课程测试题一Word格式.docx

课程测试题一Word格式.docx

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一、PackagingTerms（名词解释）（15points）：

　　（用中文解释下面术语）

packaging;

corrugatedboard;

TetraPak;

MAP;

thermoplastics

二、TrueorFalse（判断题）（16points）：

1.Typically,theinform/sellfunctionplaysamoresignificantroleinindustrialpackaging.

2.Topreventaproductfromdamageresultedfromvibration,theprotectivepackagingshouldtakeintoaccounttheresonantfrequenciesoftheproduct.

3.Vacuumpackagingcanbeusedinfruitsandvegetables.

4.Immediateadvantagesoftwo-piececansarereducedmetalusage,improvedappearance,andtheeliminationofapossibleleakagelocation.

5.DoubleWallreferstothreesheetsoflinerboardwithtwomediumsinbetween.

6.Paperpropertiesdependsuponthepaper'

sdirectionality

7.Iftheg-factorisestimatedtoolow,theproductwillbeunder-packaged.

8.Significantcompressivecreepwillleadtothepackageditemlooseninginthecushion.

三、MultipleChoices（单选题）（30points）：

（The15choicesarebaseduponthefollowingmessage）

LiquidConstantLevelFilling

Introduction.Althoughtheremaybeslightvariationsinthesizesorshapesofbottlesandjars,itisfrequentlydesirabletohavethefilllineatthesameheightoneachcontainersothatallofthemappeartobefilledexactlythesamewhentheyareonthedisplayshelf.Somemanufacturersdeliberatelyaddextraproductandoverfillsomeoftheir“seethrough”containersinordertoimprovetheirappearanceandtoguaranteethatallofthemcontainatleasttheminimumdesiredamountofproduct.

Inthissectionyouwilllearntheoperationoffivebasicmethodsusedforconstantlevelfillingofstillliquidsandsemi-liquidsandonemethodusedforfillingcarbonatedproducts.Youwillalsolearnwaysinwhicheachmethodisusedandtheirbasicmachinemaintenancerequirements.

Moldingandformingtechniquescancauseminorirregularitiesinthesizesofshapesofrigidglassandplasticbottlesandjars,andsomesemi-rigidcontainersmayalsochangetheirshapeandvolumeslightlyduringthefillingprocess.Itisfrequentlymoreeconomicaltouseadditionalproductintheoversizedcontainersthanitwouldbetomorecloselycontroltheformingprocesses1.Constantlevelfillingtechniquescompensatefortheminorchangesandvariationsinthecontainersandproducetheuniformappearancethatisimportantinthesaleofmanyproductsin“seethrough”containers.

PureGravityFilling.Puregravity（Figure20.14）isnotonlyoneoftheoldestandsimplestconstantlevelfillingmethods,butitisalsooneofthemostaccurateonesforfillingfree-flowingproducts.Somegravityfillerscaneliminatetheneedforoverflowandrecirculationoftheproduct,andsomecanholdaerationoftheproducttoaminimum.

Puregravityfillingcanbeusedformoststillliquidsandsomesemi-solids.Productswithconsistenciesasheavyascatsupormustardcanbefilledinthisway,butcaremustbetakenwiththeheavierproductstoassurethatthetemperatureandconsistencyoftheproductismaintainedatalevelatwhichtheproductflowsfreelyandevenly.Althoughtheconstantlevelfillerscanbeadjustedtoautomaticallyoperateatslowerspeedswhentheproductflowsmoreslowly,thischangeinrateofflowcanaffectthetimingoftheconveyingsystemandothermachinesinthepackagingline.

Theproductflowisproducedinthepuregravitysystembylocatingtheproductsupplytankhighenoughsothatforcesofgravitycanbeusedtomovetheproductthroughthefeedmechanismsintothecontainers.

Theflowisstartedandstoppedbytheactionofaspringloadedfillingvalvethatisopenedbytheforceofmakingcontactwiththetopofthecontainer.Somemachinesplacethecontaineronaplatformandraiseitup

againstthevalveinthefillerhead,andotherslowerthefillerheaddownontothetopofthecontainer.

Whenthepressureofthecontactissufficient,thespringopensthefillingvalve,andtheproductflowsfrom

Figure20.14Puregravityfilling

thesupplytankintothecontainer.Inthemachineshownintheaboveillustration,theairinthecontainerisforcedoutthroughtheventtubeastheproductentersthecontainer,andwhentheliquidcoverstheportoftheventtubetheaircannolongerescape.Thebackpressurestopstheflowofproductintothecontainer.

Whenthecontactbetweenthefillerheadandthecontainerisbrokenthespringclosesthefillervalveandpreventsdrippingoftheproductastheheadisremovedfromthecontainerandpositionedforthenextfill.

