Pyrometers measure thermal radiation without contacting the surface of the object that they are measuring to determine its temperature. This is particularly convenient for moving objects and surfaces that cannot be touched or are impossible to reach for some reason. While pyrometry started out with a simple disappearing filament, there are many varieties currently made to function in different situations
Disappearing Filament Optical Pyrometer
This very first type that was made was the first thermometer that did not require contact to measure temperature. Disappearing filament units provided a very simple but accurate method to measure temperatures within the range of 600°C to 3000°C. Still made, the operation of this variety requires the human eye of the operator to judge temperature. They are also unsuitable for recording purposes. They do provide effective spot measurement, though, and are useful in calibrating total radiation thermometers.
Total Band Pyrometer
This variety is made to detect over 90% of an object's emitted radiation and requires parts that are sensitive to nearly the entire light spectrum, including lenses and filters. Total band pyrometer are rarely used because they can experience significant errors.
Fiber Optic Pyrometer
Fiber optics units are made of glass fiber, an optical head and a signal processor. The device's optical head contains no electronics, simply the optics. Radiation comes in via the optical head and is transmitted through the lens and into the fiber - which can be up to 30 meters long - ending in the converter. At higher wavelengths, the glass fiber stops being transparent, making its ability to measure temperatures restricted to surfaces that are over 150°C. Fiber optic units have some big advantages, including being able to measure within strong electromagnetic fields and inside a vacuum.
Ratio pyrometers
Also called a two-color, this variety is typically more expensive, even though its accuracy is poor in some conditions. It does, however, attempt to overcome the problem of calibrating the device for each and every object it measures. Ratio pyrometers are used for particularly difficult tasks, such as blocked view because of smoke or dust, changing or low emissivity, and very high temperatures. The main disadvantage of this variety is that its rotating filter wheel does not allow signals to arrive at the same time. This means that recorded temperature could be inaccurate if the surface moved or its temperature fluctuates quickly.
Automatic Optical Pyrometer
Automatic optical pyrometers consist of two components - an electronic amplifier and an optical head. This variety utilizes an electrical radiation detector instead of depending on the judgment of the eye of the operator. This means that it isn't limited to the spectrum's visible wavelengths. It can read a long way into the infrared and near ultraviolet areas of the spectrum.
Disappearing Filament Optical Pyrometer
This very first type that was made was the first thermometer that did not require contact to measure temperature. Disappearing filament units provided a very simple but accurate method to measure temperatures within the range of 600°C to 3000°C. Still made, the operation of this variety requires the human eye of the operator to judge temperature. They are also unsuitable for recording purposes. They do provide effective spot measurement, though, and are useful in calibrating total radiation thermometers.
Total Band Pyrometer
This variety is made to detect over 90% of an object's emitted radiation and requires parts that are sensitive to nearly the entire light spectrum, including lenses and filters. Total band pyrometer are rarely used because they can experience significant errors.
Fiber Optic Pyrometer
Fiber optics units are made of glass fiber, an optical head and a signal processor. The device's optical head contains no electronics, simply the optics. Radiation comes in via the optical head and is transmitted through the lens and into the fiber - which can be up to 30 meters long - ending in the converter. At higher wavelengths, the glass fiber stops being transparent, making its ability to measure temperatures restricted to surfaces that are over 150°C. Fiber optic units have some big advantages, including being able to measure within strong electromagnetic fields and inside a vacuum.
Ratio pyrometers
Also called a two-color, this variety is typically more expensive, even though its accuracy is poor in some conditions. It does, however, attempt to overcome the problem of calibrating the device for each and every object it measures. Ratio pyrometers are used for particularly difficult tasks, such as blocked view because of smoke or dust, changing or low emissivity, and very high temperatures. The main disadvantage of this variety is that its rotating filter wheel does not allow signals to arrive at the same time. This means that recorded temperature could be inaccurate if the surface moved or its temperature fluctuates quickly.
Automatic Optical Pyrometer
Automatic optical pyrometers consist of two components - an electronic amplifier and an optical head. This variety utilizes an electrical radiation detector instead of depending on the judgment of the eye of the operator. This means that it isn't limited to the spectrum's visible wavelengths. It can read a long way into the infrared and near ultraviolet areas of the spectrum.