飞机液压系统管路和接头

《BasicAircraftsystem》-AMT106GuangzhouCivilAviationCollegeBasicAircraftSystems—HydraulicSystemRIGIDFLUIDLINESAsingleaircrafttypicallycontainsseveraldifferenttypesofrigidfluidlines.Eachtypeoflinehasaspecificapplication.However,asarule,rigidtubingisusedin:StationaryapplicationsLong,relativelystraightrunsSystemsthattypicallyutilizerigidtubingincludefuel,oil,oxygen,andinstrumentsystems.BasicAircraftSystems—HydraulicSystemRIGIDFLUIDLINESMATERIAL1.RigidlinesinearlyaircraftManyfluidlinesusedinearlyaircraftweremadeofcoppertubing.However,coppertubingprovedtroublesomebecauseitbecamehardandbrittlefromthevibrationencounteredduringflight,andeventuallyfailed.Tohelppreventfailuresandextendthelifeofcoppertubing,itmustbeperiodicallyannealedtorestoreittoasoftcondition.BasicAircraftSystems—HydraulicSystemRIGIDFLUIDLINESMATERIAL1.RigidlinesinearlyaircraftAnnealingisaccomplishedbyheatingthetubeuntilitisredhotandthenquenchingincoldwater.Whenworkingonanaircraftthathascoppertubing,thetubingshouldbeannealedeachtimeitisremoved.Furthermore,copperlinesmustberegularlyinspectedforcracks,hardness,andgeneralcondition.BasicAircraftSystems—HydraulicSystemRIGIDFLUIDLINESMATERIAL2.RigidlinesinmodernaircraftAluminumalloy（铝合金）Corrosion-resistantsteel（耐腐蚀钢）Titaniumalloy（钛合金）Aluminumtubing:Aluminumtubingcomesinavarietyofalloys.purealuminumtubingmadefrom1100-H14(half-hard),oraluminumalloy3003-H14(half-hard)—lowpressuresystems(below1,000psi)suchasthoseusedforinstrumentairorventilatingairBasicAircraftSystems—HydraulicSystemRIGIDFLUIDLINESMATERIAL2.RigidlinesinmodernaircraftAluminumtubing:linesmadeof5052-Oaluminumalloy—Lowpressurefuelandoilandmediumpressure(1,000to1,500psi)hydraulicandpneumaticsystems.Thisalloy,eveninitsannealedstate,isaboutoneandthree-quarterstimesstrongerthanhalf-hard,commerciallypurealuminum.Occasionally,2024-Taluminumalloyisusedforfluidlinesbecauseofitshigherstrength.However,itisnotasflexibleand,therefore,ismoredifficulttobendandflarewithoutcracking.BasicAircraftSystems—HydraulicSystemRIGIDFLUIDLINESMATERIAL2.RigidlinesinmodernaircraftAluminumtubing:Aluminumalloytubesareidentifiedinanumberofways.onlargertubes,thealloydesignationisstampeddirectlyonthetube'ssurface.onsmalltubing,thealloydesignationistypicallyidentifiedbyacoloredband.Thesecolorbandsarenomorethan4incheswideandarepaintedonthetube'sendsandmidsection.Whenabandconsistsoftwocolors,one-halfthewidthisusedforeachcolor.[Figure10-1]BasicAircraftSystems—HydraulicSystemRIGIDFLUIDLINES2.RigidlinesinmodernaircraftCorrosion-resistantsteeltubing:Corrosion-resistantsteeltubing,eitherannealedor1/4hard,isusedinhighpressuresystems(3,000psi)Applicationsincludehighpressurehydraulic,pneumaticandoxygensystems.Corrosion-resistantsteelisalsousedinareasthataresubjecttophysicaldamagefromdirt,debris,andcorrosioncausedbymoisture,exhaustfumes,andsaltair.Suchareasincludeflapwellsandexternalbrakelines.BasicAircraftSystems—HydraulicSystemRIGIDFLUIDLINES2.RigidlinesinmodernaircraftCorrosion-resistantsteeltubing:Anotherbenefitofcorrosion-resistantsteeltubingisthatithasahighertensilestrengthwhichpermitstheuseoftubingwiththinnerwalls.Asaresult,theinstallationweightissimilartothatofthicker-walledaluminumalloytubing.BasicAircraftSystems—HydraulicSystemRIGIDFLUIDLINES2.RigidlinesinmodernaircraftTitaniumalloytubing:Thistypeoftubingandfittingisusedextensivelyintransportcategoryandhighperformanceaircrafthydraulicsystemsforpressuresabove1,500psi.Titaniumis30percentstrongerthansteeland50percentlighterthansteel.Cryofitfittings（冷装配接头）orswagedfittings（型锻接头）areusedwithtitaniumtubing.BasicAircraftSystems—HydraulicSystemRIGIDFLUIDLINES2.RigidlinesinmodernaircraftTitaniumalloytubing:Donotusetitaniumtubingandfittingsinanyoxygensystemassembly.Titaniumandtitaniumalloysareoxygenreactive.Ifafreshlyformedtitaniumsurfaceisexposedingaseousoxygen,spontaneouscombustioncouldoccuratlowpressures.BasicAircraftSystems—HydraulicSystemRIGIDFLUIDLINESIdentificationoftubematerialRepairstoaircrafttubingmustbemadewithmaterialsthatarethesameastheoriginal,orareanapprovedsubstitute.Onewaytoensurethatareplacementismadeofthesamematerialistocomparethecodemarkingsonthereplacementtubetothoseontheoriginal.Ifthemanufacturer'smarkingsaredifficultorimpossibletoread,analternativemethodofidentificationmustbeused.BasicAircraftSystems—HydraulicSystemRIGIDFLUIDLINESIdentificationoftubematerialWhilealuminumalloyandsteeltubingarereadilydistinguishedfromoneanother,itisoftendifficulttodeterminewhetheramaterialiscarbonsteelorstainlesssteel,orwhetheritis1100,2024,3003,or5052aluminumalloy.Forthisreason,samplesoftubingcanbetestedforhardness,magneticproperties,andreactiontoconcentratednitricacid.[Figure10-2]BasicAircraftSystems—HydraulicSystemRIGIDFLUIDLINESIdentificationoftubematerialHardnessistestedbyfilingorscratchingamaterialwithascriber,whereasamagnetdistinguishesbetweenannealedausteniticandferriticstainlesssteels.Typically,theaustenitictypesarenonmagnetic,whereasthestraightchromiumcarbonandlow-alloysteelsarestronglymagnetic.S