Pyrometer

November 1, 2021

Have you ever wondered how many degrees gold must reach to melt? Or have you been curious to know how the extremely high temperatures to which metals must be subjected to reach a liquid form are measured ? These measurements are made with a Pyrometer, which offers an accurate measurement at a safe distance.

What is a Pyrometer?

The Pyrometer is an instrument that measures, with great precision, the temperature of substances, without coming into direct contact with them .

It was designed to cover measurements between -50 degrees and +4000 degrees Celsius, making it the perfect instrument when measuring extreme temperatures, such as those generated by incandescent metals during casting processes.

What is a Pyrometer for?

Since its invention, the pyrometer has been an artifact designed to measure extreme temperatures without coming into contact with the object or substance that produces it.

It is used more frequently in the industrial area, as well as in the environment, as this tool is capable of measuring very low temperatures, such as liquid nitrogen, or very high temperatures such as volcanic matter, without the need to come into contact with the material under investigation or measurement.

Its manageability, easy reading and high precision, makes it an important instrument in industrial processes, which require constant monitoring.

How does a pyrometer work?

Each of the metals or any object that enters the melting process at a temperature greater than (0) kelvin or (273.15) Celsius emits thermal radiation and this radiation will be captured by the Pyrometer to generate a measurement.

There are two ways to generate this measurement, one is through the absorption and emission process that determines the temperature of the gases that is released in the radiation process.

In the case of incandescent metals, the color of this must be observed through the Pyrometer. The temperature of an incandescent filament projected in the field of vision of the apparatus is adjusted and when the colors generated by both metal and filament are identical, the temperature can be read.

Uses of the Pyrometer

The pyrometer must be used in those measurements in which conventional thermometers fail to meet the objective of measuring a body or substance, because it exceeds its measurement range.

This measuring instrument is required on environmental surfaces with extreme temperature levels, such as active volcanoes. Also in:

  • Incandescent Metal Casting Industries
  • Wherever you want to measure the temperature of moving objects or masses.
  • Where measurement of atmospheric pollution is required.
  • Where the measurement of rapidly varying temperatures is required.
  • If the area that needs to be measured is difficult to access.

Undoubtedly, the pyrometer is a very useful instrument, having one of them in the laboratory will facilitate the study processes and obtain optimal results.

Types of Pyrometer

At present, there are various types of Pyrometers , however, there are three that stand out for being commonly used in industries.

It is worth noting that their difference lies in the way in which they capture radiation, to emit the most accurate temperature measurement , depending on the conditions and requirements.

  • Radiation Pyrometer

These types of artifacts base their actions on the Stefan – Boltzman law, emphasizing that the intensity of the radiation emanated by a certain body will increase proportionally to the fourth power of the absolute temperature of said body.

This pyrometer uses a thermal sensor to capture the heat of radiation and from there it determines the temperature. This type of pyrometer is used to measure temperatures between 550º C and 1600 C.

This pyrometer absorbs energy radiated by a body, redirects it to a kind of warehouse in which a signal proportional to temperature is generated, this generates a quantum result that can then be read reliably.

It is very sensitive to small variations in radiant energy and very resistant to vibrations or shocks.

This basic characteristic makes it perfect for measuring surface temperatures, the temperature of moving objects, temperatures above the amplitude of thermocouples, when high speed response to temperature changes is required.

  • Infrared Pyrometer

Even though its operation is very similar to the Radiation pyrometer, infrared pyrometers detect radiation with a greater range of amplitude in the wave space , which allows the spectrum of degrees to be measured to be broadened (from -50 to 4000ºC ).

This measuring system is commonly used in cases related to moving objects such as rollers, conveyor belts; or in those cases in which it is required to maintain a greater distance, either for reasons of contamination or imminent danger, such as high voltage.

  • Optical Pyrometer

His work is based on Wien’s law of distribution of thermal radiation. lm = A / T, where A = 0.2897 if lm comes in cm.

This type of pyrometer uses a comparison method as the basis of operation.

