International Society for Industrial Process Tomography

Electrical Capacitance Tomography for Condition Monitoring During the Regeneration of Reclaimed Foundry Sand

Alice Fischerauer^*, Christoph Kandlbinder-Paret, and Gerhard Fischerauer

Chair of Measurement and Control Systems, Centre for Energy Technology, Universität Bayreuth
Universitätsstr. 30, 95447 Bayreuth, Germany

^*Email: mrt@uni-bayreuth.de

ABSTRACT

There exists a strong demand for moulding sand for the production of cast components. New sand, which is the basic material of moulding sands and core sands, has therefore become quite an expensive raw material. In addition, suitable landfills for the deposition of used sands are getting scarce. Foundries therefore strive for an efficient regeneration of used sands with minimal energy cost. This can be achieved by monitoring the sand condition during processing and making the process control respond to the collected data. Suitable quantities for this condition monitoring are the electrical conductivity and the relative permittivity. These material parameters in turn determine the impedance of a sand sample of defined geometry. We have investigated if the impedance spectra of sand samples feature enough details to serve as indicators for the sand condition. As a consequence, we propose and evaluate an in-situ measuring system utilizing electrical capacitance tomography (ECT) on measurement objects that are no good insulators. The attention focuses on extracting characteristic features from the ECT reconstruction results rather than an exact determination of material parameter distributions. The method appears to have the potential of being a solution to the problem of non-invasive in-situ sand condition monitoring.

Keywords Casting, sands, electrical capacitance tomography, image reconstruction

Industrial ApplicationFoundry, process technology, chemical industry