Understanding Infrared Thermography Reading 3

More documents

Recommendations

Info

Thermocouple General description: Thomas Seebeck discovered in 1821 that when two wires composed of dissimilar metals are joined at both ends and one of the ends is heated, there is a continuous current which flows in the thermoelectric circuit. (Seebeck effect). The junctions can be exposed, grounded or ungrounded. The thermocouple is normally directly connected to a standard temperature controller. Thermocouples are among the easiest temperature sensors used in science and industry and very cost effective. (usually less than $50.00) thermocouple embedded in Dalton cartridge heater Charlie Chong/ Fion Zhang http://www.deltat.com/thermocouple.html
Thermocouple A thermocouple is a temperature-measuring device consisting of two dissimilar conductors that contact each other at one or more spots, where a temperature differential is experienced by the different conductors (or semiconductors). It produces a voltage when the temperature of one of the spots differs from the reference temperature at other parts of the circuit. Thermocouples are a widely used type of temperature sensor for measurement and control, and can also convert a temperature gradient into electricity. Commercial thermocouples are inexpensive, interchangeable, are supplied with standard connectors, and can measure a wide range of temperatures. In contrast to most other methods of temperature measurement, thermocouples are self powered and require no external form of excitation. The main limitation with thermocouples is accuracy; system errors of less than one degree Celsius (°C) can be difficult to achieve. Any junction of dissimilar metals will produce an electric potential related to temperature. Thermocouples for practical measurement of temperature are junctions of specific alloys which have a predictable and repeatable relationship between temperature and voltage. Different alloys are used for different temperature ranges. Properties such as resistance to corrosion may also be important when choosing a type of thermocouple. Where the measurement point is far from the measuring instrument, the intermediate connection can be made by extension wires which are less costly than the materials used to make the sensor. Thermocouples are usually standardized against a reference temperature of 0 degrees Celsius; practical instruments use electronic methods of cold-junction compensation to adjust for varying temperature at the instrument terminals. Electronic instruments can also compensate for the varying characteristics of the thermocouple, and so improve the precision and accuracy of measurements. Thermocouples are widely used in science and industry; applications include temperature measurement for kilns, gas turbine exhaust, diesel engines, and other industrial processes. Thermocouples are also used in homes, offices and businesses as the temperature sensors in thermostats, and also as flame sensors in safety devices for gas-powered major appliances. Charlie Chong/ Fion Zhang http://en.wikipedia.org/wiki/Thermocouple
Page 1 and 2:
Infrared Thermal Testing Reading II
Page 3 and 4:
Infrared Thermography ~-- ... ... .
Page 5 and 6:
Infrared Thermography Charlie Chong
Page 7 and 8:
See Through & Fun Thermal Camera Ex
Page 9 and 10:
How to see through clothing 2 I'
Page 11 and 12:
Apache IR Thermal Weaponry ■ http
Page 13 and 14:
