ABSTRACT
Getting Oriented 156 Special Requirements 157
Differential Pressure 157 Reynolds Number 160 Energy Costs 161
Example 161 Orifice Plates 164 Venturi Tubes and Nozzles 164 Sonic Venturi Meters 166 Pitot Tubes 166 Elbow Taps 166 Target (or Impact) Meters 167
Electromagnetic Meters 167 Turbine Meters 167 Vortex Meters 167 Variable-Area Meters 167 Positive-Displacement Meters 168 Ultrasonic Meters 168 Metering Pumps 168 Mass Flowmeters 168 Low-Flow Applications 169 Specifying the Key Requirements 169
Inaccuracy 169 Safety 170 Installation 171 Cost 171
References 171 Bibliography 172
2.2 ANEMOMETERS 173
Mechanical Anemometers 174 Thermal Anemometers 175 Doppler Anemometers 175 Conclusion 176 Bibliography 176
2.3 BTU FLOWMETERS FOR HEAT EXCHANGERS 177
Mechanical BTU Meters 178 Electronic BTU Meters 179 Reference 179 Bibliography 179
2.4 BTU FLOWMETERS FOR GASEOUS FUELS 180
Measuring Heat Flow by Wobble Index 180 The BTU Flowmeter Loop 181 Applications 181 Conclusion 182 Bibliography 182
2.5 CROSS-CORRELATION FLOW METERING 183
Nuclear Power Plant Applications 184 Determining the Transit Time 184
Reliability and Accuracy 185 Nuclear Power Applications 185 The TTFM System 186
References 188 Bibliography 188
2.6 ELBOW TAPS 189
A Simple Flowmeter 189 Location and Size of Taps 189
Units 191 Other d/p-Producing Elements 192 References 192 Bibliography 192
2.7 FLOW SWITCHES 193
Design Variations 195 Solids Flow Switches 197 Bibliography 197
2.8 JET DEFLECTION FLOW DETECTORS 198
Operating Principle 198 Hot-Tapping 199 Conclusion 200 Bibliography 200 Other Sources 200
2.9 LAMINAR FLOWMETERS 201
Theory 201 Hagen-Poiseuille Law 202 Design Parameters 203 Design Calculations for Liquid Service 203
Error Sources 204 Range Extension Techniques 205 Commercially Available Units 206 Conclusion 206 References 206 Bibliography 206
2.10 MAGNETIC FLOWMETERS 208
Theory 210 Advantages 211 Limitations 211
Types of Magnetic Flowmeters 212 AC Magnetic Flowmeters 213
DC Magnetic Flowmeters 213 Dual-Frequency Excitation 214 Other Types 215
Construction of Magnetic Flowmeters 215 Ceramic Liners 217 Probe-Type Units 217
Applications of Magnetic Flowmeters 218 Accuracy and Calibration 220 Errors in Magnetic Flowmeters 220
Effects of Electrical Conductivity of Fluid 221 Installation 222 Signal Considerations and Demodulation
Techniques 223 Bibliography 224
2.11 MASS FLOWMETERS, CORIOLIS 225
Measuring Principle and Theory 226 Principle 226 Theory 227
Design of CMF 228 Balancing Systems for CMF 229 Dual-Tube Meters 229 Single-Tube Meters 229 Tube Geometries 229 Sensors 230 Temperature Sensors 230 Security 231 Electronics 231 Signal Processing 231 Communication/Output 231
Technical Data 231 Measuring Accuracy/Range 231 Pressure Drop 231 Influences on the CMF Reading 232
Temperature 232 In-Line Pressure 232 Mounting 232 Vibration 232 Humidity 232 Fluid Velocity 233 Gas Measurements 233 Two-Component Flow 233 Corrosion, Erosion 233 Reynolds Number 233
Installation 233 Mechanical Installation 233 Zero-Point Adjustment
(Static/Dynamic) 234 Applications 234 Advantages of CMFS 235 Limitations of CMFs 235 References 235 Bibliography 235
2.12 MASS FLOWMETERS-MISCELLANEOUS 237
Radiation-Type Mass Flowmeters 238 Angular Momentum-Type Mass Flowmeters 238
Impeller-Turbine Flowmeter 239 Constant Torque-Hysteresis Clutch 239 Twin-Turbine Flowmeter 239 Coriolis 240 Gyroscopic 240
Linear Mass Flowmeters 240 Indirect Mass Flowmeters 241
Calculating the Mass Flow of Steam 241 Steam Density and Accounting 241 Example 241
Conclusion 241 Reference 242 Bibliography 242
