Afterstudythischapter,thestudentwillbeableto:Explainthepurposeofvalvesinindustrialmanufacturing.Identifythebasiccomponentsofagatevalve.Identifythebasiccomponentsofaglobevalve.Explaintheoperationanddesignofaballvalve.Identifythebasiccomponentsofacheckvalve.Describethedesignandoperationofabutterflyvalve.Describethedesignandoperationofaplugvalve.Describethedesignandoperationofadiaphragmvalve.Describethedesignandoperationofareliefvalveandsafetyvalve.Describethedesignandoperationofaautomaticvalves.Para1:valves’importance(2ndsent.)Primarypurpose：（P23，line3）Characteristics:Para2:ThetypesofvalvesClassificationofValves:BridgewallMarkings:someusefulinformationspecifictothevalve.Characteristics:mostcommontape;Bonnet机罩Verylittlerestrictionoccurswhenitisintheopenposition.CommonGates:P26,Fig.2.3-2springline2P26,Para4/thispartSolidwedge整体楔形闸板→shouldneverbeovertightened；Solidsplitgate整体开口闸板→highT；Paralleldiscs平行闸板→thehighertheP,themoretightlythediscfitsintotheseat.Gatevalves3.Body→largestpart.4.Handwheel→isattachedtothevalvestem;Turnclockwise→closes;Turncounterclockwise→opened.GateValveMaterialsBrass黄铜line7黄铜是铜与锌的合金。最简单的黄铜是铜——锌二元合金，称为简单黄铜或普通黄铜。改变黄铜中锌的含量可以得到不同机械性能的黄铜。黄铜中锌的含量越高，其强度也较高，塑性稍低。工业中采用的黄铜含锌量不超过45%，含锌量再高将会产生脆性，使合金性能变坏。Castiron铸铁（生铁）line9caststeelRisingStemandNonrisingStemQ6Rising（RS，升杆式，即明杆）:thehandwheelcountclockwise→open→stem(inthecenterofthehandwheel)rises.Lookat→tellNonrising（NRS，非升杆式，即暗杆）:acollarcannotlookat→cannottell.Maintenance(HW)Characteristics:截止阀Globevalvesmustbeinstalledproperlytoworkwell.Ifthevalvesisinstalledbackwarditwilltendtowearunevenlyandpushtheflow-controlelementdown.(1)结构比闸阀简单，制造与维修都较方便。(2)密封面不易磨损及擦伤，密封性好，启闭时阀瓣与阀体密封面之间无相对滑动，因而磨损与擦伤均不严重，密封性能好，使用寿命长。(3)启闭时，阀瓣行程小，因而截止阀高度比闸阀小，但结构长度比闸阀长。Thetypicalglobevalveconsistsof:Thediscisattachedtothesteminthreeways:Thehollowballrotatesintotheopenorclosedposition.Characteristics:Fig.2.5-1Material:plastic-coatedmaterial----theseats.specifications技术要求Para1:PrimaryfunctionPara2:4typeso