Charlie Chong/ Fion Zhang
Page 15 and 16:
Greek alphabet Letter Name Sound An
Page 17 and 18:
Greek letter l fl 0 I1 p u w Charli
Page 19 and 20:
SGuide-IRT Content Part 1 of 2 ■
Page 21 and 22:
1.1 Introduction to Principles & Th
Page 23 and 24:
The infrared thermal imaging equipm
Page 25 and 26:
The three modes of heat transfer ar
Page 27 and 28:
The three modes of heat transfer ar
Page 29 and 30:
Temperature and Temperature Scales
Page 31 and 32:
Boston Tea Party - New governances
Page 33 and 34:
The Mighty Fahrenheit & ⅝”, Eng
Page 35 and 36:
Absolute zero is equal to - 273.16
Page 37 and 38:
The Fourier conduction Law expresse
Page 39 and 40:
The Fourier conduction Law ( One di
Page 41 and 42:
Convective Heat Transfer Convective
Page 43 and 44:
Figure 1.2: Convective heat flow T
Page 45 and 46:
Newton's cooling law defines the co
Page 47 and 48:
Radiative Heat Transfer Radiative h
Page 49 and 50:
Figure 1.4: Infrared radiation leav
Page 51 and 52:
Thermal infrared radiation impingin
Page 53 and 54:
Reflections off Specular and Diffus
Page 55 and 56:
Reflections off Specular and Diffus
Page 57 and 58:
Radiant Energy Related to Target Su
Page 59 and 60:
The Stefan-Boltzmann law: W= σƐT
Page 61 and 62:
Figure 1.6: Typical blackbody distr
Page 63 and 64:
1.4 Practical Infrared Measurements
Page 65 and 66: Characteristics of the Target Surfa
Page 67 and 68: Referring back to Figure 1.5, the t
Page 69 and 70: Characteristics of the Transmitting
Page 71 and 72: Figure 1.10; Transmission of 10m (3
Page 73 and 74: Figure 1.11: Transmission, absorpti
Page 75 and 76: Figure 1.12: Transmission curves of
Page 77 and 78: Chapter 1 Review Questions Q&A 1. b
Page 79 and 80: Q4. Heat can only flow in the direc
Page 81 and 82: Q10. The follow ing spectral band i
Page 83 and 84: Q16. In forced convection, the boun
Page 85 and 86: Q22. In the 8 to 14 μm spectral re
Page 87 and 88: 2.1 Materials Characteristics A kno
Page 89 and 90: For an emissivity reference table t
Page 91 and 92: Errors because of point source refl
Page 93 and 94: View Angle The angle between the in
Page 95 and 96: Thermal Conductivity Thermal conduc
Page 97 and 98: Thermal Diffusivity As in emissivit
Page 99 and 100: Partial 2.1 Table 2.1: d i'ffusivit
Page 101 and 102: Partial Table 2.2 Table 2.2: Normal
Page 103 and 104: Chapter 2 Review Questions Q&A 1. c
Page 105 and 106: 4. When measuring the temperature o
Page 107 and 108: 10. A highly textured surface is sa
Page 109 and 110: 3.1 Thermal Instrumentation Overvie
Page 111 and 112: Thermopile- Thermoelectric Seebeck
Page 113 and 114: What is a IR Thermopile? (non-conta
Page 115: IR Thermopile Quad Sensor (non-cont
Page 119 and 120: Bourdon Gas Thermometers 5 f\G.3 0
Page 121 and 122: Liquid Crystal Thermometer A liquid
Page 123 and 124: Bimetallic Thermometers Dial Spiral
Page 125 and 126: In RTD devices; Copper, Nickel and
Page 127 and 128: Platinum Resistance Thermometer Cha
Page 129 and 130: RTD Materials Different materials u
Page 131 and 132: Operations of RTD An RTD takes a me
Page 133 and 134: Benefits of Thin Film RTD There are
Page 135 and 136: Thermistor +V r===~ Op A p V to A I
Page 137 and 138: 3.2 Contacting Thermal Measuring De
Page 139 and 140: ■ Thermocouple Thermocouples are
Page 141 and 142: ■ Thermistors Thermistors arc als
Page 143 and 144: 3.3 Optical Pyrometers Optical pyro
Page 145 and 146: Pyrometer A pyrometer is a type of
