Hot properties

New sensor technology will enable engineers to accurately measure the position, speed and motion of materials at temperatures as high as 1,000°C, its UK developer has claimed.

The technology, which is being commercialised by an Oxford University spin-out called Oxford RF Sensors, has already been adapted for use in turbochargers for diesel engines. The company has demonstrated the technology with a Mercedes V8 engine, and is adapting it for use in big diesel trucks. Oxford RF Sensors also hopes to apply the sensors to monitoring the turbine blades of jet engines.

The sensors are capable of identifying four different electromagnetic signatures that metals and plastics share. By measuring these parameter the sensors can identify any metal or plastic, said the firm.

Oxford RF Sensors claimed its sensors will be used for their ability to measure position, speed and motion with greater accuracy than is currently possible from robust sensor technologies. According to the company, existing sensors, such as digital callipers, are accurate enough to meet engineers’ requirements. They stop working, however, if they come into contact with even a drop of fluid.

The four-signature sensors, on the other hand, continue to work perfectly after being hit with a hammer, said Oxford RF.

The company has also developed the electronics used to process the data from the sensors. Dr. John Gregg from the University of Oxford’s physics department, said: ‘The electronics are capable of processing the information so that it can tell you if there’s anything there and what it is.’

According to Gregg, unlike the three types of existing robust sensor technology, the new sensors can operate at temperatures greater than 200°C and as high as 1,000°C.

The sensor, composed of ceramic platinum, is separated from the silicon that processes the information by a standard transmission line.

The other sensor technologies — devices that detect eddy currents, the Hall effect and variable reluctance — would all fail at high temperatures. Sensors that measure the Hall effect, for example, would need to put a semiconductor into the hot environment — where it would melt, said Gregg.