Basic Process Measurements

by Cecil L. Smith

Overview

Basic Process Measurements provides a unique resource explaining the industrial measuring devices that gauge such key variables as temperature, pressure, density, level, and flow. With an emphasis on the most commonly installed technologies, this guide outlines both the process variable being measured as well as how the relevant measuring instruments function. The benefits of each technology are considered in turn, along with their potential problems. Looking at both new and existing technologies, the book maintains a practical focus on properly selecting and deploying the best technology for a given process application.

Resolve problems with currently installed devices

Upgrade currently installed devices to newer and better technologies

Add instruments for process variables not previously measurable

Evaluate device installations from a perspective of both normal process operating conditions and abnormal conditions

Determine the best technology for a given set of process conditions

Designed for a wide range of technical professionals, Basic Process Measurements provides a balanced treatment of the concepts, background information, and specific processes and technologies making up this critical aspect of process improvement and control.

Product Details

ISBN-13:	9781118216132
Publisher:	Wiley
Publication date:	11/30/2011
Sold by:	JOHN WILEY & SONS
Format:	eBook
Pages:	358
File size:	9 MB

About the Author

Cecil L. Smith, PhD, has over thirty-five years' experience in process control, his expertise encompassing every control technology being applied in industrial production facilities. In continuous processes, he has worked with oil refining, pulp/paper, power generation, and ore processing. In batch processes, he has experience with both single-product processes (such as PVC reactors and pulp digesters) and the multiproduct (flexible batch) processes that are the norm in specialty chemicals. His primary focus is on designing a control strategy for a process and then commissioning the controls; that is, the process aspects as opposed to systems aspects. He also develops and teaches continuing education courses for practicing engineers on various aspects of process control and instrumentation.

Table of Contents

Preface vii

1 Basic Concepts 1

1.1 Continuous vs. Discrete Measurement 2

1.2 Continuous vs. Sampled Measurement 8

1.3 In-Line, On-Line, and Off-Line 8

1.4 Signals and Resolution 12

1.5 Zero, Span, and Range 17

1.6 Turndown Ratio and Rangeability 22

1.7 Accuracy 24

1.8 Repeatability 27

1.9 Measurement Uncertainty 31

1.10 Measurement Decision Risk 36

1.11 Calibration 45

1.12 Measurement Device Components 48

1.13 Current Loop 50

1.14 Power Supply and Wiring 55

1.15 Serial Communications 56

1.16 Smart Transmitters 60

1.17 Environmental Issues 64

1.18 Explosive Atmospheres 68

1.19 Measurement Device Dynamics 75

1.20 Filtering and Smoothing 82

2 Temperature 88

2.1 Heat and Temperature 88

2.2 Temperature Scales 90

2.3 Thermowells 94

2.4 Bimetallic Thermometers 104

2.5 Thermocouples 106

2.6 Resistance Temperature Detectors 121

2.7 Thermistors 133

2.8 Temperature Transmitters 137

2.9 Pyrometers 142

2.10 Others 153

3 Pressure 158

3.1 Force and Pressure 159

3.2 Measures of Pressure 162

3.3 Pressure-Sensing Elements 167

3.4 Indicators and Switches 170

3.5 Pressure Sensor 171

3.6 Strain Gauge Pressure Sensors 173

3.7 Capacitance Pressure Sensors 176

3.8 Resonant Frequency 180

3.9 Installation 182

3.10 Differential Pressure 187

4 Level and Density 196

4.1 Level, Volume, and Weight 197

4.2 Pressure Transmitter 202

4.3 Differential Pressure Transmitter 210

4.4 Capacitance and Radio Frequency 216

4.5 Ultrasonic 223

4.6 Noncontact Radar 227

4.7 Guided Wave Radar 233

4.8 Nuclear 236

4.9 A Few Others 240

4.10 Level Switches 244

4.11 Interface 249

4.12 Density 255

5 Flow 260

5.1 Mass Flow,Volumetric Flow, and Velocity 261

5.2 Static Pressure and Fluid Velocity 264

5.3 Flashing and Cavitation 267

5.4 Fluid Dynamics 270

5.5 Flow Meter Application Data 276

5.6 Orifice Meter 279

5.7 Head Meters 285

5.8 Coriolis Meters 291

5.9 Magnetic Flow Meter 304

5.10 Vortex-Shedding Meter 309

5.11 Transit-Time Ultrasonic Flow Meter 312

5.12 Doppler Ultrasonic Flow Meter 318

5.13 Thermal Flow Meters 324

5.14 Turbine Meter 330

5.15 Other Flow Meters 334

5.16 Flow Switches 337

Index 341