The principal aim of the research is to develop a new generation of a non-invasive flow instrument for the measurement of flowrates and imaging of the internal structure of complex, unsteady two- or three-phase flows. The research is multi disciplinary covering the aspects of flow mechanics and metering, process tomography, signal processing and multi-variable data fusion. The instrument, based on electrical impedance tomography (EIT) sensors coupled with the principles of electromagnetic and Venturi flowmeters and density meter, will potentially be able to measure the volumetric flow rate and mean volume fraction of each phase in three-phase flows, to image time dependent distributions of the local 3D velocity vectors and volume fraction of the dispersed phase, as well as to visualise complex flow patterns, in which one of the phases is electrically conducting and other phases are electrically non-conducting. These draw upon several recent breakthroughs in the measurement capability arising from the proposer's research teams that now enable the development of an advanced flow meter that can address some longstanding limitations in conventional multi-phase flow metering relevant to the productivity in the petroleum, petrochemical, food, nuclear fuel, mineral process and environmental sectors. In principle, the proposed methodology can be applied to flows with their continuous phase being conductive (e.g. water continuous) or non-conductive (e.g. oil continuous) or even with transitional phase. Within the scope of this research, only vertical flows with a conductive continuous liquid phase will be targeted. Without using a radioactive source, we present the concepts and methods as a new approach to derive all six flow components of three-phase flows, as well as to visualize the complex, unsteady multiphase flows. This will potentially lead to a new generation of an advanced flow measurement and visualisation technology.