1、超声波的概念与书语及超声波流量计测量的原理PT878液体超声波流量计的组成PT878液体超声波流量计安装考虑因素PT878液体超声波流量计的故障判断PT878液体超声波流量计的操作超声波的概念与书语 频率:次声波 0 to 20 Hz声波 20 Hz to 20 kHz(Human hearing)超声波 20 kHz超声波的概念超声波的概念传感器工作原理 传感器电能 机械能机械能 电能压电晶体的变化每个传感器能发射和接受VVVVVV发射接收超声波流量计原理：时差法超声波流量计原理：时差法 传感器既发送信号又接收 信号V tup=超声波被流体减速 tdn=超声波被流体加速tuptdnttupd
2、n tttupdn=-DtPc-Vsinup=qtPc+Vsindn=qVqLP 声信号传播时间逆流传播,tup顺流传播,tdnVqLP声速 c=Ptavg,ttt2avg=dnup+Q=Velocity AreaQ=V A体积流量tt tttupdnupdn=-DtPc-VsintPc+Vsinupdn=qq流速 V C2L2 t超声波流量计原理：时差法超声波流量计原理：时差法夹装式传感器 折射原理 Snells Lawcsincsincsin112233qqq=c1=传感器内传播速度c2=管壁的传播速度c3=流体内的传播速度S=传感器的间距c1q q1c2q q2q q3c3LSW.T.C
3、lassic“clamp-on”approachPT878液体超声波流量计的组成1主机传感器信号线充电器红外线转RS232测厚探头偶合剂仪器包PT878液体超声波流量计的组成2 1.OKS传感器夹具 2.CRS和CPT传感器夹具 3.CF-LP传感器夹具所配传感器的特性及用途传感器代码型号C-RS402C-RS401C-PT116CF-LP 23OKSSpecial(91)形状频率1.0 MHz0.5 MHz1.0 MHz4.0 MHz2.0 MHz发射角度42423559.5传播时间17.320.327.55.85传播速度248424842674.63328使用温度-40 to 150 C-
4、40 to 150 C-20 to 210C-40 to 230C-200 to 360 C传感器选用原则 1.温度要求.2.信号要求.导声较差的介质和大的管道选择低频探头.3.精度要求.频率越高精度越高.2寸以下一般用CF-LP探头.管道要求 1.直管段要求:前10后5.即在传感器安装位置前10倍直径长度和后5倍的直径长度无弯头,阀门等引起流体扰动的装置.2.准确测量管经外径周长或直径.3.确定管道材质和壁厚及接触温度.4.确定是否有内衬及种类和厚度.介质要求 1.已列出的介质直接选择 2.未列出的介质需输入声速或选择跟踪窗口测试 3.确定声速的目的是在窗口中央将信号检出.END OF TR
5、ANSMITGOOD SNRWINDOW安装方式 1.根据管道大小和信号强度选择安装方式 A.单声程:大管道和复杂应用 B:双声程:首选方式,安装简单.C:多声程:小管道,信号特强.安装位置:水平管道 3点和9点位置 垂直管道必须是介质向上流校准 1.标定后输入校验系数 2.雷诺数修正.Re=雷诺数#V=流体流速ID=内径=运动粘度(ft2/sec or m2/sec)k=11.1190.011 l og ReRe-Re=VID absolute viscosityfluid density=进行信号诊断 介质充满管道后需检测的参数和信号 流向是否正常 信号强度SSup;SSdn 声速SNSP
6、 波型等 根据诊断参数调整有关输入参数得到准确结果进行信号诊断 信号强度SSup;SSdn 50-55 偏低可能不稳定 55-60 低一点,可以接受 60-65 好 65-75 非常好 75-99 信号饱和,分辨率可能降低 0.电缆线开路 100.控制器故障 声速SNSP应在合理范围内.如水1500m/s左右 进行信号诊断 错误代码 E0:无错误 E1:信号太低 E2:声速错误 E3:流速超出范围 E4:信号质量太差 E5:流速变化太大 Features Large,Backlit LCD Simplified Keypad Graphical User Interface(GUI)Faste
7、r Update Rate Improved Peak Detection Larger,more powerful Data Logger XML-format Site Files Flash memory Simple UpgradesPT878 Ultrasonic FlowmeterIrDA -compatible wireless data transferUp to 11 hours run time per chargeLCD Display240 x 200 resolutionRoom for 1 to 4 measurementsLarge signal waveform
8、 displaysWhite EL BacklightPT878 Ultrasonic FlowmeterLCD Display240 x 200 resolutionRoom for 1 to 4 measurementsLarge signal waveform displaysWhite EL BacklightPT878 Ultrasonic FlowmeterKeypadRubberized keysClick actionSimple universal layoutSoft Function KeysPT878 Ultrasonic FlowmeterGraphical User
9、Interface(GUI)Keeps related information togetherAll choices visible at the same timePT878 Ultrasonic FlowmeterGUI ControlsMenus Related items grouped together Use to move through choices Use to change menus Press Enter to selectPT878 Ultrasonic FlowmeterGUI ControlsTabs Quick access to related forms
10、 Use to select form Press Enter to open the formPT878 Ultrasonic FlowmeterGUI ControlsButtons Selects between mutually exclusive choices Use to select button Press Enter to activatePT878 Ultrasonic FlowmeterPT878 Ultrasonic FlowmeterGUI ControlsLists Choose from all applicable settings Use to move o
