欢迎来到人人文库网! | 帮助中心 人人文档renrendoc.com美如初恋!
人人文库网
全部分类
  • 图纸下载>
  • 教育资料>
  • 专业文献>
  • 应用文书>
  • 行业资料>
  • 生活休闲>
  • 办公材料>
  • 毕业设计>
  • ImageVerifierCode 换一换
    首页 人人文库网 > 资源分类 > DOC文档下载  

    外文翻译--一个简化双螺杆旋转食品挤压机设计制造和检验.doc

    • 资源ID:96797       资源大小:1.28MB        全文页数:19页
    • 资源格式: DOC        下载积分:5积分
    扫码快捷下载 游客一键下载
    会员登录下载
    微信登录下载
    三方登录下载: 微信开放平台登录 支付宝登录   QQ登录   微博登录  
    二维码
    微信扫一扫登录

    手机扫码下载

    请使用微信 或支付宝 扫码支付

    • 扫码支付后即可登录下载文档,同时代表您同意《人人文库网用户协议》

    • 扫码过程中请勿刷新、关闭本页面,否则会导致文档资源下载失败

    • 支付成功后,可再次使用当前微信或支付宝扫码免费下载本资源,无需再次付费

    账号:
    密码:
      忘记密码?
        
    友情提示
    2、PDF文件下载后,可能会被浏览器默认打开,此种情况可以点击浏览器菜单,保存网页到桌面,就可以正常下载了。
    3、本站不支持迅雷下载,请使用电脑自带的IE浏览器,或者360浏览器、谷歌浏览器下载即可。
    4、本站资源(1积分=1元)下载后的文档和图纸-无水印,预览文档经过压缩,下载后原文更清晰。
    5、试题试卷类文档,如果标题没有明确说明有答案则都视为没有答案,请知晓。

