ConverterSelectionof VFEIntelligent Type Vortex Flowmeter

1.IntroductiontoConverter Performance

Advanced FFT spectrum analysissignal processing circuit

The converter adopts advanced FFT spectrum analysis signal processing circuit module,which can accuratelydetect the vortex informationinasmall signal and low flow area,so that the instrument has super high stabilityand reliabilityinthelow flowarea,and the measurable flow range of the instrument is greatly expanded.Besides,the fluid situation in thepipe can be analyzed,and the best judgment and adjustment can be madeaccording to the analyzed data,reflecting high stability,intelligenceand vibrationresistance.

Real-time temperature and pressure compensation function

The temperature,pressure and operating flow of the mediumcan be measured inreal time,and these parameters can be converted into standard flow or mass flowof themedium.

Intelligent automatic zero setting

Whenitis confirmed that there isno flow in the pipeline,this function can be used to effectively remove the inherent interference signal.

HARTcommunication

Communication signal: HART communication signal( 1 2 0 0 { H z } and 2 2 0 0 { H z } analog signals are superimposed on ( 4 { ~ } 2 0 ) { m A } DC signal);

Communication load resistance:250Ω

Communication distance:up to 1 ~ { k m } in case of usingmulti-stranded cable.The communication distance varies according to the type of cable used.

Self-diagnosis and alarm output

Incaseofanalarm(outofrange,EEPROM error and other abnormalities),an alarm output signal is generated and displayed.

Data protection function in case of power loss

Data (parameters,accumulated flow, etc.) are saved in EEPROM,and no spare battery is required.

Damping time

Damping time is 5s-200s,which can be set by keypad;

The minimum delay time is 5s;

Linearcompensation function

Meterpolyline correction:5approximate polylines canbe used to correct and compensate the linear error of themeter.

Reynolds number compensation: The output error when the Reynolds numberis less than 1O,OoO can be compensated by5approximate polylines.

Interchangeability

The converter can be used with sensors of various diameters.

Display

The low-power consumption 1 2 8 { x } 6 4 full-dotmatrixLCD isadopted,with clearand intuitive display;

Instantaneous flow,cumulative flow and percentage flow (expressed in % )can be displayed at the same time; shortmessageof self-diagnosis can be displayed,and output current,pulse and other information can be displayed bykeypad.

Explosion-proof performance (please refer to GB3836.1,GB3836.4and GB3836.2 for detailed explosion-proof parameters)

Explosion-proof grade:Exia IIC T6,Exd IIC T6; EX Indicates that the electrical equipment
conforms to the regulations on explosion-proof type; ia Intrinsically safe type category a; d Explosion-proof type; IIC Electrical equipment for other explosive gas
environment except coal mine; T6 Temperature group;

Small signal excision

When the flowislower than the setlow flowvalue, the output is 4 { m A } or O pulse;

2.SelectionTableofVFEIntelligentTypeVortexFlowmeter Sensor Converter VFE Xxx 区 区 X XX XX X X X 冈区 Main name Diameter:DN15\~DN300 Threedigits:the first and second digitsof DN and the number of zeros following the first two digits(unit:mm).DN125is special,which is indicatedby121. Norminal pressuer 1:1.6MPa 2:2.5MPa 3:1.0MPa 4:ANSI1505:40MPa 6:ANSI300 Structure material Material combination sequence: body-generator-probe 3:304-304-316L 4:304-316L-316L 5:316L-316L-HC 6:316L-316L-316L 7:316L-HC-HC 8:316L-HC-316L Measuring medium 2:Gas 3:Steam Operating environment General places:ambient temperature:(-30\~70)℃ Hazardous places:ambient temperature:(-20\~60)℃ 1:Mediumtemperature:(-40\~120)℃ 2:Medium temperature:(40\~200)℃ 3:Mediumtemperature:(-40\~350℃ Connection method 3:Flange connection type Accuracy grade A: Class 1.0 E: special Pressure sensor 00:N/A 01:1.6MPa 02:4.0MPa Outgoing line seal 1:G1/2"internal thread 2:1/2"NPT internal thread 3:M20×1.5 Type VH: Integrated type Power supply 1:24VDC Display assembly 2:With display Output signal 1:4\~20mA.DC output, two-wire system 2 4 { ~ } 2 0 { m A } DC output and pulse outpu 3: with pulse output,no 4 { - } 2 0 { m A } DC output Note:4-20mA.DCoutputand485communicationcannotbeboth selected.For theconverterwith485communication protocol,3 is required. Explosion-proofrequirements 1:Generalplaces:notexplosion-proof2:Hazardousplace:intrinsicallsafeexplosion-proof3:Hazardous place:explosio-proof Displaydirection 1:Standard direction Language

