《水處理技術(shù)（雙語）》課件-轉(zhuǎn)子流量計

Rotorflowmeters轉(zhuǎn)子流量計轉(zhuǎn)子流量計的特點Featuresofrotorflowmeters轉(zhuǎn)子流量計又稱浮子流量計，浮子流量計作為直觀流動指示或測量精確度要求不高的現(xiàn)場指示儀表，它可測量液體、氣體和蒸汽的流量，被廣泛地用在電力、石化、化工、冶金、醫(yī)藥等流程工業(yè)和污水處理等方面。Rotorflowmeter,alsoknownasfloatflowmeter,floatflowmeterasanintuitiveflowindicationormeasurementaccuracyrequirementsarenothighfieldindicationinstrument,itcanmeasuretheflowofliquid,gasandsteam,iswidelyusedinelectricpower,petrochemical,chemical,metallurgical,pharmaceuticalandotherprocessindustriesandsewagetreatment.其特點有：Itscharacteristicsare:轉(zhuǎn)子流量計的特點Featuresofrotorflowmeters壓力損失小且恒定smallandconstantpressurelosses測量范圍比較寬

arelativelywidemeasuringrange.量程比1:10arangeratioof1:10.工作可靠且刻度線性，reliableoperationandlinearscale.使用維修方便，對儀表前后直管段長度要求不高；easytouseandmaintain,withlowrequirementsforthelengthofthestraightpipesection

beforeandaftertheinstrument.

但受被測液體的密度、黏度、純凈度以及溫度、壓力的影響，也受安裝垂直度的影響，其測量精確度為±2％左右。However,itisaffectedbythedensity,viscosityandpurityoftheliquidbeingmeasuredaswellasthetemperatureandpressure,andalsobytheverticalityoftheinstallation,anditsmeasurementaccuracyisaround±2%.轉(zhuǎn)子流量計工作原理Rotorflowmeterworkingprinciple

浮子流量計的流量檢測元件是由一根自下向上擴(kuò)大的垂直錐形管和一個沿著錐管軸上下移動的浮子組所組成。工作原理如圖所示。Theflowdetectionelementofafloatflowmeterconsistsofaverticalconicaltubethatexpandsfromthebottomupwardsandasetoffloatsthatmoveupanddownalongtheaxisoftheconicaltube.Theoperatingprincipleisshowninthediagram.被測流體從下向上經(jīng)過錐管1和浮子2形成的環(huán)隙3時，浮子上下端產(chǎn)生差壓形成浮子上升的力，當(dāng)浮子所受上升力大于浸在流體中浮子重量時，浮子便上升，環(huán)隙面積隨之增大，環(huán)隙處流體流速立即下降，浮子上下端差壓降低，作用于浮子的上升力亦隨著減少，直到上升力等于浸在流體中浮子重量時，浮子便穩(wěn)定在某一高度。Themeasuredfluidfromthebottomupthroughtheconetube1andfloat2toformtheringgap3,thefloatupperandlowerendofthedifferentialpressuretoformthefloatrisingforce,whenthefloatbytherisingforceisgreaterthantheweightofthefloatimmersedinfluid,thefloatwillrise,theareaoftheringgapthenincreases,thefluidflowrateattheringgapimmediatelydrop,thefloatupperandlowerendofthedifferentialpressuredecreases,therisingforceonthefloatalsodecreases,untiltherisingforceisequaltothefloatimmersedinfluidWhentheweightofthefloatisimmersedinthefluid,thefloatwillbestabilizedatacertainheight.浮子在錐管中高度和通過的流量有對應(yīng)關(guān)系。Thereisacorrespondencebetweentheheightofthefloatinthe

taperedtubeandtheflowratethroughit轉(zhuǎn)子流量計工作原理Rotorflowmeterworkingprinciple轉(zhuǎn)子流量計工作原理Rotorflowmeterworkingprinciple體積流量

的基本方程式為：Thebasicequationforvolumetricflow

isWhenthefloatisanon-solidcorehollowstructure,thebasicequationis轉(zhuǎn)子流量計工作原理Rotorflowmeterworkingprinciple式中α－儀表的流量系數(shù)，因浮子形狀而異；whereα-theflowcoefficientoftheinstrument,whichvariesaccordingtotheshapeofthefloat.

