Traceable Temperatures: An Introduction to Temperature Measurement and Calibration, Second Edition

Cover Page......Page 1
Title: Traceable Temperatures......Page 3
ISBN 0471492914......Page 4
2 UNCERTAINTY IN MEASUREMENT......Page 5
3 THE ITS-90 TEMPERATURE SCALE......Page 6
5 CALIBRATION......Page 7
6 PLATINUM RESISTANCE THERMOMETRY......Page 8
7 LIQUID-IN-GLASS THERMOMETRY......Page 9
8 THERMOCOUPLE THERMOMETRY......Page 10
APPENDIXES......Page 11
Preface to First Edition......Page 13
Preface to Second Edition......Page 15
Proceedings of Symposia on Temperature......Page 16
Acknowledgements for First Edition......Page 18
Acknowledgements for Figures and Tables......Page 19
1.1 Introduction......Page 21
1.2.1 What is a measurement?......Page 22
1.2.2 Measurement scales......Page 23
1.2.3 The problem of definition and the importance of purpose......Page 29
1.2.4 Decision, risk and uncertainty......Page 31
1.3 Temperature......Page 32
1.3.1 The evolution of the temperature scale......Page 33
1.3.2 Thermodynamic temperature......Page 36
1.3.3 Meteorological temperatures......Page 38
1.4.1 Defining traceability......Page 41
1.4.2 Achieving traceability......Page 43
1.5.1 The Metre Convention......Page 44
1.5.2 The SI units and conventions......Page 45
1.6 Documentary Standards......Page 49
1.7 Laboratory Accreditation to ISO/IEC 17025......Page 50
1.8 National Measurement System......Page 52
Thermodynamic measurements......Page 54
General reading on temperature measurement......Page 55
2.1 Introduction......Page 57
2.2 Risk, Uncertainty and Error......Page 58
2.3 Distributions, Mean and Variance......Page 60
2.3.1 Discrete distributions......Page 61
2.3.2 Continuous distributions......Page 63
2.4 The Normal Distribution......Page 65
2.5 Experimental Measurements of Mean and Variance......Page 67
2.6 Evaluating Type A Uncertainties......Page 70
2.6.1 Evaluating uncertainties of single-valued quantities......Page 71
2.6.2 The Student’s distribution......Page 72
2.6.3 Evaluating uncertainties for distributed quantities......Page 74
2.7 Evaluating Type B Uncertainties......Page 76
2.7.1 Identification and recording of influences......Page 77
2.7.2 Theoretical evaluations......Page 78
2.7.3 Evaluations based on single subsidiary measurements......Page 80
2.7.4 Evaluations based on data provided from other sources......Page 83
2.7.5 Evaluations based on intuition and experience......Page 85
2.8 Combining Uncertainties......Page 86
2.9 Propagation of Uncertainty......Page 89
2.10 Correlated Uncertainties......Page 93
2.11. Interpolation......Page 97
2.11.1 Lagrange interpolation......Page 98
2.11.2 Propagation of uncertainty......Page 99
2.11.3 Interpolation error......Page 101
2.11.4 Other interpolations......Page 102
2.12 Least-squares Fitting......Page 103
2.12.1 Propagation of uncertainty......Page 105
2.13.1 Application to non-normal distributions......Page 109
2.13.3 The nature of confidence intervals......Page 110
2.14.1 How many decimal places?......Page 111
2.14.2 Presentation of uncertainty statements......Page 112
Propagation of uncertainty with interpolation......Page 114
3.1 Introduction......Page 115
3.2.2 The triple point of water – defining the unit......Page 116
3.2.3 Using the triple-point cell......Page 119
3.2.4 The ice point......Page 122
3.3.2 The metal fixed points......Page 125
3.3.3 The cryogenic triple points......Page 132
3.3.4 The cryogenic vapour-pressure points......Page 133
3.3.5 Platinum resistance thermometry......Page 134
3.3.6 Radiation thermometry......Page 140
3.3.7 Cryogenic thermometry......Page 141
3.4 The Propagation of Uncertainty on ITS-90......Page 142
Precision thermometry and a description of the physics of temperature measurement......Page 144
4.1 Introduction......Page 145
