Ceramic injection molded clevis sensor for online substance concentration measurement

The current research presents recent respective to the work development of a ceramic clevis sensor for online substance concentration measurements. The aim is to develop a robust and acid-resistant sensor device, which can be easily included in existing procedural pipeline systems. To achieve those goals a lot of factors had to be checked. For the substance concentration measurements a capacitive sensor effect has been chosen. With this method even low substance concentrations down to one-tenth of a per cent can be indentified. For the package material zirconium oxide (tetragonal zirconia polycrystal TZP) was used. Zirconium oxide is a technical ceramic. Characteristic features are wear-resistant, acid-resistant, low thermal conductivity and electrical insulation. Zirconium oxide can be used in a ceramic injection molding (CIM) process. In the phase of sensor design multiple geometries for the sensor effect had to be considered. The integration space for the evaluation electronics is also an important determining factor. A standardized DN 40 DIN 32676 flanged joint was also added for an unproblematic connection to the pipelines. All these needed geometries had to be integrated into one ceramic element. As a result of these requirements a 3D CAD model of the sensor element was designed. The CAD-file has shown that there was only the CIM technology left to comprehend developed sensor geometry. CIM is a low cost process for large-scale production which is distinguished by high size accuracy. The material behavior in the molding process was simulated with a FE-tool. The simulation results were used for the optimized design of the needed molding tool. Furthermore the material shrinkage had to be considered as an oversize of the tool cavity in the CIM process. This effect is caused by the needed debindering and sintering steps. The developed ceramic clevis sensor was successfully tested in multiple fluidic systems. It passed the test phase and is now ready for maturity ph- - ase.