Infrared Pyrometers

About Infrared Pyrometers

Applications of Industrial Pyrometers

Industrial pyrometers are utilized across a wide variety of industrial work to maintain correct temperature control, product quality, and process throughput. In manufacturing processes that operate at high temperatures and include multiple stages, processes such as melting and forming require careful non-contact temperature measurements, which can easily be accomplished by using pyrometers to efficiently measure temperature in real time.

• Steel Manufacturing: Temperature measurement is critical for processes such as melting, casting, heat treatment, and rolling in production of steel. Throughout production, pyrometers are used to continuously measure temperature of molten metal and the surface of hot steel to ensure thermal control of the material, which is important for the related structural integrity and mechanical strength, and durability of the final steel product. Bad or inconsistent temperature control can lead to defects and performance issues and possible reject of poor products.
• Glass Production: In the glass industry, temperature control must be measured with precision throughout the melting, refining, and forming processes. Melting raw materials, such as silica (sand) into glass is complicated and, in addition to desired optical clarity or lack of translucent shade, it must be strictly controlled for consistency, strength, and chemical stability. In glass production, pyrometers are continuously measure furnace temperatures to ensure glass remains at set thermal ranges so to promote melting uniformity and to minimize or eliminate defects such as bubbles, streaks or distortion.
• Ceramics: In the ceramics sector, temperature control and monitoring is equally important, especially during the firing stage in kiln systems. Pyrometers are utilized for continuous monitoring and control of kiln temperatures to achieve appropriate conditions for sintering and glazing. With accurate temperature measurement, the ceramic material will obtain appropriate hardness, finish, and structural integrity quality. With kiln temperature variation, poor glaze will be formed, product strength will be lowered, or colour quality may be inconsistent.
• Cement Industry:  The temperature of the kiln must be controlled during cement production (for the sake of both building clinker quality and the quality of the final product). To continuously measure the interior temperature of the rotary kiln, pyrometers are utilized so that the operator can increase or decrease heating input as required by the shifting process conditions. This would allow operations to ensure that they do not let a kiln get too hot, nor too cold, both of which would affect the final cement’s strength and composition. Further, monitoring the temperature actively works to reduce fuel/energy input, allowing the operation to improve energy efficiency and reduction.
• Pharmaceutical Industry: Infrared pyrometers in the pharmaceutical sector, provide accurate, non-contact temperature measurements that are needed for temperature-sensitive components, materials, and fragile packaging. The ability for continuous monitoring temperature of products and equipment during manufacturing, packaging, and sterilization is invaluable. The non-contact aspect of pyrometry ultimately protects the integrity of the product, quality assurance, and regulatory compliance without risk of contamination.
• Semi-Conductor Industry: In the semiconductor sector, pyrometers provide precise non-contact temperature measurement during critical processes in wafer fabrication, annealing, and etching. By measuring from infrared radiation, infrared pyrometers can ensure real time monitoring and control leading to consistency in quality of the product and the minimization of defects. Pyrometers are also excellent and very useful in high temperatures environments and under difficult process conditions where contact sensors would typically not be able to provide accurate measurement.

Industrial pyrometers are essential across a wide range of materials and processes—including steel, glass, ceramics, and semiconductors. Their ability to provide accurate, rapid, and non-intrusive temperature measurements makes them a cornerstone of industrial temperature control, significantly influencing product quality and process efficiency.

Some of the advantages of noncontact pyrometry: –

• Records temperature within fractions of seconds.
• It requires less maintenance and hence the longer lifetime.
• It can be used to measure temperature of the moving objects.
• As it is not in direct contact with target so high temperature can be measured.
• Being noncontact technique, it will not tamper the target mechanically.

Spectral Range

(Spectral range is also referred to as “spectral response”)

The spectral range of an infrared thermometer defines the range of wavelengths to which the instrument is sensitive. Manufacturers may specify this range differently, but a common approach is to report the wavelengths at which the instrument’s response reaches 50% of its maximum output, known as the Full Width at Half Maximum (FWHM). 

• For low-temperature measurements, the most widely used spectral range across industrial, scientific, medical, and commercial applications is 8–14 µm. This range is often referred to as a long-wavelength wideband spectral range.
• For high-temperature measurements, spectral bands of 1 µm and 1.6 µm are commonly employed. These are typically classified as short-wavelength narrowband spectral ranges.

Although there is no universally agreed-upon definition for “wideband” or “narrowband,” in practice, a narrowband spectral range is generally considered to have a bandwidth less than 0.5 µm.

The spectral range selection is critical because it determines the accuracy and applicability of temperature measurement, depending on the temperature range and the material’s emissivity.

Why is spectral range significant?

For most applications, the spectral range is selected with precision to coincide with the infrared emissions from non-solid materials such as glass, thin-film polymers, or hot gases of combustion.

For instance, when taking a temperature reading of combustion gas in a combustion chamber, the reading is taken through a column of gas molecules rather than through a particular surface or part of the gas stream.

Selecting the appropriate spectral range is also critical when measuring emissivity change on metal surfaces. As opposed to measuring combustion gas, there are numerous applications where it is critical to see through combustion gas, and this calls for a different spectral range.