ERT for Characterisation of Physical Stability in Liquid Compositions

T. York1, J. Davidson1, M. Flanagan2 and A. Kowalski21

2University of Manchester, School of Electrical & Electronic Engineering,

Email: t.york@manchester.ac.uk

2Unilever R&D Port Sunlight Laboratory, Quarry Road East, Bebington, Wirral CH63 3JW, UK

ABSTRACT

The paper describes experiments to investigate the feasibility of using electrical tomography for early characterisation of physical stability in selected products. The Manchester LCT tomograph has been applied to an 8-plane sensor hosted in a 1 litre vessel. Measurements have been taken over periods up to 76 hours. Tomographic measurements and reconstructed images are consistent with visual observations associated with experiments that readily generate a distinct visible ‘separated layer’. Observed diurnal excursions in the measured voltages have been investigated and related to changes in temperature. Later experiments have been performed in a temperature controlled environment. Conductivity values have been extracted from the reconstructed images for selected pixels. These reveal behaviour which is indicative of instability prior to visually discernible effects.

Keywords Electrical resistance tomography; product ageing; 3D image reconstruction