A novel use has been found for the technology that's used in mammography to image breast tissues. Durban-based company Advanced Imaging Technologies (AIT) is using it to x-ray fast moving fabric-reinforced conveyor belts .
"Imaging the internal structure of breast tissue is similar to imaging the internal structure of fabric-reinforced conveyor belts from an X-ray attenuation point of view," says AIT MD Mike Alport.
Previously it was believed to be impossible to produce X-ray images of fabric-cord reinforced conveyors with sufficient contrast - especially if they were moving at high speed.
The effort to find a solution began in 2002 when Eskom TSI (now part of Eskom Holdings) approached Alport, then head of the university of KwaZulu Natal's applied physics group, with a problem: The monitoring of Eskom's many kilometres of fabric-reinforced conveyor belting was labour intensive and subject to human error. Because conveyor belts are used to transport tons of coal to, and ash from, Eskom's coal-powered power stations, unplanned downtime caused by belt failure raises costs and limits productivity.
X-ray technology has been used to image defects in steelcord-reinforced belting, but Eskom was unable to develop a similar system for its fabric conveyors.
"We spent time at Addington Hospital drawing from the knowledge of William Rae, a medical physicist with experience in mammography," says Alport.
In 2003, Alport and a team of graduate physics students demonstrated the proof of principle for an online X-ray imaging system that they dubbed DiXI (Digital X-ray Imaging). It uses their knowledge of optical imaging applied to X-ray diagnostics, and is capable of monitoring a belt that moves at speeds of up to 6 m/sec.
Apart from using cutting-edge X-ray sensors and sources, the innovation, says Alport, lies in the software. "It uses imaging processing algorithms to capture and analyse the video data automatically and generates a hard-copy report containing photos and positions of belt damage and edge tracking signatures within 24 hours of the survey. Previous optical belt surveys took at least a week."
Alport formed AIT in 2004 and was joined by graduate physics students Jacques Basson (PhD, Cambridge) and Thavashen Padayachee (MSc, Natal). The university has granted Alport an extended special leave of absence to launch the company - though he continues to teach honours applied physics courses at the university.
Last year Eskom TSI contracted AIT to develop and test a DiXI prototype. This was successful and AIT, realising that DiXI could be used in other industries besides its immediate application at Eskom, plans to license the technology from Eskom (which owns the intellectual property).
