英文文献年产万吨的苹果汁工厂设计Word格式.docx

英文文献年产万吨的苹果汁工厂设计Word格式.docx

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Roofsandceilings

Walls

Windowsanddoors

Floors

Lightingandpower

Watersupplyandsanitation

Layoutofequipmentandfacilities

Ingeneral,abuildingshouldhaveenoughspaceforallproductionprocessestotakeplacewithoutcongestionandforstorageofrawmaterials,packagingmaterialsandfinishedproducts.However,theinvestmentshouldbeappropriatetothesizeandexpectedprofitabilityoftheenterprisetoreducestart-upcapital,thesizeofanyloanstakenoutanddepreciationandmaintenancecharges.

Intropicalclimates,overhangingroofskeepdirectsunlightoffthewallsandoutofthebuilding.Thisisparticularlyimportantwhenprocessinginvolvesheating,tomakeworkingconditionsmorecomfortable.Fiber-cementtilesoffergreaterinsulationagainstheatfromthesunthangalvanizedironsheetsdo.Highlevelventsinroofsbothallowheatandsteamtoescapeandencourageaflowoffreshairthroughtheprocessingroom.Theventsmustbescreenedwithmeshtopreventinsects,rodentsandbirdsfromenteringtheroom.Ifheatisaseriousproblem,theentrepreneurcouldconsiderfittingelectricfansorextractors,althoughthisclearlyincreasescapitalandoperatingcosts.

Raftersorroofbeamswithintheprocessingandstorageroomsareunacceptable.Theyallowdusttoaccumulate,whichcanfalloffinlumpstocausegrosscontaminationofproducts.Similarly,insectscanfallfromthemintoproducts.Theyalsoallowpathsforrodentsandbirds,withconsequentrisksofcontaminationfromhairs,feathersorexcreta.Itisthereforeessentialtohaveapaneledceilingfittedtoanyprocessingorstore-oom,withcarefulattentionwhenfittingthemtoensurethattherearenoholesinthepaneling.Careshouldalsobetakentopreventbirds,rodentsandflyinginsectsgainingaccesstotheprocessingroomthroughgapsintheroofstructureorwheretheroofjoinsthewalls.

Asaminimumrequirement,allinternalwallsshouldberenderedorplasteredwithagoodqualityplastertopreventdustformingintheprocessingroom.Anexperiencedplasterershouldbeusedtoensurethatnocracksorledgesremaininthesurfacefinish,whichcouldaccumulatedirtandinsects.Thelowerareaofwalls,toatleast1.08metres（fourfeet）abovethefloor,ismostlikelytogetdirtyfromwashingequipment,fromproductsplashingetc.andspecialattentionshouldbepaidtoensurethatthisareaiseasilycleaned.Higherareasofwallsshouldbepaintedwithagoodqualityemulsion.Thelowerpartsofwallsshouldbeeitherpaintedwithawaterproofglosspaint,preferablywhite,toallowthemtobethoroughlycleaned,orideallytheyshouldbetiledwithglazedtiles.Iftilingaprocessroomistooexpensive,itispossibletoselectparticularareassuchasbehindsinksormachineryandonlytiletheseparts.InsomecountriesthereisalegalrequirementforspecifiedinternalfinishesandthisshouldbecheckedwiththeMinistryofHealthorotherappropriateauthority（seealsoSection2.4.2）

Windowsillsshouldbemadetoslopefortworeasons:

topreventdustfromaccumulatingandtopreventoperatorsfromleavingclothsorotheritemslyingthere,whichinturncanattractinsects.Windowsallowstafftoworkinnaturaldaylight,whichispreferabletoandcheaperthanelectriclighting.However,intropicalclimatesthereisanaturalinclinationforworkerstoopenwindowstoallowgreatercirculationoffreshair.Thisprovideseasyaccessforflyinginsects,whichcanreadilycontaminatetheproduct.Windowsshouldthereforebefittedwithmosquitomeshtoallowthemtobeleftopen.

Normallydoorsshouldbekeptclosed,butiftheyareusedregularlythereisagainatendencyforthemtobeleftopenwithsimilarconsequencesofanimalsandinsectsenteringtheplant.Inthiscase,thinmetalchainsorstripsofmaterialthatarehungverticallyfromthedoorlintelmaydeterinsectsandsomeanimals,whileallowingeasyaccessforstaff.Alternativelymeshdoorscreenscanbeused.Doorsshouldbefittedaccuratelysothattherearenogapsbeneaththemandallstoreroomdoorsshouldbekeptclosedtopreventinsectsandrodentsfromdestroyingstockoringredients.

Itisessentialtoensurethatthefloorsofprocessingroomsandstoreroomsareconstructedofgoodqualityconcrete,smoothfinishedandwithoutcracks.Insomedevelopingcountries,itispossibletobuyproprietaryfloorpaintsorvinylbasedcoatings,buttheseareusuallyveryexpensive.Generally,itisnotadequatetousetheredwaxfloorpolishesthatarecommonlyfoundinhouseholds,asthesewearawayeasilyandcouldcontaminateeitherproductsorpackages.Overtime,spillagesofacidicfruitproductsreactwithconcreteandcauseittoerode.Attentionshouldthereforebepaidtocleaningupspillagesastheyoccurandtoregularlymonitortheconditionofthefloor.

