Multi-electrode Electromagnetic Flowmeter with Electrical Impedance Tomography

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The Intelligent Electrical Tomography instrument was developed by En’Urga to provide imaging of multi-phase flow through pipes. The void fraction within the fluid cross-section is computed. The system is also capable of providing flow rate based on the void fraction by comparing the propagation of the phase distribution image from the upstream and downstream layers.

  • Fast scan rate of 1000 Hz.
  • Accuracy is within 10% for dispersed multi-phase flow with up to 30% void fraction
  • Accommodate pipe sizes as small as 25 mm dia. to large pipes
  • No moving parts. Does not induce pressure drop or contribute much to flow losses

The instrument is very useful for flow diagnostics in the following industries:

  • Nuclear power generation industry
  • Petrochemical transportation, production and processing
  • Chemical
  • Pharmaceutical
  • Biological
  • The product consists of measuring/detector section with 8 embedded electrodes. This section will be incorporated in the part of the flow network that would experience two-phase flow.
  • The electrodes are connected to a control box that performs the multiplexing between the electromagnetic flow meter and the electrical impedance tomography. The control box has the control circuits for both functions as well as an analog to digital converter.
  • Data from the control box is fed to a PC-based data acquisition system. The PC also has software that outputs the flow rate, void fraction and other numerical as well as graphical data.

The instrument combines two functions into one system. The first is the Electro-Magnetic Flow metering (EMF) function and the second is the Electrical Impedance Tomography (EIT) function. Both functions are performed with one set of electrodes but they cannot be performed in parallel. There are usually eight electrodes arranged in a ring around the inner surface of the test section. An electromagnetic coil from an off-shelf flow meter is used in conjunction with the electrodes to find out the flow rate of the fluid. A multiplexer will allow the EMF to take data and then switch to the EIT function. The Tomography system has a much faster response time and occupies less time of a duty cycle. The Impedance Tomography data will provide the phase distribution of the flow and give a more accurate flow rate for two-phase flows. A thermocouple will also be incorporated to take temperature data for calculation of the dielectric constant of the fluid.

All of En’Urga’s products are custom-made. Please provide details in the Contact Form for any modifications of performance specifications, or any change in the physical configuration of the desired instrument. A description of your application is helpful.