4.2.1 Conduction......Page 146
4.2.2 Convection......Page 147
4.2.3 Radiation......Page 149
4.3.1 Thermal conductivity......Page 151
4.3.2 Heat capacity......Page 152
4.4.1 Immersion errors......Page 154
4.4.2 Heat capacity errors......Page 159
4.4.3 Settling response errors......Page 160
4.4.4 Lag errors with steadily changing temperatures......Page 163
4.4.5 Radiation errors and shielding......Page 165
4.5 Models and Methods......Page 166
4.5.1 Electrical analogue models......Page 167
4.5.2 Composite systems......Page 168
4.5.3 Temperature in non-equilibrium situations......Page 171
4.5.4 Immersion revisited......Page 173
4.5.5 Time constants revisited......Page 175
4.5.6 Guarding......Page 176
4.5.7 Temperature control......Page 177
Thermal effects in temperature measurement......Page 178
5.1 Introduction......Page 179
5.2.1 What is a calibration?......Page 180
5.2.2 What is not a calibration?......Page 181
5.3.1 The thermometer under test......Page 183
5.3.2 The client’s needs......Page 187
5.3.3 Establishing the link to the SI......Page 189
5.3.4 Assessing the uncertainty......Page 192
5.3.5 Reliability and generic history......Page 194
5.3.6 Recalibration and specific history......Page 197
5.4.2 Calibration procedures......Page 199
5.4.3 Uncertainty analysis and best measurement capability......Page 200
5.4.5 Calibration certificates......Page 202
5.5.1 Collating the information......Page 203
5.5.2 A calibration procedure......Page 205
5.5.3 Rising-temperature comparisons......Page 207
5.5.4 Example: Calibration of a short-range working thermometer......Page 209
5.5.5 Fixed-temperature comparisons......Page 213
5.5.6 Example: Calibration of a reference thermometer......Page 215
Further Reading......Page 221
6.1 Introduction......Page 223
6.2.2 The effects of temperature on resistance......Page 224
6.2.3 The effects of impurities on resistance......Page 225
6.3.1 Electrical properties of platinum thermometers......Page 226
6.3.2 Construction of platinum thermometers......Page 227
6.3.4 Partially supported platinum thermometers......Page 228
6.3.5 Fully supported platinum thermometers......Page 230
6.3.7 Sheathing......Page 231
6.4 Resistance Measurement......Page 232
6.4.1 General principles......Page 233
6.4.2 Two-, three- and four-lead measurements......Page 235
6.4.3 D.C. resistance measurement......Page 237
6.4.4 A.C. resistance measurement......Page 238
6.4.5 Verification and calibration of resistance bridges......Page 240
6.5.1 Immersion errors......Page 241
6.5.3 Radiation errors......Page 242
6.5.4 Self-heating......Page 243
6.5.5 Mechanical shock and vibration......Page 245
6.5.6 Thermal expansion effects......Page 246
6.5.8 Contamination......Page 248
6.5.9 Compensation and assessment of drift......Page 249
6.5.10 Leakage effects......Page 251
6.5.11 A.C. leakage effects......Page 253
6.5.12 Electromagnetic interference......Page 254
6.5.13 Lead-resistance errors......Page 255
6.5.14 Thermoelectric effects......Page 256
6.5.15 Reference resistor stability and accuracy......Page 257
6.6.1 Choosing and using a thermometer......Page 258
6.6.2 Care and maintenance......Page 260
6.7.1 Calibration equations......Page 261
6.7.2 Calibration at fixed points......Page 262
6.7.3 Calibration by least squares......Page 263
6.7.4 A calibration procedure......Page 264
6.8.1 Thermistors......Page 269
6.8.3 Rhodium–iron thermometer......Page 271
Standard platinum resistance thermometry......Page 272
Resistance measurement......Page 273
7.1 Introduction......Page 275
7.2.1 Solid-stem thermometers......Page 276
7.2.2 Enclosed-scale thermometers......Page 280
7.3.1 Time constant effects......Page 282
7.3.3 Pressure effects......Page 283
7.3.4 Bulb hysteresis and drift......Page 285
7.3.7 Separated columns......Page 286