To generate a result, the pyrometer compares the incandescence of the light emitted by the heat source with a standard source, and expresses its results with Yellow – Red colors, depending on the brightness and hue of these colors, a specific result will be expressed.

This instrument measures temperatures higher than 700º . This is widely used in foundries, boilers, blast furnaces and the steel industry.

It is about choosing the pyrometer that suits the needs of the laboratory. It evaluates its characteristics and inclines its selection based on the laboratory and the studies that are usually carried out in it.

Pyrometer Features

The most outstanding characteristics of Pyrometers in general are: Ability to offer high precision measurements without the need to come into contact with the object; they have a wide spectrum of ºC to be measured; fast response speed.

Importance of the Pyrometer

The importance of the Pyrometer is that it does not endanger the integrity of the personnel or worker who carries out the measurement . In addition, it facilitates measurement tasks due to its easy reading.

This is because it is an instrument that works remotely, that is, it fulfills its objective without having to come into contact with the object, substance or space that maintains an extreme temperature.

Having all the necessary equipment in a laboratory is very important, because it facilitates rigorous studies and experiments. In the case of the pyrometer, its usefulness in industry, and in the environmental sphere, is highly outstanding for its usefulness. Choose the one that best suits your needs and get started

Parts of the Basic Pyrometer

Pyrometers in general are made up of several parts and other systems that together make up a specific system.

  • Optical system that collects the energy emanated by the substance or object under study.
  • Compact infrared temperature sensor / transmitter.
  • A system that detects energy and transforms it into electrical signals.
  • A system that avoids affecting the measurement by temperature variations within the sensor.
  • Modern electronic systems that allow the use of complex algorithms that provide greater temperature precision.

Knowing the parts of the pyrometer in detail guarantees you skill in handling this equipment. Remember that it will depend, to a large extent, obtaining accurate results.

Differences between pyrometer and thermometer

Derived from the function that both devices perform, it is often confused between the pyrometer and the thermometer. However, there are several differences that determine the successful use of each device.

The pyrometer has the ability to measure the temperature remotely, while the thermometer must come into direct contact with the studied object.

The pyrometer has a very wide measurement range in extreme temperatures from -50º Celsius to 4000º Celsius, while the thermometer maintains a much smaller range.

The pyrometer measures the temperature by means of the radiation emitted by objects subjected to casting at temperatures higher than (0) kelvin, while the thermometers accurately measure the temperature of the objects studied.

Origin of the Pyrometer

The exact provenance of this device is unknown, however, its creation is attributed to the Dutch physician and physicist, Pieter van Musschenbroek (1692 – 1761) and to the English potter and designer Josiah Wedgwood (1730 – 1795) who, with the common purpose to advance their investigations, they developed artifacts similar to the  Pyrometer.

There is no specific date of its creation, however, it is estimated to have been in the mid-1700s.

Some records of the time highlight that this artifact was built, in principle, to study the dilation that was observed in metallic bodies, when their temperature was modified.

Evolution of the Pyrometer

It was created to measure the temperature of ovens. He compared the color of clay when subjected to fire at known temperatures.

Later, its evolution began and with it, it was possible to measure the size to which the pieces of clay shrunk.

Later in 1900, an optical pyrometer was invented , in which the temperature of a bright and incandescent object is compared with the light emitted by a filament subjected to heat, and with various adjustments it was possible to obtain a result.

To eradicate technical errors with optical pyrometers, work began on the basis of Planck’s law, which relates temperature to the intensity of radiation emitted at individual wavelengths, generating so-called radio pyrometers, which are two pyrometers of different brightness in one instrument.

Dr. Loony Davis5
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Born and raised in Brussels in an English family, I have always lived in a multicultural environment. After several work experiences in marketing and communication, I came to Smart Water Magazine, which I describe as the most exciting challenge of my career.
I am a person with great restlessness and curiosity to learn, discover what I do not know, as well as reinvent myself daily, someone who is curious about life and wants to know. I enjoy sharing knowledge.
This is my personal project but I also collaborate in other blogs, it is the case, the most important web on water currently exists in the US, if you are interested you can read my articles here.

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