ΔF-流通環(huán)形面積m2;

ΔF-circulationringarea,m2.g-重力加速度，m/82;

g-accelerationofgravity,m/s2.Vf-浮子體積，如有延伸體亦應(yīng)包括，m3;

Vf--floatvolume,includingextensionsifany,m3.Pf-浮子材料密度，kg/m3;

Pf-densityoffloatmaterial,kg/m3.

P-被測流體密度，如為氣體是在浮子上游橫截面上的密度，kg/m3。

P-densityofthefluidbeingmeasured,inthecaseofagasisthedensityinthecross-sectionupstreamofthefloat,kg/m3;Ff-一浮子工作直徑(最大直徑)處的橫截面積，㎡

Ff-cross-sectionalareaattheworkingdiameterofthefloat(maximumdiameter),m2.Gf-一浮子質(zhì)量，kg

Gf-floatmass,kg.轉(zhuǎn)子流量計工作原理Rotorflowmeterworkingprinciple流通環(huán)形面積與浮子高度之間的關(guān)系如式（3-3）所示，當(dāng)結(jié)構(gòu)設(shè)計已定，則d、β為常量。Therelationshipbetweentheflow-throughannulusareaandthefloatheightisshowninequation(3-3).Whenthestructuraldesignhasbeendetermined,thendandβareconstants.式中有h的二次項，一般不能忽略此非線性關(guān)系，只有在圓錐角很小時，才可視為近似線性。Thereisaquadratictermofhintheequation,andthisnon-linearrelationshipcannotgenerallybeignored,andcanonlybeconsideredapproximatelylinearwhentheconeangleisverysmall.轉(zhuǎn)子流量計工作原理Rotorflowmeterworkingprinciple式中d---浮子最大直徑（即工作直徑），m；

whered-themaximumdiameterofthefloat(i.e.theworkingdiameter),m.h--浮子從錐管內(nèi)徑等于浮子最大直徑處上升高度，m；h-heightofriseofthefloatfromtheinnerdiameteroftheconetubeequaltothemaximumdiameterofthefloat,m.