11、ne item Use to scroll the listPT878 Ultrasonic FlowmeterGUI Controls Numeric Entry Press Enter to begin entering digits Press to erase a digit Press Esc to cancel and restore original value Press Enter to accept the new valueValues can be entered or displayed in either Metric or English units withou
12、t having to change meter defaultsPT878 Ultrasonic FlowmeterGUI ControlsCheck Boxes Used to turn an option:On Off Press Enter to toggleGUI ControlsFunction Keys Change according to form or menu active Press F1,F2,or F3 to selectPT878 Ultrasonic FlowmeterGUI Controls Locale-SpecificChange date,time,an
13、d decimal formats for local custom:MM/DD/YYYYDD-MM-YYYYYYYY-MM-DD11:59 PM23:59123.45123,45PT878 Ultrasonic FlowmeterData Logger 1 Megabyte storage 100,000 records From 1 to 12 items per log Multiple logs can run simultaneously Log interval from 1 second to 99 minutes Programmable Start and End Date/
14、Time Cyclic Logs Error logsPT878 Ultrasonic FlowmeterFlash MemoryInstall new program in minutes over IRNo EPROMs to changePT878 Ultrasonic FlowmeterIrDA -Compatible WirelessCommunicationsInfrared data transferUp to 115KbpsUp to 1 meter rangeDrag&Drop file transfersAutomatic No settings No cable adap
15、ters requiredPT878 Ultrasonic FlowmeterBatteryNiMH rechargeable 9 to11 hour run time(longer than NiCd)6 hour recharge None of the memory problems associated with NiCd Fewer charge cycles than NiCd NiCd performs better in cold NiCd or disposable AA alkaline cells can be used instead of NiMHPT878 Ultr
16、asonic FlowmeterBatteryContinuous battery level gauge Simple icon indicates chargeUniversal charger 100-250VACPT878 Ultrasonic FlowmeterBatteryRun time up to 11 hours,depending on features selected.Run time is reduced by:Prolonged use of the backlight Loop-powered 4-20mA transmitters High resistance
17、 loads on 4-20mA outputRun time is increased by:Using Sleep modePT878 Ultrasonic FlowmeterPT878 Ultrasonic FlowmeterEnvironmentalMeets IP67 rating Withstands submersion in waterDurable polymer boot Prevents damage if dropped Integrated wire standPT878 Ultrasonic FlowmeterMeter SetupA.Select UnitsB.S
18、elect TransducerC.Select PipeD.Select LiningE.Select FluidF.Adjust PathG.Correction FactorsH.Save to a SitePT878 Ultrasonic FlowmeterSelect UnitsThe PT878 can default to either Metric or English units.From the Meter menu,select Units.Press OK to use the new settings.PT878 Ultrasonic FlowmeterSelect
19、Transducer Select Wetted or Clamp-on Choose Transducer from List List only shows applicable transducers All parameters filled in automatically Choose SPECIAL to enter customer parameters Allows each parameter to be specifiedPT878 Ultrasonic FlowmeterSelect Pipe Select Pipe Material from List Pipe So
20、und Speed automatically filled in Select OTHER for unlisted material Enter Sound Speed Enter Dimensions Outer Diameter(OD)or Circumference(ODxPI)Wall thicknessPT878 Ultrasonic FlowmeterSelect Pipe If pipe material has a schedule,ID can be used to automatically enter dimensions.Uses ANSI(English)or D
