Process Temperature Measurement Practice--Radiation Thermometry

By Gary Freeman, ABB Measurement Products

Non-contacting temperature measurement techniques for the processing industries complement thermocouple and RTD sensors. Innovations in infrared technology are reducing their cost and size while increasing reliability.

Non-contacting temperature measurements offer several advantages:

• Fast, permitting more consecutive measurements in a given time interval, such as for temperature distribution measurements.
• Measurements on moving objects (conveyer processes, rolling mills, etc.).
• Measurements in dangerous or inaccessible locations (objects at high voltage, long distance measurements).
• High measuring temperatures up to 3000 °C (5432 °F). In such applications, contacting thermometers have a limited life span.
• No interaction with the measured object measurement (suitable for poor heat conductors such as plastics and wood.)
• No mechanical influences on the measured surface (painted surfaces, foams, elastomers.)
• No contamination of the measured object (hygienic applications).