The Advantages of Infrared Pyrometers
Temperature is commonly measured in manufacturing operations to monitor and control product quality and process productivity. Many applications use contact devices like thermocouples and RTDs, but all too often these devices are inaccurate, too slow, difficult to use, or require frequent replacement, creating process downtime and reducing productivity. For many applications, infrared pyrometers are the perfect solution because they can accurately and reliably measure a target’s temperature without contact.
This capability is ideal for applications involving:
High Temperatures | Moving or Inaccessible Targets
Hostile or Hazardous Environments | Fast Response Times
With the Silver, Gold, and Pro Series products, Williamson offers the optimal pyrometer for a wide range of applications.
How Infrared Pyrometers Work
Every object emits infrared energy proportional to its temperature. Hotter objects emit more energy; cooler objects emit less energy. Infrared pyrometers collect the infrared energy emitted by an object and convert it into a temperature value. The amount of energy collected by a sensor is influenced by the emissivity characteristics of the target and the transmission characteristics of any intervening optical obstructions between the sensor and the measured target. The influence of these factors varies significantly at different infrared wavelengths.
Selecting a pyrometer filtered at an appropriate wavelength makes all the difference in achieving accurate readings. Emissivity is a term used to quantify a material’s tendency to emit infrared energy. It is related to the reflective and transmissive characteristics of the material and is measured on a scale of 0.0 to 1.0. In practical terms, emissivity is the opposite of reflectivity. For example, a highly reflective surface like aluminum has a low emissivity of 0.1, while a dull surface like refractory brick has a higher emissivity of 0.9. Intervening optical obstructions such as steam, water vapor, flames, or combustion gasses have the potential to interfere with the amount of energy that is measured by the sensor.
Where Wavelength Matters
The most important Williamson difference is our particular emphasis on wavelength.
By carefully selecting the wavelengths in our pyrometers, we can view through intervening optical obstructions, reduce emissivity variation and provide more stable and accurate temperature measurements. For over 60 years, Williamson has been making the most accurate pyrometers for demanding industrial applications. With a history of engineering customized solutions, our philosophy is that there is a specific pyrometer for every application, not a handful of pyrometers to fit every application.
Why Wavelength Matters
For temperature measurements in ideal laboratory settings, all that matters is the calibration accuracy of the pyrometer. However, most industrial applications involve less than ideal operating conditions with a number of interferences and factors that contribute to inaccurate readings. Thoughtful wavelength selection can dramatically reduce or even eliminate errors due to optical obstructions, emissivity variation, background reflections, and misalignment. Most pyrometer manufacturers focus on calibration accuracy, optics, and temperature range but not wavelength selection. At Williamson we emphasize thoughtful wavelength selection to ensure our pyrometers provide the most accurate temperature measurement under any operating condition.
Advanced Infrared Technologies
Single-Wavelength (SW)
- Pyrometers with the ability to better tolerate emissivity variation and optical obstruction
- For most applications, selecting the shortest practical wavelength is recommended
Two-Color (TC)
- Ratio pyrometers designed to compensate for emissivity variation and modest optical obstruction or misalignment.
Dual-Wavelength (DW)
- Ratio pyrometers designed to measure the hottest temperature viewed.
- Select wavelength sets tolerate water, steam, flames, plasma, and laser energy.
- More tolerant of scale, misalignment, and optical obstructions than Two-Color.
Multi-Wavelength (MW)
- Used for non-greybody materials such as aluminum, copper, stainless steel, and zinc.
- Application specific algorithms adjust for complex emissivity characteristics.
Consult With One of Williamson’s Temperature Experts
We would love to discuss your temperature measurement application with you.