β－錐管的圓錐角；β-coneangleoftheconetube.a，b-常數(shù)a,b-constants透明錐形管浮子流量計如圖所示。Thetransparentconicaltubefloatflowmeterisshowninthediagram.透明錐形管用得最普遍的由硼硅玻璃制成，習(xí)慣簡稱玻璃管轉(zhuǎn)子流量計。Themostcommonlyusedtransparentconicaltubeismadeofborosilicateglassandiscustomarilyreferredtoasaglasstuberotameter.流量分度直接刻在錐管外壁上，也有在錐管旁另裝分度標(biāo)尺。Theflowisgradeddirectlyontheouterwalloftheconicaltube,butthereisalsoaseparategraduationscaleinstallednexttotheconicaltube.（1）玻璃管轉(zhuǎn)子流量計Glasstuberotameter轉(zhuǎn)子流量計的特點Featuresofrotorflowmeters轉(zhuǎn)子流量計的特點Featuresofrotorflowmeters321較大口平滑面內(nèi)壁儀表采用導(dǎo)桿導(dǎo)向。Largermouthswithsmoothinnerwallgaugesareguidedbyguiderods.錐管內(nèi)腔有圓錐體平滑面和帶導(dǎo)向棱筋（或平面）兩種。Theinnerchamberoftheconicaltubehasasmoothconesurfaceandaguiderib(orflat)oftwokinds.浮子在錐管內(nèi)自由移動，或在錐管棱筋導(dǎo)向下移動，Thefloatisfreetomovewithintheconetube,orintheconetuberibbedguidetomove.轉(zhuǎn)子流量計的類型Typesofrotorflowmeters（2）金屬管轉(zhuǎn)子流量計Metaltuberotorflowmeter金屬管轉(zhuǎn)子流量計與玻璃轉(zhuǎn)子流量計具有相同的測量原理Metaltuberotameterandglassrotameterhavethesamemeasuringprinciple不同的是其錐管由金屬制成，這樣不僅耐高溫、高壓，而且能選擇適當(dāng)?shù)牟馁|(zhì)以適合各種腐蝕性介質(zhì)的流量。Thedifferenceisthatitsconicaltubeismadeofmetal,sothatitisnotonlyresistanttohightemperatureandpressure,butalsoabletochoosetheappropriatematerialtosuittheflowofvariouscorrosivemedia.轉(zhuǎn)子流量計的類型Typesofrotorflowmeters浮子的位移量與流量的大小成比例，通過磁耦合系統(tǒng)，以不同接觸方式，將浮子位移量傳給指示器指示出流量的大小，并通過轉(zhuǎn)換器，將流量值轉(zhuǎn)換成標(biāo)準(zhǔn)的電遠(yuǎn)傳信號，從而實現(xiàn)遠(yuǎn)距離顯示、記錄、積算和控制功能。Thedisplacementofthefloatisproportionaltothesizeoftheflow.Throughthemagneticcouplingsystem,thefloatdisplacementistransmittedtotheindicatorindifferentcontactwaystoindicatethesizeoftheflow,andthroughtheconverter,theflowvalueisconvertedintoastandardelectricalremotesignal,thusachievingremotedisplay,recording,accumulationandcontrolfunctions.流量計主要由傳感器（測量管及浮子）和信號變送器（指示器）兩大基本部分組成：Theflowmeterconsistsoftwobasicparts:thesensor(measuringtubeandfloat)andthesignaltransmitter(indicator).金屬管轉(zhuǎn)子流量計在指示器的設(shè)計上可以為各種應(yīng)用場合提供可靠適用的功能組合，如現(xiàn)場指針顯示、LCD顯示瞬時和累計流量等。在指示器供電選擇方面有電池供電、24VDC供電、220VAC供電，方式根據(jù)現(xiàn)場情況選擇。金屬轉(zhuǎn)子流量計如圖所示。Metaltuberotameterintheindicatordesigncanbeforavarietyofapplicationstoprovideareliableandsuitablecombinationoffunctions,suchasfieldpointerdisplay,LCDdisplayinstantaneousandcumulativeflow,etc..Intheindicatorpowersupplyoptionsarebatterypowered,24VDCpowered,220VACpowered,thewayaccordingtositeconditionstochoose.Themetalrotameterisshowninthediagram.轉(zhuǎn)子流量計的類型Typesofrotorflowmeters

轉(zhuǎn)子流量計是污水處理廠最常用的一種流量計Rotameteristhemostcommonlyusedtypeofflowmeterinwastewatertreatmentplants通過刻有流量標(biāo)度尺的錐形玻璃管和管內(nèi)浮子的位置高度，直接觀察管道內(nèi)流體流量。Thefluidflowinthepipeisdirectlyobservedbymeansofaconicalglasstubeengravedwithaflowscaleandtheheightofthefloatpositioninthetube.它具有結(jié)構(gòu)簡單、直觀、壓力損失小、維修方便等特點。Ithasasimple,intuitivestructure,lowpressurelossandeasymaintenance.轉(zhuǎn)子流量計的特點Featuresofrotorflowmeters轉(zhuǎn)子流量計的特點Featuresofrotorflowmeters

