Temperature is one of the most common measurement parameters used for monitoring and control in process industries. In production as well as in quality control and maintenance, temperature represents an important indicator of product quality or equipment condition.

While thermocouples are among the most popular temperature measurement devices in the industry, of late there has been a growing shift towards infrared, non-contact thermometers, also known as pyrometers. The reason for this shift can be ascribed to the many advantages when using infrared thermometers.

These advantages include:

  • Fast response time (measured in milliseconds), the user gets more information per time period.
  • Measure objects that move, rotate or vibrate (e.g. conveyorised production or any moving object).
  • Measure high temperatures where contact probes will not work or have a short lifetime.
  • No mechanical damage or contamination of the surface (food, pharmaceuticals, painted surfaces, soft plastics etc.).
  • No influence of objects with high thermal-conductivity where object temperature would change if contacted (e.g. glass, wood, small or very thin objects).

Recently the IR-Sensor market has seen two major trends:

First, IR-thermometers are significantly lower in cost. The most expensive parts of an infrared thermometer are the lenses and detectors. New lens materials, technologies and mass production of IR-detectors for consumer products have resulted in lower prices for these two important components.

Together with the increased demand for industrial IR-thermometers, high volume production of standard sensors has resulted in greater manufacturing efficiency for the IR-thermometer manufacturers.

Second, IR Sensors are becoming smaller in size. In the past, the measurement of low temperatures made it necessary to use fast lenses with relatively large diameters in order to capture enough emitted energy.

Progress in detector technology and the use of better detector performance, together with improved low noise analogue preamplifier techniques have helped reduce the dimensions of the IR-sensing head dramatically.

Because the newer sensors have greater response characteristics they require less energy to achieve a usable signal. As a result, lenses can have smaller diameters.

Due to the increasing expectations of the user and competition among manufacturers, infrared thermometers are continually being improved and electronic design is an area that has seen the most improvements recently.


Marcell Brits
Temp-Tek (Pty) Ltd.
Tel. +27 11 465 8066

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