Active Thermography and its Application

Thermography or thermal imaging is a type of infrared imaging. Thermal imaging camera sensors detect heat in the infrared range of the electromagnetic spectrum (roughly 900–14,000 nanometers or 0.9–14 µm) and produce color or black and white images from heat signatures. It is widely used in manufacture and industry to do preventive maintenance for the machinery. One of the strengths of the technology is that it is non-contact, meaning inspection can take place even on live systems where there may normally be dangerous temperatures, electrical currents or high speed moving parts. So from a safety point of view it has some real benefits.

Thermography enables systems to be inspected under real operating conditions. So mission critical or high value processes such as manufacturing can continue during the thermal inspection. In high value processes the cost of maintenance can be greatly reduced by predicting when repairs or routine maintenance are needed. This enables maintenance to be planned, which in turn can minimize costly down time. Mechanical wear and tear cannot always be detected until there is a catastrophic failure. For example, if a worn bearing is put under load it gets hot, which can be detected with a thermal imaging camera.

Those two benefits: cost reduction and ease of maintenance make it powerfull tool for preventive maintenance. The following two pictures are example of thermal imaging for detection of mechanical condition and water leak detection in pipe. The high temperature shows the condition of captured device, if it is higher than boundary condition, it can be categorized as abnormal or defect area.

Example of themal imaging [1,2]

Active themography