轉(zhuǎn)子流量計適用于測量通過中小管徑（DN4～250）的流量，也可以測量腐蝕性介質(zhì)的流量。

Rotorflowmeterissuitableformeasuringtheflowthroughsmallandmediumpipediameter(DN4~250),canalsomeasuretheflowofcorrosivemedia.其中玻璃管浮子流量計結(jié)構(gòu)簡單，成本低，易制成防腐蝕性儀表，但其強度低；Rotorflowmeterissuitableformeasuringtheflowthroughsmallandmediumpipediameter(DN4~250),canalsomeasuretheflowofcorrosivemedia.而金屬管浮子流量計可輸出標(biāo)準(zhǔn)信號，耐高壓，能實現(xiàn)流量的指示、積算、記錄、控制和報警等多種功能。Andmetaltubefloatflowmetercanoutputstandardsignal,highpressureresistance,canrealizetheflowofindication,accumulation,record,controlandalarmandotherfunctions.轉(zhuǎn)子流量計的特點Featuresofrotorflowmeters轉(zhuǎn)子流量計安裝與使用Rotorflowmeterinstallationanduse儀表安裝方向絕大部分浮子流量計必須垂直安裝在無振動的管道上，不應(yīng)有明顯的傾斜，流體自下而上流過儀表。Themajorityoffloatflowmetersmustbeinstalledverticallyinavibration-freepipelinewithoutanyobviousinclination,withthefluidflowingthroughthemeterfromthebottomup.中心線與鉛垂線間夾角一般不超過5°，高精度（1.5級以上）儀表0≤20°。Floatflowmetercenterlineandtheanglebetweentheplumblinegenerallydoesnotexceed5°,high-precision(morethan1.5grade)instrument0≤20°.（1）儀表安裝方向Instrumentinstallationdirection儀表無嚴(yán)格上游直管段長度要求，但也有制造廠要求2～5D（D為連接管管徑）長度。Thereisnostrictupstreamstraightpipesectionlengthrequirementfortheinstrument,buttherearemanufacturerswhorequire2to5D(Distheconnectionpipediameter)length.轉(zhuǎn)子流量計安裝與使用Rotorflowmeterinstallationanduse應(yīng)在儀表進(jìn)水方向的上游裝過濾器。Afiltershouldbeinstalledupstreamofthemeterinthedirectionofthewaterintake.帶有磁性耦合的金屬管浮子流量計用于可能含鐵磁性雜質(zhì)流體時，應(yīng)在儀表前裝磁過濾器。Metaltubefloatflowmeterswithmagneticcouplingshouldbefittedwithamagneticfilterinfrontofthemeterwhenusedwithfluidsthatmaycontainferromagneticimpurities.浮子的潔凈程度明顯影響測量值，要保持浮子和錐管的清潔，特別是小口徑儀表。Thecleanlinessofthefloatobviouslyaffectsthemeasuredvalue,keepthefloatandtheconeclean,especiallyforsmalldiametermeters.（2）用于污臟流體的安裝Forinstallationswithdirtyfluids如果測量要求的流量范圍度寬，范圍度超過10時，經(jīng)常采用2臺以上不同流量范圍的玻璃管浮子流量計并聯(lián)；Ifthemeasurementrequirementsoftheflowrangedegreewide,rangedegreemorethan10,oftenusingmorethan2differentflowrangeofglasstubefloatflowmeterinparallel.也可按所測量擇其一臺或多臺儀表串聯(lián)，小流量時讀取下流量范圍儀表示值，大流量時讀取大流量儀表示值，串聯(lián)法比并聯(lián)法操作簡便，不需頻繁啟閉閥門，但壓力損失大。Canalsobemeasuredaccordingtothechoiceofitsoneormoremetersinseries,smallflowratewhenreadingthelowerflowrangemetertoindicatethevalue,thelargeflowratewhenreadingthelargeflowmetertoindicatethevalue,seriesmethodthantheparallelmethodofoperationissimple,donotneedtofrequentlyopenandclosethevalve,butthepressure