Workingflowcharacteristicsofcontrolvalves調(diào)節(jié)閥的工作流量特性落版在此調(diào)節(jié)閥的工作流量特性Workingflowcharacteristicsofcontrolvalves謝聰XieCong主講教師Teacher快開(kāi)Quickopening直線Linear對(duì)數(shù)Logarithmic調(diào)節(jié)閥的流量特性Flowcharacteristicsofcontrolvalves調(diào)節(jié)閥的工作流量特性Workingflowcharacteristicsofcontrolvalves謝聰XieCong主講教師Teacher不同閥芯形狀所對(duì)應(yīng)的流量與開(kāi)度之間的關(guān)系Relationshipbetweenflowandopeningfordifferentvalveplugshapes快開(kāi)Quickopening直線Linear對(duì)數(shù)Logarithmic相對(duì)行程(l/L)(%)Relativestroke(l/L)(%)相對(duì)流量(Q/Qmax)(%)Relativeflow(Q/Qmax)(%)調(diào)節(jié)閥的工作流量特性Workingflowcharacteristicsofcontrolvalves管道阻力Piperesistance前后壓差Upstreamanddownstreampressuredifference工作流量特性Workingflowcharacteristics調(diào)節(jié)閥的工作流量特性Workingflowcharacteristicsofcontrolvalves某化工廠的反應(yīng)釜溫度控制系統(tǒng)，選用了具有線性流量特性的調(diào)節(jié)閥。Acontrolvalvewithlinearflowcharacteristicsisselectedinthereactorkettletemperaturecontrolsystemofachemicalplant.調(diào)節(jié)閥的工作流量特性Workingflowcharacteristicsofcontrolvalves實(shí)際投用Actualapplication開(kāi)度在30%以下，溫度波動(dòng)非常大，很難控制；Whentheopeningisbelow30%,temperaturefluctuationsareverylargeanditisdifficulttocontrol;開(kāi)度超過(guò)70%后，出現(xiàn)了調(diào)節(jié)過(guò)于遲緩的問(wèn)題。Whentheopeningexceeds70%,thecontrolisoverlysluggish.Workingflowcharacteristicsofcontrolvalves調(diào)節(jié)閥的工作流量特性某化工廠的反應(yīng)釜溫度控制系統(tǒng)，選用了具有線性流量特性的調(diào)節(jié)閥。Acontrolvalvewithlinearflowcharacteristicsisselectedinthereactorkettletemperaturecontrolsystemofachemicalplant.實(shí)際投用Actualapplication開(kāi)度在30%以下，溫度波動(dòng)非常大，很難控制；Whentheopeningisbelow30%,temperaturefluctuationsareverylargeanditisdifficulttocontrol;開(kāi)度超過(guò)70%后，出現(xiàn)了調(diào)節(jié)過(guò)于遲緩的問(wèn)題。Whentheopeningexceeds70%,thecontrolisoverlysluggish.Workingflowcharacteristicsofcontrolvalves調(diào)節(jié)閥的工作流量特性調(diào)節(jié)閥工作流量特性Workingflowcharacteristicsofcontrolvalves調(diào)節(jié)閥裝在具有阻力的實(shí)際管道中，管道對(duì)流體的阻力隨流量大小變化，閥前后（剩余）壓（力）差也會(huì)發(fā)生變化，使調(diào)節(jié)閥固有流量特性發(fā)生畸變。Whenacontrolvalveisinstalledinapipelinewithresistance,thepipeline’sresistancetofluidchangeswiththeflow,causingtheupstreamanddownstream(residual)pressuredifferencetovary,whichdistortstheinherentflowcharacteristicsofthecontrolvalve.Workingflowcharacteristicsofcontrolvalvesinserieswithpipelines與管道串聯(lián)時(shí)調(diào)節(jié)閥工作流量特性管道系統(tǒng)總壓力ΔP等于管路系統(tǒng)的壓降ΔPG與調(diào)節(jié)閥的壓降ΔPT之和。ThetotalpressureΔPofthepipelinesystemequalsthesumofthepipelinesystem’spressuredropΔPGandthecontrolvalve’spressuredropΔPT.