4.11.3 Applications 1. Radiation pyrometers Heat-receiving Thermal Objective plate couple Eyepiece Measured object L Fig. 4.109 Operating principle for radiation pyrometer
1. Radiation pyrometers 4.11.3 Applications Fig. 4.109 Operating principle for radiation pyrometer
4.11.3 Applications U The Stefan -Boltzmann' s law can be used in radiation pyrometers The measured object is usually a gray body with its E<l. Using the blackbody radiation as a criterion for calibration, it is possible to evaluate the temperature of the measured object by means of eq (4. 130)and the definition ofa, if thee of the object is known
❑The Stefan-Boltzmann’s law can be used in radiation pyrometers. 4.11.3 Applications The measured object is usually a gray body with its 1. Using the blackbody radiation as a criterion for calibration, it is possible to evaluate the temperature of the measured object by means of Eq. (4.130) and the definition of , if the of the object is known
4.11.3 Applications Assuming that all energy radiated by the gray body is absorbed by the blackbody, their total energies must be identical. that is Eo74=E07 where 8-specific radiance of the measured object So =specific radiance of blackbody, E0=1 T=absolute temperature of object O =the Stefan-Boltzmann constant Thi us we have (4.126)
• Assuming that all energy radiated by the gray body is absorbed by the blackbody, their total energies must be identical, that is, 4.11.3 Applications 4 0 0 4 T = T where =specific radiance of the measured object 0 =specific radiance of blackbody, 0 = 1 T =absolute temperature of object =the Stefan-Boltzmann constant Thus we have 4 To T = （4.126）
4.11. 3 Applications 2. Infrared thermometry Radiation pyrometers are usually used in measurement of temperatures higher than 800C. However, the infrared thermometry we are now dealing with concerns with measurements in low temperature and infrared light range
2. Infrared thermometry 4.11.3 Applications Radiation pyrometers are usually used in measurement of temperatures higher than 800 C . However, the infrared thermometry we are now dealing with concerns with measurements in low temperature and infrared light range
4.11. 3 Applications Compensation Grating C Frequency Final-stage Pre-amp Indicator Optical selective amp amp system resist or Recorder Recorder supply Fig. 4.110 Block diagram of an infrared thermometering device
Fig. 4.110 Block diagram of an infrared thermometering device 4.11.3 Applications