7.3.8 Errors in reading......Page 290
7.3.9 Immersion errors......Page 291
7.3.10 Scale errors......Page 299
7.4 Choice and Use of Liquid-in-glass Thermometers......Page 301
7.4.1 Range and type......Page 302
7.4.2 Acceptance......Page 304
7.4.3 Etching and engraving......Page 305
7.4.5 Organic liquids......Page 306
7.4.7 Transport......Page 307
7.5.1 Short-range calibrations......Page 309
7.5.2 Calibration of reference and general-purpose thermometers......Page 310
7.5.3 Outline of a liquid-in-glass calibration procedure......Page 311
Further Reading......Page 313
8.1 Introduction......Page 315
8.2.1 The Peltier effect......Page 316
8.2.3 The Seebeck effect......Page 317
8.2.4 Exploiting the Seebeck effect to measure temperature......Page 320
8.3 Thermocouple Types......Page 322
8.3.1 Standard thermocouple types......Page 323
8.3.2 Rare-metal thermocouples......Page 325
8.3.3 Base-metal thermocouples......Page 326
8.3.4 Non-standard thermocouples......Page 329
8.4.1 Junctions......Page 330
8.4.2 Joins......Page 331
8.4.3 Extension leads and compensating leads......Page 333
8.4.4 Sheaths and thermowells......Page 334
8.4.5 Mineral-insulated metal sheaths......Page 335
8.5.1 Reference junctions......Page 337
8.5.2 Instrument types......Page 340
8.5.3 Thermocouple calibrators......Page 342
8.5.4 Alternative thermocouple circuits......Page 343
8.6 Errors in Thermocouples......Page 345
8.6.2 Inhomogeneity errors......Page 346
8.6.5 Interference errors......Page 348
8.7 Choice and Use of Thermocouples......Page 349
8.7.1 Selection of thermocouple type......Page 350
8.7.3 Assembly......Page 351
8.7.4 Inhomogeneity tests......Page 352
8.8 Calibration......Page 355
8.8.2 calibration......Page 356
8.8.3 Rare-metal thermocouple calibration......Page 359
Thermocouple theory......Page 361
Calibration......Page 362
9.1 Introduction......Page 363
9.2 Blackbodies and Blackbody Radiation......Page 364
9.3 Spectral Band Thermometers......Page 368
9.4 Errors in Spectral Band Thermometry......Page 370
9.4.1 Errors in emissivity......Page 372
9.4.2 Reflection errors......Page 376
9.4.3 Absorption errors......Page 380
9.4.5 Non-thermal emission......Page 382
9.4.7 Size-of-source effects......Page 383
9.4.9 Vignetting......Page 385
9.5.1 Choosing a radiation thermometer......Page 386
9.5.3 Using the thermometer......Page 388
9.6.1 Blackbody principles......Page 390
9.6.2 Ice-point blackbody......Page 391
9.6.3 Errors in blackbodies......Page 392
9.7.1 Calibration methods......Page 395
9.7.2 Calibration equations......Page 397
9.7.3 Tungsten strip lamps......Page 398
9.7.4 Calibrating a radiation thermometer......Page 400
9.8.2 The ratio thermometer......Page 405
9.8.3 Multi-spectral radiation thermometers......Page 407
9.8.4 Total radiation thermometers......Page 408
9.8.5 Special-purpose thermometers for plastic and glass......Page 410
9.8.6 Fibre-optic thermometers......Page 411
Fundamental measurements and blackbodies......Page 412
A.1.3 Callendar–van Dusen equation for platinum resistance thermometers......Page 413
A.1.4 The thermistor equation......Page 414
Appendix B The Differences Between ITS-90 and IPTS-68......Page 415
C.1 Reference Function......Page 417
C.2 Reference Tables......Page 418
D.2 Inverse Functions......Page 419
D.3 Type B......Page 420
Properties......Page 421
Tolerances (whichever is greater)......Page 422
Properties......Page 423
D.5 Type J......Page 424
Properties......Page 425
D.6 Type K......Page 426
Properties......Page 427
D.7 Type N......Page 428
Properties......Page 429
D.8 Type R......Page 430
Properties......Page 431
D.9 Type S......Page 432
Properties......Page 433
Tolerances (whichever is greater)......Page 434
Properties......Page 435
Index (with page links)......Page 437