The basic principles of electrical resistance tomography (ERT) are to take multiple measurements at the periphery of a process vessel or pipeline and combine these to provide information on the electrical properties of the process volume.
ERT is applied to visualise multiphase unit processes to develop understanding; optimise performance and provide a basis of control.
The most common processes relate to mixing, separation, flow and reactions.
An ITS electrical resistance tomography system consists of:
- sensor array; these are sets of electrodes grouped in measurement channels. Each of which delivers a cross-sectional image. The electrodes can be set in 8, 16 or 32 electrode groups and these are most often configured in a linear or circular array.The electrode array is held in place by the sensor body. Both can be made of robust materials to operate under challenging process conditions.
- instrument; ITS provides two main instrument platforms, p2+ which is robust, operates up to 8 measurement planes and highly configurable and the v5r which operates 2 measurement planes at high speeds. The v5r can operate at higher conductivities than the p2+.
- software; this provides three functions. Firstly it configures the instrument to fit the process conditions; secondly it analyses raw voltage measurements using inverse algorithms to provide a conductivity map; thirdly it has built in tools to allow analysis and export of tomographic data.
ERT was the first technology commercialised by ITS and many installations have been established around the world.