毕业设计资料_钱杰_3外文翻译

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1、FirePreventionandFoamsystemTheselectionoftheproperstorangtanks,theirspacingandproperdesign,isthebestsafeguardagainstfirehazards.Therearethreebasicconditionsthatmustbeforfiretostart:(1)Fuelmustbepresentindispersedformasavapor.(2)Air(supplyingoxygenforcombustion)mustbepreserntintherightproportion

2、withthefuelvaportoformamaxturethatcanbeignited.(3)Asourceofignition(hightemperatureandenergysufficienttoinitiatethechemicalactionofcombustion)mustbepresent.Startingafirerequiresallthreeessentialsexistingatthesametimeandatthesameplace.Extinguishmentusuallyrequiresthateitherthefuelorairbeeliminat

3、ed.Whenwaterisapplieddirectlytoanoilfireitoftendoesmoredamagethangood,sinceburningoilf;oatingonthewatersurfacemayactuallyspreadthefire.Waterisofassistanceinkeepingadjacenttanksandbuildingscool.Waterfog,afinelydividedspray,isusefulinshuttingoffairfromburningoilsurfaceandcoolingitbelowignitiontem

4、perature.Waterfogiseffectiveonviscousoilsorhighflashoilsinareasthatarewithintherangeofthespray.Astandardfirestreamisratedatabout250gpmusinga1.125in.nozzleand2.5in.smoothrubberlinedhose.Thisstandardstreamwillrequireanozzlepressureofabout45psiwithahydrantpressureof105psiusing400feetofhosebetweenh

5、ydrantsndnozzle.Amaindistributionpressureof125psiforhosestreamsandfoamgenerationisadequate.Whenpressureisinadequate,firepumpsareinstalled.Pumpsinthe500to1500gpmarenormallyused.Standbypumps,usuallydieselenginedrivenareprovidedforuseinlargefacilitiesorwhenelectricalpowermaybelostduringafire.A.Foa

6、mFireFightingSystemsTheprincipaloffoamapplicationistocoveraburningoilsurfacewithabblanketthatwillexcludeairandsmotherthe.Herearesomebasicdefinitions.(1)FoamConcentrate-achemicalwhichwhenmixedwithwatercanbeacratedandexpandedtoformfoam.(2)FoamSolution-themixtureoffoamconcentrateandwaterinproperpr

7、oportions,usuallyabout3-10%foamconcentrate.(3)Foam–theaeratedmixtureoffoamsolutionthatismadeupofairfilledbubblesthatformablankettosmotherfire.Themostpertinentdevelopmentswithrespecttotypesoffoamincludethefollowing:(1)proteinfoamco