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双重卷边金属及塑料容器的密封RaymondH.Carroll商业无菌包装食品培训教程UniversityofMarylandCopyright©2010UniversityofMarylandAllRightsReservedClosuresForDoubleSeamedMetalandPlasticContainersRaymondH.CarrollCommerciallySterilePackagedFoodsTrainingProgramUniversityofMarylandCopyright©2010UniversityofMarylandAllRightsReserved开孔易拉盖罐•1810年发明了马口铁罐头储存易腐食品•顶和底焊接到圆罐上HoleandCapCan•Tincaninventedin1810topreserveperishablefood•Topandbottomsolderedtocylinder易拉盖罐HoleandCapCan顶开罐•焊接边缝•两端有皱纹的，现在称为双重卷边•1920年开始取代开孔易拉盖罐OpenTopCan•Solderedsideseam•Endscrimpedon--nowcalleddoubleseaming•Replacedholeandcapcanby1920现有的双重卷边容器•熔接罐•无缝两片罐•全铝罐•塑料罐或碗•易拉罐CurrentDoubleSeamContainers•Weldedsideseamcan•Seamlesstwo-piececan•Allaluminumcan•Plasticcanorbowl•Easy-openends现今花样繁多的双重卷边金属罐VarietyofMetalDoubleSeamedCansAvailableToday金属罐生产材料•镀锡钢板•无锡钢板•金属板阳极特性对双重卷边罐的特性有影响CanManufacturingPlate•Tincoatedbasesteel•Tin-freesteel•Platecharacteristicsaffectdoubleseamcharacteristics容器结构•边缘：将罐体边缘弯曲形成钩状ContainerStructure•Flange:Fixedbodyedgethatformsbodyhook容器结构•盖卷曲：形成罐盖钩边ContainerStructure•EndCurl:Formscoverhook密封剂•在盖的环形槽使用密封剂•密封剂的类型取决于产品种类和杀菌方法SealingCompound•Sealingcompoundappliedtoannulargrooveofcanend•Compoundtypedependsonproductandmethodofsterilization双重卷边•由罐体卷曲和罐盖钩边链接而形成•罐体卷曲和罐盖钩边互相紧扣•双重卷边通过两步操作完成TheDoubleSeam•Formedbyjoiningbodyofcanwithend•Interlockofbodyflangeandcurlofend•Generallyformedintwooperations接缝卷拢SeamerChuckandRolls头道卷封•罐盖钩边与罐体卷曲扣在一起•头道卷封出现的差错在后面加工中不会被消除FirstOperation•Endcurlisinterlockedwithbodyflange•Cannotcorrectfaultyfirstoperationduringremainingsteps头道滚轮接缝的质量受以下因素影响：1.叠接的高度2.底座的压力3.滚轮的排列4.第一步卷拢的紧密度FirstOperationSeamQualityisaffectedby:1.Pingaugeheight2.Baseplatepressure3.Alignmentofrollstochuck4.Firstoperationrolltightness二道卷封•滚轮比第一步更加扁平•挤压预成型的钩以提高双重卷边的紧密度SecondOperation•Rollhasflattercontourthanfirstoperationroll•Pressespreformedhookstogethertodevelopdoubleseamtightness双重卷边•每个双重卷边由以下部分组成–三层罐盖–两层罐体–适当的密封剂•双重卷边形成了密闭的封口TheDoubleSeam•Eachdoubleseamconsistsof–threethicknessesofthecanend–twothicknessesofthecanbody–anappropriatesealingcompounddistributedthroughthefoldedmetal•Thisformsahermeticseal塑料碗PlasticBowls双重卷边的结构•通过特定卷边结构的评估对双重卷边结构品质进行判定•封口的说明由罐体和罐盖的供应商提供•最终在拆毁卷边后通过肉眼观察做出判定DoubleSeamStructure•Qualityjudgedbyevaluationofspecificseamstructures•Seamspecificationsfurnishedbycanandendsupplier•Finaljudgmentmadebyvisualinspectionoftorndownseam卷边的测量•埋头度:卷边顶端至临近卷边内壁的肩胛所测得的间距SeamMeasurements•Countersinkdepth:Seamtoptoendpanel卷边的测量•卷边厚度:卷封的罐盖、罐体钩合后的铁皮的最大厚度SeamMeasurements•Seamthickness:Distanceacrossseamlayers卷边的测量•卷边的宽度:平行于卷边身盖钩所测得的二重卷边的尺寸SeamMeasurements•Seamwidth:Dimensionparalleltoseamlayers卷边的测量(续)•身钩:罐身的翻边•叠接:卷边内部身钩和盖钩间相互钩合重叠的部分SeamMeasurements(continued)•Bodyandcoverhook:Internalpartsofseam•Overlap:Degreeofinterlockbetweenbodyandcoverhooks紧密度•以盖钩的皱纹程度来判断•RatingindicatesrelativefreedomfromwrinklesTightness•Judgedbydegreeofwrinklingofcoverhook•Ratingindicatesrelativefreedomfromwrinkles接合区域•双重卷边叠接水平焊接的部分•焊接罐的最关键点•盖钩垂唇的程度JunctureArea•Wheredoubleseamcrossessideseam•Mostcriticalpointinsolderedsideseamcans•Degreeofdroopincoverhook接缝的组成•塑料罐与金属罐的接缝比较SeamComponents•Plasticcancomponentscomparabletothoseofthemetalcan双重卷边的危险性评价一个接缝可能看似完美，但内部结构可能有缺点，并且没有达到真空密封CriticalEvaluationoftheDoubleSeamAseammayappearsatisfactory,butmayhaveafaultyinternalstructureandnohermeticseal.卷边的危险性评价对偏差进行测量，评估其严重性CriticalEvaluationofSeamsExperiencedjudgmentneededtoassessseriousnessofout-of-specificationmeasurements.埋头深度过大•导致盖钩和叠接率缩小•可能是有底座压力过大造成的ExcessiveCountersinkDepth•Resultsinshortenedcoverhookandoverlap•Excessivebaseplatepressureisonepossiblecause头道卷边松弛•可能会造成盖钩和叠接率不佳•可能是由头道滚轮不合适造成的LooseFirstOperationSeam•Maynotformgoodcoverhookandoverlap•Causemaybeimpropersettingoffirstoperationseamingroll头道卷边过紧•导致卷边底部扁平、锐边和盖钩不佳•头道滚轮设置过紧可能是原因之一ExcessivelyTightFirstOperationSeam•Resultsinflattenedseambottom,sharpseamandpoorcoverhook•Tightsettingoffirstoperationseamingrollisonepossiblecause身钩过短可能的原因是:1.升降压力不足2.Incorrectpinheightsetting顶针高度设置错误3.滚轮调校错误ShortBodyHooksPossiblecausesare:1.Insufficientlifterpressure2.Incorrectpinheightsetting3.Wrongseamingrolladjustment身钩过长可能的原因是:1.升降压力过大2.Incorrectpinheight顶针高度设置错误3.罐身翻边时不恰当LongBodyHooksPossiblecausesare:1.Excessivelifterpressure2.Incorrectpinheight3.Improperlyformedcanflange二道卷边松弛•金属板叠接没有被充分压紧实•二道滚轮设置不当•二道滚轮破损•二道滚轮轧槽太宽LooseSecondOperationSeam•Foldsofmetalmaynotbepressedtogethertightlyenough•impropersettingofsecondoperationseamingroll•Wornsecondoperationseamingroll•Secondoperationseamingrollgroovetoowide二道卷边过紧可能导致叠接缩短、锐边，和/或者内容物从接缝中溢出ExcessivelyTightSecondOperationSeamMaycausereductionofoverlap,sharpseamand/orcompoundtosqueezeoutofseam.盖钩短小可能的原因有:1.头道滚轮松弛2.升降压力过大3.埋头深度过大ShortCoverHookPossiblecausesinclude:1.Loosefirstoperationroll2.Excessivelifterpressure3.Excessivecountersinkdepth盖钩过长可能的原因是头道滚轮设置过紧LongCoverHookPossiblecauseistootightasettingforfirstoperationseamingroll.叠接不充分可能的原因是:1.罐体边缘不规则2.钩边不规则3.压盖机调校不佳InsufficientOverlapPossiblecausesare:1.Irregularcanbodyflanges2.Irregularendcurl3.Poorclosingmachineadjustment结构缺点•卷边畸形可能导致真空密封失败•在观察发现后，必须立即采取纠正措施StructuralDefects•Seama