Page 147 and 148: Brightness Pyrometers -Wien’s Law
Page 149 and 150: The processing electronics unit amp
Page 151 and 152: Infrared Detector An infrared detec
Page 153 and 154: Figure 3.2: Response Curves of Vari
Page 155 and 156: The mercury cadmium telluride (HgCd
Page 157 and 158: Infrared Optics - Lenses, Mirrors a
Page 159 and 160: Field of View (FOV) A field of view
Page 161 and 162: What is IFOV? A measure of the spat
Page 163 and 164: Instantaneous Field of View (IFOV)
Page 165 and 166: 3.5 Scanning and Imaging When probl
Page 167 and 168:
Line Scanning When the measurement
Page 169 and 170:
Two-dimensional Scanning - Thermal
Page 171 and 172:
Figure 3.5: Optomechanlcally scanne
Page 173 and 174:
Pyroelectric Vidicon Thermal Imager
Page 175 and 176:
Figure 3.6: Typical uncooled infrar
Page 177 and 178:
IRFPA Charlie Chong/ Fion Zhang htt
Page 179 and 180:
3.6 Performance Parameters of Infra
Page 181 and 182:
Performance parameters of qualitati
Page 183 and 184:
Temperature Range Temperature range
Page 185 and 186:
Temperature Sensitivity Temperature
Page 187 and 188:
Speed of Response Speed of response
Page 189 and 190:
Figure 3.7: Instrument speed to res
Page 191 and 192:
Figure 3.8: Instrument field-of-vie
Page 193 and 194:
D ≡ αd D = spot size (approximat
Page 195 and 196:
Output Requirements Output requirem
Page 197 and 198:
Spectral Range Spectral range denot
Page 199 and 200:
Spectrall y selective instrumems us
Page 201 and 202:
Figure 3.9: Spectral response of an
Page 203 and 204:
3.7 Performance Characteristics of
Page 205 and 206:
The total field of view for a line
Page 207 and 208:
Instantaneous Field of View IFOV In
Page 209 and 210:
Recalling! Temperature sensitivity
Page 211 and 212:
IFOV - MTF The 0.35 MTF refers to:
Page 213 and 214:
Fig. 2a. Slit Response Function. Ca
Page 215 and 216:
Minimum Resolvable Temperature Diff
Page 217 and 218:
EXAM score! D=σ∙d IFOV ratio = d
Page 219 and 220:
Charlie Chong/ Fion Zhang
Page 221 and 222:
Answer: D= σ•d, IFOV ration= 1/
Page 223 and 224:
Break Time - Kenya Coffee Picker Ch
Page 225 and 226:
Portable Handheld Devices Charlie C
Page 227 and 228:
Temperature sensitivity and readabi
Page 229 and 230:
Hand Held Infrared Module Charlie C
Page 231 and 232:
Note that the laser beam docs not r
Page 233 and 234:
Emissivity set controls, located in
Page 235 and 236:
IR Sensor Module Charlie Chong/ Fio
Page 237 and 238:
IR Sensor Module Charlie Chong/ Fio
Page 239 and 240:
Two-color Pyrometers or Ratio Pyrom
Page 241 and 242:
Page 243 and 244:
Page 245 and 246:
Phenomena which are non-dynamic in
Page 247 and 248:
Some ratio thermometers use more th
Page 249 and 250:
Infrared Radiometric Microscopes Ch
Page 251 and 252:
Line Scanners Line scanners are div
Page 253 and 254:
Special Purpose Devices Special pur
Page 255 and 256:
FLIR- Forward Looking Infrared Char
Page 257 and 258:
Typically, the total field of view
Page 259 and 260:
Pyroelectric devices have no direct
Page 261 and 262:
Figure 3.12: Infrared focal plane a
Page 263 and 264:
Infrared focal plane array imager C
Page 265 and 266:
Infrared focal plane array imager C
Page 267 and 268:
On-board capabilities include isoth
Page 269 and 270:
ccc Electron Microscope Image of mi
Page 271 and 272:
Platinum Silicide IrFPA 19 t«lU 98
Page 273 and 274:
Quantitative IR Image Charlie Chong
Page 275 and 276:
Quantitative Thermal Measurements S
Page 277 and 278:
In addition to the spot measurement