    外文翻译--一个简化双螺杆旋转食品挤压机设计制造和检验.doc

    Asimplifiedtwinscrewco-rotatingfoodextruder:design,fabricationandtestingS.A.M.A.N.S.Senanayakea,B.Clarkeb,*DivisionofAgriculturalandPlantationEngineering,TheOpenUniversityofSriLanka,Nawala,Nugegoda,SriLankaDepartmentofPostharvestTechnology,SchoolofAgriculture,FoodandEnvironment,SilsoeCollage,CranfieldUniversity,Silsoe,BedfordshireMK454DT,UKReceived6July1998;accepted10February1999AbstractAsimplifiedco-rotatingtwinscrewfoodextruderwasdesigned,fabricatedandtestedinEngland,followedbyextensivetestinginSriLanka.Itwasbuiltasamodeltomeetthespecificproductandfinancialconstraintsoflessdevelopedcountriesandwasexpectedtobeusedinthosecountriestowidentheproductioncapabilitiesofextrudedfoods.Themachinehadanestimateddeliveryof10kg/handwasmademainlywithmildsteel.Twotypesofscrewweremade,onewithaconstantpitchof14mmandtheotherwithvaryingpitchinsegmentsof14,12and10mm.Themachinewaspoweredbya2.2kWelectricmotorwithelectronicspeedcontrol.Themachinealsohadelectricalheatingwithatemperaturecontrollerandapressuresensingdevice.Thecostoffabricationofthemachinewasestimatedat£2000withmostofthepartsbuiltinafairlysimpleworkshop.Amixtureofriceanddriedbananawassuccessfullyextrudedasapotentialsnackfoodandonthebasisofmaximumexpansionthebestresultswasobtainedfromabarreltemperatureof120°C,screwspeed125rpm,feedmoisture15%andwithadieorificesizeof3mm.Whenthealternativecompressionscrewwastestedverysimilarresultswereachievedwithnosignificantimprovementinproductexpansion.©1999ElsevierScienceLtd.Allrightsreserved.Keywords:Twinscrewextruder;Design;Lowcost;Snackfood;Continuouscooker;Localconstruction;CerealmixturesNomenclatureaDiediameter(mm)BChannelwidth(mm)CScrewcircumference(mm)dScrewcorediameterDOuterdiameterofscrews(mm)HFlightdepth(mm)MMoisturecontent(%wetbasis)nNumberoffightturnsNSpeedangular(rev/min)pPitch(mm)QDeliveryrate(mm3/min)STotalhelicallengthofscrews(mm)tTemperature()TResidencetime(min)aOverlapangleofscrewfights(degrees)dCalendergap(mm)eSideclearance(mm)qProductdensity(g/mm3)/Helixangle(degrees)*Correspondingauthor.Fax:+01525-863277;e-mail:b.clarkecran-®eld.ac.uk0260-8774/99/$±seefrontmatter©1999ElsevierScienceLtd.Allrightsreserved.PII:S0260-8774(99)0004971.IntroductionExtrusioncookingisfindingeverincreasingapplicationsinthefoodprocessindustry.Apartfromprovidingameansofmanufacturingnewproducts,ithassuccessfullyrevolutionismanyconventionalmanufacturingprocesses(Harlow,1985,Frame,1994).Today,extruderscomeinawidevarietyofsizes,shapesandmethodofoperation.Therearethreetypesoffoodextruderfoundinindustry:hydraulicram,rollerandscrewtypeextruders(Frame,1994).Thescrewextrudersareverydifferenttotheothertwohavingspecialfeaturessuchascontinuousprocessingandmixingability.Singleandtwinscrewtypesarebothwidelyusedinthefoodprocessindustry.Unfortunately,mostofthefoodextrudersavailableinthemarketareeithersocostlythatlessdevelopedcountriescannotaffordtobuythemexceptbysomeformofassistanceoroutsideinvestmentorelsearenotappropriateforthewidevarietyofmaterialsthatneedtobeprocessed.Asaresultthegrowthofextrusiontechnologyoffoodintothesecountrieshasbeenhindereddespiteitsmanyadvantages.Fig.2.Plandrawingofthetwinscrewextruderwithdrivesystem.1-Vbeltpulley,2-gearbox,3-foodseal,4-¯angeclampbolt,5-dieplate,6-die,7-twosegmentsoftheextruderchamber,8-extruderscrew.weremadesothattheycouldbeexternallyscrewedtothedieplate.2.5.DrivesystemThemachinewasdrivenbyanelectricmotorof2.2kWusingatwinbeltdrivebetweenthemotorandagearboxshowninFig.2.Thespeedreductionintheboxwas2.08whileanelectronicspeedcontrollerwasusedtocontrolthespeedcontinuouslyovertherangerequired.Fig.3.Frontportionofbarrelshowingprovisionforheaters,temperatureandpressuresensors.1-slotsforheaters,2-endflanges,3-sideflangestobarrel,4-holeforpressuresensor,5-twinholestoformthebarrel.2.MotorpowerIntwinscrewextrudersthemotorpowerisutilizedmainlytocompressandshearthefooddoughthatsqueezesthroughvariousgapsintheintermeshingscrewsandthegapbetweenthescrewsandthebarrel.Whendealingwithawiderangeoffoodsunderdifferentprocessconditionstheshearresistancecanvarywidelybecauseofchangesintherheologicalbehaviourwhichwouldpreventaccurateestimateofthemotorpower.OwingtotheunknowncharacterthereforeofthenovelmaterialsamotorpowerwasselectedbasedonthatusedforsimilarmaterialsinsimilarsizedextruderswithasafetymarginandfromexploratorytrialsintheBrabenderextruder.RossenandMiller(1973)givearangeofspecificenergyconsumptionfiguresfordifferentextruderswhichrangedfrom0.02to0.10kWh/kg.At10kg/hthroughputthisgaveamaximumpowerrequirementof1kWwhiletheBrabendertrialstendedtoindicateapowerrequirementofabouthalfofthisvalue.The2.2kW,3phaseACmotorusedwasamplycapableofsupplyingthispowerplusallotherdrivefrictionlosses.3.GearboxIntheco-rotatingextruderthetwoscrewshaftsaredrivenatthesamespeedinthesamedirection.Themainproblemisthattheyareveryclosetogether.Thegearboxwasdesignedtodrivetwopinions,coupledtotheshaftsbyshearpins,byusingagearwheelofmorethandoublethewidthofthepinions.Inthiswaythetwopinionscould®tsidebysidedrivensimultaneouslyandmaximisetheirdiameterspaceasshowninFig.2.Lubricatedphosphorbronzethrustbearingswereusedtoresisttheaxialloadgeneratedbythematerialalongtheshaft.2.6.HeatingandtemperaturecontrolHeatingofthebarreltogivenecessarythermalinputforcookingthefoodwasdonebytwosetsofcartridgeheatershavingcapacitiesof800and1200W.TheheaterswerepositionedinthegroovesmadeonthetopandbottomofthebarreltowardsthedieendasshowninFig.3.Asingletemperaturecontrollerwassetuptogetherwithathermocoupletosensethetemperatureinsidethebarrelveryclosetodieplate.Owingtotheshortnessofthebarrelonlyonethermocouplewasconsiderednecessary.Inanearlydesignheaterswerealsousedneartothefeedhopperbutwerenotusedastheytendedtocauseprematuregelatinizationofthestarchandblockageofthefeed.4.PressuresensorPressuremeasurementsarenotsoimportantinthecommercialproductionprocessesasitcannotbedirectlycontrolledtomonitortheproductcharacteristics.Neitherwassuchadeviceneededasasafetymeasureasthiswascoveredbyanoverloadcutoutontheelectricalsupply.However,inexperimentalworkthemeasurementofpressureisusefultoascertaintherelationshipbetweenthepressureandtheothercontrollableparameterssuchasdiesize,temperature,moisturecontentandspeed.Inthisstudy,adevicewasbuiltusingstraingaugesmountedonasmallcantileverbeaminordertomeasurethepressureinsidetheextruderbarrel(Fig.4).Afourarmstraingaugebridgewasfixedatthepointofmaximumbendingmoment.Thepressurewastappedfromasmallholemadeinthedieendofthebarrelinwhichaplunger,sealedbyanO-ring,actuatedthecantileverbeamtotransmitthepressureforce.Thestraininthebeamwasdetectedasavoltagedifference.Thisfeaturecouldhavebeenusedasanautomaticsafetycut-outbutreliancewasplacedinsteadonbeltslipintheinitialdrivestageandthemotoritselfhadanoverheatingcut-out.Fig.4.Positionofpressureandtemperaturesensorsontheextruderbarrel.1-locationofstraingaugesonthepressuresensor,2-cantileversupporttoplunger,3-temperaturesensor.5.TestingandevaluationArangeofriceandbananamixtureswereselectedasbeingbothnovelyethavinghighpotentialasprocessedfoodsinSriLanka.Thesematerialsarecheapandcommoncropsinmostdevelopingcountriesandrepresentanopportunitytoproduceanattractive,nutritiousandtastysnackfood.Thiswouldprovidelabour,utilisationofexcessperishablefruitsinseasonandameansofstoringthemforatleastoneyearinappropriatepackages.Themainproductqualities

    注意事项

    本文(外文翻译--一个简化双螺杆旋转食品挤压机设计制造和检验.doc)为本站会员(上***)主动上传,人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。 若此文所含内容侵犯了您的版权或隐私,请立即通知人人文库网(点击联系客服),我们立即给予删除!

    温馨提示:如果因为网速或其他原因下载失败请重新下载,重复下载不扣分。




    关于我们 - 网站声明 - 网站地图 - 资源地图 - 友情链接 - 网站客服 - 联系我们

    网站客服QQ:2881952447     

    copyright@ 2020-2024  renrendoc.com 人人文库版权所有   联系电话:400-852-1180

    备案号:蜀ICP备2022000484号-2       经营许可证: 川B2-20220663       公网安备川公网安备: 51019002004831号

    本站为文档C2C交易模式,即用户上传的文档直接被用户下载,本站只是中间服务平台,本站所有文档下载所得的收益归上传人(含作者)所有。人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。若文档所含内容侵犯了您的版权或隐私,请立即通知人人文库网,我们立即给予删除!