調(diào)節(jié)閥的空化現(xiàn)象doc資料

1、1Educational Services - Duplication Prohibited調(diào)節(jié)閥的空化現(xiàn)象2Educational Services - Duplication Prohibited vccavCavitationPvVena ContractaDistanceP1PvcP2Liquid FlowCavitating FluidFlowFigure 23-3. Cavitation3Educational Services - Duplication Prohibited cavillusCavitation DamageCavitation DamageFigure 23-

2、4. Cavitation Damage That Results From Imploding Vapor Cavities4Educational Services - Duplication Prohibited Figure 23-5. Actual Cavitation Damage of a Valve Plug5Educational Services - Duplication Prohibited vcflashCavitatingFlashingPvVena ContractaDistanceP1PvcP2Liquid FlowFluid Vaporization(Flas

3、hing)FlowFigure 23-6. Flashing Phenomena That Occurs When P2 1.00: FlashingAr = P1 - P2 P1 - PvFigure 8. Cavitation Index Ar8Educational Services - Duplication Prohibited Influences on Cavitation Damage Proximity Of Implosions To Boundary Surfaces Pressure Drop Material Properties Cavitation in a Co

4、rrosive or Erosive Fluid Air And Gas Content Single Species Fluids Versus Mixtures Exposure TimeFigure 23-9. Influences on Cavitation Damage9Educational Services - Duplication Prohibited cavrecovPvDistanceValveInletP2P1Pressure,psiaVenaContractaValveOutletHigh Recovery ValvePvc PvFigure 23-10. The P

5、otential For Cavitation As A Function Of Pressure Recovery10Educational Services - Duplication Prohibited ValveInletValveOutletDistancePressure,psiaStage 1Stage 2Stage 3Single Port TrimMulti-Stage TrimP2PvP1multistgFigure 23-11. Pressure Drop Staging11Educational Services - Duplication Prohibited ca

6、vmatPressure,psiaDistanceValveInletVenaContractaValveOutletP1PvcP2PvCavitation DamageNo Cavitation DamageStandard Materials Of ConstructionDamage Resistant MaterialsFigure 23-12. Preventing Cavitation Damage With Damage Resistant Materials OfConstruction12Educational Services - Duplication Prohibite

7、d MaterialHardness17-4 PH H90040 Rc440C59 Rc316/Colmonoy 658 Rc316/Alloy 642 Rc420 SST HT50 Rc416 SST HT36 RcFigure 23-13. Typical Materials for Cavitation Protection13Educational Services - Duplication Prohibited TypeTrimSize P Limit (Psi)KcButterflyAllAllVlv. Limit0.50 FL2AllVlv. Limit0.67 FL21 &

8、21501.0Ball Standard3 & 41001.06 & 501.0Trim 1 & 2AllVlv. LimitFL223001.0V500Trim 33 & 42001.06 & 81001.0All MaterialsAllVlv. LimitGlobe Valve,Hardened Mtls 1 & 23001.0Cage(eg. Alloy 63 & 42001.0Characterizedseat & guide)6 & 1001.0Globe Valve,MicroformVlv. Limit0.85 FL2PlugMicrofulteAllCharacterized

9、CE, GL, EZ1001.0Globe ValveMicroflatAll10001.0Vlv. LimitC.F.TypeTrimSize P Limit (Psi)Kc6001.01 & 21440KmGlobe ValveCavitrol III5001.01-Stage3 - 61440Km4001.08 & 1440Km1 & 221601.01800KmGlobe ValveCavitrol III3 - 621601.02-Stage1200Km8 & 21601.0Globe ValveCav III 3-StageAll30001.0Cav III MicroflatGl

10、obe Valve2-StageAll21601.0Cav III MicroflatGlobe Valve3-StageAll30001.0Cav 43-StageAll35001.0Cav 44-StageAll40001.0FL2kcvaluesFigure 23-14. Typical Kc Values14Educational Services - Duplication Prohibited Valve Cavitation Index Kc PredictsResistance to Damage Kc Approaching 0.99 = Increasing DamageR

