The German sensor manufacturer Micro-Epsilon has developed a technology that can miniaturise eddy current and capacitive displacement sensors and improve their temperature stability. The embedded coil technology (ECT) is said to overcome limitations of previous eddy current sensors and to allow sensors to be produced in almost any shape.

Micro-Epsilon says that it is combining the technology with novel manufacturing methods to produce a variety of custom sensors (shown above) which can operate in temperatures up to 350°C, and benefit from low thermal expansion. The sensors are also said to be mechanically robust, resisting vibration and impact shocks and resulting in long service intervals.

Chris Jones, managing director of Micro-Epsilon (UK), reports that the company has already used to technology produce customised designs for OEMs. In one application, the resulting sensors are being used to measure the grinding gap on paper mill refiiners.

The company can also integrate electronics into the sensor head. “We are therefore able to produce a single or multiple sensor channel arrangement in one sensor body,” Jones says.

As well as the eddy current sensors, Micro-Epsilon has used ECT to produce capacitive displacement sensors. The electronic components are embedded in a stable carrier material, providing much better temperature stability than conventional capacitive displacement sensors and allowing the devices to be used in temperatures up to 200°C, or down to –269°C.