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1、PT878超声波流量计技术培训,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,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,发射,接收,超声波流量计原理：时差法,传感器既发送信号又接收 信号,tup = 超声波被流体减速,tdn = 超声波被流体
2、加速,声信号传播时间 逆流传播, tup 顺流传播, tdn,超声波流量计原理：时差法,夹装式传感器,折射原理 Snells Law,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,c1,1,c2,2,3,c3,L,S,W.T.,Classic “clamp-on” approach,PT878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,传感器选
3、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,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
4、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),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 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
5、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) Faster Update Rate Improved Peak Detection Larger, more powerful Data Logger XML-format Site Files Flash memory Sim
6、ple Upgrades,PT878 Ultrasonic Flowmeter,IrDA - compatible wireless data transfer Up to 11 hours run time per charge,LCD Display 240 x 200 resolution Room for 1 to 4 measurements Large signal waveform displays White EL Backlight,PT878 Ultrasonic Flowmeter,LCD Display 240 x 200 resolution Room for 1 t
7、o 4 measurements Large signal waveform displays White EL Backlight,PT878 Ultrasonic Flowmeter,Keypad Rubberized keys Click action Simple universal layout “Soft“ Function Keys,PT878 Ultrasonic Flowmeter,Graphical User Interface (GUI) Keeps related information together All choices visible at the same
8、time,PT878 Ultrasonic Flowmeter,GUI Controls Menus Related items grouped together Use to move through choices Use to change menus Press Enter to select,PT878 Ultrasonic Flowmeter,GUI Controls Tabs Quick access to related forms Use to select form Press Enter to open the form,PT878 Ultrasonic Flowmete
9、r,GUI Controls Buttons Selects between mutually exclusive choices Use to select button Press Enter to activate,PT878 Ultrasonic Flowmeter,PT878 Ultrasonic Flowmeter,GUI Controls Lists Choose from all applicable settings Use to move one item Use to scroll the list,PT878 Ultrasonic Flowmeter,GUI Contr
10、ols 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 value,Values can be entered or displayed in either Metric or English units without having to change meter defaults,PT878 Ultrasonic Flowmeter,GUI
11、 Controls Check Boxes Used to turn an option: On Off Press Enter to toggle,GUI Controls Function Keys Change according to form or menu active Press F1, F2, or F3 to select,PT878 Ultrasonic Flowmeter,GUI Controls Locale-Specific Change date, time, and decimal formats for local custom: MM/DD/YYYY DD-M
12、M-YYYY YYYY-MM-DD 11:59 PM 23:59 123.45 123,45,PT878 Ultrasonic Flowmeter,Data 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/Time Cyclic Logs Error logs,PT878 Ultrason
13、ic Flowmeter,Flash Memory Install new program in minutes over IR No EPROMs to change,PT878 Ultrasonic Flowmeter,IrDA - Compatible Wireless Communications Infrared data transfer Up to 115Kbps Up to 1 meter range “Drag & Drop“ file transfers Automatic No settings No cable adapters required,PT878 Ultra
14、sonic Flowmeter,Battery NiMH 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 NiMH,PT878 Ultrasonic Flowmeter,Ba
15、ttery Continuous battery level gauge Simple icon indicates charge Universal charger 100-250VAC,PT878 Ultrasonic Flowmeter,Battery Run 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 loads on
16、4-20mA output Run time is increased by: Using Sleep mode,PT878 Ultrasonic Flowmeter,PT878 Ultrasonic Flowmeter,Environmental Meets IP67 rating Withstands submersion in water Durable polymer “boot“ Prevents damage if dropped Integrated wire stand,PT878 Ultrasonic Flowmeter,Meter Setup Select Units Select Transducer Select Pipe Select Lining Select Fluid Adjust Path Correction Factors Save to a Site,PT878 Ultrasonic Flowmeter,Select Unit