調(diào)節(jié)閥Controlvalve管路及設(shè)備管道PipelineandequipmentpipelinesΔPTΔPGΔPΔPΔPGΔPTPQWorkingflowcharacteristicsofcontrolvalvesinserieswithpipelines與管道串聯(lián)時(shí)調(diào)節(jié)閥工作流量特性調(diào)節(jié)閥Controlvalve管路及設(shè)備管道PipelineandequipmentpipelinesΔPTΔPGΔPΔPΔPGΔPTPQ調(diào)節(jié)閥全關(guān)時(shí)，閥前后（剩余）壓（力）差最大，基本等于系統(tǒng)總壓力ΔP。Whenthecontrolvalveisfullyclosed,theupstreamanddownstream(residual)pressuredifferenceisatitsmaximum,essentiallyequalingtothetotalsystempressureΔP.從串聯(lián)管道中調(diào)節(jié)閥兩端壓差ΔPT

的變化曲線可看出：ThevariationcurveofpressuredifferenceΔPTacrossthecontrolvalveinserieswithpipelinesshowsthat:調(diào)節(jié)閥全開(kāi)時(shí)閥前后（剩余）壓（力）差降至最小。Whenthecontrolvalveisfullyopen,theupstreamanddownstream(residual)pressuredifferencedropstoitsminimum.Workingflowcharacteristicsofcontrolvalvesinserieswithpipelines與管道串聯(lián)時(shí)調(diào)節(jié)閥工作流量特性調(diào)節(jié)閥Controlvalve管路及設(shè)備管道PipelineandequipmentpipelinesΔPTΔPGΔPΔPΔPGΔPTPQ

Workingflowcharacteristicsofcontrolvalvesinserieswithpipelines與管道串聯(lián)時(shí)調(diào)節(jié)閥工作流量特性

相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)Workingflowcharacteristicsofcontrolvalvesinserieswithpipelines與管道串聯(lián)時(shí)調(diào)節(jié)閥工作流量特性理想直線特性的畸變Distortionofideallinearcharacteristics理想等百分比特性的畸變DistortionofidealequalpercentagecharacteristicsWorkingflowcharacteristicsofcontrolvalvesinserieswithpipelines與管道串聯(lián)時(shí)調(diào)節(jié)閥工作流量特性相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)S值越接近1，說(shuō)明閥前后壓差變化越小，工作流量特性越接近固有特性；S值越小，壓差變化越劇烈，特性畸變?cè)絿?yán)重。TheclosertheSvalueisto1,thesmallertheupstreamanddownstreampressuredifferencedeviationofthevalveandtheclosertheworkingflowcharacteristicistotheinherentcharacteristic;thesmallertheSvalue,themoredrasticthepressuredifferencedeviationandthemoreseverethecharacteristicdistortion.Workingflowcharacteristicsofcontrolvalvesinserieswithpipelines與管道串聯(lián)時(shí)調(diào)節(jié)閥工作流量特性相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)串聯(lián)管道會(huì)使調(diào)節(jié)閥的放大系數(shù)減小，調(diào)節(jié)能力降低，S值低于0.1時(shí)，調(diào)節(jié)能力基本喪失。Pipelinesinseriesreducetheamplificationcoefficientofcontrolvalvesanddiminishtheircontrolcapability.WhenSfallsbelow0.1,thecontrolcapabilityisessentiallylost.Workingflowcharacteristicsofcontrolvalvesinserieswithpipelines與管道串聯(lián)時(shí)調(diào)節(jié)閥工作流量特性相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)結(jié)論ConclusionsWorkingflowcharacteristicsofcontrolvalves調(diào)節(jié)閥的工作流量特性串聯(lián)管道對(duì)調(diào)節(jié)閥工作流量特性Effectofpipelinesinseriesontheworkingflowcharacteristicsofcontrolvalves另一種常見(jiàn)的安裝形式——與管道并聯(lián)Anothercommoninstallationform-parallelconnectionwiththepipelineWorkingflowcharacteristicsofcontrolvalvesinparallelwithpipelines與管道并聯(lián)時(shí)調(diào)節(jié)閥工作流量特性當(dāng)并聯(lián)管道上的閥門(mén)打開(kāi)（全開(kāi)或部分打開(kāi)）時(shí)，調(diào)節(jié)閥的（總管道）流量特性曲線如圖所示。