Design of a Twin-plane Sensor with Internal Electrodes for Flow Measurement

X. H. Hu, M. Yang and W. Q. Yang

School of Electrical and Electronic Engineering, The University of Manchester, PO Box 88, Manchester, M60 1QD, UK, Email: xiao.hu@postgrad.manchester.ac.uk

ABSTRACT

Conventionally, non-invasive sensors are used in ECT for non-conductive flow measurement while invasive sensors are used in ERT for conductive flow measurement. This paper presents a twin-plane sensor with internal electrodes to be used for concentration and velocity measurement of a gas-liquid flow with both high permittivity and conductivity medium, such as milk. The excitation scheme and the number of electrodes in a sensing plane have been analysed. Based on the permittivity and conductivity sensitivity distributions, it is suggested to employ voltage-excitation current-detection and 6 internal electrodes in a sensing plane. The size of the electrode is determined based on the required signal level and dimension of the sensor. Static tests were carried out, and an alternative method to estimate the milk concentration based on the raw measurement data instead of using the pixel-based method has been proposed. Other issues in the milk flow measurement are discussed.

Keywords Sensor design, electrical tomography, concentration, velocity measurement