Page 279 and 280:
Stored images can be retrieved, dis
Page 281 and 282:
Calibration Accessories Infrared ra
Page 283 and 284:
Online printers and plotters are re
Page 285 and 286:
Q1. The thermal resolution of an in
Page 287 and 288:
Q7. The 3 to 5 μm spectral region
Page 289 and 290:
Q13. A line scanner can be used to
Page 291 and 292:
Q19. For which of the following app
Page 293 and 294:
Q25. Two-color (ratio) pyrometers m
Page 295 and 296:
Chapter 4 Operating Equipment and U
Page 297 and 298:
■ Emissivity Differences ∆τ Em
Page 299 and 300:
Causes of Real Temperature Changes
Page 301 and 302:
Mass Transport Differences (Fluid F
Page 303 and 304:
Figure 4.1: An indication of water
Page 305 and 306:
Thermal Capacitance Differences ∆
Page 307 and 308:
■ Induced Heating Differences (by
Page 309 and 310:
Induced Heating Differences Charlie
Page 311 and 312:
■ Energy Conversion Differences E
Page 313 and 314:
Figure 4.3: Catalytic reformer vess
Page 315 and 316:
Infrared Thermogram Energy Conversi
Page 317 and 318:
Infrared Thermogram Energy Conversi
Page 319 and 320:
■ Combination of Heat Transfer Me
Page 321 and 322:
Infrared Thermogram of a running mo
Page 323 and 324:
■ Spectral Considerations in Prod
Page 325 and 326:
Infrared Thermogram Charlie Chong/
Page 327 and 328:
Infrared Thermogram ..... " I Charl
Page 329 and 330:
Figure 4.5: Spectral selectivity fo
Page 331 and 332:
Figure 4.7: temperature thermogram
Page 333 and 334:
Figure 4.8 shows the transmission s
Page 335 and 336:
Figure 4.9: Measuring temperature o
Page 337 and 338:
IR Filter Charlie Chong/ Fion Zhang
Page 339 and 340:
Figure 4.10: Line scanner for conti
Page 341 and 342:
Preparation of Equipment for Operat
Page 343 and 344:
If the instrument is out of cal ibr
Page 345 and 346:
The batteries mentioned on the miss
Page 347 and 348:
Comments: ■ ■ ■ Thermal resol
Page 349 and 350:
Figure 4.11 : Test configuration fo
Page 351 and 352:
3. Reduce the ΔT until the image i
Page 353 and 354:
■ Imaging Spatial Resolution Imag
Page 355 and 356:
A sample setup is illustrated in Fi
Page 357 and 358:
5. If the modulation transfer funct
Page 359 and 360:
Figure 4.13: Test configuration for
Page 361 and 362:
4. Open slit until V meas = V max .
Page 363 and 364:
■ Learning the Startup Procedure
Page 365 and 366:
■ Setting the Correct Effective E
Page 367 and 368:
Figure 4.14: Test configuration for
Page 369 and 370:
■ Measuring and Reporting Tempera
Page 371 and 372:
■ Recognizing and Avoiding Reflec
Page 373 and 374:
■ Measuring the Appropriate Backg
Page 375 and 376:
■ Temperature Differences Between
Page 377 and 378:
■ Liquid and Compressed Gases Som
Page 379 and 380:
Dewar Flask for LN Loosely fitting
Page 381 and 382:
■ Electrical Safety Failure to re
Page 383 and 384:
Table 4.1: Electric shock current t
Page 385 and 386:
4.4 Record Keeping Keeping thorough
Page 387 and 388:
Easily accessible and easily unders
Page 389 and 390:
Q1. Apparent but not real temperatu
Page 391 and 392:
Q5. The higher the temperature of a
Page 393 and 394:
Q9. Differential thermography can b
Page 395 and 396:
5.1 Overview of Applications Becaus
Page 397 and 398:
Electrical Applications Electrical
Page 399 and 400:
High electrical resistance is the m
Page 401 and 402:
Excessive heating due to a defectiv
Page 403 and 404:
Inductive currents flowing with in
Page 405 and 406:
Moisture in Airframes The detection
Page 407 and 408:
Process Control and Product Monitor
Page 409 and 410:
The differences produced by this co
Page 411 and 412:
Night Vision, Seareh, Surveillance,
Page 413 and 414:
Thermogram of helicopter taken at n
Page 415 and 416:
Aircraft Under IR Trap Charlie Chon
Page 417 and 418:
Instruments used for these applicat
Page 419 and 420:
8 to 12 μm spectral region over wh
Page 421 and 422:
Animal Studies Body heat allows inf
Page 423 and 424:
Injured equine foreleg (left) appea
Page 425 and 426:
Work energy is expended by friction
Page 427 and 428:
5.4 Fluid Flow Investigations For s
Page 429 and 430:
Figure 1.7: Thermographs of valve (
Page 431 and 432:
■ Building Insulation and Other F
Page 433 and 434:
Figures 5.8 and 5.9 illustrate thes
Page 435 and 436:
Figure 5.9: Example of air exfiltra
Page 437 and 438:
Example of air exfiltration Charlie
Page 439 and 440:
■ Refractory Systems Industrial s
Page 441 and 442:
Refractory Thermogram Charlie Chong
Page 443 and 444:
■ Subsurface Discontinuity Detect
Page 445 and 446:
Figure 5.11: An example of passive
Page 447 and 448:
The equipment necessary to perform
Page 449 and 450:
Figure 5.12: Example of active (hea
Page 451 and 452:
Typical failure modes of the materi
Page 453 and 454:
Figure 5.13: Test of aircraft deici
Page 455 and 456:
DC - 9 Charlie Chong/ Fion Zhang
Page 457 and 458:
Figure 5.14: Conceptual sketch of t
Page 459 and 460:
In this case. however, the heat pul
Page 461 and 462:
Figure 5.15: Erosion/corrosion dama
Page 463 and 464:
737 aircraft Charlie Chong/ Fion Zh
Page 465 and 466:
When there has been adequate solar
Page 467 and 468:
Liquid Level Detection Thermal capa
Page 469 and 470:
Unstimulated and Stimulated Approac
Page 471 and 472:
Subsurface Discontinuity Detection
Page 473 and 474:
1. A major area of infrared nondest
Page 475 and 476:
5. The diagnostics involved in dete
Page 477 and 478:
9. Thermography has been successful
Page 479 and 480:
Appendix A Glossary The following a
Page 481 and 482:
Ambient temperature - Temperature o
Page 483 and 484:
Figure A-1 Apparent ambient tempera
Page 485 and 486:
13.Blackbody, blackbody radiator -
Page 487 and 488:
Alas! Heat Capacity Volumetric = C
Page 489 and 490:
27.Detector, infrared - A transduce
Page 491 and 492:
Thermal Effusivity In Thermodynamic
Page 493 and 494:
Alas! Exitance = Rodiosity for my A
Page 495 and 496:
45.Frame repetition rate - The time
Page 497 and 498:
Thermal Inertia Thermal inertia is
Page 499 and 500:
Instantaneous field of View (lFOV)
Page 501 and 502:
Laser pyrometer - Laser pyrometer -
Page 503 and 504:
Figure 3.2: Response Curves of Vari
Page 505 and 506:
Compare: Minimum resolvable tempera
Page 507 and 508:
86.Radiation rererenee source - A b
Page 509 and 510:
101. Sector - For a line scanner, a
Page 511 and 512:
113. Subtense, angular - The angula
Page 513 and 514:
121. Thermal wave imaging - A term
Page 515 and 516:
125. Thermogram - A thermal map or
Page 517 and 518:
Appendix B Cost Benefit Determinati
Page 519 and 520:
Although the calculations are quite
Page 521 and 522:
96 ASNT Level Ill Study Guide: Infr
Page 523 and 524:
Appendix C, Commonly Used Infrared
Page 525 and 526:
Appendix C, Commonly Used Infrared
Page 527 and 528:
Peach - 我爱桃子 Charlie Cho
Page 529 and 530:
Good Luck Charlie Chong/ Fion Zhang
show all

Understanding Infrared Thermography Reading 3

Create successful ePaper yourself

Delete template?

Save as template?