Whenthevalveonthepipelineinparallelisopened(fullyorpartially),theflowcharacteristicscurveofthecontrolvalve(mainpipeline)isasshowninthefigure.Workingflowcharacteristicsofcontrolvalvesinparallelwithpipelines與管道并聯(lián)時(shí)調(diào)節(jié)閥工作流量特性相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)Workingflowcharacteristicsofcontrolvalvesinparallelwithpipelines與管道并聯(lián)時(shí)調(diào)節(jié)閥工作流量特性當(dāng)S=1，即旁通管道（閥門(mén)）關(guān)閉時(shí)，調(diào)節(jié)閥總流量特性與理想流量特性一致。WhenS=1,thatis,thebypasspipeline(valve)isclosed,thetotalflowcharacteristicsofthecontrolvalvematchtheidealflowcharacteristics.相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)Workingflowcharacteristicsofcontrolvalvesinparallelwithpipelines與管道并聯(lián)時(shí)調(diào)節(jié)閥工作流量特性隨著旁通閥逐漸打開(kāi)，旁通流量逐步增大，S持續(xù)減小，調(diào)節(jié)閥可調(diào)范圍不斷下降?？刂频牧髁吭絹?lái)越小，直至失去流量控制作用。Asthebypassvalveisgraduallyopened,thebypassflowgraduallyincreases,Scontinuestodecrease,andtheadjustablerangeofthecontrolvalvesteadilydeclines.Thecontrolledflowbecomesincreasinglysmalleruntiltheflowcontrolfunctionislost.相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)Workingflowcharacteristicsofcontrolvalvesinparallelwithpipelines與管道并聯(lián)時(shí)調(diào)節(jié)閥工作流量特性總管道的串聯(lián)管阻（力）會(huì)使調(diào)節(jié)閥特性發(fā)生畸變，導(dǎo)致調(diào)節(jié)閥流量控制能力進(jìn)一步下降。Theresistanceofpipelinesinseriesofthemainpipelinewilldistortthecharacteristicsofthecontrolvalve,furtherreducingitsflowcontrolcapability.相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)Workingflowcharacteristicsofcontrolvalvesinparallelwithpipelines與管道并聯(lián)時(shí)調(diào)節(jié)閥工作流量特性結(jié)論Conclusions

旁路流量占總流量比例不能太大，否則并聯(lián)調(diào)節(jié)閥流量的有效調(diào)節(jié)范圍會(huì)變得很小，失去流量調(diào)節(jié)作用。

Theproportionofbypassflowtototalflowshouldnotbetoolarge,otherwise,theeffectiveadjustablerangeoftheflowofthecontrolvalveinparallelbecomesverysmall,losingtheflowcontrolcapacity.相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)相對(duì)行程l/L(%)Relativestrokel/L(%)相對(duì)流量Q/Qmax(%)RelativeflowQ/Qmax(%)Caseanalysis案例分析Caseanalysis案例分析某化工廠的反應(yīng)釜溫度控制系統(tǒng):當(dāng)調(diào)節(jié)閥開(kāi)度在30%以下時(shí)，溫度波動(dòng)非常大，很難控制；而當(dāng)開(kāi)度超過(guò)70%后，又出現(xiàn)了調(diào)節(jié)過(guò)于遲緩的問(wèn)題。Temperaturecontrolsysteminthereactorofachemicalplant:Whenthecontrolvalveopeningisbelow30%,temperaturefluctuationsbecomeextremelysevereanditisdifficulttocontrol;whentheopeningexceeds70%,thecontrolisoverlysluggish.