傳輸過程中是否被意外改變。

·they指的是aparitybit。EXERCISES1.?Fillintheblankswiththebestchoice.(1)?Thetermmodemisderivedfromthewords

.a.modulateemphasis b.modularemulationc.multiplexordemultiplexer d.modulatedemodulate(2)?Datatransmissionspeedismeasuredin

.a.bps——bytespersecond b.bps——bitspersecondc.bps——blockspersecond d.bps——bufferspersecond(3)?Thetransmissionmethodwhichusesstartstopbitsaftereachcharacteris

.a.synchronous b.asynchronousc.fullduplex d.noneofabove(4)?A(n)

convertsdatafrompulseformtowaveformandbackagain.a.modem b.controlunit c.channel d.interface(5)Devicesormediathatoperateatdifferentspeedscanbesynchronizedbyusinga

.a.buffer b.dataset c.line d.modem(6)?Thetransmissionmethodwhichsendsmultiplecharactersinablockis

.a.synchronous b.asynchronous c.simplex d.half-duplex(7)?In

transmission,datacanbesentinbothdirectionsatthesametime.a.simplex b.half-duplex c.full-duplex d.noneofabove(8)?Whenthesendingdevice,suchasatemperaturesensor,neverrequiresaresponsefromthecomputer,weshoulduse

transmission.a.full-duplex b.half-duplex c.simplex d.noneofabove(9)?Usinga10-bitbytetorepresentacharacter(7databits,1start,1stop,and1paritybit),a2,400bpstransmissionwouldtransmit

charactersintwoseconds.a.120 b.240 c.480 d.720(10)?

