Qualitative visualization and quantitative analysis of milk flow using electrical resistance tomography Original Research Article

Product quality enhancement, reduction in waste and energy consumption and cost minimization are the results of having good automatic process control in all processes including the milk powder production process. Having an accurate, multi-dimensional and continuous knowledge of the process which is the fundamental requirement of automatic process control can be provided by the application of process tomography. Electrical Resistance Tomography (ERT), a novel, simple, and robust method of process imaging when conducted on two adjacent planes on a pipeline, provides the ability to extract multi-dimensional qualitative and quantitative flow information. The application of an ERT system to flow monitoring and control in the dairy industry has not been researched comprehensively before. Yet it is extremely desirable and beneficial to be able to remotely inspect the internal volume of pipes without invading the process, which is the aim of this research. In this study ERT has been applied to 3-dimensional qualitative visualization and quantitative analysis of the flow and velocity profile of various milk solutions in a horizontal and a vertical pipe, commensurate to milk solutions in various stages of the milk concentration process to produce milk powder. Water, a different milk concentration and cream were used as the secondary solutions for the required conductivity variance for flow measurement. These results were studied and compared in order to provide a selection criterion for the secondary solution. The results demonstrate an accuracy of ∼97.5% in flow measurement comparable to a common online flow meter. 3-dimensional qualitative visualization of non-uniformity in milk concentration, composition and temperature has also been investigated.