The ESA-funded project “REFRA-SENSE” has developed an industrial demonstrator of an embedded sensor for monitoring in-situ the thickness of the internal refractory lining of industrial boilers, kilns and furnaces. The REFRA-SENSE family of sensors also includes a range of industrial sensors, among them the “ReWiG” and the REGS sensors which were developed under other ESA projects for monitoring the recession of the Thermal Protective System of space capsules. All the sensors are able to sustain long exposures at high temperatures while continuously monitoring the material thickness.

All industrial boilers, kilns and furnaces used for producing steam, calcination and smelting are lined with high-temperature refractories which wear down over time. The only way to currently measure the thickness of the remaining refractory is to stop the process, empty the furnace and use various thickness-measuring instruments, a very expensive operation, since it requires a stop to production. Because of the criticality of the refractory lining, most industries carry out such maintenance operations very conservatively with much higher-than-optimum costs. An in-situ sensor is needed that can offer a reliable, continuous refractory thickness monitoring capability to enable accurate and cost-saving maintenance planning. The REFRA-SENSE technology allows in-situ continuous monitoring of the remaining thickness of refractory linings and thus enables major cost-savings by allowing optimum maintenance planning.