11、esistance Kc Approaching 0 = Decreasing DamageResistanceBasis for Kc Values: Recovery Coefficient (FL) Materials of Construction Test and ExperienceFigure 23-15. Kc Cavitation Index15Educational Services - Duplication Prohibited Application of Ar and Kc If Kc Ar - Control valve may experiencecavitat

12、ion damage. If Kc Ar - control valve will not experiencecavitation damage.Figure 23-16. Use of Ar and Kc16Educational Services - Duplication Prohibited stholeFigure 23-17. Single Stage Cavitation And Noise Control17Educational Services - Duplication Prohibited Figure 23-18. Isolation of Fluid Stream

13、 from Critical Boundary Parts18Educational Services - Duplication Prohibited Thin PlateLow CapacityLow RecoveryThick PlateHigh CapacityHigh RecoveryCavitrol HoleHigh CapacityLow RecoverycavholeFigure 23-19. Cavitrol Hole Design and Features19Educational Services - Duplication Prohibited CageSeat Rin

14、gSingle-StageCavitrol HoleValve PlugDistancePressure,psiaStage 1P1P2ValveInletValveOutletPvTrimCavitrol III1 StageSize1 - 23 - 68 - 12Kc = 1.0600 psid500 psid400 psidKc = FL2600 - 1 440 psid500 - 1 440 psid400 - 1 440 psidcav3_1_kcFigure 23-20. Single Stage, Drilled Hole Cage Design20Educational Ser

15、vices - Duplication Prohibited Two-StageCavitrol HoleExtended-HeightCageFlowValveInletValveOutletDistancePressure,psiaStage 1 Stage 2P1P2PvTrimCavitrol III2 StageSize1 - 23 - 68 - 12Kc = 1.02 160 psid1 800 psid1 200 psidKc = FL2NA1 800 - 2 160 psid1 200 - 2 160 psidcav3_2_kcFigure 23-21. Two-Stage,

16、Drilled Hole Cage21Educational Services - Duplication Prohibited Three-StageCageAView ATrimCavitrol III3 StageSize1 - 12Kc = 1.03 000 psidKc = FL2NAValveInletValveOutletDistancePressure,psiaStage 1 Stage 2 Stage 3P1P2Pvcav3_3_kcFigure 23-22. Three-Stage, Drilled Hole Cage22Educational Services - Dup

17、lication Prohibited FlowDrilled Hole,Radial FlowCagesAxial Flow PathThrough The ValveCav4Figure 23-23. Combination Axial Flow With Radial Flow Cage Elements; Fisher CavIV23Educational Services - Duplication Prohibited Figure 23-24. Flow Pattern Of The DST Trim24Educational Services - Duplication Pro

18、hibited 461cavFlowHardened Outlet LinerTungsten Carbide Seat RingTungsten Carbide Valve PlugFigure 23-25. A “Brute Strength” Approach To Cavitation Damage Prevention withthe Fisher Type 46125Educational Services - Duplication Prohibited FlowUpper Cage And PlugProvide A Flow DownBenefit: Cavitation P

19、rotectionAnd Erosion Control.Lower Plug AndCage Provide AFlow-Up Benefit:Plug Stability.Flashing AndOutgassingOccur WithinThe Void. DamageIs Controlled ByHardened Trim.specFigure 23-26. Super-Severe Service Valve For A Cavitating, Erosive, Corrosive, AndOutgassing Fluid26Educational Services - Duplication Prohibited Figure 23-27. Rotary Attenuator Trim Option27Educational Services - Duplication Prohibited RetainerRingAnti-ExtrusionRingSpring-LoadedPTFE SealValvePlugLapping forANSI Class VShutoffSeatRingBackup RingVIEW AVIEW BCageValvePlugcavmaintCage WallFigure 23-28. Anti-Cavitation