2.13 MASS FLOWMETERS-THERMAL 244
Heat Transfer Flowmeters 245 Bypass-Type Designs 247
Hot-Wire Probes 248 Calibrating Thermal Mass Flow Devices 249
Gas Flowmeter Calibrations 249 Liquid Calibrations 249
References 250 Bibliography 250
2.14 METERING PUMPS 251
Peristaltic Pumps 252 Piston Pumps 253 Diaphragm Pumps 254
Hydraulic-Actuated Metering Pumps 255 Solenoid-Driven Metering Pumps 256 Pulsator-Head Pumps 256
Proportioning Pumps 257 Controllers 257
Pulse-Input Type 257 Analog-Input Type 257 Start/Stop Type 257
Conclusions 257 Reference 258 Bibliography 258
2.15 ORIFICES 259
Head-Type Flowmeters 260 Theory of Head Meters 260 Head Meter Characteristics 261
The Square Root Relationship 261 Density of the Flowing Fluid 261
β
(Beta) Ratio 261
Reynolds Number 262 Compressible Fluid Flow 262 Choice of Differential-Pressure Range 262 Pulsating Flow and Flow “Noise” 263
Pulsating Flow 263 Flow “Noise” 263
The Orifice Meter 263 Flow through the Orifice Plate 264 Location of Pressure Taps 264
Eccentric and Segmental Orifice Plates 265 Quadrant Edge and Conical Entrance
Orifice Plates 266 The Integral Orifice 267 Installation 268 Limitations 269 Orifice Bore Calculations 271
The Old Approach 271 Orifice Accuracy 275 References 275 Bibliography 276
2.16 PITOT TUBES AND AREA AVERAGING UNITS 277
Theory of Operation 278 Pressure Differential Produced 279 Static Pressure Measurement 279 Single-Ported Pitot Tube 280
Calibration of Pitot Tubes 282 Multiple-Opening Pitot Tubes 282 Area-Averaging Pitot Stations 283 Special Pitot Tubes For Pulsating Flow 285 References 286 Bibliography 286
2.17 POLYPHASE (OIL/WATER/GAS) FLOWMETERS 287
Wet-Gas Metering 288 Venturi Meters 288 Algorithms for Wet-Gas Measurement 288 Theory of Operation of Wet-Gas Metering 288 de Leeuw Wet-Gas Venturi Correlation 289 Liquid Mass Flow Rate Correction
Algorithm 289 Liquid Density Calculation Algorithm 290 Upstream Temperature Correction
and Pressure Recovery 290 Gas Mass Fraction Estimation Using Tracer
Techniques 290 Solartron-ISA Dualstream II™ Theory 290
Multiphase Flowmeters 291 References 293 Bibliography 293
2.18 POSITIVE-DISPLACEMENT GAS FLOWMETERS 294
The Diaphragm Meter 295 Rotary Meters 295
The Lobed Impeller 296 Sliding-Vane Meters 296 Rotating-Vane Meters 296
High-Precision Gas Flowmeter 296 Application Notes 296 Testing and Calibration 297 Advantages 297 Bibliography 297
2.19 POSITIVE-DISPLACEMENT LIQUID METERS AND PROVERS 299
Overview 300 Rotating Lobe and Impeller (Type A) 300 Nutating Disk (Type B) 301 Oval-Gear Flowmeters (Type C) 301 Piston Designs (Type D) 302
Reciprocating Piston 302 Oscillating Piston 302
Rotating Vane (Type E) 303 Viscous Helix (Type F) 303 High-Precision and Specialized (Type G) 304 Provers (Type H) 304 Accessories and Intelligent Electronics 305 Bibliography 305
2.20 PURGE FLOW REGULATORS 307
Detection of Low Flows 307 Purge Rotameters 308 Bibliography 309
2.21 SEGMENTAL WEDGE FLOWMETER 310
References 312 Bibliography 312
2.22 SIGHT FLOW INDICATORS 313
Design Variations 313 Dual-Window and Full-View Designs 316 Conclusion 317 Bibliography 317
2.23 SOLIDS FLOWMETERS AND FEEDERS 318
Solids Handling Equipment 319 Hoppers and Accessories 319
Material Characteristics 320 Taking Samples 320
Feeder Designs 321 Vertical-Gate 321 Rotary-Vane 321 Screw Feeders 321 Vibratory Feeders 322 Shaker Feeders 322 Roll Feeder 322 Revolving-Plate Feeders 323
Gravimetric Feeders 323 Early Belt Feeder Designs 323 Feed Rate Control 324
Belt Load Control of Constant-Speed Belts 324
