Thermal Imaging – The Technology Strides On
Published: 12 July, 2010
Originally highly exclusive, thermal imaging is now mainstream. In a relatively short time frame this technology has become the universal tool for effective predictive maintenance and it's easy to see why.
Thermal imaging can be applied to so many different tasks. In addition to spotting any thermal irregularities in electrical and mechanical systems that could indicate impending failure, it"s ideal for locating the source of energy loss and for detecting faults in the fabric of buildings. Indeed thermal imaging now provides manufacturers with an exceptionally powerful means of maintaining productivity and minimising overheads.
The dramatic growth in the popularity of this technology has seen it become eminently affordable. It is now widely used across a range of markets. In addition to its maintenance, building and automation applications, it provides vision enhancement for car drivers and a vital sixth sense in the maritime, security and surveillance markets.
This diversification has led to volume production. Economies of scale mean the cost of thermal imaging is now well within the grasp of all engineering sectors. For example, a FLIR i5 fully radiometric thermal imaging compact camera now costs almost a third less than the purchase price it carried when it was introduced 2008.
Every day thermal imaging is finding new applications but that doesn’t mean that the technology has now fully matured in its prime markets such as plant maintenance. Camera capability continues to be refined and enhanced.
The smallest of temperature differences can now be detected with a standard portable infrared camera. Not only does this allow the smallest anomaly to be seen in electrical or mechanical installations, it also allows the camera to produce sharper images. Models designed for predictive maintenance are now able to see temperature differences as small as 0.03°C or 30mK. They also incorporate clever features such as IR window correction which automatically adjusts the camera’s sensitivity when inspecting high voltage installation through safety IR windows.
The big development however is that thermal imaging is getting smarter. Never before has it been so easy, quick and cost effective to use a thermal imaging camera to detect a problem. And one of the key drivers is the parallel development of PC-based analysis and reporting software and application specific software that maximise advances in hardware performance.
Software advances
In line with the price fall of thermal imaging cameras, so too has that of software. Good reporting and analysis software is now available for less than £1000 and adds considerable value to the overall thermal imaging package. It allows findings to be properly documented so that trends can be plotted and the preventative maintenance programme effectively managed.
Application specific software is also considerably enhancing the effectiveness of thermography for set tasks. Those involved in building maintenance were amongst the first to benefit from the introduction of sector-specific cameras with dedicated application functions. As well as a dew point alarm that detects areas at risk from condensation, building cameras are available with a relative humidity alarm that indicates a site of potential mould build-up. The same cameras additionally have a built-in insulation alarm that identifies areas that don’t fulfil insulation requirements.
Reporting options are now extensive with packages providing the user with numerous pre-designed report templates. An energy cost comparison report is one example that allows the easy calculation of achievable cost savings when the identified structural problems are fixed.
Instant reports can now be created in the camera and downloaded onto a memory stick. The necessary data is then instantly available so that repairs can be scheduled and costs saved.
Exceptional value
The greatest advantage of thermography remains its breadth of application and even sector-specific cameras, such as those whose primary function is building inspection, can be used to spot general thermal anomalies. The technology is perfectly suited to a broad range of electro-mechanical, electrical and HVAC predictive maintenance tasks that combine to minimise running costs.
A major benefit in factory management is an infrared camera’s ability to scan a wide area in one pass to highlight potential reliability problems. All kinds of problems show up thermally for further investigation.
Good examples are overheating connections and electrical cables or fuse problems on pumps; process valve leakage; scale build-up in pipelines and overheating motor bearings and windings or misalignment. The technology is also ideal, and extremely safe, for inspecting outdoor high voltage switchgear and transformers as well as low voltage installations. And of course the target doesn’t need to be excessively hot to signify inefficient performance. A problem can also be characterised by an abnormally cool temperature profile.
The wide-ranging ability of today’s infrared camera gives it great cost-saving potential. It is perfectly possible for the same camera to be used to check a roof for water ingress, examine the integrity of building insulation, monitor the efficiency of underground waterpipes, inspect bearings on a motor, look for loose terminal connections in a control cabinet or study a dynamic process. The return on investment is accelerated with every application added to the list.
Applications for a general purpose infrared camera can now also include research and development tasks. This is possible as features that were once solely the preserve of the most expensive cameras are starting to be incorporated into less sophisticated models. For example, image streaming is now available in mid-range cameras.
This means, for example, the user can watch a process at start-up and acquire radiometric data at a reasonable speed. In other words a predictive maintenance camera can also be used for some research tasks. Periodic storage is another example. This allows snapshots to be taken at pre-determined intervals allowing the camera to act as a watchman for a variety of applications.
Meters talk to cameras
The inclusion of new communication technology is also playing its part in the wider application of thermal imaging. For example, a new development allows portable meters to transfer their measurement data directly to the infrared camera via Bluetooth™. And this brings much greater intelligence to the IR environment. Users can transmit key readings such as current or voltage from a clamp meter to a camera making it possible to establish a relationship between heat and load.
Similarly in the building environment, when moisture is identified on an infrared image, an exact reading can be taken by a moisture meter and psychrometer. Its readings are then transmitted to the infrared camera and recorded on the image along with other readings such as relative humidity and ambient temperature.
Bluetooth technology is also being used to provide wireless headset connection to cameras for easier recording of voice comments associated with inspection.
In summary, the continuous and combined development of infrared camera hardware and software has provided industry with the means to ensure efficiency and cut costs across a range of engineering disciplines. But there is definitely more to come. Thermal imaging is a dynamic technology and its potential is huge.
