Applications of Infrared Pyrometers and Thermometers

 

 

 

Infrared pyrometers are used across many industries to measure high temperatures remotely and without contact. They play an essential role in metallurgy, glass production, semiconductor manufacturing, and the operation of industrial ovens and furnaces. These devices help monitor processes such as glass tempering, induction heating of metals, and assessing gas temperatures in boilers or incinerators.

 

Beyond industrial use, IR pyrometers are also valuable in atmospheric science research, food processing, and packaging—anywhere precise, non-contact temperature measurement is required.
 

 

Jump To:

Learn more about the difference between contact and non-contact temperature measurement.

 

 

 

Temperature Measurement in Boilers and Incinerators

 

Combustion Gas Temperature Measurement using Infrared Pyrometers

 

HEITRONICS has more than 25 years of experience using infrared pyrometers to measure a wide range of incinerator and boiler processes. 


The HEITRONICS incinerator and boiler pyrometer, an infrared radiation thermometer (IRT), provides unique spectral responses for CO2 gas emissions, which produce the highest quality measurements of the gas temperature.  The pyrometer is installed outside the furnace and is therefore not exposed to the high temperatures or aggressive gases, and is easy to access.


HEITRONICS combustion gas pyrometer solution characteristics include:
 

  • 6.5 °C (12 °F) Accuracy @ 900 °C (1650 °F) gas temperature (also known as furnace exit gas temperature)
  • The IR Thermometer is installed outside the furnace and therefore not exposed to the high temperatures nor aggressive gases and is easy to access (with furnace in operation when using a valve or sapphire window)
  • Unique wavelength responses for CO2 gas emissions produces highest quality measurements
  • Exceptional long and short term stability due to the HEITRONICS chopped radiation method of measurement
  • Optional Certificate of Calibration is traceable to national standards
  • More than 25 years of experience on a wide range of furnace and fuel types


Read more about HEITRONICS combustion gas pyrometer applications:  Combustion Gas Temperature Measurement using Infrared Pyrometers -Application Summary (PDF)



Advantages of Infrared Pyrometers for Temperature Measurement in Boilers and Incinerators


The use of infrared radiation thermometers to measure temperature in incinerators offers the following advantages:
 

  • No aging or regular replacement as experienced with thermocouples
  • Calibration using a blackbody radiation source
  • Proven standard solution for MSW incineration plants
  • Applicable to coal fired boilers and furnaces, etc.
  • Gas temperature measured in combustion chambers or ducts
  • Fast response times
  • Adaptable to different tasks

 


Additional Resources on Combustion Gas Temperature Measurement


SNCR Operating in the Optimized Temperature Window in a Municipal Solid Waste (MSW) Incinerator

The ammonia consumption of the SNCR (Selective Non-Catalytic Reduction) can be reduced significantly if the injection takes place in the optimum temperature window of 850..1000 oC. Knowledge of the actual temperature distribution within the incineration chamber is a crucial precondition to do this.

Read more:  SNCR Operating in the Optimal Temperature Window in a Municipal Solid Waste (MSW) Incinerator

 

 

Infrared Thermometer Measures Combustion Gas using Focused High Precision Optics to Simplify the Installation

The use of Infrared Radiation Thermometers (also called infrared pyrometers or IRTs) for combustion gas temperature requires a channel or view port with diameter larger than the field of view of the IRT.

Read more: Infrared Thermometer Measures Combustion Gas with Focused High Precision Optics to Simplify Installation

 

 

Displaying the Temperature Distribution of Gas Temperatures in Combustion Chambers

HEITRONICS TempControl 2.0 displays the thermal distribution of gas temperatures in a combustion chamber, and provides intuitive detection of hot spots and imbalances by graphical image of the temperature distribution.

Read more: TempControl Thermal Distribution of Gas Temperatures in a Combustion Chamber

 

 

Infrared Radiometers for Atmospheric and Oceanic Sciences

 

Non-contact temperature measurement for Atmospheric and Oceanic Sciences using Infrared Radiation Thermometers


Infrared radiation thermometers (also called IRTs, radiometers or pyrometers) make it possible to provide remote, non-contact temperature measurement of sea, snow, ice and land surfaces, as well as sky and clouds. 