scansapieceofpaperandconvertsitsimageintocodedformfortransmissionoverthetelephonesystem.a.Scanner b.Modemc.Printerd.Faxmachine2.?Answerthequestions.(1)?Describethebasiccomponentsofacommunicationssystem.(2)?Listanddescribethethreetypesofdatatransmission(direction)thatareused.(3)?Describethetransmissionmodes:asynchronousandsynchronous.PassageCCommunicationEquipmentandSoftwareIfaterminalorapersonalcomputeriswithinapproximately100feetofanothercomputer,thetwodevicescanusuallybedirectlyconnectedbyascale.Over1,000feet,however,theelectricalsignalweakenstothepointthatsometypeofspecialcommunicationsequipmentisrequiredtoincreaseorchangethesignaltotransmititfarther.Avarietyofcommunicationsequipmentexiststoperformthistask,buttheequipmentthatauserismostlikelytoencounterismodems,fax/modems,faxmachine,etc.ModemsAmodemconvertsthedigitalsignalsofaterminalorcomputertoanalogsignalsthataretransmittedoveracommunicationschannel.Italsoconvertsanalogsignalsitreceivesintodigitalsignalsthatareusedbyaterminalorcomputer.Thewordmodemcomesfromacombinationofthewordsmodulate,whichmeanstochangeintoasoundoranalogsignal,anddemodulate,whichmeanstoconvertananalogsignalintoadigitalsignal.Amodemisneededatboththesendingandreceivingendsofacommunicationschannel.Anexternalmodemisaseparate,orstand-alone,devicethatisattachedtothecomputerorterminalbyacableandtothetelephoneoutletbyastandardtelephonecord.Anadvantageofanexternalmodemisthatitcanbeeasilymovedfromoneterminalorcomputertoanother.Aninternalmodemisacircuitboardthatisinstalledinsideacomputerorterminal.Internalmodemsaregenerallylessexpensivethancomparableexternalmodemsbutonceinstalled,theyarenotaseasyasmove.Fax/ModemsBesidessendingandreceivingdata,manymodemstodaycananswerthetelephonethewayanansweringmachinedoesandstorethemessageontheharddisk.Someevenhavecomprehensivevoice-mailcapabilitiessimilartobusinessvoice-mailsystems.Furthermore,themajorityofmodemshavefacsimile(fax)capabilities;thatis,theycansendgraphicimagesandtextbetweendistantlocations.Suchmodemsemulatefaxmachines,allowingyoutoreceiveandsendfaxtransmissionsdirectlyviayourcomputer.Afax/modemisdifferentfromastandardfaxmachineinthewayithandlesdocuments.Thefax/modemcanonlysenddocumentsthatarealreadyinthecomputer;theycandisplaythedocumentsonthecomputerscreenorprintthemwhentheyreceivethem.Howdoesthefax/modemuserfaxdocumentsnotinputtedintothecomputer?Onewayistouseascannertoscandocumentsintothecomputer.Nevertheless,thetraditionalfaxmachineismoreversatilethanthefax/modem.Itisalsomoreexpensive.FaxMachinesThededicatedfaxmachineisacombinationscanner,faxmodem,andprinter.Thismachinescansapieceofpaperandconvertsitsimageintocodedformfortransmissionoverthetelephonesystem.Ontheotherend,afaxmachinereconvertsthetransmittedcodeandprintsoutafacsimileoftheoriginalsheetofpaper.Sometimescommunicationsequipmentispreprogrammedtoaccomplishitsdesignedcommunicationstasks.Othertimes,theusermustloadaprogrambeforetransmittingdata.Theseprograms,referredtoascommunicationssoftware,canperformanumberoftasksincludingdialing(ifaswitchedtelephonelineisused),filetransferanddataencryption,etc.Dialingsoftwareallowsyoutostore,review,selectanddialtelephonenumbersofcomputersthatcanbecalled.Thesoftwareprovidesavarietyofmeaningfulmessagestoassistyouinestablishingaconnectionbeforetransmittingdata.Forexample,apersonwhousesapersonalcomputerathometocommunicatewithacomputerattheofficecouldusedialingsoftwaretoestablishthecommunicationsconnection.Thesoftwarewoulddisplaytheofficecomputer’stelephonenumberontheuser’spersonalcomputerscreen.Theuserwouldentertheappropriatecommandforthedialingsoftware,workingwithamodem,tobegindialingtheofficecomputerandtoestablishaconnection.Duringthe10or15secondsthatthisprocesstakes,thesoftwarewoulddisplaymessagestoindicatespecificallywhatwashappening,suchas“DIALING”,“CARRIERDETECT”?(whichmeansthattheofficecomputerhasanswered),and“CONNECTED”(toindicatethatthecommunicationsconnectionhasbeenestablishedanddatatransmissioncanbegin).Filetransfersoftwareallowsyoutomoveoneormorefilesfromonesystemtoanother.Generally,youhavetoloadthefiletransfersoftwareonboththesendingandreceivingcomputers.Dataencryptionprotectsconfidentialdataduringtransmission.Dataencryptionistheconversionofdataatthesendingendintoanunrecognizablestringofcharactersorbitsandthere-conversionofthedataatthereceivingend.Withoutknowinghowthedatawasencrypted,someonewhointerceptedthetransmitteddatawouldhaveadifficulttimedeterminingwhatthedatameant.第一節(jié)活塞式空壓機的工作原理第二節(jié)活塞式空壓機的結(jié)構(gòu)和自動控制第三節(jié)活塞式空壓機的管理復(fù)習(xí)思考題單擊此處輸入你的副標題，文字是您思想的提煉，為了最終演示發(fā)布的良好效果，請盡量言簡意賅的闡述觀點。第六章活塞式空氣壓縮機

piston-aircompressor壓縮空氣在船舶上的應(yīng)用：

1.主機的啟動、換向；

2.輔機的啟動；

3.為氣動裝置提供氣源；

4.為氣動工具提供氣源；

5.吹洗零部件和濾器。

排氣量:單位時間內(nèi)所排送的相當(dāng)?shù)谝患壩鼩鉅顟B(tài)的空氣體積。單位：m3/s、m3/min、m3/h第六章活塞式空氣壓縮機

piston-aircompressor空壓機分類：按排氣壓力分：低壓0.2～1.0MPa；中壓1～10MPa；高壓10～100MPa。按排氣量分：微型<1m3/min；小型1～10m3/min；中型10～100m3/min；大型>100m3/min。第六章活塞式空氣壓縮機

piston-aircompressor第一節(jié)活塞式空壓機的工作原理容積式壓縮機按結(jié)構(gòu)分為兩大類：往復(fù)式與旋轉(zhuǎn)式兩級活塞式壓縮機單級活塞壓縮機活塞式壓縮機膜片式壓縮機旋轉(zhuǎn)葉片式壓縮機最長的使用壽命-

