Radiation Thermometers (RTs)

Radiation Thermometers (Pyrometers, if you will) are noncontact temperature sensors that measure temperature from the amount of thermal electromagnetic radiation received from a spot on the object of measurement.

This group of sensors includes both spot or “point” measuring devices in addition to line measuring radiation thermometers, which produce 1-D and, with known relative motion, can produce 2-D temperature distributions. Strictly speaking, thermal imagers, or area measuring, thermometers which measure over an area from which the resulting image can be displayed as a 2-D temperature map of the region viewed, are also radiation thermometers.

These are significant devices in all their manifestations because they enable improvements in processes, maintenance, health and safety that save both lives and money.

They are used widely in many manufacturing process like metals, glass, cement, ceramics, semiconductors, plastics, paper, textiles, coatings, and more.

They enable automation and feedback control that boost productivity while improving yield and product quality.

They save lives and improve safety in fire-fighting, rescues, and detection of criminal activities. In hospitals, nursing homes and home care, they have enabled a new , quick and reliable method to monitor and measure human body temperatures with one second time response.

In reliability and maintenance needs from building heating to electrical power generation and distribution, they save downtime and help optimize practices. Without these devices, our lives would be vastly different, much like the status of the 1950’s and 60’s.

Some confusion exists about this whole class of sensors for a variety of reasons. Not the least of these reasons is the variety of names given to the devices in this class, e.g.:

Optical Pyrometers, Radiation Pyrometers, Total Radiation Pyrometers, Automatic Infrared Thermometers, Ear Thermometers, Continuous Radiation Thermometers, Line-Scanners, Thermal Imaging Radiometers, Infraducers, Infracouples, Fibreoptic Thermometers, Gold Cup Pyrometers, Surface Pyrometers, Ratio Pyrometers, Two-Color Pyrometers, Infra-Snakes, or something similar.

It seems to be more of an indication that there are few standards, especially ones relating to nomenclature.

There are a few and they are listed on the Standards page and the term used in most of them to technically describe these devices is: “Radiation Thermometer”.

If you are seeking information or more knowledge about any of the following, you are at the right page.

Then, too, the mysterious terms like emissivity, blackbody and spectral crop up so often that the average engineer unskilled in them can get fully turned in circles very quickly. Imagine what the unskilled person thinks?

Is it magic? No, it’s technology, like semiconductors and integrated circuits, a bit difficult to learn, but technology indeed.

What’s a poor person to do when faced with a need to specify something for which even the manufacturers cannot agree on names let alone the terms used to specify the operational properties?

Fortunately a great literature database exists about these devices and there are the few standards as described above.

Many of the base references are listed on our references page that has been moved to a companion website being built as a temperature & moisture sensor directory of suppliers and resources.

Then, too, the European Union (EU) and collaborating groups around the world has recently completed a major technology effort on terminology that published in 2009 as an IEC Standard.

It but the first step in efforts to standardize both the terminology and the methods used in the practice of this technology.

If you persist, you can get there. You wouldn’t want it too easy, would you?


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