Electrical Capacitance Tomography
Electrical Capacitance Tomography
Electrical Capacitance Tomography (ECT) is a measurement technique for obtaining information about the contents of process vessels and pipelines. Multiple electrodes are arranged around the boundary of the vessel at fixed locations in such a way that they do not affect the flow or movement of materials. For electrically insulating pipes the electrodes can be mounted externally and for electrically conducting pipes the electrodes must be mounted internally.
What of the applications of the technique?
A typical application is real time monitoring of multicomponent flows within pipelines. Specific applications where ECT has been successfully exploited include solid/gas and liquid (organic)/gas systems such as fluidised beds, pneumatic conveying and multi-phase flow. In principle, ECT can be used to investigate and monitor any process where the main continuous phase is non- conducting and the other phases and components have differing values of permittivity.
How does it work?
An ECT system produces a cross-sectional image showing the distribution of electrical permittivity of the contents of a process vessel or pipeline from measurements taking at the boundary of the vessel. Our m3000 system injects a voltage on to an electrode and measures the resultant voltage difference between this and other electrodes according to a pre-defined measurement protocol. This interrogates an entire ‘slice' through the measurement zone - analogous to a ‘body-scan' in medical imaging. A single measurement set for a 12-electrodes sensors consists of 66 voltage measurements. The voltage measurements are processed by an image reconstruction algorithm to determine the electrical permittivity distribution.
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