21、IN(metric)schedule.Schedule Materials:Stainless SteelCarbon SteelCast IronPVCCPVCPT878 Ultrasonic FlowmeterSelect LiningChoose lining material from list,or Other to specifyLining option is not available when using Wetted transducersPT878 Ultrasonic FlowmeterSelect Fluid Enable/Disable Tracking Windo
22、wsUse for fluids with unknown or highly variable sound speedSpecify minimum and maximum soundspeed Choose fluid from list or Other for unlisted fluidIf fluid not listed,specify the nominal soundspeed onlyPT878 Ultrasonic FlowmeterSelect FluidFor Energy applications with water as fluid,specify the%Gl
23、ycol concentrationAdjust Path For clamp-on,Path length P and Axial length L are automatically calculated.Select the number of traverses.Spacing is automatically recalculated.Spacing can be changed by entering a new value.PT878 Ultrasonic FlowmeterFinish UpYour changes will not take effect until you:
24、Press OK to keep all changesPress CANCEL to discard all changesPT878 Ultrasonic FlowmeterCorrection FactorsReynolds Correction Use a single value for Kinetic Viscosity(K/V).Table option is not availablePT878 Ultrasonic FlowmeterCorrection FactorsK-Factor Correction Use a single value for K-Factor mu
25、ltiplier Use a Table to relate K-Factor to another measure.Only Velocity can be used to interpolate the K-Factor.PT878 Ultrasonic FlowmeterSave to a Site FileTo keep the new settings,you must save them to a Site File:Choose Save Now to replace the settings in the current site.Choose Manager to creat
26、e a new site.PT878 Ultrasonic FlowmeterSite ManagerUse the Site Manager to:Save settings to a new site.Use and existing site.Delete sites.Rename sites.Print or Transfer sites.PT878 Ultrasonic FlowmeterSite ManagerOpen the Site Manager menu by pressing Menu,Enter.Choose Save As to name the site and s
27、tore it.PT878 Ultrasonic FlowmeterSite ManagerEnter a file name of up to 8 characters:Use arrows to move around the grid.Press Enter to select the character.Use Delete to erase a character.Press OK when done.Hint:A descriptive Site Message can be entered from the Site MenuPT878 Ultrasonic FlowmeterS
28、ite Files Up to 32 sites stored in PT878 Can be transferred to/from PC for unlimited capacity Software versions need to match to ensure compatibility XML*Format Files print as shown here Some outputs are coded Set-ups are best viewed through a meter Site Files should not be edited with a PC or lapto
29、p*eXtensible Markup Language PT878 Ultrasonic FlowmeterDiagnosticsDisplay all Diagnostics Simultaneously Select“Diagnostics”in the Service Menu Press EnterPT878 Ultrasonic FlowmeterDiagnosticsAll Diagnostics viewed simultaneously Easy and efficient analysisPT878 Ultrasonic FlowmeterNote The above presentation reflects PT878 Instrument Program INST.001.J and ECO 4958New functionality and capabilitiesMinor changes in menusAll meters with serial#1294 and above will include these modificationsMeters with serial#1293 and lower can be upgraded(consult the factory)PT878 Ultrasonic Flowmeter