Belt Speeds and Blending 325 Belt Speed Selection Guidelines 325 Varying the Belt Speed 325 Limitations of Belt Speed Control 325 Precision of Weighing 326 Nuclear Belt Loading Detectors 326 Digital Control 326 Batch vs. Continuous Charging 327
Vertical Gravimetric Feeders 327 Loss-in-Weight Flowmeters 328
Continuous Operation 328 Equipment 328 System Sizing 329
Conclusion 329 Dual-Chamber Gravimetric Feeder 329 Dynamic Solids Flowmeters 330
Impulse-Type Solids Flowmeter 330 Accelerator-Type Flowmeter 330 Volumetric Flowmeters 331
Cross-Correlation Solids Flowmetering 331 Solids Flow Switches 332 Mass Flow Measurement of Pulverized Coal 332
Detecting Mass Concentration 332 Measuring the Coal Velocity 333
Bibliography 333
2.24 TARGET METERS 335
Drag-Body Design 336 Bibliography 336
2.25 TURBINE AND OTHER ROTARY ELEMENT FLOWMETERS 337
Liquid Turbine Meters 339 Electronic Display Units 340 Linearity and Repeatability 340 Viscosity and Density Effects 340 Meter Sizing 341
Pelton Wheel Meters 342 Meter Characteristics and Features 343 Mechanical Installation 344 Electrical Installation 344
Gas Turbine Meters 345 Twin-Rotor Turbine Meters 346
History 346 Twin-Rotor Design 346
Applications and Features 347 Dual-Turbine Designs 348
Dual Turbines Rotating in the Same Direction 348
Operation 348 Dual Turbine with Counter-Opposed
Rotation 348 Comparing the Three Two-Turbine Designs 350
Impeller and Shunt Flowmeters 350 Insertion-Type Flowmeters 350
Optical Flow Sensors 351 Paddlewheel Flowmeters 352
Bibliography 352
2.26 ULTRASONIC FLOWMETERS 353
Transit-Time Flowmeters 355 Frequency-Difference Type 355 Flowmeter Construction 355 Application and Performance 356
Doppler Flowmeters 357 Application and Performance 358
Displays, Receivers, and Intelligent Units 358 Advantages of Ultrasonic Flowmeters 359 Recent Developments 360 References 360 Bibliography 360
2.27 VARIABLE-AREA, GAP, AND VANE FLOWMETERS 362
Rotameters 363 Sizing 365
Liquids 365 Gases or Vapors 365
Rotameter Characteristics 365 Rotameter Types 367 Bypass and Pitot Rotameters 367
Tapered Plug and Piston Meters 368 Gates and Vanes 369 Bibliography 370
2.28 V-CONE FLOWMETER 371
Theory of Operation 371 Operating Features 372 Bibliography 373
2.29 VENTURI TUBES, FLOW TUBES, AND FLOW NOZZLES 374
The Classic Venturi 375 Short-Form Venturies 375
Installation 377 Flow Calculations 377
Flow Tubes 378 Flow Nozzles 379
Application Considerations 380 Critical-Velocity Venturi Nozzles 380 Accuracy 381 Differential Pressure Measurement 381 Conclusion 381 Reference 383 Bibliography 383
2.30 VORTEX AND FLUIDIC FLOWMETERS 384
The Vortex Shedding Phenomenon 385 The Detector 386
Features 388 Selection and Sizing 388 Installation Requirements 390
Vortex-Precession (Swirl) Meters 392 Fluidic (Coanda Effect) Meters 393
Characteristics 393 Conclusion 393 Bibliography 394
2.31 WEIRS AND FLUMES 395
Weirs 396 The Parshall Flume 397 The Palmer Bowlus Flume 398 The Kennison Nozzle, Parabolic Flume,
and Leopold Lagco Flume 399 Detectors for Open-Channel Sensors 399 References 400 Bibliography 400
No industrial measurement is more important than the accurate detection of the flow rates of gases, liquids, and solids. In this section, an overview is given of the availability and characteristics of some of the most widely used flow sensors. In addition, emphasis is given to the latest developments, such as the polyphase (oil/water/gas) and the wide-rangeability dual-rotor turbine flowmeters. General guidelines are provided about selecting the best flow sensor for a particular application.
