Information on the boundaries between phases is required for the optimal design and operation of multi-component processes involving particulate suspensions, emulsions and for conveying dry powders. This paper describes a capacitance tomography system which images the boundaries contained within the cross-section of a process or pipeline. The target spatial resolution is one part in twenty by projection distance (one in four hundred by area). The electrical properties of each imaged boundary are functionally related to the imaged value, so that the component ratio of a two-component mixture within a boundary can be measured, although in the case of a colloidal dispersion the particles themselves cannot be imaged.
The fundamental limit to the frame rate of this all-electronic type of imaging system is better than 1,000 frames per second. The paper describes a system providing 70 frames per second images of an industrial pipeline, this lower limit being due to the use of only four T414 INMOS transputer chips for image reconstruction. It is anticipated that future developments of this type of instrumentation will have a number of applications in design and for monitoring dispersed phase processes by enabling information to be acquired from hitherto inaccessible systems.