AS a pioneer of thermography in Australia, Stowe Australia adopted the technology back in 1982, when it purchased the Hughes infra-red scanner.
At the time, it was similar to the thermographic cameras being used by NASA to test the temperatures on space shuttles, and there was only one other company in NSW that had access to the same technology.
Originally, the technology was used to test electrical switchboards in real time and real-life scenarios without isolating them in order to identify potential failure points by helping to identify high resistance ‘hot joints’, within an installation.
Today, it has become the go-to method of predictive and preventative maintenance, allowing thermographers to identify component faults long before they become component failures.
Stowe Australia specialises in thermography and ultrasonic scanning within the industrial and high-voltage and high energy, low voltage sectors of the electrical industry.
It uses thermography as just one of its arsenal of preventative maintenance tools that form a part of its electrical maintenance package, covering everything from distribution boards and main switchboards to high-voltage transformers and switchgear as well as reticulation systems such as overhead lines.
Accurate thermography has the ability to identify areas that require extra attention during routine maintenance and shutdowns, as well as being able to greatly improve the efficiency of these shutdowns by scanning to identify trouble hotspots.
Thermography in mining: how does it work?
By detecting infrared light that is invisible to the human eye and converting it into an image that can be seen, thermographic cameras allow operators to see the infrared heat that all objects emit.
High voltage and industrial account manager and trained thermographer and ultrasonic technician, Paul Collier, said that every object known to man emits this infrared light, as long as those objects are above absolute zero, or 0° Kelvin, or -273.15°C.
“As an object heats up, its level of infrared light emitted increases and objects can start to produce their own visible light once they begin to gain enough heat energy, such as when a piece of metal is heated and begins to glow red hot: this is now a source of visible light which itself has a temperature,” he said.
“With this knowledge and understanding of how infrared light behaves, we can adapt the use of thermography to mining in many ways, especially for ongoing live recording of systems in actual use, and their performance, without the need for shutting down plant for monitoring purposes.”
Thermography systems are now at a point where they can inspect very widely from the monitoring of rolling stock within conveyors and their motors for bearing conditions to electrical systems, from low voltage switchboards to high-voltage systems and everything in between.
Mr Collier said that thermography can also be used for moisture detection and can even be used to check levels in certain kinds of sealed tanks.
However, versatile as it may be, there are limitations to this technology due to the nature of infrared light.
“Infrared light will not pass through the majority of objects like that of visible light, and even the cleanest, most clear piece of glass is in fact a mirror for infrared light,” Mr Collier said.
“This means that when performing inspections on electrical switchboards, all covers including internal perspex covers need to be removed to thoroughly perform infrared scanning, although there are ways around this and they are by installing perspex that is slotted or by the installation of IR windows, which are made of a special material that allow the infrared light to pass through.
“Another complementing technology that we employ at Stowe Australia is ultrasonic scanning, whereby we are able to use a device that can detect sound outside of the normal human hearing level and convert it into audible sound that a trained technician can interpret, identify, record, analyse and then identify any anomalies.
“This can help to assist condition monitoring and fault identification within electrical systems, both high and low voltage, steam systems, bearings, and can also be used on pneumatic/air systems particularly for leak detection.”
A technology in flux
The improvements in camera technology have seen thermography evolve from an ultra-high-tech service with prohibitively expensive equipment designed for NASA, to a stalwart of minesite predictive and preventative maintenance.
The biggest improvements, according to Mr Collier, are the addition of functions such as picture-in-picture overlays, as well as the improved clarity of the infrared images which give the technician a much greater chance of accurately identifying a fault.
“This is greatly important, as not all faults present as something that is excessively hot, but by way of heat dispersion and image patterns,” he said.
So, what does it mean for mining? In short, thermography has become a widely accepted and regularly used technology by industry for diagnostic purposes, and for regular preventative maintenance.
More organisations than ever are able to accurately use thermography as a preventative maintenance tool that helps to identify faults that can be dealt with during planned maintenance periods before they become expensive failures.
Thermography can assist with predictive maintenance by being able to be performed on equipment whilst it is still in service, and this allows for maintenance schedules to be amended prior to shutdowns to redirect where needed the resources to areas of concern that may not have been identified through other means.
Stowe Australia has in excess of 1500 staff throughout Australia. To become a thermographer, as a minimum each technician is electrically trade qualified and then certified in Level 1 Thermography.
The company also employs specialist high-voltage trained technicians.
All of Stowe Australia’s technicians are Level 1 thermography-certified, along with electrical qualifications, and the company has specialist high-voltage trained technicians too.
Level 1 trained thermographers have the ability to perform the day-to-day testing, analysis and reporting using thermographic cameras.
Stowe Australia also employs a number of Level 2 trained thermographers who, along with performing the tasks of Level 1 thermographers, can formulate thermographic maintenance programs and recommendations for clients.
Thermography practically applied
When JJL’s annual inspection of its Barangaroo International Towers switchboards came up, the company employed Stowe Australia to use thermography and ultrasonic technology as the best method of non-invasive, low-voltage switchboard inspection.
This meant the switchboards were energised throughout the entire procedure.
As highlighted in the report, this busbar was only emitting around 20°C – which is an acceptable temperature for barwork of this nature– but the patterning of infrared light suggested that a fault was present.
When this was compared with the switchboard’s current rating of 2000A and the actual current flowing in that portion of the busbar, about 260A, just over 10pc of the rating, an isolation and further investigation was suggested by the technician.
When this was isolated it was found that the connecting bolts of this barwork were only finger-tight.
Had this been under full load, the temperature would have been greatly increased and to a level of danger to the installation.
Looking to the future, Mr Collier said that as fully automated mines become more and more of a reality, thermography may become fundamental for heat monitoring of a different, much more direct kind – fire detection.
As mines become less and less reliant on human monitoring in favour of machines, thermography’s uses can extend further to that of a ‘watchdog’ style monitoring device for areas that experience increasing temperatures, such as a flammable product on a belt becoming too hot.
Infrared detectors could send a signal to an alarm or even a fire extinguishing device that could then douse the belt and prevent a fire.
Thermography is just the beginning
Thermography is not the only service that Stowe Australia provides.
The company also offers other electrical maintenance services including transformer maintenance and repairs, oil sampling and analysis, HV circuit breaker and switchboard servicing and testing, low voltage circuit breaker and switchboard servicing and testing, protection relay testing and motor inspection, maintenance and testing, slipring inspection, maintenance and testing and power factor correction unit maintenance and repair.
More information:
Website: www.stoweaustralia.com.au
Phone: (08) 9429 9600
Email: [email protected]