低轉(zhuǎn)速（1460RPM），動件少（軸承與滑片），潤滑油在機件間形成保護膜，防止磨損及泄漏，使空壓機能夠安靜有效運作；平時有按規(guī)定做例行保養(yǎng)的JAGUAR滑片式空壓機，至今使用十萬小時以上，依然完好如初，按十萬小時相當(dāng)于每日以十小時運作計算，可長達33年之久。因此，將滑片式空壓機比喻為一部終身機器實不為過。滑(葉)片式空壓機可以365天連續(xù)運轉(zhuǎn)并保證60000小時以上安全運轉(zhuǎn)的空氣壓縮機1.進氣2.開始壓縮3.壓縮中4.排氣1.轉(zhuǎn)子及機殼間成為壓縮空間，當(dāng)轉(zhuǎn)子開始轉(zhuǎn)動時，空氣由機體進氣端進入。2.轉(zhuǎn)子轉(zhuǎn)動使被吸入的空氣轉(zhuǎn)至機殼與轉(zhuǎn)子間氣密范圍，同時停止進氣。3.轉(zhuǎn)子不斷轉(zhuǎn)動，氣密范圍變小，空氣被壓縮。4.被壓縮的空氣壓力升高達到額定的壓力后由排氣端排出進入油氣分離器內(nèi)。4.被壓縮的空氣壓力升高達到額定的壓力后由排氣端排出進入油氣分離器內(nèi)。1.進氣2.開始壓縮3.壓縮中4.排氣1.凸凹轉(zhuǎn)子及機殼間成為壓縮空間，當(dāng)轉(zhuǎn)子開始轉(zhuǎn)動時，空氣由機體進氣端進入。2.轉(zhuǎn)子轉(zhuǎn)動使被吸入的空氣轉(zhuǎn)至機殼與轉(zhuǎn)子間氣密范圍，同時停止進氣。3.轉(zhuǎn)子不斷轉(zhuǎn)動，氣密范圍變小，空氣被壓縮。螺桿式氣體壓縮機是世界上最先進、緊湊型、堅實、運行平穩(wěn)，噪音低，是值得信賴的氣體壓縮機。螺桿式壓縮機氣路系統(tǒng)：

A

進氣過濾器

B

空氣進氣閥

C

壓縮機主機

D

單向閥

E

空氣/油分離器

F

最小壓力閥

G

后冷卻器

H

帶自動疏水器的水分離器油路系統(tǒng)：

J

油箱

K

恒溫旁通閥

L

油冷卻器

M

油過濾器

N

回油閥

O

斷油閥冷凍系統(tǒng)：

P

冷凍壓縮機

Q

冷凝器

R

熱交換器

S

旁通系統(tǒng)

T

空氣出口過濾器螺桿式壓縮機渦旋式壓縮機

渦旋式壓縮機是20世紀90年代末期開發(fā)并問世的高科技壓縮機，由于結(jié)構(gòu)簡單、零件少、效率高、可靠性好，尤其是其低噪聲、長壽命等諸方面大大優(yōu)于其它型式的壓縮機，已經(jīng)得到壓縮機行業(yè)的關(guān)注和公認。被譽為“環(huán)保型壓縮機”。由于渦旋式壓縮機的獨特設(shè)計，使其成為當(dāng)今世界最節(jié)能壓縮機。渦旋式壓縮機主要運動件渦卷付，只有磨合沒有磨損，因而壽命更長，被譽為免維修壓縮機。

由于渦旋式壓縮機運行平穩(wěn)、振動小、工作環(huán)境安靜，又被譽為“超靜壓縮機”。

渦旋式壓縮機零部件少，只有四個運動部件,壓縮機工作腔由相運動渦卷付形成多個相互封閉的鐮形工作腔，當(dāng)動渦卷作平動運動時，使鐮形工作腔由大變小而達到壓縮和排出壓縮空氣的目的?；钊娇諝?/p>