搜索
Lesson17Oilseparator分油机1.Toensuregoodcombustionindieselenginesandreducewearandcorrosionintheengine,itmaybenecessarytoremovecertainimpuritiesfromfuelandlubricatingoils.•为了确保柴油机的燃烧良好，减轻发动机的磨损和腐蚀，可能需要除去燃油和润滑油中的某些杂质Whenimpuritiesaresuspendedsolidsorimmiscibleliquids,theycanberemovedreasonablysuccessfullybyoneormoreofanumberofmethods.•当杂质是悬浮固体或不互溶的液体时，可以通过一种或多种方法将其非常成功的除去。Themethodsusedatseaare:heatingtoallowseparationofwaterpresent,coarseandfinefilteringtoremovesolidparticlesandalsocentrifuging.Ofthesethreemethodscentrifugingisthemostwidelyused•船上常用的方法有：加热分离水分，粗细滤器去除固体颗粒和离心分离。这三种方法中，离心分离是应用最为广泛的。2.Formanyyearsmarinecentrifugesweredesignedforbatchoperation,thatis,themachineswererunforaperiodduringwhichsolidsaccumulatedinthebowl.•很久以来，船用分油机被设计成断续工作的，也就是说，这种机器在运行的时间内分离出的固体集聚在分离筒内。Themachinewasstoppedwhentheaccumulatedsolidsbegantoimpairitsperformanceandthesolidswereremoved•当集聚的固体杂质开始影响其功能时，停下分油机，清除油泥。Batchcentrifugingisstillcommonlyusedespeciallyforlubricatingoilpurification,butmanymachinescapableofcontinuousorsemi-continuoussludgedischargearenowatsea.•间歇工作式分油机仍然广泛使用，尤其是在分离润滑油时，不过现在船上有很多能够连续或半连续排渣的分油机。3.Thecentrifugalseparatorisusedtoseparatetwoliquids,forexampleoilandwater,oraliquidandsolidsasincontaminatedoil.•离心式分油机被用来分离两种液体，比如油和水，或者一种液体和固体，比如脏油。Separationisspeededupbytheuseofacentrifugeandcanbearrangedasacontinuousprocess.•使用离心分离可以加快分离速度，并可以设计成一个连续的过程Whereacentrifugeisarrangedtoseparatetwoliquids,itisknownasa“purifier”（seefig17-1}.•当分油机被用来分离两种液体时，叫做“分水机”。Whereacentrifugeisarrangedtoseparateimpuritiesandsmallamountsofwaterfromoilitisknownasa“clarifier”.•当分油机被用来分离油中的杂质和少量的水时，叫做“分杂机”Acentrifugeconsistsofanelectricmotordrivetoaverticalshaftonthetopofwhichismountedthebowlassembly.•离心分油机由一个电马达驱动的立轴及其上安装的分离筒组件组成。Anouterframeworksurroundstheassemblyandcarriesthevariousfeedanddischargeconnections.•分离筒组件外部是机壳，机壳上装有各种进排接头。Thebowlcanbeasolidassemblywhichretainstheseparatedsludgeandoperatesnon-continuously,orthebowlcanbearrangedsothattheupperandlowerpartsseparateandthesludgecanbedischargedwhilethecentrifugeoperatescontinuously•分离筒可以是整体容渣式并间歇运行的，或者是上下部分分开，油渣可以在分油机连续运行时排出的。5.Theliquidisfedintothestackeitherfromtheouteredgeofthediscsorviadistributionholestowardstheperipheryofthediscsdependingonthemakeofthemachine,andflowsalongthespacesbetweenadjacentplates.•液体根据分油机的不同类型从分离盘片外边缘或经过分配孔进入分离盘片，沿着相邻的分离盘流动。Theplatesthenactasanextendedsettlingsurface,theheavyphaseparticlespassingthroughthelightphaseandimpingingontheundersurfaceofthediscs.