An induction heating plant supplier has developed a patented system for cooling inductive proximity switches in a ceramic tube. This allows normal commercial sensors to be used in extreme, high-temperature applications. In this cooling system application, Contrinex Series 700 outperformed other commercial inductive sensors.
- Best performance in SCS
- Long operating distances that remain the same for different metals
- Insensitive to accumulated dirt and mechanical stresses
- All-metal V2A stainless steel housing, including sensing face
- IP68 and IP69K protection class
- Operating distances up to 40 mm
- Factor 1 on steel and aluminum
In cooperation with institutes of aeronautics and space development, a sensor cooling system was developed that encases the sensor in the same ceramic material as the tiles that insulate space shuttles against extremely high temperatures on re-entry to the earth’s atmosphere. Engineers from the University of Stuttgart developed two- and three-dimensional computerized simulations using COMSOL Multiphysics software. A prototype Sensor Cooling System (SCS) was then built on the basis of these simulations. The SCS prototype demonstrates a foundry application, optimizing the fill level of molten metal in a pressure controlled induction furnace. Contactless eddy current detection is applied to a range of molten metals (e.g. copper, aluminum, steel) using the same operating distance for all metals. The normal commercial sensor selected for the SCS must demonstrate reliability in environments up to 1200°C, be insensitive to accumulated dirt and mechanical stresses, and adapt easily to pre-existing installations and controllers.
An Extreme range inductive sensor from the Full Inox family (series 700), type DW-AD-713-M30 performed very well in this application. Its all-metal, stainless steel housing (including sensing face) and IP68 and IP69K class protection make it suitable for such an extreme environment. With operating distances up to 40 mm and factor 1 for steel and aluminum, it fulfills application-specific requirements. In the initial test phase, the water-cooled test piece was equipped with several temperature sensors and heated in a tube furnace to 1100°C. This test confirmed the computer simulations of the cooling system model. By optimizing sensor isolation, it was possible to compensate temperatures up to 1200°C. Additional cooling of air in the tube is achieved with an air exchanging device.