Taking a look on the inside

Most industrial facilities, such as steel mills, oil refineries and power stations, are expensive to build and operate, so minimising downtime is of prime concern for owners and operational staff. Any unplanned stoppages could cost millions of dollars each day.

Visualising the condition of the components of industrial machinery, such as engines, drive shafts, tanks and pipes, without having to take them apart can save time and money. Non-destructive testing is the term used for the examination of materials and components in a way which does not change or destroy their usefulness.

There are many benefits for companies using the correct application of non-destructive testing. A major one is protection of capital investment by instituting predictive maintenance programs which allow for servicing and repairs to take place at a predetermined time in order to minimise disruption and cost. Other benefits include compliance with technical and statutory requirements and the safety of both plant and personnel.

To be most effective, non-destructive testing must be reproducible, so all principal methods of non-destructive testing are covered by Australian standards. More and more companies are recognising the importance of NDT through corporate membership of the Australian Institute of Non-Destructive Testing and collaboration with other member companies and individuals in the development and refinement of NDT standards. There is a commitment to offering the best solutions to the needs of customers and industry in general through the development of new technologies, products and services that maximise the benefits of NDT.

One type of NDT is remote visual inspection (RVI), which uses cameras attached to flexible probes to view the inside of an encased object or structure. Imaging can be done in two ways - firstly, by looking at the insides directly with an optical camera, or secondly, graphically, by plotting the echoes and reflections generated, for example, by phased array ultrasonics.

One way to directly view the inside of an encased object or structure is to use an industrial videoscope. RVI of materials, components and structures allows technicians to detect cracks, corrosion, surface burning and other flaws that might lead to failure or other problems with equipment. By using stereo measurement technology, it is possible to accurately gauge the size of observed cracks and defects. In addition, videoscopes can directly embed condition data into recorded images to easily catalogue information so that trends can be deduced and factored into preventive maintenance schedules.

RVI uses purely optical methods to view interiors and you don’t need much of a hole to see through. With the latest fibrescopes, you only need an opening 0.9 mm across to pass the viewing tip into the inside. Advances in analysis software and hardware miniaturisation have led to the development of smaller and more sophisticated videoscopes, some of which combine both the light source and optical sensor into a unit at the tip of the probe. The probe, which can be up to 30 metres long, may also have small motors embedded in it which allow the operator to remotely move the LED and lens assembly.

Not only can the newest videoscopes put a lot more light out of the end of the probe, but that light can be used far more effectively, through reducing flaring off surfaces and washing out, in order to generate high-quality images.

Brendan Slaven is an imaging professional, specialising in industrial photography. With more than 15 years’ experience in imaging technology, Brendan is currently the Remote Visual Inspection (RVI) and High Speed Video (HSV) Product Specialist for Olympus Australia, and is always looking for new ways to apply new technologies and techniques to acquire diagnostic images from extreme environments.