Ocean weather research buoy - nomad type


HEITRONICS' radiometers have been successfully used for decades on Airborne Platforms, Marine Vessels, and Ground Based Systems to measure temperature.  In 1997, a HEITRONICS system was the first commercial infrared pyrometer to be part of a scientific experiment in the Columbia Space Shuttle SpaceLab project.

 

HEITRONICS infrared radiometers support the following Atmospheric and Oceanic Science applications:

 
  • Surface temperature for ≤ 5m sight path distance
  • Surface temperature for > 5m sight path distance
  • Sky and cloud temperature
  • Air temperature via CO2 emissions in long sight path
  • Weather protection tube option available
  • Unmanned Arial Vehicle's (UAV's) and when mounting space is limited
 

Read more about applications of HEITRONICS infrared radiation thermometers for Atmospheric & Oceanic Science:  Application of Infrared Radiometers to Meteorology

High Latitude Sea Surface Skin Temperatures Derived from Saildrone

From May 15 to October 11, 2019, six Saildrone un-crewed surface vehicles (USVs) were deployed for 150-day cruises collecting a suite of atmospheric and oceanographic measurements from Dutch Harbor, Alaska, transiting the Bering Strait into the Chukchi Sea and the Arctic Ocean.

 

Saildrone Sea Surface Temperatures Derived from Infrared Pyrometer Measurements

Saildrones are predominantly powered by wind and solar, and are equipped with advanced meteorological and oceanographic instruments and artificial intelligence technology.

 

Two Saildrones funded by NASA, SD-1036 and SD-1037, were equipped with HEITRONICS infrared radiation pyrometers having a 8..14 micron spectral range, positioned on the deck for the determination of the ocean sea surface skin temperature.  One infrared pyrometer aimed up at the sky, and the other two aimed towards the sea.  The resulting measurement represents the temperature of the top 10-20 μm layer of sea surface while compensating for the sky temperature reflecting off the sea surface.

 

The sea-viewing infrared radiation thermometer (IRT) was CT15.10 and the sky-viewing IRT was CT09.10.  Both infrared radiometers have the merits of long term calibration stability and temperature measuring stability while subjected to varying ambient temperature due to the HEITRONICS chopped radiation method.


Read the article:  High Latitude Sea Surface Skin Temperatures Derived From Saildrone Infrared Measurements | IEEE Journals & Magazine | IEEE Xplore

 

See also this article from the New York Times on the use of the crewless Saildrone surface vehicles for the collection of vital sea-level data from inside a storm:   The Tiny Craft Mapping Superstorms at Sea


 


Infrared Pyrometers for Calibration

 

Accurate calibration of an infrared pyrometer is essential to ensure that the temperature-measuring instrument delivers reliable and repeatable results. Because infrared thermometers determine temperature by detecting infrared radiation rather than making direct contact, their performance can be influenced by factors such as emissivity, ambient conditions, optical alignment, and detector sensitivity.

 

Special infrared pyrometers called "transfer standards" are often used in the calibration of infrared pyrometers to ensure measurement accuracy and traceability to recognized temperature standards.  A transfer standard is itself a highly accurate and well-characterized infrared pyrometer that has been calibrated against a primary standard.

 

Infrared Calibration Equipment Brochure - Performance & Features Summary
 

To perform a calibration of an infrared temperature measuring instrument requires a radiation source with well-defined emissive properties.  The radiation source must either be calibrated, or alternatively, a transfer standard must be used to determine the temperature emitted by the radiation source.

 

What is the role of a transfer standard in calibrating an infrared pyrometer?

 

When using a radiation source that has been calibrated by the original manufacturer or by a third-party laboratory, it is important to recognize that mechanical shock or rough handling during transport can compromise the validity of the certified calibration. Internal components—such as heating elements or embedded temperature sensors—can shift from their original positions during certification without causing the source to fail or appear damaged. Even a small displacement can alter the actual emitted temperature while still allowing the source to operate, leaving the user unaware that the source no longer represents the certified calibration state.