•分离盘片充当了延伸的沉淀表面，重质颗粒穿过轻质成分,冲击向分离盘片的下表面。Oncetheparticleshaveimpingedonthediscsurfacestheyareabletoaccumulateandeventuallyslidealongthediscstowardstheperiphery•一旦颗粒撞击到分离盘的表面，就会聚集在一起并最终沿着分离盘片滑向外围。Attheperipheryofthediscthewaterglobulesandsolidparticlesleavethestack.Theheaviersolidparticlespasstothebowlwall,•在分离盘片外沿，水珠和固体颗粒离开分离盘组。较重的固体颗粒到达分离筒壁，andthewaterissandwichedbetweenthesolidsandtheoil,whichorientatesitselftowardsthebowlcenter.•水分夹在固体和油的中间，并自动流向分离筒中央。Theboundariesatwhichsubstancesmeetareknownasinterfaces.•物质相连接的边界叫做分界面。6.Themechanicaldesignofthecentrifugerequiresthattheinterfaceisconfinedwithincertainstrictlimits.Togainthefullestadvantagefromthediscstacktheinterfaceshouldbelocatedoutsideofit.•离心机的机械设计要求分界面被限定在一个严格的范围内。为了从分离盘组获得最好的分离效果，分界面应当位于分离盘组的外面。Ontheotherhandiftheinterfaceislocatedoutsidethewateroutletbaffle(topdisc)dischargeofoilinthewaterphasewilltakeplace.Factorsinfluencingtheinterfacepositionare:•另一方面，如果分界面位于出水口挡板的外面，就会发生出水口跑油。影响分界面位置的因素有：*Oilviscosityanddensity油的粘度和密度Ahighoildensitywillpositiontheinterfaceclosertothebowlperipherythanwillalowdensity.•高密度的油比低密度的油的分界面更靠近分离筒边缘。*ThroughputandbackpressureAsarule,theinterfacewillbelocatedclosertothebowlperipheryatahighthroughputthanatalowone.•分油量和背压•作为一种规律，分油量大时分界面更靠近分离筒边缘。Thesameeffectisproducedbyahighbackpressure,andalowonerespectively,inthecleanoiloutlet.•净油出口背压高低会相应的产生同样的效果。*Gravitydisc比重盘Thelocationoftheinterfaceisadjustedbyalteringtheoutletforthewater,i.e.exchangingthegravitydisc.•分界面的位置可以通过改变出水口，即更换比重盘来调节。Changingtoagravitydiscwithlargerholediameterwillmovetheinterfacetowardsthebowlperiphery,whereasadiscwithsmallerholediameterwillpositiontheinterfaceclosertothebowlcenter.•换用大孔径的比重环会使分界面朝分离筒外边缘移动，相反，小孔径的比重环会使分界面朝分离筒中心移动。7.Normallyatableisprovidedwiththemachine,givingthediscdiameterrequiredforpurifyingoilsofvariousspecificgravities.•通常，分油机会配有一个表格，给出分离不同比重的油时需要用的比重环的直径。8.Itisimportanttorealizethatvariationinoiltemperaturewillcauseaproportionalvariationinspecificgravityandforthisreasonthefeedtemperaturemustremainconstant.•重要的是要认识到油温的变化会导致其比重成比例的变化，因此，供油温度必须保持恒定。Tosomeextentthefeedratewillhaveaneffectontheinterface:excessivefeedshouldbeavoidedinanyeventsincethequalityofseparationdeteriorateswithincreaseofthroughput.•在某种程度上供油率也会影响分界面：任何情况下都应避免过量供油，因为分油量的增多会导致分离效果恶化。Topreventoilpassingoutofthewatersideonstartupitisnecessarytoputwaterintothebowluntilthewatershowsatthewaterdischarge.Thebowlisthenhydraulicallysealed.•为了避免启动时出水口跑油，需要向分离筒内注水，直到水侧有水流出为止。于是分离筒就被液压密封了。