Deployment and field evaluation of a non-nuclear densitometer, based on electrical resistance tomography
CEDA Dredging Days 2017 - Sustainable Dredging - Continued Benefits
Hazineh W., McCormack D., Primrose K., Qiu C., Wei K.
Abstract: Measurement of density and flow are two important parameters to optimise the performance of hydraulic conveying in dredgers. At present almost all densitometers use attenuation of nuclear sources as a measurement principle and this presents operational, cost and safety implications. These limitations have led to a widespread interest in developing non-nuclear alternatives. The measurement principle is based on scanning an array of electrodes placed around the inside circumference of a pipe and analysing these data to determine the distribution of electrical conductivity in a cross-sectional volume of the pipe. This data can be used to determine average volumetric concentration of solids as well as visualising the flow conditions. Industrial Tomography Systems has pioneered the deployment of this measurement methodology in industry and has worked with Van Oord to apply ERT to dredging. At Wodcon XXI ITS presented a paper on the development and deployment of a density meter based on electrical resistance tomography. Over the last 18 months ITS has worked with a number dredging companies in Europe, N America and Far East, and this paper presents a summary of performance of the system under different field conditions and with different operators; new developments in data collection, automating calibration to adjust for changes in conditions and integration of the instrument with flow data. With the ability of the Dens-itometer to determine flow conditions, this also opens up the possibility of significantly improving the efficiency of dredging operations. It is believed that this work has led to the development of a viable alternative to nuclear based density meters.
Keywords: Gamma densitometer, Electrical tomography, Non-nuclear instrumentation.