Thecomerswherethefloorandthewallsjoinareplacesfordirttocollect.Duringconstructionofthefloor,itshouldthereforebecurveduptomeetthewall.Itispossibletoplacefilletsofconcrete（or'

coving'

）inthecomersofanexistingfloortofilluptherightangle,butcareisneededtoensurethatnewgapsarenotcreatedwhichwouldharbourdirtandinsects.

Thefloorshouldslopeatanangleofapproximately1in8toacentraldrainagechannel.Attheendofaday'

sproduction,thefloorcanbethoroughlywashedanddrained.Properdrainagepreventspoolsofstagnantwaterforming,whichwouldinturnriskcontaminationofequipmentandfoods.Thedrainagechannelshouldbefittedwithaneasilyremovedsteelgratingsothatthedraincanbecleaned.Wherethedrainexitsthebuilding,thereisapotentialentrypointforrodentsandcrawlinginsectsunlesswiremeshisfittedoverthedrainopening.Thistooshouldbeeasilyremovedforcleaning.

Generalroomlightingshouldbeminimizedwhereverpossible.Fulluseshouldbemadeofnaturaldaylight,whichisbothfreeandbetterqualitylight,especiallyforintricatework.Whereadditionallightingisneeded,florescenttubesarecheapertooperatethanincandescentbulbs.However,ifmachineryisusedthathasfastmovingexposedparts,theseshouldbelitwithincandescentbulbsandnottubes.Thisisbecauseeventhoughthepartsshouldhaveguardsfitted,arotatingmachinecanappeartostandstillifitsspeedmatchesthenumberofcyclesofthemainselectricitythatpowersfluorescenttubes-withobviousdangerstooperators.

Allelectricpowerpointsshouldbeplacedatasufficientlyhighlevelabovethefloorthatthereisnoriskofwaterenteringthemduringwashingthefloororequipment.Ideally,waterproofsocketsshouldbeused.Itisimportanttouseeachpowerpointforoneapplicationandnotusemultiplesocketswhichriskoverloadingacircuitandcausingafire.Ifthereareinsufficientpowerpointsfortheneedsofaprocess,additionalpointsshouldbeinstalled,eventhoughthisismoreexpensive.Allplugsshouldbefittedwithfusesthatareappropriateforthepowerratingoftheequipmentandideallythemainssupplyshouldhaveanearthleakagetripswitch.Ifthree-phasepowerisneededforlargermachinesorforheavyloadsfromelectricheating,itisimportantthatthewiringisinstalledbyaqualifiedelectriciantobalancethesupplyacrossthethreephases.

Waterisessentialinnearlyallfruitandvegetableprocessing,bothasacomponentofproductsandforcleaning.Anadequatesupplyofpotablewatershouldthereforebeavailablefromtapsaroundtheprocessingarea.Inmanycountries,themainssupplyisunreliableorperiodicallycontaminatedanditisthereforenecessaryfortheentrepreneurtomakearrangementstosecurearegularsupplyofgoodqualitywatereachday.Thiscanbedonebyinstallingtwohighlevel,coveredstoragetankseitherintheroof-spaceoronpillarsoutsidethebuilding.Theycanbefilledalternatelywhenmainswaterisavailableandwhileonetankisbeingused,anysedimentinwaterintheothertankissettlingout.Assedimentationtakesseveralhours,thecapacityofeachtankshouldbesufficientforoneday'

sproduction.Thetanksshouldhaveaslopingbaseandbefittedwithdrainvalvesabovetheslopeandatthelowestpoint.Inuse,wateristakenfromtheuppervalveandwhenthetankisalmostempty,thelowervalveisopenedtoflushoutanysedimentthathasaccumulated.

Waterthatisincludedinaproductshouldbecarefullytreatedtoremovealltracesofsedimentandifnecessary,itshouldbesterilised.Thisisparticularlyimportantiftheproductisnotheatedafterwaterhasbeenmixedinasaningredient.

Therearefourwaysoftreatingwateratasmallscale:

byfiltration;

byheating;

byultra-violetlightandbychemicalsterilants,suchashypochlorite（alsonamed'

chlorinesolution'

or'

bleach'

）.Otherwatertreatmentmethodsaregenerallytooexpensiveatasmallscaleofoperation.

Filtrationthroughdomesticwaterfiltersisslow,buthavingmadethecapitalexpenditure,itisrelativelycheap.Largerindustrialfiltersareavailableinsomecountries.Heatingwatertoboilingandholdingitatthattemperaturefor10-15minutesissimpleandhaslowcapitalcosts,butitisexpensivebecauseoffuelcostsanditistimeconsumingtodoroutinely.Heatingsterilisesthewaterbutdoesnotremovesedimentandboiledwatermaythereforerequirefilteringorstandingtoremovesediment.

Ultra-violetlightdestroysmicro-organismsinwaterandcommercialwatertreatmentunitsthatusethisprinciple（Figure38）arecomingdowninpricetothepointthat