0:N/A 1: HART 2:Modbus(RS 485)

Compensation mode

T:Temperature compensationL:Low temperature type temperature and pressure compensation(-40\~200)℃ H:High temperature type temperatureand pressure compensation(-40\~350℃)

Notes:

1.Whenmeasuringflammableandexplosiegasessuchasoxygenandnaturalgasthesensormustbedegreasedfirstoavoidaidents.
2.TheconectingfageisproideditheblegapitewashFangoctiotyevortefowmeterispoidedithpipfas
boltsindeliveycaroessdsesmseescsedectlseasateemetdng
3.Theprobeisprovided withagraphitewasher.
4.IP gradeis Ip65bydefault.
5.The operatingpressure of VFE vortex flowmeter shallbe less than theallowable valueofpressure sensor.

TechnicalData InstallationofVortexFlowmeteronPipeline

SelectionofVortexFlowmeterandPrecautionsforUse

Because the vortex flowmeterhas low fault rate in normal use,the proportion of the vortex flowmeter is gradually increasing.To make better use of the flowmeter, the following precautions shall be noticed:

Correct selection of flowmeter diameter

Generally,the flowmeter diameter shall not be selected according to the inner diameterof the pipe,but shall be selected accordingto theminimum flow,the maximum flow,the common flow and the medium parameters (such as temperature,pressure,density, viscosity,etc.).Generally,the common flow shall be more than 20 % of the measurable range.

Correctselection of flowmeterinstallation point

The flowmeter shall not be installed in placeswith intense vibration to avoid vibrating objects such as motors and water pumps.If necessary,a support fixture shall be installed at the pipe where the flowmeter is installed.

Grounding of split vortex flowmeter

To improve the working stability of the split vortex flowmeter,the grounding terminal of the flowmeter sensor,the grounding terminal of the converter and the cableshieldingwireshallbeconnectedtotheearthina uniform manner.

The fluid shall not contain too many particles, impuritiesand filaments

To ensure stable generator signal,the measuring medium shall not contain too many particles,impurities and filaments

Temperature and pressure compensation in steam and gasmeasurement

The measured value of the vortex flowmeter is only the volume flow under the working conditions.For the medium with little change in temperature and pressure, the average temperature,pressure and density can be set, and the measured flow value of the flowmetercan be madeto be mass flow or standard flow to meet the requirements of trade calculation. However, if the temperature and pressure fluctuates greatly,it is necessary to measure them in real time and compensate them for temperature and pressure.Otherwise,major errorwill be caused.For example,for saturated steam at 6MPa,the measurement error will reach 1 3 % without compensation.

Accurate parameter seting

Asthere are many internal parameters of the vortex flowmeter,the parameters are set according to the parameters during user ordering.However,because the parameters in actual use are often inconsistentwith those in the original design,the parameters need to be adjusted according to the actual situation to achieve the expected measurement effect.

Process pipe and installation mode

There shall be a straight pipe section in front of and behind the flowmeter,and the inner diameter of the straight pipe section shall be the same as or slightly largerthan that of the flowmeter,the center of the flowmeter shall be kept consistent with that of the pipe during installation,and the sealingwashers on both sides of the flowmeter shall not be protruded in the pipe to avoid measurement errors and measurement fluctuations.

Gasparameters

When users provide the flow range of gas measurement, they often confuse the operating flow ( { m } ^ { 3 } / { h } ) with the standard flow ( { N m } ^ { 3 } / { h } ) ，resulting inwrong selection.Because the operating flow refers to the flow under thepressureand temperature inactual use,while the standard flow refers to the flow value with the operating flowconverted to the standard condition( { 0 ^ { \circ } C } 1atm).The difference between the two is often several times.

GuideforSelectionofVortexFlowmeter

2.InstructionsforSelection DesignSteps

(1)Which operating condition data shall be known when selecting flowmeter?

Data:

(2)How to determine nominal diameter of the flowmeter?

Because the improvement of efficiency and the reduction of pressure loss are taken into consideration in fluid transmission,the pipe is generally selected with a large diameteranda low flow rate,but when the flowmeter is in normal service,there are certain requirements for lower limit of flow rate,and the diameterof the flowmetershall be generally selected according to the flowand medium densityand viscosity rather than the innerdiameter of the original pipe.For specific selection,please referto our flowmeter selection sample and provide parameters for selection and production by us.

