Today, even low-cost, entry-level thermal imaging cameras are surprisingly smart. They are suitable for quick and easy troubleshooting but they are not best suited to every task. Where clear visual evidence of thermal difference is needed in mission or process-critical application, a camera that has a thermal sensitivity of no less than 30mK is essential.
Indeed, a Dutch company specialising in electrical inspection provides a good illustration. It recently won a contract from the Danish cargo airline, Star Air, on the strength of its camera's ability to see thermal anomalies in considerable detail. The customer knew that thermal imaging had the potential to speed up pre- and post flight inspections but it needed to be sure that the technology was sufficiently sensitive to detect the early signs of an electrical fault.
Aircraft cockpit inspections comprise a wide range of routines that need to ensure the safety of passengers and crew during a flight. Whilst this work is vital, aircraft time on the ground is costly. Star Air was therefore very interested in an approach proposed by Thermografisch & Adviesbureau Uden BV to use thermal imaging as a way of speeding up electrical inspection without any compromise on accuracy and reliability.
Ralf Grispen, the company's owner, explains: "We have a long history of industrial electrical inspection using FLIR thermal imaging cameras and we had also used the technology for inspecting the composite fabric of aircraft for signs of water ingress. But the customer wanted to be certain of its capability in the cockpit."
The trial inspection on the cockpit of a Boeing 767-200 freight aircraft was a success. The inspection team used a FLIR P640 thermal imaging camera for the job and it immediately provided thermal evidence of an initial defect in a resistor.
This aircraft model came into service in 1982, and as such its reliability can be greatly enhanced by routine inspection. Thermal imaging was therefore suitable for the preventative maintenance programme for the aircraft, as it allows detailed inspections to be performed quickly and cost efficiently.
Carsten Holm, Technical Vice President, Star Air, comments: "Thermal imaging has proved great for cockpit inspection, because it gives us an instant and accurate view of the condition of our aircraft systems. We do everything in our power to guarantee that all equipment is operating optimally and safely. FLIR thermal imaging is helping us to achieve that."
The FLIR P640 used for this application has the largest detector available in portable, off-the-shelf thermal imaging cameras. It has a 640 × 480 array which guarantees greater temperature measurement accuracy, particularly for small objects. And for the professional thermographer this means clear practical benefits.
This capability is also important from a safety perspective. A more powerful camera allows an image to be seen in far greater detail over distance, an important credential for the safe thermal inspection of high-voltage lines and substations. Interchangeable optics is another factor in this regard. A seven degree lens, for example, provides almost 3.5 times magnification to a 24 degree lens, making it suitable for applications such as overhead power line inspection.
Thermal imaging is a useful preventative maintenance tool whatever the application, but it definitely is not a case of "˜one size fits all'. The low-end thermal imaging cameras are suitable for detecting general hotspots, but if the application needs a high level of thermal detail and image clarity, a professional model is the best option.
To learn more about thermal imaging cameras, please go to www.flir.com.