To mitigate this risk, Transfer Standards are often used. A Transfer Standard is a certified temperature sensor used to independently verify the true temperature of the radiation source. In this approach, the radiation source itself is not certified; only the Transfer Standard carries the calibration traceability. A Transfer Standard may be a high-accuracy certified thermocouple or a high-precision certified infrared thermometer, depending on the application.


Calibration Schemes
 

For many radiation sources, a contact sensor cannot be used to accurately determine the true radiated temperature, because the presence of a contact probe would disturb the radiating surface or fail to sense the emitted infrared energy correctly. When calibration relies solely on the radiation source’s internal sensors—rather than an external certified sensor—this approach is referred to as a Scheme I calibration.

 

A Scheme II calibration uses a Certified Infrared Transfer Standard to independently verify the temperature of the radiation source.

 

Scheme IIa calibration is performed when the instrument under test and the Transfer Standard operate over the same, or nearly the same, spectral range (also known as spectral response or spectral sensitivity).

 

Scheme IIb calibration is performed when the instrument under test and the Transfer Standard have different spectral ranges.

 

Because spectral matching minimizes measurement errors related to emissivity and spectral response differences, Scheme IIa typically provides the lowest calibration uncertainties.

 

Check Infrared Pyrometer Services for information on Wintronics' infrared pyrometer calibration services.
 


Additional Resources on Infrared Calibration:

 

Blackbody Calibration Source ME30 for Infrared Thermometers and Thermal Imaging Cameras

 

Blackbody Calibration Sources are required to calibrate infrared radiation thermometers and thermal imaging cameras. ME30 will satisfy many requirements including fever/elevated body temperature measuring instruments used, for example, for COVID-19 virus screening.

Read more:  Blackbody Calibration Source ME30 for Infrared Thermometers and Thermal Imaging Cameras


 

Introduction to Radiometric Calibration of Thermal Imaging Cameras and Other Infrared Instrumentation

 

Infrared Calibration Equipment includes two key items: a Blackbody Radiation Source (BBR) and a Reference Thermometer. The Reference Thermometer can be either a Contact Probe or a Transfer Radiation Thermometer (TRT). This article focuses on using a TRT to obtain the best achievable uncertainties via the Scheme II method of calibration.

Read more:   Introduction to Radiometric Calibration of Thermal Imaging Cameras

 

 

 

Contact vs Non-Contact Temperature Measurement
 

A variety of effects can be used to measure temperature, from a change of length vs temperature (e.g. bi-metal strips) to volume change vs. temperature (e.g. mercury thermometer) to voltage change vs. temperature (e.g. thermocouples).  For all of these measuring approaches, the sensor has to be in direct mechanical and thermal contact with the measured object.  After contact is established, time is required for heat transfer, and then the sensor "measures" its own temperature.

 

When measuring with contact, acceptable results can be produced as long as the heat conduction is good and the thermal mass of the object is much larger than the sensor.  However, in the case of poor heat conduction or low mass objects, the object's temperature is not completely transferred to the sensor and the measurement fails.  In addition, for moving objects, or those which are far away, it is difficult to establish a mechanical contact.  This is where non-contact temperature measurement enters the game.

 

How does non-contact temperature measurement work?

Any matter at a temperature above 0 Kelvin emits electromagnetic radiation.  The spectrum and intensity of the radiation is governed by Planck's law, a universal mathematical relationship between temperature and radiation.  WIth non-contact temperature measurement, the electromagnetic radiation emitted by the object is what the infrared pyrometer measures.  The advantages are apparent:

 

  • No direct contact between the Infrared Radiation Thermometer (IRT) and the measured object
  • The IRT is not being heated/cooled, which leads to fast measurement
  • No direct influence of the IRT on the measured object
  • Moving objects can easily be measured

 

 

For more information on Infrared Pyrometers, see Infrared Explained.

 

Wintronics Calibration provides the highest level of measurement service available today to ensure the exacting quality you demand from your measurement equipment.

 

 

 


Wintronics' Field Engineer Services manages all your engineers' calibration needs - from equipment scheduling and tracking to shipping and calibration - and provides quality reports and certificates of calibration.