制浆造纸专业单词4

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1、Chapter10PaperManufacture-WetEndOperationTheartoftruepapermakinghaditsorigininChinaaround100ADbasedonthediscoverythatadilutesuspensionoffibers(obtainedbymaceratingtheinnerbarkportionofbamboo)couldbeformedintoamatbyfilteringthesuspensionthroughafinescreen.Thematwasthenmadesuitableforwritinganddra

2、wingbypressing,dryingandsizing.Papercontinuedtobemadebyhanduptothebeginningofthe19thcentury.AFrenchman,LouisRobert,wasthefirsttopatentadesignforacontinuouspapermachinein1799.thefirstmachineevertobebuiltandsuccessfullyoperatedwasstartedupinEnglandin1803.TheFourdrinierbrotherstookoverdevelopmentri

3、ghts.ThemachineeventuallybecameknownastheFourdrinrermachine.Theearlypapermachinesconsistedofaheadboxaddingpaperstocktoamovingwiresupportedbetweentorolls.Thewetsheetwaspressedonceonthewireandthentakentoafeltandrunthroughanotherpressnipbeforebeingaccumulatedonarollforeventualdryinginsheetedform.10

4、.1INTRODUCTIONTOTHEPAPERMACHINESincethedaysofLouisRobert,thepapermachinehasundergonecontinualdevelopment,makingitpossibletoproduceawiderwebofpaperateverincreasingspeedandtomoreexactingstandardsofquality.Abasicfourdrinier-typemachineisillustratedinFigure10-1,andthefollowinggivesabrieffunctionalex

5、planationforeachmajorcorrmonent:Theflowspreadertakesintheincomingpipelinestockflowanddistributesitevenlyacrossthemachinefrombacktofront.Thepressurizedheadboxdischargesauniformjetofpapermakingstockontothemovingformingfabric.-Theendless,movingfourdrinierfabricformsthefibersintoacontinuousmattedweb

6、whilethefourdriniertabledrainsthewaterbysuctionforces.(onothertypesofpapermachines,thesheetmaybeformedbyothermeans,e.g.betweentwofabrics,oronafabric-coveredcylinder.)-Thesheetisconveyedthroughaseriesofrollpresseswhereadditionalwaterisremovedandthewebstructureisconsolidate(i.e.,thefibersareforced

7、intointimatecontact).-Mostoftheremainingwaterisevaporatedandfiber-to-fiberbondsaredeveloperasthepapercontactsaseriesofsteam-heatedcylindersinthedryersection.-Thesheetiscalenderedthroughaseriesofrollnipstoreducethicknessandsm