核心原因Thecorereason實(shí)際工況中調(diào)節(jié)閥的工作流量特性偏離了理想的線性流量特性。Thedeviationofthecontrolvalve'sactualflowcharacteristicsfromtheideallinearflowcharacteristicsunderrealoperatingconditions.Caseanalysis案例分析某化工廠的反應(yīng)釜溫度控制系統(tǒng):當(dāng)調(diào)節(jié)閥開(kāi)度在30%以下時(shí)，溫度波動(dòng)非常大，很難控制；而當(dāng)開(kāi)度超過(guò)70%后，又出現(xiàn)了調(diào)節(jié)過(guò)于遲緩的問(wèn)題。Temperaturecontrolsysteminthereactorofachemicalplant:Whenthecontrolvalveopeningisbelow30%,temperaturefluctuationsbecomeextremelysevereanditisdifficulttocontrol;whentheopeningexceeds70%,thecontrolisoverlysluggish.在理想狀態(tài)下，線性流量特性的調(diào)節(jié)閥流量與開(kāi)度成線性關(guān)系，能均勻調(diào)節(jié)流量。Underidealconditions,amongthelinearflowcharacteristics,theflowofthecontrolvalvehasalinearrelationshipwiththeopening,enablinguniformcontroloftheflow.Caseanalysis案例分析調(diào)節(jié)閥并非孤立存在，會(huì)受到管道阻力和前后壓差變化的影響：Controlvalvesdon'toperateseparatelybutwillbeaffectedbypipelineresistanceandupstreamanddownstreampressuredifferencedeviation:當(dāng)調(diào)節(jié)閥開(kāi)度在30%以下時(shí)，閥門(mén)開(kāi)度小，流通面積小。Whenthevalveopeningisbelow30%,thevalveopeningissmallandtheflowareaisalsosmall.此時(shí)管道系統(tǒng)的阻力主要集中在調(diào)節(jié)閥上，閥前后壓差較大。Insuchcase,theresistanceofthepipelinesystemismainlyconcentratedonthecontrolvalveandthereisasignificantupstreamanddownstreampressuredifference.Caseanalysis案例分析但由于開(kāi)度小，流量對(duì)開(kāi)度的變化非常敏感，微小的開(kāi)度變化就會(huì)導(dǎo)致流量大幅波動(dòng)，進(jìn)而引起反應(yīng)釜溫度劇烈變化，表現(xiàn)為“難以控制”。Duetothesmallopening,theflowishighlysensitivetothechangeintheopenings-tinychangesinopeningcausesignificantfluctuationsinflow,triggeringviolenttemperaturefluctuationsinthereactor,manifestingas“difficultcontrol”.Caseanalysis案例分析而當(dāng)開(kāi)度超過(guò)70%后，閥門(mén)流通面積較大，此時(shí)管道系統(tǒng)的阻力更多由管道自身承擔(dān)，閥前后壓差變小。Whentheopeningexceeds70%,theflowareaofthevalveisrelativelylarge.Atthispoint,theresistanceofthepipelinesystemismainlybornebythepipelineitself,andtheupstreamanddownstreampressuredifferenceofthevalvebecomessmaller.Caseanalysis案例分析此時(shí)流量隨開(kāi)度的變化變得平緩，即使開(kāi)度有較大調(diào)整，流量變化也不明顯，導(dǎo)致對(duì)反應(yīng)釜溫度的調(diào)節(jié)作用減弱，表現(xiàn)為“調(diào)節(jié)過(guò)于遲緩”。?Atthispoint,theflowchangesbecomestableastheopeningdegreechanges,evensubstantialopeningadjustmentsgenerateminimalflowvariations,weakeningtemperaturecontrolfunctionofthereactorandmanifestingas“overlysluggishcontrol”.?Caseanalysis案例分析管道系統(tǒng)的存在Thepipelinesystem改變了調(diào)節(jié)閥實(shí)際的壓差和流量關(guān)系A(chǔ)ltersthevalve'sactualrelationshipbetweenthepr