(3)How to determine the type of the converter?

The converter shall be selected according to explosion-proof requirements and fluid output mode.

(4)How to determine the vortex flowmeter as integrated type orsplittype?

The vortex flowmeter can be divided into two parts in structure: flowmeter sensor (body part) and flowmeter converter (electronic part).The integrated type is to combine the two parts together,and the split type is to place the two parts separately and connect them through thespecial cable supplied by Chongqing Chuanyi Automation Co.,Ltd.Flowmeter Branch.

The integrated type has a simple structure and is suitable for situations with easy installation and low medium temperature ( < 2 8 0 ^ { \circ } { C } ) .Exampleof integrated model:

VFC20111211A001VH121111

It represents the integrated intelligent clamped vortexflowmeterwithadiameterof 2 0 0 {mm } ：

The split type is suitable for high medium temperature { ( > 2 8 0 ^ { \circ } C ) } ,orfor easy observation of the display on the converter.The model specification of the split flowmeter consists of three parts,such as:

VFC50011211A101VR121111

It representsa split flowmeter with a diameter of
5 0 {mm } （204号 Where:VR121111 Represents the converter of the flowmeter (with
display header) A10 Represents the special cable length of10m

(5)Installation Diagram of Vortex Flowmeter

The clamped type of the nominal diameter DN15- DN300 of the vortex flowmeter produced by us is clamped and fixed by external flangesand longbolts on the pipe.See Fig.6 below.

Fig.6InstallationModeofClampedFlowmeter

The flowmeter with nominal diameter DN15-DN6o0 is of flange type,as shown inFig.7 below.

Fig.7InstallationModeofFlangeFlowmeter

(7)Flange dimensions

For the convenience of design,flange dataof the most commonly used connection methods are now provided according to HG/T20592-2009

Fig.10 Slip-on-weldingPlate Steel Pipe Flangeswith FlatFace(FF)

Fig.11 Slip-on-weldingPlate Steel Pipe Flangeswith Raised Face(RF)

Unit: (mm)

Vortexflowmeter

(8)How to determine the installation place,front and rear straight pipe sections of the flowmeter?

The flowmeter shall be installed in the place with minor vibration rather than beside vibration sources such aswaterpump,motor,etc.

The front straight pipe section shall be generally 15D(D is nominal diameter,unit mm),and the rear straight pipe section shall be generally 5D.

Ifa gate valve is installed upstream of the flowmeter,the front straight pipe section shall be greater than 20D.

Ifa reducing pipe is installed upstream of the flowmeter,the front straight pipe section can be 10D.

Refer to the installation data of the vortex flowmeterfordetails.

(9) What is temperature/pressurecompensation?

Generally，temperature/pressure compensation is for steam or gas.

Because the vortex flowmeter isaspeed flowmeter, the measured flow is the operating volume flow { Q } _ { { p } } while the mass flow { Q } _ { { m } } isgenerally adopted for steam tradesettlement,and therelationship between thetwo is: { Q } _ { { m } } { = } { Q } _ { { f } } { * } \rho { = } { Q } _ { { r } } .Where,p represents the steam density,and for superheated steam \rho ,it varies with pressure and temperature.For saturated steam,because there is a certain relationship between pressure and temperature,p varieswith temperature or pressure.

When the pressure or temperature of the measured steam has littlechange,an average density \rho (check the steam table) can be obtained by taking the average pressure andaverage temperature.When the pressure or temperature of the measured steam changes greatly and the measurement accuracy requirement is high,Lili temperature sampling shall be adopted,and then through the secondary instrument, the density \rho can be calculated from the pressure and temperature,and the mass flow { Q } _ { { m } } can be obtained from { Q } _ { { m } } = \mathbf { Q } _ { { i } } \mathbf { * } \mathbf { \rho } ,which is called temperature/pressure compensation.

Generally,the saturated steam can be measured by temperature compensation,superheated steam shall be measured bytemperature and pressure compensation.

Sometimes only pressure or temperature compensation can be adopted to save costs.

unit : mm

Fig.12 Compensation Diagram

Note:

Pressure compensation can generally be adopted for gases to save platinum resistor.
Temperature compensationcan generally be adopted for saturated steam to save pressure transmitter.
Temperature and pressure compensationcan generallyadopted for superheated steam.
Temperature compensationcan be adopted for liquid if necessary.

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