Someothertypesofgravityfillersusetimingdevicestoopenandclosethevalvestocontroltheflowofproductintothecontainers.Insteadofanairventtube,anoverflowpipeislocatedatthefilllinetocarryanyexcessproductintoanoverflowtankfromwhichitcanbepumpedbackintothesupplytank.Thistypeofsystemdoesnotrequireatightsealbetweenthecontainerandthefillerhead.

Themaintenancerequirementsofthepuregravityfillingsystemarerelativelysimple.Thefillercomponentsmustbekeptcleanandwelllubricated,andthebearings,bushings,andspringsmustbereplacedwhentheywearexcessively.Themovementofthemachinepartsmustbemonitoredandadjustmentsmadetotimeandpositionthemcorrectlyforthefilllevelthatisdesired.

Theconsistencyoftheproductandthefreemovementofallmovingpartsarecriticalforsmoothoperation.Underfillmaybecausedbyconstrictionoftheairventtubeorbyfailureofsufficientproducttomoveintothecontainerduringthetimeperioditisunderthefillerhead.

Figure20.15Purevacuumfilling

PureVacuumFilling.Purevacuumfillingsystems（Figure20.15）areusedprimarilyforfillingnarrowneckedglassbottleswithstillliquids.Itisnotnormallyusedwithplasticorothernon-rigidcontainers,becausethevacuumpressurethatisusedtodrawtheproductfromthestoragetankintothecontainercancausenon-rigidcontainerstocontractandbecomedistorted.

AsshowninFigure20.15,thevacuumtubewithinthefillingsleeveisconnectedtoavacuumchamberwhichismaintainedataconstantvacuumlevelbyavacuumpump.

Whenthebottleisinposition,anairtightsealisestablishedbetweenthetopofthebottleandthefillerhead.Asthevalvesareopenedavacuumisdrawnonthebottle,andthispressuredifferentialdrawstheproductfromthesupplytankintothebottle.Thefilllevelisdeterminedbythepositionofthevacuumportinthebottle,becausetheexcessproductisdrawnoutthroughtheport.Thelengthofthefilltimeisusuallycontrolledbyacamoperationorsomeothertypeoftimingmechanism.

Theproductoverflowfromthecontainerisdrawnthroughthevacuumportintothevacuumchamberonwhichavacuumismaintainedbytheactionofthevacuumpump.Theexcessproductispumpedbackintothesupplytank.

Thepurevacuumfillingsystemisgenerallyfasterthanapuregravitysystem,butthevacuumsystemalwayshassomeoverflowandrecirculationofproduct.Thevacuumfillerworksonlywhenthereisasealbetweenthebottleandfillervalve,sochippedorcrackedbottlescannotbefilled.

Avacuumlevelofbetween25and28inchesofmercuryisnormallymaintainedtoprovidesmoothandefficientoperation,butthelevelmayvaryondifferentmachinesasaresultofthedifferencesinmanufacturers'

designsandspecifications.

Thevacuumfillerissomewhatmoredifficulttocleanthanasimplegravitysystembecauseofitscomplexityandsmallvacuumtubesthatcanbecomeplugged.Allthefittingsmustbekepttightforefficientoperation.

Thesealingwashersmustbereplacedwhentheyshowsignsofdamageorwear,andthereplacementsshouldalwaysbeoftherecommendedtypeandmaterial.

Careshouldbetakentoassurethatthepropertypeoffillingnozzleisalwaysusedfortheproductbeingfilled,becausefoaming,aeration,andsplashingcanbeincreasedbyrapidmovementoftheproduct.

Figure20.16Gravityvacuumfilling

GravityVacuumFilling.Gravityvacuumfillingsystems（Figure20.16）combinethefeaturesofboththegravityandthevacuumsystems.Alightvacuumoffrom3to5inchesofmercuryismaintainedinthesystemtoassistindrawingtheairoutofthecontainersandtostabilizetheflowoftheliquid.

InthefillershowninFigure20.16alightvacuumismaintainedintheareaabovetheproductinthesupplytank,andtheventtubefromthecontaineropensintothisareaofthesupplytank.Whenthesealisestablishedbetweenthefillerheadandthebottletheventisopened,andavacuumisautomaticallydrawninthecontainer.Thisvacuuminthecontainerhelpsmaketheproductflowintoitmorerapidlyandsmoothly.

Asinthegravityfillingsystems,whentheproductreachesthefillleveltheventportisclosedbytherisingliquid,andtheflowstops.

Thegravityvacuumsystemdoesnothavetheoverfloworrecirculationofproductthatisinherentinthepurevacuumsystem,anditproducesminimumamountsofturbulenceandaerationoftheproduct.Thistypeofsystemisparticularlywellsuitedtofillingdistilledspiritsandwinebecausethereisvirtuallynolossofproof.

Sincethefillingnozzleisspringloadedandoperatedonlywhenthevacuumispresent,achippedorcrackedbottleonwhichasealisnotformedwillnotbefilled.

Thevacuumgravitysystemmustbekeptcleanandclearofanyobstructionsthatcouldaffecttheflowthroughthevacuumtubes.Thesealsan